RCMF

Level 1 => Jet Turbines => Topic started by: HarryC on May 31, 2010, 23:12:50 PM

Title: Mick Reeves Lightning build
Post by: HarryC on May 31, 2010, 23:12:50 PM
It is odd that it has taken me so long to get around to this, my all time favourite aeroplane, but here we go at last.  I bought this kit second hand a couple of years ago and the previous owner had it for some years before that, I think it is one of the early kits so I don't know how it compares to a kit bought now, I don't know if Mick updates them at all.

The first task I undertook was to prepare the retract units.  I do this with any retracts not just these MR ones, and indeed these had fewer faults than the more expensive ones with my AD F-100.  Leaks and swarf are the main reasons for tackling the retracts.  The forward retracting noseleg unit rotates through far more than 90 degrees in order to lift the wheel up inside the upturning fuselage, the main units look like they rotate through a bit more than 90 degrees too, perhaps 100 degrees.
I take the retract units apart and then dunk the cylinders in water and pump some air in each end in turn and watch for bubbles.  A typical leak is around the seal for the pushrod and this can usually be fixed by a squirt of silicon oil into the cylinder, but these units all sealed fine at the pushrod and the end caps.  There was a leak though from the forward nipple on the noseleg, not sealing in the aluminium end cap.  The nipples do not seem to be regular screw in items, but a slightly crude brass tube with a raised ring around them, it looks like a push fit into the end cap.  Soldering around the base of the nipple was not an option since the end cap is aluminium.  The main units are aluminium cylinders and don't look like I could get the end caps out, but the noseleg is a brass tube with push fit end caps sealed with o rings and kept in place at one end by the pivot bolt and at the other by rolled steel pins through the brass tube into holes in the end cap, so it was easy to completely dismantle the nose cylinder assembly.  this was especially good as their was some contamination in the rear end of the cylinder and inside the brass nipple so i was able to thoroughly clean them out.  To seal the brass nipple into the aluminium end cap I dropped on some thin cyano to the joint so it could wick down into the tiny gap then gave it a hit of accelerator.  Further pressure testing under water showed it has sealed fine.  For cylinders I can open like this, I repack the o rings with silicon grease and drop some silicon oil inside before reassembling.  For the ones I can't open, I pop the nozzle of the silicon dropper on the nipple and pull/push the pushrod to suck some oil inside, to both sides of the piston.  Silicon oil can be the stuff sold by BVM, I use silicon oil from motors and rotors which is I think meant for model car shock absorbers.
Then I clean the whole retract assembly and examine it.  The pivot blocks of these units have some rough machining for the slot that the pushrod passes through and there were tiny slivers of swarf in there, and on one unit the machining had pushed the rough edges out onto the surface that the pushrod T piece runs along, so that was removed.  Then all rubbing surfaces are lubricated, I used to do this by rubbing with a very soft 6B pencil but at the moment I use a wax lubricant which is designed to not trap dust and to push it out and carry it away.  Finally it is reassembled with thread locker on every bolt, even on smooth running jets I have occasionally had retract bolts come undone if not locked.
After all that I have retracts which don't leak (at least at the time they go into the model), which don't have swarf waiting to block them, and operate nice and smoothly.
The noseleg forward nipple is installed at an odd angle, pointing at the side frame rather than upwards

So, onto the first bit of construction.  I will need to make a bigger building table than I currently have in order to build the wings, so it is the fuselage first.  This starts with installing the ply formers at the joint between front and rear parts.  It's a whopper of a model, standing upright the fuselage is about 7 feet tall, almost touching the ceiling of my workshop and that is without the nosecone and jetcones.  The joint is not a finely made butt joint such as on my F-104, the forward fuz has a recessed lip to fit inside the rear portion but the recess is crudely defined and the joint will need a lot of filling and sanding later on to hide it.  I want the two formers to mate against each other when the fuz is put together so I have glued in the front fuz former first as it will sit at the back of the recess flush with the rear edge, and then the former inside the rear fuz can be installed at a place to match it.  The fit of the 1/4" ply former to the fuselage is loose - it fits where it touches!

Buy shares in loctite because this is going to need a lot of hysol.  I applied hysol around the inner edge of the fuz and the edge of the former, installed the former then sat the fuz on its rear edge and pushed the former down flat onto the workbench so it is flush with the rear edge of the lip.  Then with gloved hand, I applied lots of hysol from my finger all around the joint and pushed it down into the gaps.  When that has cured tomorrow I can apply more into any remaining gaps from the other side, and I will have a ponder about reinforcing the joint with epoxy glass bandage - these two formers when bolted together hold the large fuz together during high G loads, landing shocks etc so I don't want any risk of them being able to work their way loose.
Title: Re: Mick Reeves Lightning build
Post by: CF-FZG on June 01, 2010, 00:25:51 AM
Ooh, nice one Harry :af

I've been looking forward to this since you mentioned you'd bought it :study:


Mark
Title: Re: Mick Reeves Lightning build
Post by: Dizz on June 01, 2010, 03:19:29 AM
Will be watching with interest too.  See it at Merryfield next year???? :af
Pete
Title: Re: Mick Reeves Lightning build
Post by: Rafale on June 01, 2010, 09:06:12 AM
Oh Harry!!

it just gets better and better!!
 
Do you want to adopt me as a long lost son?!!   :D  ;D ;)


Cheers

Nige.
Title: Re: Mick Reeves Lightning build
Post by: Mark H on June 01, 2010, 10:18:35 AM
Harry
Glad your doing this thread I'm onto my second one.. Ian Wilde has my original one campaigning it very well and into its goodness knows what season now.......I'm doing a far more detailed one and its so much better to have another brain working on the same project......There are problems to solve but as you know if you persevere with Micks kits you are rewarded with a light extremely scale good flying aircraft....anyway I'll be following your progress and chipping in with questions I'm sure
Regards
Mark
Title: Re: Mick Reeves Lightning build
Post by: HarryC on June 01, 2010, 10:47:39 AM
Aha!  If you are the MH I think you are, I was given your email by DS when I bought the kit from him and was thinking of contacting you with a few questions.  I have only ever seen one MR Lightning, at Abingdon and it may have been IW with the one that he got from you.  I had a look at the wing mounting system in the fuz which had been beefed up, the original design does look flimsy for my liking.  There are lots of things I want to consider for amending to my way of liking.

My intention is to add extra detailing like the vents etc.  I have a brake chute for it.  Not sure about panel lines since the original is so well made they are not easily seen, and rivets are near invisible so I can't see the point in replicating them.  What I will do is modify the underlying colour, instead of all black, for the aluminium coating and that will give a panel effect but again the full size was remarkably homogenous in its shading.

I would like a Mk3 most of all - still the small belly tank but the larger, squared off fin, so that mod will be considered.

It will be superb if you take part in this build thread and bring your experience of one already under your belt, as it will if Nmacwarbirds does too.
Title: Re: Mick Reeves Lightning build
Post by: The Saint. (Owen) on June 01, 2010, 10:49:24 AM
What engine will you use Harry?  :)
Title: Re: Mick Reeves Lightning build
Post by: HarryC on June 01, 2010, 10:56:05 AM
What engine will you use Harry?  :)
No firm decision yet but my thinking is to use a Wren 160.  That is far too much power for straight flight but I can (and do!) throttle back.  The reason for so much power is that the engine is the same size and weight as a 120 so there is no penalty there (though will probably want to carry a bit more fuel for it), and the party trick of the Lightning is to get airborne, raise the wheels and go vertical off the end of the runway.  If it can't do that, it is not a Lightning, imo!  I can't see the point in having a Lightning that can't do that with ease on every take off.  So why carry a 120 that will struggle to do that when for much the same weight I can have a 160 that will do it easily?

My model will be carrying a bit more weight - the aluminium coating requires several layers of paint, there is the brake chute, the twin ring afterburner system, added detail etc.  So I want the engine to have all the oomph I can get.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on June 01, 2010, 11:08:05 AM
Some questions for you MH!

Did you use the nosewheel or main wheel brakes, and if the nosewheel brake what did you think of it?

The MR main wheels have no bearing/bushes, just the plain ally hub running on a threaded bolt.  My experience with the Typhoon is that it is not a good idea!  At least oilite bushes would be a big improvement.  Have you modded the main wheel bearings/bushes?  Or perhaps you found it does work ok?

The main oleo springs seem too soft, the model will sit near the bottom of travel.  Looking at pics on MR website, they seem to confirm this, the links are closed as the oleo is fully compressed.  Did you add harder springs?

The oleo link has no travel limit to stop it being pulled straight, so it locks and prevents the oleo from working.  Robart oleos have a metal tab welded onto the leg to stop the link from straightening.  Did you make any mods to the MR oleos to prevent this problem?

The main wheels have foam tyres, I don't know how long those will last!

The tailplanes have one rib in them where the pivot tube ends, so they are very flexible and make me wonder if they will bend in flight when pulling elevator.  Have you found this to be a problem and if so how do you solve it, other than pull the proskin top and bottom apart and build more structure into them?

The top hatch is such a poor fit it almost seems to come from a different model.
Title: Re: Mick Reeves Lightning build
Post by: The Saint. (Owen) on June 01, 2010, 11:57:23 AM
No firm decision yet but my thinking is to use a Wren 160.  That is far too much power for straight flight but I can (and do!) throttle back.

That makes a lot of sense Harry.  :af :af :af
Title: Re: Mick Reeves Lightning build
Post by: Pat Barnes on June 01, 2010, 16:55:50 PM
Looking forward to seeing this progress Harry.
Title: Re: Mick Reeves Lightning build
Post by: Mark H on June 01, 2010, 18:45:05 PM
Harry
The Lightning you saw at Abingdon was probably the one I did it's in the OCU scheme.......The changes I have made on the new one are proper wing tubes which I made up by laminating cloth over the wing tubes themselves....makes a much better rigid structure....main wheel brakes instead of the nose brake...looks like you have the first generation of retracts..new ones are stronger with larger air rams...one major problem is when lowering the gear as the wheel rotates on the down stroke and flat plates to the airflow it sometimes did not lock until the airspeed decayed allowing the wheel to complete its rotation. The video of the airworld version I saw did the same. I have thought of electric or even hydraulic actuation but as the new rams are bigger I will probably leave as is. I have made the airbrakes active and modified the nosewheel steering to cables. I'm considering ballracing the stabs....structure wise mine are ok with foam laminated into the structure which I think was'nt there on my original. The machining on the new legs is better with no resistance to rotation. I know Colin found a couple of problems with his gear when he did the reveiw but mine are fine. I'm finishing up a Vampire T11 at the moment and once done will be back on the Lightning full time.
Mark
Title: Re: Mick Reeves Lightning build
Post by: Mark H on June 01, 2010, 18:58:22 PM
Harry
Just thought of a couple more things....yes the hatch takes ALOT of work you have to cut away quite abit of the bottom of it and P38 to bring the shape back.. time consuming not difficult. Aileron actuation.. I'm using external horns to give a more solid linkage as the distance from hinge to ball link on the original is small. On the two piece fus I have made the join flat rather than having the lip I just found it easier to hide the join. Rudder on my new version is robart hinged with the servo inside the fin with a small external horn... Micks system works but I am going for a more robust linkage same as the aileron. Happy building !
Mark
Title: Re: Mick Reeves Lightning build
Post by: HarryC on June 01, 2010, 19:00:52 PM
I'm considering ballracing the stabs....structure wise mine are ok with foam laminated into the structure which I think was'nt there on my original.
Plenty to think about there Mark, I may get better retracts.  I was wondering about using ballraces to mount the tailplanes, the system on my AD F-100 is excellent, with special alumnium holders for the races.
Title: Re: Mick Reeves Lightning build
Post by: Bill Stevenson on June 01, 2010, 20:05:38 PM
My all time favourite aircraft. One day I hope to build one too.  :af :uk:
Title: Re: Mick Reeves Lightning build
Post by: JohnMac on June 01, 2010, 20:17:19 PM
No firm decision yet but my thinking is to use a Wren 160.  That is far too much power for straight flight but I can (and do!) throttle back.  The reason for so much power is that the engine is the same size and weight as a 120 so there is no penalty there (though will probably want to carry a bit more fuel for it), and the party trick of the Lightning is to get airborne, raise the wheels and go vertical off the end of the runway.  If it can't do that, it is not a Lightning, imo!  I can't see the point in having a Lightning that can't do that with ease on every take off.  So why carry a 120 that will struggle to do that when for much the same weight I can have a 160 that will do it easily?

My model will be carrying a bit more weight - the aluminium coating requires several layers of paint, there is the brake chute, the twin ring afterburner system, added detail etc.  So I want the engine to have all the oomph I can get.
Just one question Harry, What is straight line flight? ;D
I think your choice of engine is appropriate, as an underpowered Lightning should attract a fixed penalty notice. I stick in a milkbottle should be an appriate launch method. Good luck with it.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on June 01, 2010, 20:24:37 PM
Harry
modified the nosewheel steering to cables.
Yes, I can see that if the leg is not aligned straight ahead as it comes down, the steering peg will not engage in the servo disc.

No work on the Lightning this evening, I have been making the bigger building table to accommodate the Lightning wing.
Title: Re: Mick Reeves Lightning build
Post by: Vinceyboy on June 03, 2010, 09:43:53 AM
Hi Harry, after reading Mark's alterations and suggestions on this lovely looking aircraft, I think it will keep you out of mischief for a while ;D

I remember at the Nats last year, Shane Harding had his lovely Lightning there, whereby he unfortunately suffered flutter on the elevator causing the balance part on the end to snap off, great shame as it was a cracking looking model.

Anyway, good luck with the build :af

Vince.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on June 03, 2010, 12:33:41 PM
I am tempted to make my own tailplanes from solid balsa.  I have found a supplier of ballraces in holders that can be bolted to the mounting plate.
Title: Re: Mick Reeves Lightning build
Post by: JohnMac on June 05, 2010, 09:00:37 AM
I am tempted to make my own tailplanes from solid balsa.  I have found a supplier of ballraces in holders that can be bolted to the mounting plate.
Hi Harry,
Have you considered a balsa lamination? In this way you can choose the thickness of the "core" to be the same as the diameter of your pivot rod which makes alignment very simple. One this and any other bits are glued in the remaing gaps around the rods can be filled and the tailplanes sheeted to make up the final thickness. By altenating the grain direction you can make the whole thing stiffer too.
Regards,

John
Title: Re: Mick Reeves Lightning build
Post by: lightning on June 08, 2010, 22:17:10 PM

 signed in & watching my all time fav jet
  :af :af  :af

 early in the day i know but any idea on colour schemes
(schemes being a loose term ) sqd marking prob a better term for the
lightning

 andy
Title: Re: Mick Reeves Lightning build
Post by: HarryC on June 08, 2010, 22:47:07 PM
Well, it has to be a bare aluminium finish because I like bare metal jets and I am getting not bad at simulating bare metal, so it won't be a camo or grey scheme (don't think the F1A or F3 were anyway?)  I really like the 111 Sqn Lightning flash on the nose, with black and yellow fin and spine and their crest on the tail, and I already have the graphics on computer for doing that from my F-4.  I also like 92 Sqdn blue fin and spine, with red and yellow arrow head on the nose.  So at the moment, those are the 2 in the lead, my own preference is 111Sqn but that has been done by others, I haven't seen any photos of the model in 92 Sqn colours so that is in its favour.
Title: Re: Mick Reeves Lightning build
Post by: CF-FZG on June 08, 2010, 23:11:15 PM
Are you doing a F Mk 1A or an F Mk 3 Harry?

My favourite would be a 5 Sqn, but a bit hard to see, or my other choice

F Mk 1A - 56 Squadron RAF 1965

(http://www.clavework-graphics.co.uk/aircraft/ee_lightning/F1A_56Sqn.png)

or F Mk 3 - 56 Squadron RAF 1966

(http://www.clavework-graphics.co.uk/aircraft/ee_lightning/F3_56Sqn.png)


Mark
Title: Re: Mick Reeves Lightning build
Post by: HarryC on June 09, 2010, 06:43:52 AM
The kit is an F1A fin, but I prefer the F3 fin and will consider if it can be modified when I get to that part of the build.  I did the 56 Sqn scheme on my Flair Lightning (XM174 as per your photo!) and it is a justifiably popular scheme which means there are a few models with it and I don't want to have just another 56 Sqn Lightning, which is why it is not being considered.  The only thing I have against the 111 Sqn scheme is that there is a photo on MR's website of Colin Strauss's in that scheme and I don't like to have what other people already have, if I wanted that I would buy a BARF!  That's why the 92 Sqn scheme is attractive to me.
However I do like the second 56Sqn scheme you have shown, with the chequerboard fin and arrowhead on the nose.  That is rarely modelled.  I also like the big red H on the airbrake, good of them to put my initial on the plane!  I think that scheme willbe considered when the time comes to paint it.

These are the other 2 schemes I like:
http://www.clavework-graphics.co.uk/aircraft/ee_lightning/f2_002.html (http://www.clavework-graphics.co.uk/aircraft/ee_lightning/f2_002.html)
http://www.clavework-graphics.co.uk/aircraft/ee_lightning/f1a_004.html (http://www.clavework-graphics.co.uk/aircraft/ee_lightning/f1a_004.html)
Title: Re: Mick Reeves Lightning build
Post by: Thorjet on June 09, 2010, 07:36:32 AM
I like the 92 Sqn :af
Title: Re: Mick Reeves Lightning build
Post by: lightning on June 09, 2010, 10:15:00 AM

how about this one ??
slightly differant but still got some colour
andy
Title: Re: Mick Reeves Lightning build
Post by: HarryC on June 09, 2010, 10:35:28 AM
Nice but it fails the test of natural metal finish!  It's primarily the two-tone grey scheme.
Title: Re: Mick Reeves Lightning build
Post by: lightning on June 09, 2010, 16:23:51 PM

 not a in service scheme but can still do the alli look ,t5 but could be adapted to f3
andy
Title: Re: Mick Reeves Lightning build
Post by: Mark H on June 09, 2010, 16:53:21 PM
Hi Harry
Any progress?.. Can you PM me the ballrace supplier if you get a chance please I was wondering how to mount them......I'm making good progress on the Vampire so I'll be on the Lightning very soon...can't wait....I'm using Micks metalcoat and probably 92 sqn but I do like the OCU scheme I did originally. First time using the foil I was torn between that and the new ali paints with different shades of undercoat....will have to see..I did a test of the metalcoat on one of the stabs and have to say it looks good...I'm a bit of a ludite with PC's so will get up to speed on posting pics of progress so far
Rgds
Mark
Title: Re: Mick Reeves Lightning build
Post by: SteveBB on June 09, 2010, 17:14:40 PM
Had a quick look; no idea which sqns they are, but there's one with a particularly colourful fin... I suppose a T5 is out of the question?  :''


I double clicked the images this time, and there are two F6's in the photos, the one with teh yellow fin and the one with the black fin.. and teh yellow finned one is grey, sorry!  :embarassed:
Title: Re: Mick Reeves Lightning build
Post by: HarryC on June 09, 2010, 23:13:03 PM
Hi Harry
Any progress?.. Can you PM me the ballrace supplier if you get a chance please I was wondering how to mount them......I'm making good progress on the Vampire so I'll be on the Lightning very soon...can't wait....I'm using Micks metalcoat and probably 92 sqn but I do like the OCU scheme I did originally. First time using the foil I was torn between that and the new ali paints with different shades of undercoat....will have to see..I did a test of the metalcoat on one of the stabs and have to say it looks good...

PM sent.
Have you used the MR metal foil on a model that is in use, or just the test piece so far?  I am assuming that the MR foil is the same as Flite-metal, and I have always heard from users that Flite-metal is so soft it gets damaged the moment you start moving the model around the workshop, the car and so on.  Having done an F-86 with BVM metal-kote and recently an F-100 with Sikkens Argentum I know I can get a good effect with them, and pretty hard wearing. 

You can't do 92Sqn, what will I paint mine then! ;D
Title: Re: Mick Reeves Lightning build
Post by: Gordon W on August 26, 2010, 21:52:55 PM
Found this in WH Smiths today.  It's turning out to be a good read even though I do have a ton of Lightning books already.

Gordon
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 02, 2010, 22:19:33 PM
Can you stand the pace of this build!!   :D  I glued another two parts together last night!  Then tonight discovered I should not have  >:(  The nose cone should be screwed, not glued to the intake fairing so it can be removed for access.  No problem, got them apart again easily enough.

On my other jets with split fuselages, the fuz moulding wraps inwards at 90 degrees at the join, and a wooden former is placed inside to beef it up, so it is mechanically held in place by the moulding.  On this model there is no inward lip at the join so we rely purely on the glue to hold the formers that bolt the two halves together.  I am paranoid about a former coming unglued so I have backed up the joint with 200g cloth and epoxy resin.

I have been looking at the noseleg.  Steering is done by a long grub screw protruding from the back of the leg locating into a slot in a servo disc mounted behind the leg.  Well that's fine if the leg comes down precisely aligned with the slot, which of course it won't, so the end of the screw will sit on the outside of the disc, leg won't come fully down, will be off centre and won't steer.  Spoke to MR, they now use a centreing spring, I can make one no problem but I still find it hard to believe the leg will come down perfectly aligned.  Unless the slot is wide which means steering slop, chances are the screw will not go into the slot.  I considered screwing another disc onto the servo disc to give it more depth and making a funnel entry to the slot, but the sharp edge of the grub screw is likely to catch on it on its way in.  Or, I could drill and tap the top of the leg for an M3 bolt either side, to use as tiller arms for cable steering but I don't think there is enough room for a servo between the retracted wheel and the front intake lip.
Any thoughts, musings or ideas anyone?

I have been indulging in some Lightning motivation, a couple of weeks ago swmbo and I visited the Midlands Air Museum at Coventry where I took lots of photos of the fine detail on their two Lightnings.  As well as those they have an F-104, F-86, F-100, F-4, what an excellent museum, all my kind of planes!  Was great to see the heat discolouration on the back of an F-100 for real.
Then last weekend we went to Bruntingthorpe open day and stood within a few feet of a Lightning F6 in full reheat as it shot past: the air shook, the ground shook, we shook, the crosswind blew the heat and fumes into us, it was great, swmbo was dead impressed and wanted it to come back and do it again!
Title: Re: Mick Reeves Lightning build
Post by: STORM on September 02, 2010, 23:03:52 PM
Harry, it's a similar setup on the Javelin, with spring works fine, file a radius on the inner top of the servo slot to help guide the pin in. One of those large red arms works best.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 03, 2010, 08:48:38 AM
Thanks, that's very helpful to know it works well enough.  I know the thick red arms you mean, my Multiplex servos come with them. might add another to double the thickness and make a really wide funnel.
Title: Re: Mick Reeves Lightning build
Post by: Mark H on September 03, 2010, 20:12:22 PM
Harry
Glad to see your back on the Lightning...I've been flying the Vampire I've just finished so once I've splashed some paint on that I'll be onto the Lightning full time..It seems we're having the same thoughts re fus joint and nosewheel steering anyway lets see some pics soon..happy building
Mark
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 04, 2010, 13:10:34 PM
nmacwarbirds has kindly reported that he has had no problems with the steering as per the design, over many flights, so I will continue with that method.

A few weeks ago I spoke to Jim Reeves and discussed a few items.  Starting with the tailplanes, they now make them with a foam lining which makes them much stiffer, although they have no reports of problems with the original.  I bought a pair and they are so much stiffer, it gives me peace of mind, I would always have been worrying about the originals.  It transpires they are not made from proskin over a couple of ribs as I had thought, but are laid up in moulds.  I also bought a set of the main wheel brakes and the disks to modify the wheel hubs for the brake pad.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 05, 2010, 08:41:54 AM
The two fuz sections are held together by three M4 bolts into blind nuts, though I am pondering whether four would be better as per my F-100 and F-104 purely from the point of view of preventing any rocking, I am sure the three M4 bolts can take the loads.  For now, the two upper bolts and nuts are in place.  The formers have holes in them for the bolts though of course after fitting the formers to the fuz with all the slack etc they have, the holes are well out of line.  I opened up the holes on the rear fuz former until they were big enough to include the true 4mm hole in the front section.  Then I made 1/4 ply plates, curved to the fuselage, and installed the blind nuts on them, then hysoled them into the back of the former, with the M4 bolt in place with penny washers to spread the load pulling them up tight and thus also guaranteeing they are perfectly aligned.  So the fuz is now partly bolted, the one (or maybe I will fit two) bottom bolts still to go.  It's a whopper of a fuz, in this state it is about 7 feet long, without the nose cone, pitot probe or tailpipes in place.




Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 05, 2010, 18:43:00 PM
It's time to sort out the servos in case I need to order any.  First of all I calculate what is required by taking various measurements and feeding them into a sophisticated spreadsheet.  After all there is no point in buying JR8511s for everything if they are not needed.

I run the calcs for the Lightning at an airspeed of 200mph, I don't think it will achieve that so it seems a safe top speed to use, but I run the flaps calc at 100mph.

I told the spreadsheet to use a conservative 70 degrees of servo rotation in case of any restrictions, and this has a useful side effect of increasing the torque required so it errs on the side of caution.  The result is suggested to be multipled by 1.3 to give a margin of error and overspec, but I prefer to multiply by 1.5 to give plenty room and as we shall see this still results in surprisingly low demands.

Aileron, 2.8kgcm, so x 1.5 = 4.2kgcm
Rudder, x 1.5 = 6.8kgcm
flap, x 1.5 = 5kgcm

The flap torque is probably way over done, because it lies at 60 degrees to the airflow rather than head on which the spreadsheet assumes, it will generate far less force than is shown.

That's not as much as you expected eh!  Why so much for the slim rudder?  Because its horn is much shorter than that for aileron or flap so it takes more effort to move it.

The plans suggest a Futaba 9001 on ailerons, it's a coreless, analogue, plastic geared servo of 5.2kgcm at 6V so it is a contender as it has sufficient torque, approx £28
The plans suggest a Perkins S136 on the flaps, that is a Supertec low profile servo, analogue, plastic geared, 8kgcm, approx £20

The tailplane is much harder to work out, as the Lightning tailplane is a complex shape to calculate its MAC, and then it is not pivoted side to side like the F-86, F-100 etc but the pivot is swept back like the tailplane.  It probably has a very low torque requirement.

So as you can see, to satisfy the torque demands even at very high speeds, it does not need very expensive, metal geared, monster torque servos.

However....
 The spreadsheet doesn't take account of flutter, that would be very complex to compute.  A servo with just enough torque and small plastic gears may work forever doing the normal job, but lose in an instant if flutter occurs where a much stronger digital servo with big metal gears might hold it at bay.  So there is a case for going up a notch in specification beyond the minimum.  But then again, how far up?  What if you go up in spec but it is still just below what is needed to prevent the flutter that the surface will generate, then the overspec is wasted anyway?

I have a drawer full of servos so I am off now to do an inventory of what I have, and match it up to what the Lightning needs.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 06, 2010, 10:42:17 AM
The tailplanes will probably work fine with plastic gear standard servo but in case of flutter I think a metal geared, ball raced, digi will be best.  Each tailplane has its own servo so it doesnít need to be super powerful. It must be from a brand with a history of reliability.  I am considering 3 types of servo that fit that, they are:
Multiplex Tiger MG digi 4  about £52
Futaba S3050 about £34
Spektrum S6020 about £27

Thoughts or suggestions anyone?  I include the Spektrum since afaik it is made by JR?  and it is a good cost saving.  But does it have any history yet, good or bad?  Please donít suggest Hitec, I wonít touch them, no exceptions, no ifs or buts, I wonít even let them in the house!  I am curious about Hyperion and Savox but am not aware of them being around for long enough under their own brand name, in use in valuable models, to trust them yet on a primary flight control.
Title: Re: Mick Reeves Lightning build
Post by: selleri on September 06, 2010, 11:50:57 AM
Harry Savox makes the Spektrum servos.
Title: Re: Mick Reeves Lightning build
Post by: Alex48 on September 06, 2010, 14:40:55 PM
I think Als Hobbies are doing a special on 8411's £60 when I last looked 
Title: Re: Mick Reeves Lightning build
Post by: Mole Hunter on September 06, 2010, 14:43:14 PM
Is that spreadsheet available? It looks very interesting.

Watching this build with great interest. If you decide against silver in the end I have some photos I took at the Museum of Flight last week that may be of interest.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 06, 2010, 14:58:32 PM
I think Als Hobbies are doing a special on 8411's £60 when I last looked 

£120 for the pair or £68 for the Futabas!  No need to install and pay for something as powerful as the 8411s when not needed.  Also, as standard now they come with plastic not metal gears.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 06, 2010, 15:04:34 PM
Is that spreadsheet available? It looks very interesting.


In order to understand it you really need to read the article from RC Jet International mag, and this thread, links to the spreeadsheet are in post #12
http://www.rcuniverse.com/forum/m_9638239/mpage_1/key_/tm.htm (http://www.rcuniverse.com/forum/m_9638239/mpage_1/key_/tm.htm)


Quote
If you decide against silver .....

I will, when Ian Paisley goes to Mass!  I love bare metal finishes.
Title: Re: Mick Reeves Lightning build
Post by: Pat Barnes on September 06, 2010, 17:11:43 PM
... 8411s .... as standard now they come with plastic not metal gears.

Interesting! I was not aware of that - thanks for the info Harry.  I'm quite keen on the SAVOX range - their servos have some impressive specs, and the feedback (albeit limited...) I've seen is positive.
Title: Re: Mick Reeves Lightning build
Post by: STORM on September 06, 2010, 18:01:07 PM
I've been thrashing a pair of Savox in the tail of my Elan and am happy enough to install in my new 1:5 L39 all round.
As Sverrir rightly says the new Spektrum servo's are made by Savox.  Standard Savox servo's are Titanium geared.
Gary.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 06, 2010, 18:02:08 PM
It surprised me too Pat, it used to be a metal gear servo, although it gained some criticism for wearing rapidly maybe that's why they changed it, or maybe to make people who want a metal gear pay extra for the 8511, see the following for the latest spec
http://www.macgregor.co.uk/jrpropo/DS8411.htm (http://www.macgregor.co.uk/jrpropo/DS8411.htm)
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 06, 2010, 18:07:18 PM
lozza has some hyperions, he took the top off one a few weeks ago, we were well impressed by how chunky the gears are.  I just want to see hyperion and savox get more widespread use in critical controls on high value models for a longer period before I will feel comfy using them, and even then I will start them on non-critical items like brake valves and chute releases.  I got badly burned with Hitec and I will not allow a repeat of that, so until then I stick to Multiplex, JR and Futaba.
Title: Re: Mick Reeves Lightning build
Post by: Alex48 on September 06, 2010, 18:58:58 PM
didn't know that, the last lot I had a few months ago, 14 in total had metal gears....

what about a 579 good solid servo although not digital.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 06, 2010, 19:13:39 PM
Of course, MacG's site could be wrong.  But the USA importer has had a plastic gear version of the 8411 for many years so it is not inconceivable that it should have been changed to plastic
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 06, 2010, 21:15:25 PM
what about a 579 good solid servo although not digital.

A good thought, I found a couple of the 579s when I inventoried my drawer of servos last night, have pencilled them in for the flaps.  They are the same price as the Futaba digi, or by allowing analogue then it brings in the similarly priced Multiplex tiger MG.  Choices choices!
Title: Re: Mick Reeves Lightning build
Post by: Alan Smithie on September 06, 2010, 22:41:03 PM
...and the feedback (albeit limited...) I've seen is positive.

That could be disastrous - servo feedback should of course be negative...

PDR
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 07, 2010, 09:07:02 AM
servo feedback should of course be negative...
Did someone say "hitec"?  ;D
Title: Re: Mick Reeves Lightning build
Post by: Alan Smithie on September 07, 2010, 11:40:44 AM
Did someone say "hitec"?  ;D

Bless you!

PDR
Title: Re: Mick Reeves Lightning build
Post by: Alex48 on September 07, 2010, 12:01:22 PM
lol, I was sent this lot the other week from a customer, all was good until I inspected the contents and found a blue box among the white.... ;)

Title: Re: Mick Reeves Lightning build
Post by: selleri on September 07, 2010, 12:33:05 PM
lol, I was sent this lot the other week from a customer, all was good until I inspected the contents and found a blue box among the white.... ;)

I'm sure it was just to keep the other things from moving around in transit.    :''
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 07, 2010, 13:04:19 PM
Anyway, back to the Lightning build...

The bottom bolt joining the fuselage sections is at an angle since it has to be accessed via the underside of the model, through a hole in the belly tank.  Bevelled hardwood points are supplied in the kit to provide a right angled surface for the bolt head and blind nut, I Hysoled them to the formers.

In case you think my Hysoling the wood mounts for the bolts/nuts is unnecessary bling, remember that it is no longer a wood to wood joint.  You will recall that I have reinforced the former to fuselage join with epoxyglass so the surface of the former is now epoxyglass, not bare wood, and therefore the Hysol provides a much better joint.  If it was still wood to wood then I would use Devcon as normal, I don't think Hysol is especially good for wood to wood as it is so viscous I doubt it penetrates into the surface much.  To improve Hysol's adhesion to the wooden parts I either drill 2mm holes into them or scratch them with the tip of a scalpel to give it plenty of mechanical grip.

On the front section, I drilled a 2mm pilot hole facing forwards and downwards through the former at an angle to come out of the bevelled section at right angles, then followed this up with a 3mm drill.  Then through that hole i could feed an exceptionally long 3mm drill bit that I have, about 8 inches long, and score the fuselage to indicate where to drill the access hole, which I did with 6mm drill for the moment.  Then I put the 2 fuz sections together, and fed the extra long 3mm bit through the fuz, through the former just drilled a moment ago, so it now touches the former on the rear section at the correct place and correct angle, and commenced drilling. When done, separate the fuz sections and I drilled out the rear section to 5.5mm to take an M4 blind nut.  Drill out the front section former to 4mm and put the fuz back together, put long M4 bolt into place with a penny washer, slip on the blind nut and tighten it up to pull the blind nut into the wood.

So all three fuselage bolting points are complete.  But thinking about access to the lower bolt through the hole, I think I will install a plastic pipe from the fuz to the former to be a guide for the bolt and driver.

I took a look at the plan for attaching the nose cone to the intake bullet, it shows one dowel floating in space, and one tiny screw, I think I may glue 3 little patches of lite ply inside the bullet and attach the nosecone with 3 tiny screws instead.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 08, 2010, 22:58:53 PM
I was intending to install a guide tube for the bottom fuz bolt, between the fuz and the former, but I did not have a tube of sufficient diameter for the M4 bolt head.  So what has happened is actually better, I installed a tube too narrow for the head and cut it short so that the bolt can't fall out, it will always be held there and not go missing, meanwhile the guide tube will point the hex drive to the bolt head, see photo


the noseleg retract has consumed a lot of time.  The main pivot block is free to move side to side by less than 1mm, but since the steering depends on the leg's position relative to the slot in the servo arm that it engages, the leg will be turned a little off centre, or struggle to get the peg in the slot, if it is not consistent.  So I took the unit apart again and installed washers cut from mylar hinge tape, until all the gap was taken up and it can no longer move from side to side.  Then I discovered the T end piece on the pushrod from the piston was coming off, it has a threaded hole to engage the threaded end of the pushrod, but the hole is too large and only at one side does it engage the pushrod for about 1 turn, so I took it apart and cleaned it and put it back together with 30 minute devcon, I do hope it holds against the bang-bang stress of the retract.  Maybe solder and a 100W iron would have been better?

A shaped and drilled /14" ply plate is supplied for mounting the retract, along with 1/8" spacers, and 1/4" ply pieces for the servo mount.  To this I added 1/4" ply backing to take the blind nuts.  Although the mount is pre-drilled for these retracts, the retract mounting flange tries to occupy the same space as the steering servo.  I checked some different servos and this one is actually quite shallow at the top i.e. height above the mounting lugs, most servos I have are worse and really conflict badly with the retract.  So I had to file some material off the end of a retract mounting flange to allow both it and the servo to go into place.

I chose a Multiplex digi metal gear servo.  Overkill?  I don't think so.  For example, my F-86 steering is done by a micro Futaba servo, so why have so much power and MG in this application?  Well, the Sabre steering has a straight noseleg, not trailing link.  The tyre's contact point with the ground is straight down below the steering axis.  No matter which way the tyre points, it feels no force trying to centre it or drive it further away - it has neutral stability so the servo has very little force to overcome, and no "blowback" force against it, it won't feel any shocks through the steering.  But the Lightning has a trailing link which has positive stability, so whenever it is moved off centre it will generate "blowback", and it can get shocks back through the steering.  So a metal gear servo seemed right, and the spare one I had was a digi so there it is!  I had intended to use the very thick arms/discs that come as options with Multiplex servos now, but those are for the Hitec derived servos and they have different output shafts compared to this real Multiplex servo, so I screwed together 2 discs to give me the depth to cut a funnel shape into the slot
Title: Re: Mick Reeves Lightning build
Post by: lozza on September 08, 2010, 23:09:44 PM
Slot in that horn wants tidying up with a file looking a bit ruff on the edges  ::) ::) BUILDERS, we won't mention the car  :banghead:

lozza
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 08, 2010, 23:24:50 PM
This photo shows the leg in the down position with the peg in the servo arm slot.  Just to add to the problems, the hole for the peg has not been drilled at right angles to the leg so it is slightly off to one side when the leg is straight, and the trailing link arms seem slightly skewiff putting the wheel slightly at an angle, so getting the nosewheel straight will take some trimming.

Which leads on to a poser of a problem, that of making a centering mechanism so that when the leg comes down, the steering peg goes into the slot in the servo arm.  The pivot block has an M3 hole with a grubscrew deep down inside it, so into this I put an M3 6mm bolt to take the centering spring.  I made the spring from fine piano wire wrapped round 1.5 turns around the bolt

But of course I can't rely on the bolt holding the spring in that orientation, some force from the leg turning could cause it to turn with the leg and then the centering has been lost.  That can be solved easily by drilling a small hole either side of the spring arms and popping in a small peg.  But now comes the real problem.  The location of those pegs will determine the centre that the spring returns to.  But taxi trials always show a need for trimming the steering, and as soon as the leg is retracted the spring will take the leg back to the centre position which is no longer coincident with the position of the servo, so when it comes down the peg will hit the servo arm instead of going into the slot.

I am still not happy about that steering, it just seems too much opportunity for the leg to come down and miss the steering slot.  The result would be a nosewheel way off centre when the Lightning lands, and that would be catastrophic.  Have to say I am still tempted to enquire of Unitracts about a custom made unit with integral steering servo, or just contact Aviation Design and get the unit they use on the F-100.

I ditched the idea of 3 screws to hold the nose cone to the bullet, and followed the concept shown on the plan, though a dowel floating in space doesn't help much!  I used sliding fit carbon tubes and balsa blocks to make this fitting at the top of the cone , there will then be just the one screw at the bottom
Title: Re: Mick Reeves Lightning build
Post by: Alan Smithie on September 08, 2010, 23:36:52 PM
1. Can you fit a longer steering pin, and grind a taper onto it to improve the chances of engagement?

2. [assuming you'll be driving this with a proper Tx] Could you set up a logic switch that removes the rudder (and trim) input from a nosewheel steering servo mixer when the gearswitch widget = "up"? Then you could have another input (probably a fixed numeric value) to keep the pin aligned regardless of any nosewheel trim that is found to be necessary.

PDR
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 08, 2010, 23:43:03 PM
1. Can you fit a longer steering pin, and grind a taper onto it to improve the chances of engagement?

2. [assuming you'll be driving this with a proper Tx] Could you set up a logic switch that removes the rudder (and trim) input from a nosewheel steering servo mixer when the gearswitch widget = "up"? Then you could have another input (probably a fixed numeric value) to keep the pin aligned regardless of any nosewheel trim that is found to be necessary.

PDR

1. No, it has already been ground down to the minimum by MR, the socket head defines the minimum size at the end.

2.  The leg and the servo can do what they like when "up" is selected, one can go hard left and the other hard right for all we care.  The problem arises when "down" is selected since in that configuration the steering servo needs to be in the trimmed position and the leg will be coming down to engage the peg into it.
Title: Re: Mick Reeves Lightning build
Post by: STORM on September 09, 2010, 08:29:53 AM
Harry, the simple solution would be to taper the servo arm into a v shape, that way even if the leg drops off centre it will still be guided into the arm.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 09, 2010, 08:44:21 AM
Harry, the simple solution would be to taper the servo arm into a v shape, that way even if the leg drops off centre it will still be guided into the arm.
Won't work Gary, the peg is coming at the disc from "above" rather than from the side so it could be a hole in the disc, doesn't need to be a slot all the way in from the side.  That's why I added a second disc, to give some depth, the top disc slot is cut in a V shape to give a funnel entry for the peg.  The peg doesn't go near the edge of the disc.
Title: Re: Mick Reeves Lightning build
Post by: STORM on September 09, 2010, 08:52:54 AM
Understood,  sorry.
Title: Re: Mick Reeves Lightning build
Post by: nmacwarbirds on September 09, 2010, 19:45:26 PM
Harry,
If I get a chance I will take a picture of ours at Tibenham tomorrow.

Regards Phil G.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 10, 2010, 09:17:22 AM
That would be great, thanks Phil.  All ideas welcomed.  Have a good time at Tibenham, Lozza and Trebor from over here are on their way to join you.

I decided to put the fuz aside for a little while and make a start on the wings, so last night I got the starboard wing dry assembled and ready for gluing, photos to follow soon.
Title: Re: Mick Reeves Lightning build
Post by: Alex48 on September 10, 2010, 20:38:58 PM
Can you make a stainless servo plate that would be clamped between the oleo and the retract?  This would mean the servo would retract and extend with the gear allowing you to have a more traditional linkage set up.  Obviously from the pictures I cannot tell if this would be suitable but just in case....



Title: Re: Mick Reeves Lightning build
Post by: Alan Smithie on September 10, 2010, 21:23:07 PM
Hmmm....

Well I've had a thought which involves a completely different linkage system.  Add some flat "pads" on each side of the rotating part of the leg. Add a belcrank to the mount which has rollers on each side in a position such that the pads just contact the rollers when the leg is locked down. Drive the belcrank with the steering servo (mounted in any convenient location). When the leg retracts the pads move away from the rollers and the steering is disengaged.

The "pads" could be a machined part that screws to the leg with a bolt in the hole your current steering peg is in, or it could be a bent steel sheet item (also screwed on in the same way).

Well it's an option...

PDR
Title: Re: Mick Reeves Lightning build
Post by: STORM on September 10, 2010, 21:46:12 PM
Don't know why things are getting so damn complex, this works fine, can't be that much different on the Lightening, or can it?
Title: Re: Mick Reeves Lightning build
Post by: nmacwarbirds on September 11, 2010, 17:31:55 PM
Dear Harry
I had a look at our set up for the Lightning steering
and it is exactly as you have it with the double disk.
When the nose wheel retracts it sits in for want of a better word(s)
a plastic piece (supplied with the kit) which keeps it straight,
76 flights later and we have never had a problem with it.

The wheel can become misaligned if the model is pushed backwards,
the steering piece will flip out of the wire guide.
If you include a visual check of the wire and make sure it is engaged correctly
when you do your walk round and as a preflight check, everything will be fine.

Regards Phil G.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 11, 2010, 20:33:03 PM
I don't suppose you have a photo of the plastic part Phil?
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 13, 2010, 22:27:53 PM
The wing parts are mainly made of routed 1/8" ply (might be a form of lite-ply) - the front and rear spars and all ribs.  Pre-cut and slotted leading edge and false trailing edges for the flaps and ailerons are from balsa.  On first putting the leading edge on the plan, it seemed that the notches for the front of the ribs were cut wrong, being too far apart so that if the root rib notch is in the correct place, the notches by mid way were wrong and by the tip they are miles out

As it turns out, the leading edge is correct, the plan is smaller than all the parts (or all the parts are bigger than the plan!) so this will have to be factored in when cutting wood for the ailerons and flaps.
The two spars and the leading edge all come in two parts, with an S shaped cut as the joint to be glued, for which I used epoxy.  Note the leading edges are not straight, the leading edge kinks downwards towards the root between ribs 4 and 5, and the ribs towards the root have an increasing undercamber at the nose, so this seems to be fairly scale and replicates the complex change in sections and shifts in thicknesses along the wing, rather than take the easy option of a simple section and constant taper all the way from root to tip.

The ribs slide flat into position in the spars and are then rotated upright, the fit is very good.  The two aluminium tubes slide into place, again the holes in the ribs for these were accurately cut, the false trailing edges slot into place, and the massive root rib slots into place.  When happy that all is aligned, it can be glued but for this the leading edge near the root needs to hang off the edge of the board because it hangs below the tabs on the main spar.  I pinned the spars down hard to their tabs to ensure correct alignment then flooded every rib to spar joint with thin Zap.  Most held well, some didn't due to slight gaps so I flooded again and hit with kicker, that locked it all.  The backs of the ribs don't align perfectly straight, so when attaching the false trailing edges I used big dollops of pva, put the wood into place and used a ruler to ensure they are straight and just have to accept the glue filling some big gaps.  Now it has all been left to cure until my next session some days from now, when I will glue on the root rib, again using a ruler to ensure straightness, the balsa leading edge, and a couple of other minor parts.  The wing tubes are left in but not glued at this stage
So here is something you see less and less of these days, especially in a jet - a fully built up wing.  It's a shame to have to cover it up!
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 13, 2010, 23:00:49 PM
Some points for discussion -

The plan shows the ailerons being top hinged with leaf and pin hinges, by cutting slight rebates into the surface of the wing skin for the leaf to sit in.  Something I liked with my glow motor models is a hinge I think is from M&M developments, which is two pieces of solartex stitched together, the stitch forming the hinge.  It is applied along the entire length so it has massive gluing area, a very long hinging to take the strains, and being so flexible offers no reistance to moving, and seals the joint line. Some models, e.g. Glens CAP use iron on film, single piece, as the hinge.  How about using just one piece of solartex ironed onto the wing and aileron as a hinge before glassing over?  Lots of small holes could be cut in the 'tex to allow resin to flow through to the wood below and secure it very well.  Good idea or bad idea?

Does anyone have long-term experience of either Flite-metal or the aluminium sheeting that Mick sells?  Flite-metal looks incredible but has a reputation for being damaged if you sneeze near it, I would like to know if it is just too soft to cope with everyday flying and handling in car and house?

Title: Re: Mick Reeves Lightning build
Post by: Maximum maxage on September 14, 2010, 01:53:55 AM
The tailplanes will probably work fine with plastic gear standard servo but in case of flutter I think a metal geared, ball raced, digi will be best.  Each tailplane has its own servo so it doesnít need to be super powerful. It must be from a brand with a history of reliability.  I am considering 3 types of servo that fit that, they are:
Multiplex Tiger MG digi 4  about £52
Futaba S3050 about £34
Spektrum S6020 about £27

Thoughts or suggestions anyone?  I include the Spektrum since afaik it is made by JR?  and it is a good cost saving.  But does it have any history yet, good or bad?  Please donít suggest Hitec, I wonít touch them, no exceptions, no ifs or buts, I wonít even let them in the house!  I am curious about Hyperion and Savox but am not aware of them being around for long enough under their own brand name, in use in valuable models, to trust them yet on a primary flight control.



How about a set of these beasts
A few people including myself love them

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=6221&Product_Name=Towerpro_MG996R_10kg_Servo_55g_/_10kg_/_.20sec (http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=6221&Product_Name=Towerpro_MG996R_10kg_Servo_55g_/_10kg_/_.20sec)


chocks away

Neil B :af
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 25, 2010, 09:40:32 AM
No-one with experience of flite metal, or thoughts on solartex hinging of the ailerons?

The second wing is now mostly built.  Taking experience from the first wing I thought I could make a better job of it but the parts just aren't accurate so both wings have the same problems.  In particular the very long root rib is not straight, it wavers in and out a great amount.  It is attached to the rear edge of many main ribs and their rear edges are nowhere near a straight line, so the root rib waves in and out in order to be attached to them.  You could not butt the root up against the fuselage, there will be huge gaps, which is no doubt why the instructions say to leave an overhang in the wing sheeting.  This will be shaped to fit the fuz and hide the gaps.  Also the profile of the root rib does not match the rest of the wing.  It's trailing edge should meet one end of the false t/e that the flaps are mounted to, the position of the false t/e is set by all the ribs it is attached to, but the root rib t/e is about 4mm higher than them.  This occurred on both wings.  To get it to match I had to make two saw cuts from the bottom of the rib almost all the way up to the top, crack/bend the rear of the rib downwards thus closing the saw cut, and re-glue.  The leading edge should overhang the end of the root rib or at least reach it, but it doesn't quite so there is a small gap to be filled with spare block balsa or light filler.

The retracts are a fraction too deep for the wing, the top edge on one side just rest on the top sheeting about 1mm before the retract flanges reach their mount, so I will have to file/grind some material off the retract sides.

Mick shows an interesting idea for operating and sequencing the undercarriage doors.  Drive them by small servos.  Open the servo and cut one of the power wires to the motor.  (Big problem with many modern servos being soldered onto the pcb and having no wires to cut!)  Attach long wires taken outside the servo and fit a diode and micro switch in parallel.  Fit the micro switch so that when the leg reaches the up position it will push and close the switch.  When up is selected, the servo tries to close the door but power to the motor is blocked by the diode and open switch.  When the leg gets up it closes the switch and the servo can then close the door.  When down is selected the power to the motor is reversed so it can get to the motor through the diode and it doesn't matter that the switch will open as the leg moves.  Advantages?  Each door depends on its own leg being up so won't try to close and jam a leg that isn't up.  No chance of an air leak from the doors emptying the air tank.  No expensive electronic sequencer required.  Disadvantages? 2 mains and 2 noseleg doors needs 4 servos which for many people is a lot of daisychain Y leads and that is likely to cause problems for the servos.  Not a problem for me with 22 programmable outputs on the Rx to drive each servo totally independently!  Can't say I would normally bother with the mods to the servo, my tx or Rx can handle all the sequencing, though it will be time controlled rather than individual leg control as per Mick's idea so it loses the failsafe of the door not closing against a slow leg.

But, a device that I am fitting to the Lightning bricks Mick's idea right back into contention.  I am fitting a Tamjets gear failsafe.  This excellent device has already saved my F-100 when it sensed an air leak caused by a ruptured pipe to a door ram and it dropped the u/c about 20 seconds into a flight.  Had it not done so I would have finished the flight with wheels up, selected down and nothing would have happened, the model would then have been very seriously damaged or destroyed on landing.  The device plugs in between the Rx and retract servo/valve, and has an air line to the main u/c air system.  You program a failsafe pressure.  As long as the air pressure is above that value the device just passes your commands through it, but if pressure drops below that value it takes over and commands the servo to the down position.  Disadvantages?  It only has one input and one output, so tx or Rx sequencing of the legs and doors can't be done, because closed doors will probably prevent the legs from coming down.  You would need to fit a device to each channel and they ain't cheap but it can be done.  On my F-100 the gear failsafe outputs to the Jet-tronic sequencer which then outputs to the legs and doors so when the gear failsafe says "down" the sequencer handles the door opening as well as lowering the legs.

The Lightning has simple door sequencing, open or closed, rather than the closed open closed sequence of some planes.  No point in buying an expensive add-on sequencer for that, but, it means the single output from the gear failsafe must operate the doors as well as the legs and that prevents me using tx or Rx sequencing.  I know SM makes a relatively cheap sequencer but the one person I know who had one has put me off it.  I can try Mick's servo technique, or use an air system with an air switch such as my Starfighter originally had.  That proved troublesome because the small spring pressure of the switch acting on the noseleg was just enough to sometimes jam the mechanism against the retract's spring down action.  Air down should be ok for that, and I could go further - rather than one air switch on the noseleg, copy Mick's servo idea and have an air switch for each door at each leg.  Either a servo or air ram with its own switch is appealing due to their independence against the chance of a slow leg, otoh it introduces lots of new components to fail!  Servo set up would be easier as I can give each one its own programmable output from the Rx, thus easily set the travel.  No air lines and connectors and rams to leak precious air.  Sods law is I buy 4 small servos, and their motors are all soldered direct to the pcb!

Discuss!
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 25, 2010, 20:22:00 PM
Photo shows the ailerons mostly built, upside down awaiting ply inserts for hinges and bottom sheeting.  The riblets are supplied but there were 5 of one size, 4 of another and one of another, and none were correct!  I had to re-cut them all.

Title: Re: Mick Reeves Lightning build
Post by: Gordon W on September 25, 2010, 20:43:20 PM
The Lightning's little nose doors might work with an over-centre spring-locked setup like I have on my Hawk.  The doors are dragged up and pushed down by the noseleg.  My air-up spring down unit has no problems working the door.  One door doesn't close perfectly on my Hawk, most likely because mine is a bit crudely made, but a bit more effort on my part could probably sort that out.

The main gear doors could use a mechanical lever system, similarly opened and closed by the legs.  These diy systems were common on complex scale models years ago and a typical main gear system, which I eventually used on a Spitfire F24, is illustrated in a certain sport scale book   ;)

That way you could use the Tam fail-safe and omit all the servo wiring or pneumatic spaghetti for the doors.

Gordon
Title: Re: Mick Reeves Lightning build
Post by: STORM on September 25, 2010, 21:42:36 PM
Makes my job look easy Harry.  ;)
Title: Re: Mick Reeves Lightning build
Post by: JohnMac on September 26, 2010, 08:31:45 AM
Hi Harry,
No experience of flite metal as yet but I have heard the same stories of it being delicate. As for the solartex hinging personally I wouldn't use it as I am not convinced it will stay in place permanently. Solartex always "moves" to some degree on my models in the past. Heat and cold will affect it I suspect.  Personally I will use chunky plastic flat hinges like the large Kavan type and put them in at an angle (in side profile) into balsa blocks.  Only the knuckle then will be at skin level and there is a bit more "meat" to take the strain on the hinges.

As for undercarriage sequencing, I have yet to discover the perfect system. There are a number of issue regarding using servos for doors and legs that I will mention. You may already be aware of these.
The first point is to use a separate battery for the gear system to your radio. The chances of a servo stalling are quite high and the result could be a fire. This happened to me a long time ago and it made a hell of a mess. I would fit a fuse!

Obviously UC systems take a lot of hammer on jets and things can move. They certainly wear. Getting the movements just right on the servos is usually critical, and if the system gets a knock or just wear, the linkages may need regular adjustment. An air ram on the other hand is far less critical; you can overdirive a gear door onto the stops with impunity, and if it does all snarl up, it won't mind a bit, nothing will burn out.

Not that I am a big fan of air systems, I just think that on balance they are the lesser of two evils.
Probably of no practicle value for your current project but at Jetpower there where a number of people selling electric retracts. Behotec had a large range and Jets Munt had some on there stand. There where others too. Nothing new here you say except the controllers are smart, progammable, current limiting devices. So if a leg gets jammed, it stops and will reverse direction when you select the opposite sense on the retract switch. The legs move at scale speed too.
Regards,
John
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 26, 2010, 09:19:20 AM
Good points on the servo for doors John, I will stay with air rams, I have plenty of them looking for a home.
In this last week I have been thinking about electric retracts for the Lightning especially when I spotted Grumania now stocks Lado.  But I recall a recent thread from rcu which discussed electric retracts and some people gave good reasons for not using them.  Equally there are good reasons for not using air retracts, so for the moment I decided to stay with what we know on an expensive and prized model and let other people troubleshoot and prove electric retracts.  In 1986 I bought a pair of electric mains from MR himself at the Nats to go in a Royal Bearcat, I sold everything off before I got round to using them, but on the bench they were the best retracts I have ever seen - scale speed, staggered timing, adjustable endpoints, very powerful.  He doesn't make them now, but makes air retracts for his models, there has to be a reason why!
Title: Re: Mick Reeves Lightning build
Post by: Alex48 on September 26, 2010, 10:28:10 AM
Hi Harry

I use the Airpower Multi Function Valves on all my builds, the last 6 models I've built have had them.  Work very well as long as you use water traps on your compressor and don't leave the tanks full when in storage!  They do Brake, Gear, Doors, Failsafe and all timings are adjustable.  Not everyone's cup of tea but I really like them.  The failsafe saved one of my models from a belly landing on tarmac  :)
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 26, 2010, 17:50:47 PM
I have considered them Alex, but the thing I don't like about them is so many items in one box, if one goes wrong you have the expense of replacing the entire box rather than the small cost of replacing just one small servo or valve.
Title: Re: Mick Reeves Lightning build
Post by: Alex48 on September 26, 2010, 20:08:34 PM
Sounds sensible...

The unit I had a few years ago that went funny Ali just replaced free of charge  :)
Title: Re: Mick Reeves Lightning build
Post by: JohnMac on September 27, 2010, 07:25:24 AM
Interesting point about the water trap Alex, but where do you get them please? I have one in my current F14 build.
Harry I think people saw the benefits of electric retracts long ago. The problems where as I have already described with stalling them and drawing large unfettered currents. The second problem was the limit switches which back in the day used electro-mechnical micro switches. I have these on my BT Spitfire and they are the MR units you described. Setting up and maintaining these switches is a lot off work and a bumpy landing or engine vibration can cause them to go out of spec.
The electronic controller overcomes the stalling problem and they now use solid state switches (at least one of the companies who sold them told me this and they make the electric bits for the Behotec range). You are right about Ilya selling them too. He had them on his stand along with a new scale Eurofighter Typhoon.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 27, 2010, 09:34:21 AM
I got a water trap for my compressor from Ali, he has 2 brands though they look identical apart from colour.  Not sure how well it works, there seemed to be as much water coming out of the trap as was going in!

One criticism I read of electric retracts is that if any grit gets onto the screw, it jams when it reaches the nut.  Any grit on an air piston rod simply gets pushed along by the cylinder when the rod moves.  Presumably you have not suffered that in your use of them?

I looked at Behotec's website retracts but didn't see electric ones, have you a link?  I'm a bit iffy about Lado as they have a poor reputation on rcu for not delivering orders for months, though if Ilja has them in stock there is no risk but then the next problem is they don't have a noseleg of the correct retraction angle so it would probably still have to be air driven.  "Down and Locked" have started making electric retracts but not been going long enough to hear anything about them.

I will continue with the air system for now.  They can be incredibly reliable, like my F-86 retracts and doors which have never failed and had zero maintenance, in 6 years.
Title: Re: Mick Reeves Lightning build
Post by: Pat Barnes on September 27, 2010, 18:24:44 PM
Hi Harry

I see that gear doors are a hot topic for everyone! I've just spent ten days sorting the doors on my Raptor, and hopefully have a reliable setup now! Unbelievable the amount of fiddling that went into setting them up to work properly! My legs are air up spring down, and I have used servos on each of the doors through a jetronics sequencer, which works pretty well. My only concern is the pull pull steering cables - I hope they don't snag on any of the hinges or servo linkages now filling the tight nose leg bay!  Sadly there is no space for any of the nose steering methods discussed here, so I have to stick with the cables!

Personally, I like the air systems, so I think you are going the right way with yours. Good luck with the setting up - I hope you have more space to work in than I did!

PB
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 27, 2010, 19:39:17 PM
Doors always seem to be a major source of trouble.  One thing to watch out for is that legs sometimes take longer to retract in the air than they do in the workshop so it is a good idea to program a longer delay time for the doors for the test flights.
Pat, my experience is that if the steering cables are loose enough to snag on anything, they will, and that prevents the leg from coming down properly and makes it turned off to one side.  On my Starfighter they would even snag on the rounded ball link covers on the door's air rams.  If you can, pull the cables out of the way with the cable tie/heatshrink method.

Something that would concern me about electric retracts is their power source.  Despite having current cut-out, I would not like them to be drawing from the radio battery.  Splicing in an external battery is easy isn't it.  But is it always possible, for example with my weatronics rx with the regulated output taken off 2S lipos, does the external battery have to match the Rx voltage output since they will be sharing the same negative lead to complete the circuit for the data signal?  Or will the two systems work independently, allowing a simple 4 cell nicad to power the retract while sharing the negative lead with whatever output the rx has?
Title: Re: Mick Reeves Lightning build
Post by: JohnMac on September 27, 2010, 22:38:00 PM
Doors always seem to be a major source of trouble.  One thing to watch out for is that legs sometimes take longer to retract in the air than they do in the workshop so it is a good idea to program a longer delay time for the doors for the test flights.
Pat, my experience is that if the steering cables are loose enough to snag on anything, they will, and that prevents the leg from coming down properly and makes it turned off to one side.  On my Starfighter they would even snag on the rounded ball link covers on the door's air rams.  If you can, pull the cables out of the way with the cable tie/heatshrink method.

Something that would concern me about electric retracts is their power source.  Despite having current cut-out, I would not like them to be drawing from the radio battery.  Splicing in an external battery is easy isn't it.  But is it always possible, for example with my weatronics rx with the regulated output taken off 2S lipos, does the external battery have to match the Rx voltage output since they will be sharing the same negative lead to complete the circuit for the data signal?  Or will the two systems work independently, allowing a simple 4 cell nicad to power the retract while sharing the negative lead with whatever output the rx has?
Hi Harry. Using a separate battery is quite simple. The retract battery provides the power only to the retract system not to the Rx. The Rx supplies a negative and signal. I don't know for sure whether the retract battery need to be the same as Rx battery, and the answer could be system dependant. It may work with one and not another. The reason for this is that the signal as you know is a series of pulses. The pulse voltage needs to be over a certain threshold level, so it is possible that you end up with a pulse that the decoder see as indeteminate.  However, you can suck it and see. It will either work or not and should do no harm.  Personally I have only used matched battery voltages.
So far as dirt on the leadscrews is concerned, so far this has been no problem on the Spitfire. On the Lado retracts the whole system is enclosed so I don't see that dirt can enter easily.
Title: Re: Mick Reeves Lightning build
Post by: JohnMac on September 27, 2010, 22:55:40 PM
Hi Harry,
Try this link: www.gz-retracts.com (http://www.gz-retracts.com). These guys partner Behotec so far as I can see. The alsoo make linear electric drives, brakes controllers etc. BTW, how is you German? Babblefish translation from German to English is only recomended after abou the 3rd pint of beer, at which point it becmes hilarious. Without the beer It is impenatrable.
There where these guys as well but there is not much on the site: www.electron-retracts.com (http://www.electron-retracts.com)
Regards,

John
Title: Re: Mick Reeves Lightning build
Post by: Pat Barnes on October 04, 2010, 20:27:38 PM
I like the look of those GZ retracts. If they are typical German quality, they look very promising!
Title: Re: Mick Reeves Lightning build
Post by: HarryC on October 12, 2010, 10:06:58 AM
The flap construction is pictured below

The only pre cut parts are the riblets, the top and bottom sheet are cut from planks of 1/8" balsa using the plan as a reference.  It's nice to go back to the basics after so many moulded models!  The hinging is by piano wire in brass tubes.  4 brass tubes are supplied and in total there is plenty of length but none is long enough for the flap so I joined two sections with a short piece of the next size up of tube from my own stock.  Other sections of brass tube are glued into holes in the wing ribs at either end.  The piano wire is then passed through the whole affair from the root rib end.

With the flaps made and the ailerons carved to rough shape, the top sheeting can be finished off again to rough shape.  The flaps are not hinged off the false trailing edge but from well behind it so the sheeting doesn't simply stop at the false t/e but hangs out some distance behind.  The easiest way to do it is to sheet well beyond the false t/e and well beyond the ribs at the tip end and round the inner tip corner, then offer up the flaps and ailerons and mark their positions onto the sheeting and cut off the overhang.

I have been looking at the fuselage again, as the wings are close to the point where no more work can be done until they are fettled to the fuselage mounting points.  I have cut out part of the cockpit area using a diamond wheel so I can get good access to the front section.  The next tasks are to glue in the nose bullet and then the two front formers with the nose retract system.  To get that all aligned correctly the first thing I will do is cut out the noseleg doors.  These, along with many other panel lines and fasteners are actually moulded into the surface of the fuselage.  From a short distance the fuselage looks smooth but it does actually have quite a lot of fine detail in it.  This would survive a fine spray of primer and humbrol silver, but anything more or any sanding, will destroy it.  However at the moment it gives me a guide as to where to cut the doors, I am checking that the leg and wheels will actually fit, before I cut it.  I am also considering applying a light carbon fibre bandage to the area before cutting, to help it and the doors hold their shape when cut and any stresses become released.  It will depend on me being able to get thin enough c/f cloth, it doesn't need the usual very heavy thick cloth.

Looking at the wing mounting, I am thinking about what can be done there. The design is that the wing tube is bolted at its inner end to a ply plate, and the tube then passes through a hole cut into the fuselage side and this takes most of the flight and weight loads.  The area of the hole has been reinforced at manufacture by a very thin layer of unidirectional (i.e not woven at 90 degrees) carbon fibre mat.  I would never expect this to hold the flight loads for any length of time, not sure I would even taxi around with it, and I know many people have re-designed this aspect.  At the very least I think gluing a short tube to the fuselage for the wing tube to pass through, would be a great help, as the load of the fuselage weight will then be spread by that extra tube all around the hole, rather than taken on the tiny top edge in contact with the wing tube.  Perhaps plywood butresses to the tube/fuselage joint as well?  Another possibility is to make an entirely new ply plate that tubes bolt to, which extends all the way out to the fuselage holes, with an outer tube all the way, so that ply plate will take some of the bending loads off the fuselage.
Title: Re: Mick Reeves Lightning build
Post by: STORM on October 12, 2010, 10:38:13 AM
Hi Harry.
Regarding the wingfitting, it sounds as though it's exactly the same system employed on the Javelin.
My model has had many flights over time and shows no signs of even whittling away at the fuse root holes.
I suspect this is because when all is clamped the very fact that the wing root rib is such a good fit with the fuse nothing seems to move, strange but true.
I understand your concerns and if you are worried then a piece of carbon mat glued inside the holes would give you peace of mind.
In other words Mick's system works better than you would expect, no need to over engineer the wing tubes at all in my humble opinion,
Regards,
Gary.
Title: Re: Mick Reeves Lightning build
Post by: Alan Smithie on October 12, 2010, 10:47:08 AM
there is plenty of length but none is long enough for the flap so I joined two sections with a short piece of the next size up of tube from my own stock.

I'm mopved to ask why - the tube is only a bearing bush and so won't be taking any bending or tensile loads. In fact you could probably get away with short pieces at each rib station if you were confident that they would maintain alignment for final assembly.

£0.03 supplied,

PDR
Title: Re: Mick Reeves Lightning build
Post by: HarryC on October 12, 2010, 10:49:13 AM
the very fact that the wing root rib is such a good fit with the fuse
ha ha, not on the Lightning!  The root rib follows an S curve, the fuselage is flat.  Yeah, I think an extra layer of c/f and a short guide tube to spread the load all around the hole rather than just the top edge, should be fine for peace of mind.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on October 12, 2010, 10:53:15 AM
I'm mopved to ask why - the tube is only a bearing bush and so won't be taking any bending or tensile loads. In fact you could probably get away with short pieces at each rib station if you were confident that they would maintain alignment for final assembly.
I did think about that at the time, in fact it doesn't even need them at every rib just at the root and tip ribs but decided that when I come to install it and push the piano wire through, it only needs to misalign a tiny fraction at any one section of tube/hole in rib and it will be a pain trying to get the hinge wire all the way through.  Since there is more than enough brass pipe supplied, and the weight penalty is in grammes, having a contimuous bearing tube along the entire flap seemed the best idea.
Title: Re: Mick Reeves Lightning build
Post by: boeing247 on October 27, 2010, 19:49:39 PM
Hi Harry,
On the previous page you mentioned using a button air valve to control the doors.
What I've done is to control the valve from the servo and not rely on the struts to trigger it. By using an "overcenter" linkage from the servo to the retract valve, you can use the servo slow feature on the transmitter to slow the  retract servo so the gear has enough time to retract fully, then a cam cutout on the servo wheel will trip the valve. This system also has the advantage of not putting any loads on the gear strut or the servo.
You have to play around with the cam profile and timing, but once set up, it works great.
Jon
Title: Re: Mick Reeves Lightning build
Post by: HarryC on November 06, 2010, 11:44:54 AM
I have been doing work on the wings which involves a lot of fitting flaps and ailerons, checking the fit, removing them, sanding and filling them and the wing sheeting, putting the parts back on and repeating several times.  From above I now have what look like Lightning wings, the underside is still not sheeted as that has to wait for other work.

The front intake bullet with the detachable nose cone is now glued into place and gives it the unmistakeable Lightning look

Behind that go the two formers carrying the noseleg mounting plate.  Although the hysol mixing nozzles are somewhat wasteful of this expensive glue, they are invaluable for this sort of situation for putting a bead of glue along both sides of the former to fuz joint, and then smoothing down with a gloved finger.

The fit of the formers to the fuz is poor vertically but that allowed wiggle room to get the noseleg plate to a suitable angle so that the wheel is just inside the fuz when it is retracted - the front former is as high as it can go in the fuz with a large gap at the bottom, and the rear former is as low as it will sit with a large gap at the top.  If both formers are pushed to the bottom or top then the wheel sits partially outside the fuz when retracted.

Title: Re: Mick Reeves Lightning build
Post by: STORM on November 06, 2010, 13:21:06 PM
Starting to come together!
Title: Re: Mick Reeves Lightning build
Post by: marcs on November 12, 2010, 09:28:44 AM
Harry,

Hi, just subscribed and great subject matter. I usually spend most of my time posting builds on RCU but time to broaden my scope!
I also use alot of Hysol in builds, never use those nozzles though, big waste. I buy 10ml and 5ml syringes from a medical supplier, the unit cost is very small, then if you need to extend the 'tip' to reach into difficult places I push a small piece of silicone fuel tube (IC model bore stuff) over the syringe end, take a cotton bud (Boots ones with plastic shafts - again very cheap) cut the buds of each end and you have a tube which you can cut to length to push into the other end of the silicone tube to get an application nozzle, you can even cut the tip at 45 degrees to give a good application.

It sounds a faf but if you cut up a 1m length of fuel tube into 2cm lengths and do the same with some cotton buds it takes seconds to make a nozzle. I mix the Hysol in small plastic cups first, again you can get these from a medical supplier.

marcs
GBRJET
Title: Re: Mick Reeves Lightning build
Post by: HarryC on November 12, 2010, 10:22:46 AM
That's brilliant marc, thanks for that.  I have just one nozzle left and was pondering about getting more but I hate the waste of glue that they entail.  I already have box loads of syringes as I work in the medical world and sometimes they have to throw out time expired stuff (sterility guarantee runs out) so I shall be making nozzles tonight.  I mix my glues and fillers on post-it pads, medical reps give them out by the shed load.
Title: Re: Mick Reeves Lightning build
Post by: lozza on November 12, 2010, 10:59:46 AM
Harry,

Hi, just subscribed and great subject matter. I usually spend most of my time posting builds on RCU but time to broaden my scope!
I also use alot of Hysol in builds, never use those nozzles though, big waste. I buy 10ml and 5ml syringes from a medical supplier, the unit cost is very small, then if you need to extend the 'tip' to reach into difficult places I push a small piece of silicone fuel tube (IC model bore stuff) over the syringe end, take a cotton bud (Boots ones with plastic shafts - again very cheap) cut the buds of each end and you have a tube which you can cut to length to push into the other end of the silicone tube to get an application nozzle, you can even cut the tip at 45 degrees to give a good application.

It sounds a faf but if you cut up a 1m length of fuel tube into 2cm lengths and do the same with some cotton buds it takes seconds to make a nozzle. I mix the Hysol in small plastic cups first, again you can get these from a medical supplier.

marcs
GBRJET

Now i like that allot

lozza
Title: Re: Mick Reeves Lightning build
Post by: marcs on November 12, 2010, 11:42:57 AM
Lozza, cheers - have to say your pics are the best  ;)
Another use of cotton buds is for cyano applicators - info on my website.

marcs
Title: Re: Mick Reeves Lightning build
Post by: HarryC on November 23, 2010, 21:01:01 PM
Here's a sight for Lightning lovers, the shape is coming together

The two formers that the wing tubes bolt to have been glued in with hysol beads around them, thanks to marcs's tip it was done quickly and consistently with a syringe to apply a good bead, then put on a latex glove and run a finger along the bead to make a a good concave bead with max area on the fuz and former.

While that hysol cures, move on to make a start on the tailplane mounting on the rear fuselage.  This piece comes ready assembled
The tailplane rods are a solid aluminium rod in a brass tube which is held down by copper straps.  There is an M3 threaded hole in the outer part to which the tailplane is bolted, the inner part has an M4 hole with a custom made brass fitting as a control arm.  The control arm passes through a slot in the plywood which acts as a sideways motion limiter, but it is quite a bit wider than the control arm so I will probably line it with thin plasticard once everything esle is in place, to prevent any sideways movement of the tailplanes.

The control arm bothers me a bit, see photo below.  It is a brass M4 bolt with a ball head, and aluminium spacers to keep it the correct arm length from the torque rod.  The pushrod attachment to the ball is one of those open circle links that just pops onto the ball, which to my mind could also pop off under stress or vibration.
I would far rather use a ball that bolts through so the bolt head/washer prevents the pushrod connection from coming off, but the ones I have are for M3 bolts.  Do you get M4 bolt through ball links?  I can't see a way of making something to work, I don't have a lathe or special metal working abilities to make anything.  Does anyone have any ideas?
Title: Re: Mick Reeves Lightning build
Post by: selleri on November 23, 2010, 22:39:59 PM
Phil at Fighteraces sourced some heavy duty ball links he used for Ali's Skyraider, worth checking with him.

You could also try hobbystores that carry spare parts for cars IIRC I've seen 4mm ball links in that capacity.
Title: Re: Mick Reeves Lightning build
Post by: Thorjet on November 23, 2010, 22:41:09 PM
Looking good Harry
Title: Re: Mick Reeves Lightning build
Post by: Alan Smithie on November 23, 2010, 22:56:10 PM
The control arm bothers me a bit

Is that all that bothers you? Personally I'd be more concerned abour the use of copper plumbing straps (at least that's what they look like to me) to restraing the tailplanes of a fast jet. Copper isn't exactly reknowned for its resistance to cracking under cyclic loads, and it age hardens to make it even worse. I'd be looking to find a better solution to this area before worrying about the ball links!

PDR
Title: Re: Mick Reeves Lightning build
Post by: Norfolk'n'Good on November 23, 2010, 23:05:31 PM
Is that all that bothers you? Personally I'd be more concerned abour the use of copper plumbing straps (at least that's what they look like to me) to restraing the tailplanes of a fast jet. Copper isn't exactly reknowned for its resistance to cracking under cyclic loads, and it age hardens to make it even worse. I'd be looking to find a better solution to this area before worrying about the ball links!

PDR


I have to agree that stuck out like a sore thumb to me although I may have mentioned it in a slightly alternate manner  ;)
Title: Re: Mick Reeves Lightning build
Post by: HarryC on November 24, 2010, 09:56:16 AM
Thats easily dealt with.
Back to the ball link, am I being too worried?  I would not be keen on using that ball link on a .40 glow model let alone a large jet, but is there any data to support that?
Title: Re: Mick Reeves Lightning build
Post by: Davie Matthews on November 25, 2010, 18:59:07 PM
Thats easily dealt with.
Back to the ball link, am I being too worried?  I would not be keen on using that ball link on a .40 glow model let alone a large jet, but is there any data to support that?

Well Harry,  If you have doubts in your own gut.  LISTEN to it.  I think you answered it in your post above. 

Nice work so far.  Best of luck with her.

Davie
Title: Re: Mick Reeves Lightning build
Post by: HarryC on November 25, 2010, 19:41:37 PM
I think I have an excellent solution, parts now on order from a tractor spares company of all things!  Will do photos when I have the parts and made the alternative control rod.
Title: Re: Mick Reeves Lightning build
Post by: nmacwarbirds on November 26, 2010, 14:14:17 PM
Dear Harry
Looking on with interest, I take it you will be using phenolic tube
to support the wing tubes where they enter the fuselage and protrude through to a fore and aft former?

I hope that makes sense.

Regards Phil G.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on November 26, 2010, 17:45:20 PM
Looking on with interest, I take it you will be using phenolic tube
to support the wing tubes where they enter the fuselage and protrude through to a fore and aft former?
Going to make my own tubes, as can't guarantee getting a good size match of phenolic tube by mail order other than from MR and I don't want to buy and pay postage on tubes many times longer than I need.
Title: Re: Mick Reeves Lightning build
Post by: Vinceyboy on November 27, 2010, 09:07:20 AM
I definitely think you are going the right way with the build Harry :af can't beat the old gut instinct as Davie puts it, the belt and braces attitude is better, and as you say, the parts are out there, you just need to look further modelling suppliers :af
Title: Re: Mick Reeves Lightning build
Post by: HarryC on December 22, 2010, 09:26:20 AM
It's gone very quiet in this thread.....!
There has been a break whilst I assemble a float plane Beaver, a leccy one at that.  Shock horror, Harry flies things other than jets!  Also been waiting for some parts to arrive and having a major ponder over the tailplane system.

The Weatronic 12-22 Rx with 2 built in gyros has arrived so I have started programming up the Tx and Rx so that I can test different tailplane systems, and to check the operation of the gyros.  The Rx has to be built into the model in a particular orientation so that the gyros align with the required axes.  I have been getting them working and watching the servos react as I move the Rx.  Before now I would have said the Rx had a faulty connection if servos twitched when I moved the Rx!

Why gyros and why 2 of them, and why built in rather than external?  Highly swept models such as Lightning can wobble from side to side in roll and it looks poor, a gyro will stop that, so it is for cosmetic reasons.  The Weatronic rx has a choice of 2 or 3 but not of 1 gyro, and the 2 gyro rx costs £70 more than the normal rx, which is much cheaper than a single ACT Fuzzy Pro gyro so it makes sense to get the 2 gyro Rx.  But isn't the Fuzzy Pro very good, and much easier to mount its small sensor the correct way than mount the huge 12-22 rx the right way in a constricted space?  True, and I do have a Fuzzy Pro for the Lightning but I trialled it in my Typhoon which can rock noticeably, and it made such an improvement it is staying in the Typhoon.  With 2 gyros I can use one on ailerons, and if needs be one on the nosewheel steering and on the rudder.  Being built in and controlled by software, the same gyro can be independently assigned and managed for many different servos, so the one gyro can be assigned to steering and rudder but have independent gain on each, so it can do the job of two external gyros.  Only "rate" mode is available, they haven't got HH mode yet but it's rate mode that I want, and like many external gyros a Tx channel can be used to control the gain, even the gain curve has 5 points which can be adjusted in software.  So for example, on test flights I can take off with aileron and rudder gain at zero, and use the two sliders on the Tx to alter the gain as required for each of them independently.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on December 22, 2010, 14:04:44 PM
My plan to replace the brass ball-link with an M4 high-tensile bolt and M4 steel clevis with ball link is going well, and forms a very strong, bolted, slop free linkage at the tailplane horn end of the system.  The remaining problem is at the servo end.  One servo is mounted 1/4" higher than the other because the pushrods cross each other and however you try it, the clevis meets the servo arm at quite an angle, which doesn't work, clevises need to be parallel to the plane of the servo arm/disc.  Plan "A" was to get the servo arms that incorporate a ball link from fighteraces, I did and they are gorgeous, but the smallest size that has an M3 link is just a bit too big, the arms of the two servos clash into one another at up elevator.  Plan "B" Was to cut the ply plate to move the servos much further back and away but the different planes between the tailplane horn and the existing servo cut outs puts the servos even further out of kilter with the horns.  Plan "C" was to get metal servo discs and fit ball links at the servo end of the pushrod (metal because plastic servo arms with pushrod attached by ball link above or below the arm can cause the arm to twist and lose some motion and I guess eventually weaken it) but I think I am dropping that in favour of Plan "D" which has just occurred to me, which is to completely re-mount the servos on their sides so that the servo arm is in the same plane as the horn and in line wih it too, and maybe then be able to use the fighteraces servo arms too.  This will probably require me to cut a completely new 1/4" ply tailplane mount.
Title: Re: Mick Reeves Lightning build
Post by: rcfanuk on December 22, 2010, 15:22:36 PM
Harry, plan D sounds the best option, you will be able to keep the servo geometry's the same.  :af

Good to see you back on this build

Steve
Title: Re: Mick Reeves Lightning build
Post by: HarryC on December 23, 2010, 09:41:40 AM
I did some trial fits last night but there is not space to mount the two servos on their side where they need to be in order to line up with the torque rod horns, so they must remain upright (actually it is inverted when the whole assembly is fitted into the fuz)

This shows the first problem, that of the angle that the pushrod arrives at the raised servo, using the pre-installed pushrods.
The clevis is clearly not going to work connected to the servo arm at that angle.  One servo is raised because the pushrods cross one another.  The other servo is not fitted at the moment, the camera view is pointing from the missing servo to the other torque rod horn.  Can you see the other horn?  No!  So the other pushrod has to pass through the servo that you can see, which will take a bit of magic.  Solution?  Use longer horns on the torque rod, that will raise the pushrod above the servo, and on the one that you can see will bring it in line with the servo arm.  But to compensate for the travel required, longer servo arms are needed which starts to bring the rods and servo bodies back into conflict.


The above photo and this photo show my concern about the ball link
I just donít feel that is meaty enough or secure enough to drive these large tailplanes in a fast model.  It would not be easy but it is conceivable that the plastic fitting could be popped off the ball.  I want something that doesnít have the option of coming apart.

This is my solution
On the left is the original brass M4 rod and ball top with its aluminium spacers and plastic coupler for M3 pushrod.  It was only long enough to screw half way down into the torque rod. I will replace the brass bolt/ball with an M4 high tensile bolt from the other side so it passes all the way through the torque rod and is locked into place.  Onto the bolt goes the fitting on the right.  This starts off as the M4 steel clevis shown in the middle.  Clevises are available in many sizes, the snag is that the pin matches the thread, so an M4 thread gets a 4mm pin which means 4mm holes through the arms.  Ball links have 2 or 3mm holes.  I was able to get this M4 clevis as normal arms or long arms so I got the long arm, cut off the bit with the hole and am still left with enough arm to make a 3mm hole and fit the ball link.  I had intended to drill a 3mm hole but unless the drills and bolts and my machining are really precise, there will be some slop in the fit of the the bolt passing through the clevis, so instead I drilled smaller and tapped the clevis arms for M3.  So a short M3 bolt screws through the clevis, firmly holding the ball link, finger tight means the threads nip up in the clevis arms so the bolt has zero slop in the clevis and the nut adds a final bit of security to keep the bolt in place.

Since the clevis arrangement screws down onto the bolt coming out from the torque rod, I can easily adjust the length of the arm to suit all the pushrod clearances and angles required.  Using the 17mm Futaba arms on the servo just manages to give the tailplane travel shown in the plans.
Title: Re: Mick Reeves Lightning build
Post by: slippery on December 23, 2010, 10:28:26 AM
Just a thought maybe use an aluminiun output arm bent to a suitable angle for the clevis to locate at a better angle.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on December 23, 2010, 11:05:56 AM
But then it is bent the wrong way when the arm rotates 45 degrees each way from centre.
With a longer horn on the torque rod the angle isn't quite so bad.  I think I will chamfer the raised mounts so that the servo sits at an angle with the pushrod.
Title: Re: Mick Reeves Lightning build
Post by: JimG on December 23, 2010, 11:13:37 AM
Do you have room to raise one end of the servo so it is fitted at an angle? This will bring the servo arm in line with the pushrod.

Jim
Title: Re: Mick Reeves Lightning build
Post by: HarryC on December 23, 2010, 11:23:06 AM
Do you have room to raise one end of the servo so it is fitted at an angle? This will bring the servo arm in line with the pushrod.

Jim
See previous post!
Title: Re: Mick Reeves Lightning build
Post by: JimG on December 23, 2010, 11:38:31 AM
Didn't see that before posting. ;D ;D

Jim
Title: Re: Mick Reeves Lightning build
Post by: zippo - is leaving the building on December 23, 2010, 11:57:19 AM
Is there space to mount the servo upside down? If so, it would put the output arm more in line with the tailplane horn. Just a thought - though I'm sure you have already considered that option.
Title: Re: Mick Reeves Lightning build
Post by: The Saint. (Owen) on December 23, 2010, 12:00:17 PM
What about low profile servos.  :af
Title: Re: Mick Reeves Lightning build
Post by: HarryC on December 23, 2010, 13:41:08 PM
Is there space to mount the servo upside down?
neat idea but no, the assembly is fairly close to the bottom of the fuselage so the amount of headroom is limited

Quote
What about low profile servos.
My experience of low profiles is that they are low below but not above the mounting line.  If there are any that are low above the mounting line, and are digital and of the required spec and made by Futaba or JR then they will be very expensive!  Multiplex don't make any, and I won't allow anything other than Mpx, JR or Futybut servos in my expensive models.
Title: Re: Mick Reeves Lightning build
Post by: Tiger on December 23, 2010, 14:17:08 PM
I don't like any of it..................

It all looks like a bodge to me..............

Sorry to be so negative, but there are so many bad things here. I don't like the long brass ball ended screw, Have you thought what the dia of the solid rod might be that runs up the centre of the threads ? If it's an M3 thread then the O/D is going to be about 2.8/2.9 the thread depth is 0.3 mm, both sides. So, the solid bit of BRASS wire up the middle is at best 2.3 dia but could be 2.2 or even 2.1. The point that it enters the torque tube is the point of highest stress.
I wouldn't have it ........................chuck most of it in the bin ! !
Redesign the method of attaching the horns to the torque tube in such a way that it improves the geometry with the servos.

You need an engineer with some machines ................... sorry I'm busy just now.

All, just my opinion, of course  :D  

Watching with interest. :af

Tally Hooooooooooooooooooooooooo  :uk:

Andrew

  
Title: Re: Mick Reeves Lightning build
Post by: HarryC on December 23, 2010, 14:30:15 PM
I don't like the long brass ball ended screw, .....................................

I wouldn't have it ........................chuck most of it in the bin ! !
As you've probably gathered Andy, it is on its way to the bin!   ;D And check it again, it is M4 not M3, and has been replaced by M4 high tensile steel bolts.
How's the Rafale coming along?
Title: Re: Mick Reeves Lightning build
Post by: Tiger on December 23, 2010, 15:03:19 PM
OK....................M4 is a bit better, steel is better than brass, the core dia of M4 is 3.14 mm.
An accurately machined fitted ally collar incorporating the horn, pinned and 'Loctited/Hysoled" to the torque tube would be much better.

The Rafale has gone back home to France, waiting for me.  :D

Tally Hoooooooooooooooooooooooooooo  :uk:

Andrew
Title: Re: Mick Reeves Lightning build
Post by: Tiger on December 23, 2010, 15:07:59 PM
Or............. has the torque tube sufficient wall thickness to machine a tread on it. The collars could be 'screwed on' and Loctited then...............

T. H.  :uk:

Andrew
Title: Re: Mick Reeves Lightning build
Post by: HarryC on December 23, 2010, 15:25:00 PM
Not sure what you are meaning Andy, it's a rod not a tube, solid aluminium about 10mm in diameter with an M4 threaded hole right through it for the bolt that forms the horn.
Title: Re: Mick Reeves Lightning build
Post by: Gordon W on December 23, 2010, 21:32:03 PM
Hereís Keith Whiddettís solution for operating the all-moving tail on his Gnat.  Itís a modified JR aluminium servo arm bored out to fit the shaft.  The pinch bolt allows adjustment of the armís position, and it looks as if thereís a grub screw for final locking.  The shaft is 6mm dia, so this actual solution isnít usable on your 10mm shaft.  But a larger pair of horns could easily be knocked up from a bit of ally plate using a hacksaw, file, pillar drill and taps.

This brings back memories of making replacement conrods for my Elfin 2.49 back in the early Ď60s.

Gordon
Title: Re: Mick Reeves Lightning build
Post by: Tiger on December 24, 2010, 00:44:49 AM
Not sure what you are meaning Andy, it's a rod not a tube, solid aluminium about 10mm in diameter with an M4 threaded hole right through it for the bolt that forms the horn.

OK..............that's even better then, you've got something really solid to fix to. The idea shown in Gordon's post is the sort of thing I'm thinking of.

Tally H  :uk:

Andrew
Title: Re: Mick Reeves Lightning build
Post by: wayne the iceman on December 27, 2010, 14:34:36 PM
hi guys
 been following the thread with interest ,dont want too be the profit off doom here, but my mate built well it got 3/4 built before he scrapped it if im honest, problem after problem ,and i also had the same problem with his 1/4 scale spit nothing fits or plans wrong , you may as well get your money and put a match too it  :banghead:,   unless you have nothing better too do with your time than  solve problems that should have been tryed and tested you will need a whole lot of time and nerves of steel not too mention a cement mixer too fill the fuselage :'', anyway best of luck you will need it ,
          regards and happy landings  :uk:
Title: Re: Mick Reeves Lightning build
Post by: HarryC on December 27, 2010, 17:04:38 PM
Here's the completed tailplane assembly.  I stayed with clevises at the servo end, the raised servo has had its mountings angled so that the plane of the servo arm is in line with the pushrod.  The pushrod from the raised servo will not be at right angle to the horn from the torque rod but any tiny differential can be taken out in software during the final setting up.  You can see my new attachments to the torque rod are very substantial - M4 high tensile bolt screwed all the way through from below the supplied solid aluminium rod, double safety from the nyloc nut then on top which also acts to soak up the large lateral slack in the slot in the plywood, then the steel M4 clevis with ball link bolted through with M3 through the arms and ball, thread tapped into the clevis arms and double safety from M3 nut.  I don't see that lot coming apart!  It is all very solid and slop free, the only movement is the servo gear lash.

Title: Re: Mick Reeves Lightning build
Post by: Gordon W on December 27, 2010, 20:27:20 PM
It does look plenty strong enough, though I always aim for a far longer horn than servo arm to give the servo more mechanical advantage, and also to use up as much of the available pot movement as possible for best resolution.  I've had pots wear a bad spot in the middle through using too little of the available movement.  I guess that the space available above the linkage is restricted, and in any case I'm sure that you'll have used your spreadsheet to check that what you have is OK in terms of torque.  The swept hinge line is presumably close to the 25% chord line of the tailplane for minimum effort in moving it.

FWIW, I googled your S3050 servo to find the specs, and discovered this rather good database which appears to have the specs of all servos ever made, which I've now bookmarked   http://www.servodatabase.com/servo/futaba/s3050 (http://www.servodatabase.com/servo/futaba/s3050)

Gordon
Title: Re: Mick Reeves Lightning build
Post by: HarryC on December 27, 2010, 22:36:46 PM
It does look plenty strong enough, though I always aim for a far longer horn than servo arm
The lengths are dictated by the tailplane travel required, I am already running the servo travel at equivalent to a JR tx turned up to 110% and am only just getting the required travel.  Can't make the tailplane horns any longer.  They are a lot longer than they look in the photos, bear in mind the mid point is 5mm inside the torque rod, and the rod is below 6mm ply, so total horn length is something like 20 - 25mm
Title: Re: Mick Reeves Lightning build
Post by: lozza on December 28, 2010, 10:24:53 AM
I'd like too comment but im not a modeller   :'' :''
Title: Re: Mick Reeves Lightning build
Post by: HarryC on December 29, 2010, 11:03:08 AM
It does look plenty strong enough, though I always aim for a far longer horn than servo arm to give the servo more mechanical advantage, and also to use up as much of the available pot movement as possible for best resolution. 

I measured it last night Gordon, my control horn is 28mm compared to the MR brass one which is 24mm, and servo arm is 17mm.
There will now be another break in progress while I finish off another two models that have been hanging around part-done for a while (prop jobs, hush, keep it quiet!)
Title: Re: Mick Reeves Lightning build
Post by: Gordon W on December 30, 2010, 23:33:47 PM
The angle at which you've taken the pics masks the relative lengths very well, Harry.

My li'l scratchbuilt EDF Lightning had the same elevator horn length as yours, but the servo arm was only 14mm long.  I note from an old RCGroups thread I ran about mine that it did need more elevator movement than I expected, though I didn't note down the figures, possibly up to 15deg each way, and also that following first flights I zeroed the expo as the elevator response was too soft with 20% expo.

There are plenty of MR Lightnings flying around successfully though, so obviously you'll use the recommended elevator movements.  The MR Ltg did help me in one important respect ...  I learned from one forum discussion on it the CG as % of root chord.  I'd set my model's CG too far forward, and when I moved it back to the Reeves location its handling was much improved.

I've never seen a MR Lightning flying in the flesh, so hope you get yours to CJ, Merryfield or Westonzoyland  (if Westonz..  does begin holding jet fly-ins) in the future!

Hurry up with those prop jobs (I'm in the middle of building one too).

Gordon  
Title: Re: Mick Reeves Lightning build
Post by: HarryC on December 31, 2010, 09:32:24 AM
There are plenty of MR Lightnings flying around successfully though, so obviously you'll use the recommended elevator movements.
I am hoping it is enough Gordon, because I can't get any more.  Although I could wind the clevis further down the horn, the lower pushrod would conflict with the raised servo.  Why not lower that servo?  Any lower and its pushrod that goes over the top of the lower pushrod, will come into conflict with the lower rod!  The only solution would be to put aside the ply plate and cut a new one with the raised servo moved further back so that it is no longer under the lower pushrod.  Then the clevises could be wound down and more travel obtained.  But since I have, just, got the travel specified I have to wonder if it is worth it.
Title: Re: Mick Reeves Lightning build
Post by: Gordon W on December 31, 2010, 22:33:54 PM
Whilst what you have there looks strange, Harry, I guess that it must work.

While he was still building it, I asked Shane Harding how he actuated the elevators on his 1/6th scale scratch-built all-balsa Lightning.  I seem to remember that his two servos were located aft of the tail bearings, as were the actuators on the full size - pic attached.  That way the pushrods didn't have to cross.

However, I too wonder if changing the installation in your model would be worth the effort if everyone else is getting it to work successfully.

Edit.  I've just looked at your pics again and your servos are aft of the bearings!  ::)   Possibly repositioning the horns further outboard (eg inside the long elliptical cutouts) and re-orienting the servos would let the servo pushrods connect without crossing.  Also, maybe Shane's model's pushrods did cross after all!

I give up  $%&  :banghead:

Gordon
Title: Re: Mick Reeves Lightning build
Post by: HarryC on February 08, 2011, 09:21:30 AM
I have finished only 1 of the 2 other models taking up space in the workshop but couldn't wait to get back to the Lightning so I have been working on the tailplane assembly again.  The tailplanes' neutral position is leading edge down, and since I can't get any more travel from them than the required amount, it is important to mount the assembly into the fuz at the neutral angle as there is no spare travel to use to adjust the neutral point.  After much fiddling to adjust the bearing rod exit holes in the fuz, and needing 3 arms, I have tacked an end of the ply plate into place in the fuz with 5 minute epoxy.  In the next session I will bolt on the front fuz and the wings to check that the tailplane assembly is correctly aligned, and if it is I can squirt hysol around the joint. 
Title: Re: Mick Reeves Lightning build
Post by: HarryC on February 10, 2011, 10:15:45 AM
I have encountered an unexpected problem with the tailplane pushing into the fuselage at down elevator.  My other jets with swept tails have the pivot straight across the fuz, but the Lightningís pivots are highly swept as seen in the photos above.  This means that any tailplane ahead of the pivot rotates inwards as well as up or down.  When the leading edge goes down it swings in but so does the curve of the bottom of the fuz so they donít meet, however when the l/e goes up for down elevator the l/e root swings in and hits the fuz.  Spoke to Jim at MR. who mentioned the gap between fuz and tailplane is not scale, itís about 3/16Ē and looks massive, and still the tailplane hits the fuz.  Jim suggested either re-aligning the pivot mounts to sweep the tails back another degree thus bringing the l/e root even further away from the fuz, or sanding material off the l/e root of the tails.   I wonder how the full-size does it, because there isnít some big gap between the fuz and tails.  Maybe it had hardly any down elevator travel?  Or is the full-size fuz pinched in a bit above the tails l/e root and the MR model isnít?  It explains why the root of the tailplanes have a stagger at the pivot, the root ahead of the pivot being further out than the root behind the pivot.  That gives the tail ahead of the pivot a clearance to allow for down elevator, the fuz at that point is built out to fill the gap.  Perhaps the MR model doesnít have the same amount of stagger in the root that the full-size does?  That would give me an option to solve it and make it look better, remove some tail root ahead of the pivot and build up the fuz at that point to reduce the large gap.
Title: Re: Mick Reeves Lightning build
Post by: JohnMac on February 11, 2011, 07:26:54 AM
Hi Harry, A photo of the problem might help. I have the as yet unstarted Airworld kit. Since the pivot is not yet in place I am unable to be sure but it looks as if the bulge in the mounting, and the sweep angle will ensure that the tailpllane never hits the fuselage. I had a look on the web for photos of this area but did not find anything that shows the area well enough.
Regards,

John
Title: Re: Mick Reeves Lightning build
Post by: HarryC on February 11, 2011, 09:36:54 AM
I had a good look at everything last night and worked out how it is all supposed to work on the full size.

Because of the swept pivot, the tailplane ahead of the pivot moves inwards.  That's why E.E. designed a big step in the root at the pivot, so the root ahead of the pivot is stepped out away from the fuz to allow for its inward movement.  To fill the gap at neutral, the fuz has a bulge along the chord of the tailplane root ahead of the pivot, the curve matches the path that the root takes.  Behind the pivot the root swings outward, and the fuz has a raised scallop to match it.

On examining my tailplanes, the root behind the pivot is well away from the fuz at all points of travel, the root ahead of the pivot is well away from the fuz at neutral but rapidly swings into the fuz at down elevator.  The fuz does have the raised bit and scalloped bit.  Part of the problem is that the roots of the tailplanes are not parallel to the fuz but are slightly biased in at the l/e and out at the t/e, so the l/e root is even further biased to swing into the fuz.  What is needed is a change to the pivot alignment, just a degree or two more sweep back.  Rather than try and fudge the mounting holes in the existing ply plate it would be much better to make a new one.

Playing with it all exposed another problem.  By holding the tailplane tips, it takes little force to bend the entire tail back and fore.  The reason turns out to be a combination of two things.  The solid aluminium rods pass through brass tube which are secured to the ply plate by copper plumbing straps - see previous photos.  The play in the aluminium rod to brass tube is tiny but when magnified all the way out to the tips of the tailplane it is become noticeable.  The major part of the motion though is simply the copper plumbing strips flexing very slightly, and once again the distance out to the tailplane tips greatly magnifies the travel.  Is this a problem?  With perhaps 150mph airflow and a lot of tailplane travel presenting a large area to the airlfow, I should think it is a problem!  So that really has to be replaced.

Given all these items that need dealt with I am going to make a completely new ply plate, and this time fit two ball-races (ex-F100 tailplanes) per tailplane.  That will allow me to adjust the pivot sweep and give a solid, slop free mounting.  I will also adjust the positions of the servos so that the pushrod of the lower servo isn't crossing the higher servo and limiting the travel, so I get more scope for adjustment later on.  Work is already under way, the plate has been cut and shaped, and has been marked for the new alignments and necessary slots and holes to be cut at the next session.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on February 19, 2011, 18:59:00 PM
Here's my revised tailplane mounting.  The brass tubes are a nice fit in the ballraces I have, so I have cyanoed the aluminium rod into the brass tubes.    As you can see I have staggered the servo cut-outs, so the raised servo is moved away from the pushrod of the lower servo and there is no conflict any more, so if needed I can screw the horn further down to the torque rod to get more travel.  It all weighs more than the original since there is more metal and wood, but the result is a solid mounting not relying on copper plumbing straps, less friction of the ball races compared to the aluminium rod on the brass tube, no slop of the brass tube in the ballraces compared to the aluminium rod floating in the brass tube, no conflict of the pushrod and servo so better adjustment of the travels, and slightly increased angle of sweep back to make the tailplane roots a better match against the fuselage

Title: Re: Mick Reeves Lightning build
Post by: selleri on February 19, 2011, 19:25:43 PM
Looks ace!    :af
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 06, 2011, 17:00:11 PM
Progress has been slow as I have not had much time with the model, and some of the time has been used trying to solve things I have eventually abandoned.

I spent a lot of time trying to install a brake parachute.  The chute housing doors on the Lightning don't hinge outward but are sliding doors that run upwards on curved rails inside the fuselage and trying to recreate that and fit a release servo was taking a lot of time, plus there is not really any room in the top of the fuz for a cable release mechanism.  In time I may come back to it and try again but for now that idea is abandoned.

I did not like the design of the rudder pushrod, it is hidden and so is "scale" but I did not have much faith in it and have cut into the fin to fit a servo under a hatch with an external pushrod to the rudder, choosing a fast servo to make the most of the gyro.
The aileron pushrod connects in a hidden way to the aileron, but the small horn distance and amount of travel required means either the pushrod connects to the servo almost against the centre post which isn't going to work, or the servo travel is cut to a fraction of the normal range which wastes torque and loses resolution or precision.  So once again i have changed to an external visible horn, each aileron having a pair of carbon fibre horns with an M3 ball link bolted in between them, the length of the horn designed to make perfect use of the servo travel, and once again fast servos to make best use of the gyro.  I continue to use Olivier Nicolas's spreadsheet to determine min torque requirement's and design the control and servo arm lengths.
Finally I did not like the flap horn, same reason as aileron and rudder, also its position is where a normal size servo will not fit into the wing as the box around it formed by ribs, false t/e and wing joiner tube is too small.  the horn is right at the inner end of the flap so I have made a new longer horn half way along the flap where there is room for a servo.
Aileron and flap servos have been mounted on 1/8" ply hatches and I am now sheeting the wing around them.

Wing utlities have to be installed prior to adding the bottom sheeting, as all cables and tubes have to be fed down the wing joiner tubes and can't be easily got at the inner ends of those tubes once the sheeting is done.  I intended fitting the large doors over the main wheels but the wheel and the cranked leg over the wheel are deeper than the wing by quite a bit, so the only way to have a door is for it to be very curved or have a large blister and it would look as bad as having no door, so I have opted for no door, which is a real pity.  I did a final test of the main retratcs with air pipe installed before sheeting over and one had developed a massive leak around the piston outlet so both units came out to be stripped and cleaned yet again.  I have had a serious think about getting the e-retract (formerly LADO) conversion for them but the nosewheel can't be converted as far as I can tell.  I have the main wheel brake optional set but the legs are very long and the added weight of the brake units and their steel disc would be quite a load on the lever arm so for the moment I will try the nosewheel brake.

The main leg oleo scissor links have no limiter, so the open fully when there is no load on the leg, and that locks them open so the leg can't compress on landing.  To solve that I cut a short length of 4mm piano wire, cut a groove in each end with a diamond wheel and soldered it to the inside of the scissor link so it prevents the link closing completely against the leg and locking fully open.  Then I measured the leg spring, determined it was far too soft and calculated the spring rate required and the pre-compression, removed the MR springs and installed new springs of approx the correct rate (vastly stiffer) with a dowel cut to give the correct pre-compression.

I got tube from MR and added it to the inside of the fuselage where the wing joiner tubes come in and bonded them to a large area with glass cloth, so the load from the wing no longer applies itself to a tiny edge of fibreglass but should hopefully be spread well around.

The canopy internal frame is from routed 1/8" liteply, few of whose parts seemed to fit one another and needed a  lot of sanding or adding to, to make fit,  the canopy was then bonded on, and filler applied to make a good seat to the fuselage.

All fuz formers and engine mount are in place now, the reheat rings from Wendler Modellbau have arrived and the next task when wing sheeting is done is to fit the jet pipe and reheat rings.
Title: Re: Mick Reeves Lightning build
Post by: Lee Wilson on September 06, 2011, 18:01:36 PM
great to see an update. Still watching :af
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 15, 2011, 18:54:24 PM
First photo shows the 4mm piano wire bar soldered across the inside of the scissors (is that the correct name?) to prevent them going completely flat and locking.

Second photo shows an adaptation inside the fuz.  The aluminium wing tubes seem to rest only on the very thin edge of the f/g fuz so I added these phenolic stubs with hysol and since the photo was taken they have been backed up with galss cloth to spread the load.  Then I routed a tiny sliver off the hole in the fuz edge so that the tube really does take the primary load and spread it around, rather than the load all appearing at one tiny bit of edge of the f/g skin of the fuz
Title: Re: Mick Reeves Lightning build
Post by: nmacwarbirds on September 15, 2011, 20:35:34 PM
Charlie,
It looks as if you are making progress (slowly), we have the phenolic tube on our Lightning
tied into the formers also, plus we have 1/4 ply plates attached to the inside of the fuz with carbon
the phenolic tube runs through that. Your system does not look quite robust enough, IMHO.

I hope to see your Lightning fly soon.

Regards Phil G.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 15, 2011, 21:48:07 PM
Charlie,
It looks as if you are making progress (slowly), we have the phenolic tube on our Lightning
tied into the formers also, plus we have 1/4 ply plates attached to the inside of the fuz with carbon
the phenolic tube runs through that. Your system does not look quite robust enough, IMHO.

(It's Harry!)
That's interesting Phil because I have been wondering about a single 1/4" ply plate along the fuz going past both the tubes, the F-100 had them and it would be a good load spreader.  What I have done is put a thick coating of g/f wound around the tubes and then spreading out over the fuz to spread the load, but I will have another think about the ply plates.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on October 04, 2011, 22:12:38 PM
I suddenly had a new idea about how to mount and operate the doors for the brake parachute so I have gone ahead and built it and it works.  I had been trying to emulate the full size where the doors are on runners along the inside of the fuselage skin, and though I believe I had worked out a method to do it, it was not easy as it had to be built accurately and built in place which made it difficult to do accurately.  Instead what I designed is doors that are fixed to a pivot point, pulled up by 0.06N/mm springs and held closed by a hatch latch which will be operated by a small servo.  The whole thing can be built outside the model and slides in through the rear lower pipe opening.  The photos should pretty much explain it.  Inside and out is lined with extremely thin plasticard as its shiny side is very low friction.  The box is just big enough, and lined with the low friction plasticard, so the chute drops out under its own weight and doesn't need a spring-loaded ejector mechanism.

The reheat LED rings are larger diameter than the MR scale jet nozzles so I had to make new nozzles a bit bigger and lacking the scale slight taper at the rear end.  I made the new nozzles from MR Proskin.  I started by wrapping 3 layers of 1/16" balsa strips around a lemonade bottle to make 2 rings which gave the correct diameter to then wrap proskin around them and make a nice tight fit for the reheat rings.  See last photo.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on November 11, 2011, 18:59:30 PM
The tailplanes are fixed to the aluminium pivot rod by sliding their brass tube over the pivot rod, and then putting in an M3 bolt through a hole in the brass tube into a threaded hole in the pivot rod.  I did not feel that a mere hole in the brass tube was firm enough to resist any turning on the rod due to slight oversize in the hole, or to prevent slowly eroding the hole to become bigger over time.  I also did not like just one bolt holding the tailplane on.  The first job was to improve the existing hole in the brass tube, by making a deep collar.  I did this with a brass tube of 3mm i/d and a cone of epoxy around it.  Photo shows it before cutting back to almost flush with the surface of the tailplane.  This means that the bolt is in a tube rather than just through a hole in the thickness of the wall of the main brass tube.  Not shown in the photo is the second one I have since installed in a gap between the tailplane and fuselage, having drilled and tapped a second hole in the aluminium pivot rod.  So I have gone from a hole in a brass tube with one bolt, two two bolts in deep tight fitting collars.

Title: Re: Mick Reeves Lightning build
Post by: HarryC on November 11, 2011, 19:15:59 PM
This shows the catch for the brake parachute doors, looking forward from the jet pipes.  It's a standard hatch catch, but mounted on two 1/8" beams to keep it off the fuz.  In the gap, a bit of wire is connected to the finger toggle.  A small amount of the finger toggle sticks out of a slot in the fuz.  The wire connects to a mini servo in the tailplane servo bay.  The system is that the servo only needs to pull, not push on the spring loaded catch so it only needs a wire not a rod.  By having a bit of the finger toggle stick out of the fuz, and being only connected by wire to the servo, the catch can be manually operated such as for closing up the doors when loading the 'chute, without having to have the radio on or operate the servo.

I have two servos to be operated by one switch - the door opening, and the cable release.  Both need to do different things which used to need two channels but by having programmable (Weatronic) rx I can use one Tx channel and put the curves in the rx.  So the door servo has a top hat curve so that when I operate the chute opening switch, the servo pulls the door catch open for a second, then to save it continuing to hold against the powerful spring it goes back to the closed position and by then the doors have sprung wide open and are out of the way.  For those who like such things, photo of the servo rx program shown (I know about screen printing but the rx software is on another pc and i can't be bothered emailing it to myself!)
Title: Re: Mick Reeves Lightning build
Post by: HarryC on November 11, 2011, 19:37:40 PM
The other end of the brake chute is the cable catch, which is above the fuz behind the rudder, in a tube raised slightly out of the fuz.  I made the tube from brass tube, at the back end reinforced by soldering 2 more layers of smaller tube into it.  Two holes were drilled below centre and a piece of piano wire is soldered across the inside.  Further forward, a balsa insert carries a concentric brass tube of much smaller diameter which carries and guides a piano wire driven by a servo.  It's a copy of this idea, which will let you understand how it works http://www.modelmaniacsonline.co.uk/products.php?CatID=430&SubCatID=450&ProductID=5788&Title=Multiplex+Aero-tow+coupling&ManCode=723470. (http://www.modelmaniacsonline.co.uk/products.php?CatID=430&SubCatID=450&ProductID=5788&Title=Multiplex+Aero-tow+coupling&ManCode=723470.)

The fuz at this point has to take the considerable strain of the force from the chute so I have laid up a large mat of carbon cloth inside.

The programming gets more complicated here.  It is vital not to accidentally knock the switch and open the parachute in flight.  I also need to guard against the chute doors breaking open, servo going nuts etc and opening the chute in flight.  Having a switch that allows cable release is fine but by the time you realise what has gone wrong, try and remember which switch it is and fumble for it while trying to control a Lightning that is coming to a halt in the air is not good.  I am going to copy the concept and program that I used on the F-100 and which worked well.  The cable does not need to be attached during the flight, the only time the cable catch needs to close is when I command the chute to open.  So instead of the cable being attached before flight, it is simply held in place in the catch opening.  When I give the command to open the chute doors, the cable servo moves to close the catch and capture the cable.  So if the chute gets out uncommanded in flight, it is not actually attached to the model and falls harmlessly away.  To prevent accidental knocking of the switch, I use the Tx logic commands to require that 4 controls are in the right place in order for the door and cable servos to operate.  The wheels must be down, the throttle at idle, another switch nominated as the chute arming switch put into the ON position, and finally the chute switch moved to ON.  Should I manage somehow to get all 4 like that on finals and thus accidentally open the chute, all I have to do is cancel one of them, such as opening the throttle, and the cable servo immediately releases the cable.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on November 11, 2011, 19:42:38 PM
This shows 1/4" ply reinforcement added to the fuz at each of the wing tube entry points.  The phenolic tube captures the wing tube and spreads the load around itself, it is then bonded into the hole in the ply reinforcement which spreads it out over a big area.  The ply plate is about a foot long and about 4" wide.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on November 11, 2011, 19:56:17 PM
The fin is removeable.  It has a tube installed into the fin moulding which is supposed to go into a brass tube inside the fuz which is held to a former by two copper plumbing straps.  A vertical plate sticks out of the fuz into a slot in the fin and has a screw through the fin into the plate.  A small wire stub at the front of the fin prevents turning.  I felt it would be right to add some more to this plan.  So I installed an aluminium right angle channel piece sticking out of the fuz, tapped for two bolts to hold the fin in place.  At the front rather than the anti-turning stub I installed a second tube right up inside the fin and a mount for it inside the fuz.  Way down at the back of the fin I installed a wire stub to prevent the rear of the fin, where the rudder is applying its force, from twisting.  Photo shows the former with brass pipe and copper straps, and in foreground the pipe I installed to take the additional pipe from the fin.

The second photo shows an additional idea of mine that, starting with the Lightning, will be installed on all my jets.  Its a ply plate high in the spine, with an M3 blind nut in it.  There is a corresponding 3mm hole in the top of the spine.  Why?  It is a video camera mount.  I have had a lot of fun with on-board videos from the key-fob cameras velcroed to my jets, but the velcro has to stay on the model otherwise pulling it off pulls the paint etc, and you can't always velcro in the best spot e.g. as far back in the centre as possible, due to the rounded spine etc.  So I will make a small ply plate with the camera on one side and an M3 bolt on the other, and the bolt just pops through the discrete 3mm hole in the top of the spine and winds into the mount inside.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on November 11, 2011, 20:03:41 PM
This huge block of blue foam is the starting blank for what will end up as an approx 4.2 lire (nearly a gallon!) fuel tank.  More later as it progresses through carving and sealing.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on November 11, 2011, 20:06:39 PM
The top hatch is like it is from a different model, it so barely matches this one.  It is taking a lot, a lot, of work to convert it to something that fits.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on November 11, 2011, 20:20:19 PM
I started by cutting a large amount off the bottom, see photo.  Then because it was twisted along its length (could have been from stuff sitting on it the box, not a manufacturing flaw) I bonded it to a massive flat plate of best 1/4" birch ply.  I then cut out the middle so that the hatch is now on a rectangular ring of ply. Sitting it back on the model showed the model hatch seat is twisted!  This meant cutting open the ply ring at both ends to build a new twist into the hatch to match the fuselage seat.  Then the catches at either end were installed to give a consistent position to the hatch.  I had deliberately cut more than was needed off the bottom of the hatch so that the gap between the ply base and fuz seat could be filled with filler to get a good seat, and that has worked.  The next problem is that with the spine and one flank matching the model, the other flank does not, it is inboard of the fuselage side so now I am building it out with a thick layer of filler along the entire side of the hatch.

Second photo shows the mechanism for the hidden catches.  At front and back of the hatch I have installed standard catches but upside down, so that the finger toggle is inwards, not outwards through a slot in the hatch.  Both are connected by wire to the mechanism seen in photo 2 which is inside of a discreet 3mm hole in the top of the spine.  Pop an allen key through the hole into the socket head bolt inside, twist it and the catches are opened.  The mechanism is a 1/4 lite ply plate, into which is driven a blind nut purely to act as a bearing for the M3 socket head bolt.  At the end of the bolt is the lever arm, which is a servo arm into which I have driven another blind nut by pressing it in with a 100W soldering iron so that its spikes melt down and bond into the servo arm.  The blind nut is then epoxied to the bolt, with a washer and nyloc nut on the inside so that the arm can't come loose from the blind nut and jump off it.
Title: Re: Mick Reeves Lightning build
Post by: beebread on November 25, 2011, 01:34:55 AM
This huge block of blue foam is the starting blank for what will end up as an approx 4.2 lire (nearly a gallon!) fuel tank.  More later as it progresses through carving and sealing.
Where do you obtain blocks of blue foam from?
Title: Re: Mick Reeves Lightning build
Post by: HarryC on November 25, 2011, 08:02:28 AM
Where do you obtain blocks of blue foam from?
I got a large sheet about 2" thick from an ebay shop
Title: Re: Mick Reeves Lightning build
Post by: FlyinBrian on October 13, 2012, 17:31:26 PM
Harry

Have you given up on this???
Title: Re: Mick Reeves Lightning build
Post by: HarryC on October 22, 2012, 16:37:42 PM
Harry

Have you given up on this???
No, I just don't come here any more Brian.  Some friends told me about your question.  The Lightning should be ready to fly in 2 or 3 weeks.  It has been "challenging" to build it.
Title: Re: Mick Reeves Lightning build
Post by: nmacwarbirds on October 28, 2012, 11:18:18 AM
Harry,
Yes the Lightning is a bit of a challenge to build,
but I can assure you that once you have flown it
that will all be forgotten.

Regards Phil G.
Title: Re: Mick Reeves Lightning build
Post by: Chris Channon on February 13, 2013, 16:56:17 PM
Has the Lightning flown yet ?
Regards
Chris.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on February 14, 2013, 09:03:56 AM
Not yet, awaiting tolerable weather.
H.
Title: Re: Mick Reeves Lightning build
Post by: Vinceyboy on February 14, 2013, 10:02:43 AM
No, I just don't come here any more Brian.

No this forum has died in recent times, probably due to the awful weather we've had over the last nine months, curtailing a lot of flying, plus the the state of the country's economy has tightened peoples pockets, so expensive toys are the first to go :'( apart from the few lucky people who have good jobs and surplus funds but I think Mr. average is calling it a day at the moment, judging by the the amount of stuff that is being sold, and at bargain prices too, maybe if we get a good summer it may all pick up a bit, and although the jet side of the hobby has seen some introduction of lower priced turbines and cheaper UK kits coming onto the market, which helps lower income modelers get into the wonderful side of turbine models, so roll on HOT summer weather :af
Title: Re: Mick Reeves Lightning build
Post by: warbird_fanatic on February 14, 2013, 14:45:00 PM
Couldn't agree more Vince! Everything is soo quiet at the moment, I've spent a lot of time jotting down ideas for new projects while the weather is rubbish. Just waiting for a spot of sun, if not then I want to move to Florida if only I could afford the move.......

Sent from my GT-N7000 using Tapatalk 2
Title: Re: Mick Reeves Lightning build
Post by: HarryC on April 06, 2013, 20:20:46 PM
I flew the Lightning today, two flights, quite tricky handling but should improve much as I work on the settings.
Title: Re: Mick Reeves Lightning build
Post by: STORM on April 06, 2013, 21:07:27 PM
Congrats Harry, well done.
Title: Re: Mick Reeves Lightning build
Post by: Lee Wilson on April 06, 2013, 21:16:18 PM
That's great to hear she's flown. Any pics of the completed model please?
Title: Re: Mick Reeves Lightning build
Post by: selleri on April 06, 2013, 23:52:06 PM
Good news mate!   :af
Title: Re: Mick Reeves Lightning build
Post by: HarryC on April 07, 2013, 08:41:46 AM
Thanks to Dick Spreadbury for the photo
[attachimg=1]
Title: Re: Mick Reeves Lightning build
Post by: rcfanuk on April 07, 2013, 15:34:34 PM
Great news Harry, looks very nice, more pics please  :af


Steve
Title: Re: Mick Reeves Lightning build
Post by: Lee Wilson on April 07, 2013, 15:36:44 PM
That looks great Harry, go to be the best aircraft ever built (in my opinion!)
Title: Re: Mick Reeves Lightning build
Post by: JohnMac on April 07, 2013, 18:21:14 PM
Well done Harry. It has been a labour of love I guess. Please tell us more about the handling?
John
Title: Re: Mick Reeves Lightning build
Post by: HarryC on April 08, 2013, 09:06:39 AM
Well done Harry. It has been a labour of love I guess. Please tell us more about the handling?
John
I used known settings from other people's Lightnings, but mine was very lively!  A bit too much aileron response even with a lot of expo, and way too much elevator response, so final approach was a continuous series of PIOs.  The good news was that as it got slower and slower at the top of each successive oscillation, it showed no sign of tip stalling or of stalling at modest speeds. CG would seem to be the culprit but when I retracted the wheels for the first time, on the second flight, it shifts the CG further back and makes a pronounced trim change so i was ready to flick the wheels down again if it became too unstable but it was no different. Perhaps with the redesign I did of the tailplane mount and control rods I have got a sharper response?  Who knows.  My first mods will be to keep turning the travels down as I am using Phil Goff's balance point so we know that works in the long term and the retract situtation showed it is not at a critically rearward position.
Title: Re: Mick Reeves Lightning build
Post by: nmacwarbirds on April 08, 2013, 11:49:28 AM
Good effort Harry, I am glad to hear that you have
Successfully flown the Lightning. The Lightning can seem
Like a beast when you first fly it but you will get used to it.
I use no gyros or expo on any of the models that I fly
So I am used to fairly sensitive controls, so it is gently, gently
On the controls, remember you are flying a very agile aircraft.

I take it you noticed the quite pronounced pitch trim changes
With regard to throttle settings, I use no mixes to counter that
 Instead I trim it to fly level in a nice cruise which is just under
3/4 throttle.

Having said all of this you have done the hard part,
And got yours built and flying, so we'll done that man.

I had an email from Ian W. The other day informing me that there is another MR Lightning nearing completion, how good would it be
To have four Lightnings in the air together?

What are you doing on the 5th of July?

Regards Phil G.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on April 08, 2013, 14:04:14 PM
I had an email from Ian W. The other day informing me that there is another MR Lightning nearing completion, how good would it be
To have four Lightnings in the air together?

What are you doing on the 5th of July?

Regards Phil G.
The other one was successfuly maidened the day after mine, and Mark Handley's should be ready soon. That will give 5 Lightnings!  6 if you can persuade Ian Stevens to join in!
What's on 5 July?  I tend not to go far to get toanything, due to the cost of my 30mpg petrol guzzler. I wondered about the jets over wittering meet but the £50 cost of petrol put me off.
Title: Re: Mick Reeves Lightning build
Post by: nmacwarbirds on April 08, 2013, 15:24:50 PM
Dear Harry
Excellent news regarding all these new Lightnings that are appearing on the scene.
I have an event at Tibenham Airfield Norfolk NR16 1NT on Friday the 5th of July.
Three tarmac runways in various direction, Clubhouse, food, bar, Caravan/Camping etc.
Dakota and Sea King flypasts.

I am hoping Ian W. will be able to make it with his Hunter and Lightning.
It would also be nice to see Phil H's Hunter.

You would be made very welcome as are all the attendees.

Regards Phil G.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on April 08, 2013, 15:45:52 PM
I have an event at Tibenham Airfield Norfolk NR16 1NT on Friday the 5th of July.
Sorry Phil, that's a 7 hour round trip, £80 petrol from where I live.
Title: Re: Mick Reeves Lightning build
Post by: Craig G on April 08, 2013, 16:51:19 PM
Hello chaps, great to see some activity here again and some more Lightnings being completed. I have been sitting on my kit for a few years now and hope to start work on it soon. Not sure how many of them made it to the states but imagine only a handful.

Is everybody happy with the MR retract assemblies? They are the only major component I'm lacking. Is there some magic to the mains that allows the wheels to lay flat in the wing when retracted?

Cheers,

Craig
Title: Re: Mick Reeves Lightning build
Post by: HarryC on April 09, 2013, 09:34:57 AM
Is everybody happy with the MR retract assemblies? They are the only major component I'm lacking. Is there some magic to the mains that allows the wheels to lay flat in the wing when retracted?

There are 2 separate items to consider Craig, the retracts and the oleo legs.

You are right in thinking it must be a twist and turn for the wheel to lie flat in the wing.  It is not a standard 90 degree twist and turn as the leg does not retract back at 90 degrees but at the angle of the wing sweep which iirc is around 60 degrees so that is the amount of twist required. This prevents you from using third party standard 90 degree twist and turn e.g. robart.

The MR main oleo legs are free to rotate around the pin that clamps into the retract. A link connects the leg to the ply retract mounting plate and this link then fixes the rotation angle of the leg, causing it to rotate the necessary amount as the leg retracts. It will be difficult, any other way, to get the correct rotation so for that reason plus the special scaleish shape of the main and nose legs I would get the MR legs.  In my opinion the main leg springs are too weak and I replaced them with stronger ones (otherwise the model compresses the oleo fully so there is no suspension) and also a stop needs to be fabricated and attached to the scissors to prevent the leg opening fully when unloaded, otherwise the scissors go straight and they lock the leg from working when you land!  Robart oleos use a little tab welded behind one of the scissors, I soldered a bit of piano wire across one of the scissors so it hits the leg and stops the scissor opening fully. If I were to build another MR Lightning I would not hesitate to buy MRís legs, they need a little modifying but it is easy and quick.  I am not aware of anything else available that would do the job even with a lot of modifying.

MR retracts for the Lightning are crude, but afaik, long term users such as nmacwarbirds and Ian Wilde have not had a failure yet. Maybe nmacwarbirds will confirm?  At first glance they are easily replaced by any other brand but hold on!  None of them are 90 degree retracts!  The main retracts are a bit more, I havenít measured them but maybe 95 to 100 degrees. They have to be because of the various mounting angles, a 90 degree retract would have the legs splayed outwards instead of straight down.  The nose retract is a lot more than 90 degrees, I have not measured it but perhaps 110 to 120 degrees, to get the wheel on the trailing link leg up inside the front fuselage which is curving upwards away from the retract.  So if you want to get alternative retracts you need to bear in mind the need for very special angles.  If you do get the MR retracts, take them apart, clean them, polish out all the scratches from the pushrod that passes through the O ring seal on the end of the cylinder (yep, I really had to do that!), dribble thin cyano around the nipples to seal them to the cylinder (I had to do that too to stop the leaks), refill with lots of silicon oil, do leak testing under water, etc etc.  Having said that, I leak test every retract I get even the best brands, and sometimes I have found many leaks and bits of swarf scoring the moving parts on what should be good brands!
Title: Re: Mick Reeves Lightning build
Post by: HarryC on April 09, 2013, 10:36:09 AM
Craig, if you do start building it, let me know and I will list all the structural modifications I made, for you to consider if you want to make them as well.
Title: Re: Mick Reeves Lightning build
Post by: nmacwarbirds on April 09, 2013, 11:47:33 AM
I can confirm the MR retracts are still working fine,
Touch wood.

Harry, I read in a previous post that you were concerned
About the cg moving too far aft.

I take it you balanced the Lightning in the worst case scenario
With the wheels up and with the nose very slightly down?

Regards Phil G.
Title: Re: Mick Reeves Lightning build
Post by: Craig G on April 09, 2013, 14:08:34 PM
Thank you Harry and Phil. That puts an end to my fretting about the gear and wondering if I could make some off-the-shelf Robarts work. I shall get a set from Mick.

Craig
Title: Re: Mick Reeves Lightning build
Post by: HarryC on April 09, 2013, 15:00:09 PM
I take it you balanced the Lightning in the worst case scenario
With the wheels up and with the nose very slightly down?
Bearing in mind the effect the wheels have on CG, I contacted MR and Jim told me it is balanced with the wheels down, and that it is very tolerant of the CG position.  I balanced mine to the CG you stated on rcmf some time ago, iirc 5/8" back from the MR position, with a bit of fuel in the tank because my custom tank is shaped so the rear part which is behind the CG deepens down into the belly tank.

Possible causes of the wild ride on final approach:
1. CG too far back.  It is very sensitive in flight but not uncontrollable and when wheels were retracted backwards it got no worse, so the CG is not near a critical point.
2. Elevator travel too much.  I am using known working travels from others but will turn mine down bit by bit and see what happens.
3. Flap effect. My Skyhawk behaved the same on finals but when I tried it flapless it was perfect. However since others are using the flaps and not getting this effect, I think it can be discounted.
4. Aileron mixing.  MR's instructions say mix 10% aileron with elevator so I did, but just on up elevator.  I will now remove that since the tailplanes don't need any help!
5. Fuel sloshing about in the 1 gallon tank.  It might be, I did not fit any baffles, tank is on the CG so fuel movement though heavy should have little leverage.

For the moment, removing the aileron mix and turning down the ele travels will be the main focus.
Title: Re: Mick Reeves Lightning build
Post by: JohnMac on April 09, 2013, 17:03:32 PM
It sounds tail heavy to me Harry. Item No.1 on your list will give you the effect of number 2. It is good to know that it does not want to depart, but then it should behave like a delta (albeit with a tail).

Now I am going to ask a really stupid question here Harry, and forgive me, but I am the stupid clot that made this mistake - Your expo is working in the correct sense isn't it?
Been there, done that. :embarassed:
John
Title: Re: Mick Reeves Lightning build
Post by: HarryC on April 12, 2013, 16:00:05 PM
It sounds tail heavy to me Harry. Item No.1 on your list will give you the effect of number 2. It is good to know that it does not want to depart, but then it should behave like a delta (albeit with a tail).

Now I am going to ask a really stupid question here Harry, and forgive me, but I am the stupid clot that made this mistake - Your expo is working in the correct sense isn't it?
Been there, done that. :embarassed:
John
It does sound tail heavy John, but I am using nmacwarbirds CG point, MR said it is tolerant of wide range of CG, and when the wheels were retracted it shifts the CG back quite a bit, lot of trim change, but it became no more twitchy. it wasn't too bad in flight, just sensitive, it was on finals that it started to PIO.  My Skyhawk did that and it wasn't CG or travel, turned out to be flaps blanking the tailplane. For the Lightning it might be a combo of fuel sloshing about and the marked nose up trim change as I cut the power to idle. Plenty to investigate.

It's a sensible question about expo, since you know I use a Tx that allows it both ways.  Double checked, and expo is in correct direction.

I am currently working my way through a list of 17 items to be corrected or tweaked prior to its next outing, thanks to British weather it won't be this weekend.  >:(
Title: Re: Mick Reeves Lightning build
Post by: nmacwarbirds on April 12, 2013, 21:08:57 PM
Harry,
Just to be on the safe side, I would bring the cg forward if I
Were you.

Regards Phil G.
Title: Re: Mick Reeves Lightning build
Post by: JohnMac on April 13, 2013, 09:01:18 AM
Hi Harry,
I would agree with Phil. By the sound of it you have more than enough elevator control so you can afford to sacrfice a bit and move the CG forward to calm it down in at least two axis. You should still have plenty of elevator left for the flare.
BTW do you tink it is showing tendencies to be directionally unstable as well?
It sounds like you have a good deal of head scrathing to do. Good luck and watching with interest.
John
Title: Re: Mick Reeves Lightning build
Post by: HarryC on April 17, 2013, 13:23:42 PM
It didn't seem directionally unstable John.  Directional stability meaning the yaw axis.  However it did wag its tail quite a bit in some not all turns but I get this on most swept wing jets.  The wag was slow but quite large whereas planes like my Trim Sabre have rapid but small fishtailing in some turns.  I have yaw and roll gyros fitted but no time to turn the gain on yet, that will come on the next session.  All 17 items that arose from those 2 flights have been dealt with and I look forward to another day of suitable weather and really getting it tuned in.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on April 17, 2013, 13:42:26 PM
I take it you noticed the quite pronounced pitch trim changes
I certainly did Phil.  Ian Wilde had warned me of the trim workload in the circuit so I had planned for it.  First flight left the wheels down so no trim change from them, tested flaps stage 1 and 2 at height which showed no trim stage 1 but marked nose up at stage 2 so I landed with stage 1 flap.  Having throttle back to about 1/2 shortly after take off and staying thereabouts until cutting to idle on short finals I didn't encounter the throttle trim change but it may account for, or play a part in the porpoising on short finals.
My good old Tx still has mechanical trims so I re-centred the elevator trim before the second flight, then at safe height put the wheels up, noted the marked nose up, trimmed down to level it and asked my spotter to note where the trim lever was for reference later.  Then when ready to put the wheels down I just had to pull the trim back to the centre notch to be trimmed again, used stage 1 flap so no trim change, but again on short final got the porpoising again from about the time I closed the throttle.  Lots to investigate there at safe height on the next session.

Since my spotter had noted the amount of trim required for wheels up I have programmed a trim change to coincide with the wheels travelling, and programmed a guess at the trim required for stage 2 flap.  I have enabled but left at zero a throttle to ele trim compensation as I want to test the coupling in the raw and see what level of trim change it causes at various speeds.  I guess that slamming to full power at low speed is the worst case but as I did that on a go around on the second flight and wasn't aware of any drama or problems as the thrust banged in, it doesn't seem to be a major problem.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on May 03, 2013, 09:31:52 AM
I had 6 flights of the Lightning yesterday, all was going well until the end when a brand new problem emerged which may take some tracking down.

By moving the Cg forward a bit and reducing elevator throw, the approach and landing settled down, requiring full back stick for touchdown.  Touchdowns were gentle.

I had to turn down the aileron travel to a much lower amount and use over 70% expo to get the roll to settle.  Then I brought in the aileron gyro to stop the wobble, and after more adjustments to the fade-out and expo, by the 4th flight of the day the handling was quite tolerable and it looked smooth in the air.

On the 5th and 6th flights there was an intermittent problem with pitch.  Nothing is broken or loose to explain the sudden pitch problems so I have a mountain of telemetry data to sift through to try and work out what has happened.

However Lightning came home with no damage other than a shaving off the ventral fin, and much kero was burned.
Title: Re: Mick Reeves Lightning build
Post by: STORM on May 03, 2013, 12:06:41 PM
Nice one Harry. :af
Title: Re: Mick Reeves Lightning build
Post by: HarryC on August 20, 2013, 09:38:14 AM
A poor combination of my availability and suitable weather means I have still not flown the Lightning again. I have now completed the nose doors, having decided to use servos rather than air rams for a change.  The two front nose doors are servo driven and the rear nose door is linked to the noseleg.  It took quite a bit of experimenting with the link geometry and home-made hinges to get it to work but it does work now, on the bench at least.  Itís always different when flying, undercarriages and doors that work fine on the bench go haywire when the structure is loaded and air is blowing over the parts.  It will be interesting to see if the noseleg retract can pull the door forward and shut against the airflow.  The full size had a very low speed limit of just 250kts to get the noseleg up otherwise it wouldnít close and at the rate the Lightning gained speed it meant the pilot had to be on the retract switch the moment the plane broke ground.  I will get around to fitting doors to the main legs but that will be for some later date.

With the fuselage structure now complete I have started to add the metal skin.  This is Mick Reeves metal coat, similar to flite metal, itís a thin aluminium foil with an adhesive backing.  I read flite metalís site, lots of rcu threads, and watched youtube videos of how to apply this stuff but it still got very close to me deciding to paint it instead.  Everyone has a different way of doing it and none of them worked for me.  Laying it down is not difficult, but making it look real is difficult.  As it is applied it looks like shiny chrome tape, not a metal panel. The glue is not utterly flat so the surface of the foil takes on a slightly orange peel effect whereas real metal panels are flat.  Scuffing with scotchbrite pads as one youtuber says just did not look right to me, it is much too scratchy.  Rubbing it down with coarse then finer wet or drys did not look right either as it removes the orange peel but creates a new problem, the surface looks like coarse pewter with tiny ridges and valleys along the direction of sanding.  Itís possible that the sanding action is heating up tiny particles of aluminium enough to melt them back to the surface much as happens if you try to use a permagrit or stone router in the dremel on aluminium.  Also the grits suggested by youtubers score and pit the tape so deeply that they canít be rubbed out.

I did the tailplanes first and got a reasonable effect but not good enough, and the single rib inside the moulded structure shows as it affects the rub down pattern.  I will accept them for now but at some stage later I will remove it and do them again.  Removing the foil is not quick, it takes longer than applying it, the glue is very strong and when rubbed down the foil is almost gold leaf thin so it just tears into little strips.

What did amaze me is how light it can be.  The roll of foil weighs like a lead pipe and I was really worried about the weight it will add, but when rubbed down, each tailplane weighed just 8 grams more!

Experimenting with the top hatch and about to throw the foil away and get out the spraygun, I found something that really worked well Ė 3M ultra-fine pads. These left a smooth sheet metal surface with no scoring, pitting or the pewter effect.  So then I tried some micro-mesh left over from when I metalled my F-86, and that also worked well.  I have ordered plenty new micro-mesh and decided to carry on with the foil rather than paint.

How do you get a 2D sheet to conform to a 3D compound curve or sphere such as the tailplane fairings or the under-belly fuel tank?  Well it canít unless it deforms and to my amazement the foil can be stretched a long way by clever use of the compressed paper pencil that is used to press the foil down. The entire fuz will be metalled, and only then will it be rubbed down, so for a while it will look very chrome.

I have learned a lot about applying metal foil in the last few days. It requires just the right tools used in just the right way, thereís a good reason why so few models are covered this way Ė itís a lot of work and it can go horribly wrong just at the end of a lot of work, but when it is done right it is very convincing and real.

First photo shows general progress so far including the complex shape of the fairings that the foil coped with, second photo shows two panels applied to the belly tank, see how each panel can go from one side to the other in one piece despite the compound curve.  Photos are not very good, sorry, it's hard to capture shiny metal on camera.
Title: Re: Mick Reeves Lightning build
Post by: THE BLACKBIRD on September 06, 2013, 20:11:14 PM
Hi im new to the forum and have just read this thread all the way through, I was going to buy the MR Lightning but with all that this thread has shown to be wrong with the kit I don't think ill bother now
Seems very expensive for the trouble you get
Lovely build Harry
Thank you
Tony
Title: Re: Mick Reeves Lightning build
Post by: Craig G on September 06, 2013, 20:17:49 PM
None of the problems are insurmountable, and some are more of a builder's choice than genuine issue. In my opinion well worth the money.
Title: Re: Mick Reeves Lightning build
Post by: THE BLACKBIRD on September 06, 2013, 21:12:04 PM
I Craig I see you have the Lightning kit, do you have any issues with it such as the hatch that fits nowhere, that for one thing should never be sold as is, and copper plumbing clips to hold the tail plane is nothing short of crude
But I do like the Lightning and it fly's well and looks good
Title: Re: Mick Reeves Lightning build
Post by: Craig G on September 06, 2013, 21:21:48 PM
Yes, my hatch fit and for that matter the fuse-half mating is not spectacular. Ideally these would need little to no work but I'm ok making the adjustments. Still haven't decided if the copper straps will stay. Crude they may be but with balanced stabilators I think they're up to the task.

CG
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 07, 2013, 06:01:11 AM
The Lightning is fine if you regard it as a basic outline onto which you apply your thoughts on model structures at every step. If you just assemble it as it is, it will not last long imo.
The choices are: Airworld lightning which is very big; design your own; MR Lightning which is reasonable size. If I was to build another Lightning I would get another MR without hesitation especially as I now know even more mods I would make!
Title: Re: Mick Reeves Lightning build
Post by: THE BLACKBIRD on September 07, 2013, 08:13:14 AM
Thats an interesting statement Harry that you would buy another one, cheered me up a bit because I was looking forward to getting one until I read your thread.
I have just scratch built a hunter for a Jetcat 100rx, the Shane Harding one fly's very well and thought I would do the lightning next for the same turbine as I have two do you think a 100 rx is big enough
Tony
Title: Re: Mick Reeves Lightning build
Post by: HarryC on September 07, 2013, 14:01:29 PM
I can't say if 100 is enough. Mine needs much more but it has the weight of extra strength and extra systems like the retract emergency blow down system, big and sturdy fuel tank, brake chute, main wheel brakes etc. It is a big model.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on June 16, 2014, 09:19:32 AM
Hooray, I can at last report a good flying session yesterday with the Lightning, no real problems, decent handling, low-ish passes and doing its first vertical aerobatics - 1/2 cubans, and a loop.  Also getting the hang of turning it - it's like my Typhoon it needs a lot of back pressure to crank it round rather than be gentle and end up with massive radius turns ( both have similar highly swept delta wings, the Lightning has cut outs at the t/e root!).  On flight #1 I was shaking, by flight #3 I was enjoying it.

There is plenty still to be done to get it just right for me but now it is just fine tuning, the fundamentals are all good.

Shocked that it is 13 months since I last flew it and had all those problems.  It took a while to work out what I think might have been the cause of the pitch control doing its own thing, sorting that was fairly easy and since the problem has gone it seems to be right.  Took a guess that even with the clearance I had given it, the tailplane roots were starting to jam against the fuselage as high speed airflow flexes the mechanism backwards.  It took a very hard pull back on the tailplanes to get them to jam but it was just possible, and since Colin Straus lost his RCJI mag review model to the tails jamming I had left what I thought was a decent gap.  So I removed even more root from the tailplanes and left a big gap, also fitted yet more powerful servos.  Yesterday the pitch control was fault-free.  CG is bang on MR's instructions, pitch is still a bit sensitive but can be easily adjusted now.  Roll rate is now spot on, gyro gain needs increasing and I can work gradually on that.  There was no visible fishtailing so I have not yet felt any need to bring in the rudder gyro.  Ground steering is poor, it is sensitive but never centers so it wanders left or right.  Start of take off run has to be at 1/2 power to keep steering control until the fin has enough airflow to stabilise the yaw then full power can be hit.  The flickering reheat lights work well.

A major mod I made recently was to replace the MR retracts with custom made retracts from Premier retracts
http://kingfisher-aviation.com/premier-retracts/ (http://kingfisher-aviation.com/premier-retracts/)
He made me the 3 units to the special retract angles and matched the low profiles and the mounting holes dimensions for a price I think was very good value so he will be my first choice for all retracts from now.  The cylinders are a considerably larger diameter than the MR units so they have no problem getting the wheels down against the airflow.  However the units are longer overall so I had to open up the wing and dremel out some holes in ribs to get them in.

I gave up with the MR metal coat, I can lay it down well but I found it too thin to sand it down flat, it would wrinkle and tear, so what I had laid down had to be removed and that takes forever to do.  Steve Elias gave me a piece of real Flite-metal to try and it worked a dream (it's quite a bit thicker) so I ordered a shed load of it from the USA ( http://www.flitemetal.com/ (http://www.flitemetal.com/) ).  So far I have done the tailplanes and they look really good, now with successful flying of the model I will crack on and metal the rest of it
Title: Re: Mick Reeves Lightning build
Post by: STORM on June 16, 2014, 15:51:21 PM
 :af
Title: Re: Mick Reeves Lightning build
Post by: JohnMac on June 16, 2014, 17:15:46 PM
I must say that is good to hear Harry. When (if) I ever get around to my AW F2a I will cover it in flight metal, but I may do my FEJ Sabre in it first. Having seen a few models covered this way, it is the only realistic way of doing a nataural aluminium aircraft.
Keep us posted.
John
Title: Re: Mick Reeves Lightning build
Post by: HarryC on July 20, 2014, 09:45:34 AM
The front half of the fuz is now flite metalled as photo,  back half is partly done.  The aluminium sheet can be  carefully coaxed out thinner and longer to form around compound curves or down into the figure of 8 at the back end.
lots more to do still. It has to be sanded flat and smooth, it is aluminium so that takes some doing over a large area!
Title: Re: Mick Reeves Lightning build
Post by: STORM on July 20, 2014, 10:13:31 AM
Looking good mate. ;)
Title: Re: Mick Reeves Lightning build
Post by: JohnMac on July 20, 2014, 16:18:18 PM
Nice Harry!
Title: Re: Mick Reeves Lightning build
Post by: selleri on July 24, 2014, 03:45:54 AM
Very nice mate!  :af
Title: Re: Mick Reeves Lightning build
Post by: HarryC on October 21, 2014, 08:43:54 AM
I will have the Lightning on display at the LMA Gaydon show this Sunday.
The aluminium plating is complete (what a lot of work that was!) and I am hurriedly applying paint and decals to have it looking mostly complete for the show.
Title: Re: Mick Reeves Lightning build
Post by: STORM on October 21, 2014, 12:37:00 PM
Well done Harry, looking forward to seeing it.  :af
Title: Re: Mick Reeves Lightning build
Post by: HarryC on October 26, 2014, 15:08:00 PM
At LMA Gaydon
Title: Re: Mick Reeves Lightning build
Post by: Thorjet on October 26, 2014, 16:39:23 PM
Absolutely outstanding work Harry, worth every hour spent on her!

Stunning model  :uk:
Title: Re: Mick Reeves Lightning build
Post by: trebor on October 26, 2014, 16:43:03 PM
Looks fantastic Harry, looking forward to seeing it in the air.

Rob
Title: Re: Mick Reeves Lightning build
Post by: RGN on October 26, 2014, 19:48:20 PM
I saw it at Gaydon, too - agree with the comments above. This is a stunning model!

Richard
Title: Re: Mick Reeves Lightning build
Post by: Plain ol' Puppers on October 26, 2014, 19:51:37 PM
I saw it at Gaydon, too - agree with the comments above. This is a stunning model!

Me too, very nice indeed  :af

Alan
Title: Re: Mick Reeves Lightning build
Post by: STORM on October 26, 2014, 20:46:48 PM
Looks great in flesh Harry, good job, well done mate!
Title: Re: Mick Reeves Lightning build
Post by: HarryC on May 30, 2015, 23:14:12 PM
Was out flying the Lightning today, looks fantastic in natural light though a bit dazzling in direct sun!  Should have some photos of it flying soon.
Title: Re: Mick Reeves Lightning build
Post by: HarryC on May 31, 2015, 05:01:12 AM
Photos courtesy of Dick Spreadbury
Title: Re: Mick Reeves Lightning build
Post by: jetster on May 31, 2015, 06:28:00 AM
Spectacular model Harry, quite an achievement.
Title: Re: Mick Reeves Lightning build
Post by: THE BLACKBIRD on August 04, 2015, 23:08:08 PM
Enjoyed your article in the RCJI Harry
It really is a beautiful model,
Title: Re: Mick Reeves Lightning build
Post by: HarryC on August 11, 2015, 10:10:34 AM
I have just completed converting the Lightning over to my new Jeti radio and had a glorious day with it at the weekend, getting it tuned back in to my preferences.  The Weatronic radio that came out had gyros built in, so I had to add in an ACT Fuzzy Pro gyro for the ailerons.  First flight with the Jeti was done with gyro off while I learned how it behaved and what fundamental changes I wanted to the settings in the Jeti, and it was squirrely, jittery, and uncomfortable.  On the second flight I turned on the aileron gyro and immediately had a pleasant handling model.  Making passes along the runway then turning away as I pass the pilots' box and lighting the 'burners for full effect looks so good!  Even the brake parachute managed to work perfectly on one landing and that looks great.

One of the big reasons I chose Weatronic and then Jeti is because I have a thing for metal clad jets which have the potential to give 2.4G signals a hard time.  I don't think the Wea or Jeti are any better at getting the signal to the model than any other brand, what they offer me is data recording and real time numbers to let me know how well the rx are picking up the signal and therefore to really understand how close the model is to the edge of reception.  I especially like the feature on the Jeti where I flick a switch and it speaks out the lowest two antenna readings to me, I do that when the model is at its farthest from me so I get to learn immediately if the metal coating is causing me real dangers, or if the signal is fine.  After landing I can also bring up a graph on the tx screen of the rssi for each of the 4 aerials, and LQI for each of the two rx, of the entire flight to see if there were any momentary drop outs.  I am very pleased to see that the numbers and graphs are pretty much identical to my non-metalled jets.  One pair of aerials is in the blue spine outside the metal coating, and the other pair are at the bottom of the fuselage at a patch painted with humbrol silver instead of being metal clad.


Title: Re: Mick Reeves Lightning build
Post by: STORM on August 12, 2015, 08:45:03 AM
I knew you'd like it, best money I ever spent!