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Mick Reeves Hunter kit build

Started by Turbine Tinkerer, December 06, 2013, 22:47:51 pm

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Turbine Tinkerer

I started a Mick Reeves Hunter kit last year but didn't get much done I hope to get back on it soon and see it through to completion.  Anyone interested in a build log? There's already a few about on the Internet.

Pup Cam

Still distracted by a 1953 AJS 16MS and now a 1939 BSA 250 too!

The Saint. (Owen)

Electrickery is the work of the devil.
Proper aeroplanes are powered by engines.

Saxon


Turbine Tinkerer

I'm going to finish my Reaper first (4 years in the build!) Then I'm going to get back on the Hunter. Hopefully doing a build thread will give me some enthusiasm to finish it!!

Turbine Tinkerer

Finally dug the Hunter out this evening and it dawned on me it's quite a big build! 

Anyway work on the fuz so far formers in the nose are in. Going to get the rest of the formers in next I think.  Last year I got messing around with the gear doors and gave up so going to concentrate on the main parts of the build and worry about the details later

Turbine Tinkerer

A bit more time on the hunter this evening and I think I'm going to put the large former in the fuz next that the wing tubes mount onto.  I think this is fairly critical in it's location as moving this fore and aft changes the angle of the wing tubes coming out the fuz sides. The wings are framed up but I think I might add the top skin to them first to tie in the end ribs to get a good fit on the fuz sides. It all seems like a bit of guess work at the moment.

Turbine Tinkerer

Work on skinning the wings continued today. It's my first foray in using proskin and so far so good. Cut the skin roughly to shape and then weight down with steel bars on to the ribs. Just the leading edge needing a extra help with some clamps


THE BLACKBIRD

Hi TT I used pro-skin on my hunter and I thought it was very good,
looking good


Tony
The man that never made a mistake
Never made anything

Turbine Tinkerer

I'm liking it so far, once its on it's pretty much done but I am planning on glassing ove the leading edge

Turbine Tinkerer

Managed to get the top skin of the other wing on today and spent a little time trimming the excess skin at the wing/fuselage join.

Decided to carry on with with the wings and make a start on the flaps next. These are thin!! About 6mm at the thickest part. A skin of proskin and balsa ribs/leading edge then another skin of proskin when it's finished.

Turbine Tinkerer

Got the second skin on the flaps and made a start on the ailerons today. The flaps have worked out well with the pro skin. Very thin and stiff With a dead straight leading and training edge.

The ailerons are hinged with two robart 3/16 diameter hinges. These are mounted in the extra wide ribs. Not sure whether to add one or two more of these for peace of mind??

Turbine Tinkerer

Decided to make provision for a third hinge in the centre of the aileron.

Also made a extra horn from glass fibre sheet so the ball joint can be mounted in the middle of them.

HarryC

TT, I made similar changes to my MR Lightning such as more and beefier hinges, double horns with ball joint bolted between them and so on. I also greatly extended the aileron and flap horns so instead of being hidden for scale, they stick way out but if done as per MR the Tx travel value would have been about 30% which is mechanically awful. My feeling is that you should not simply build as per MR  but question everything and redesign it to a standard that you feel safe with.

PhilH

Looking good Terry.  When I built mine the biggest battle was getting things to fit, plus a number of modifications thrown in for good measure.  Persevere and she will build into a nice model.
On the ailerons I fitted three Robart hinges as well.  Also used the hinge pockets fitted to the trailing edge which made fitting and removal of the aileron easy.  If you don't then you end up with sloppy holes after the numerous fitting and removal, and tube will be needed to support the hinge from the trailing edge.
Fitting the aileron is easy without the lower skin fitted, but due to the hinge line and the adjacent skin angles when the lower wing is skinned it makes it almost impossible without excessive bending of the hinges.  I made a section of the lower skin as a removable panel to make life easier.
The push rod attachments I also doubled up to sandwich the ball link.  Used the same length as the supplied horns which puts it at 15mm plus from the centre of the hinge, and with 10mm out on the servo gives plenty of mechanical advantage to work with.  Used an 8411 to drive it and even with a reduction to 70% on the ATV there is plenty of grunt to spare.
Have fun keep up the good work.

Phil

Turbine Tinkerer

Thanks for the words of encouragement.


Did you keep to Micks original hinge locations and add a third in the middle of them? That's what I've done on the one I've done and it then has quite a overhang towards to tip. Undecided at the moment weather to change the outer 2 outer locations so they are fairly equally spaced along the aileron or to add a fourth hinge towards the tip so I have 4 hinges fairly well spaced along??

PhilH

Used the two original locations and added the third in the middle.  It may appear to be a large section un-supported but it is very rigid at that set up.

Turbine Tinkerer

Agreed Phil, I think a fourth hinge at the tip will be overkill.

My horns will put the link 20mm from the hinge centre line that should be sufficient on the aileron.

Which part of the lower skin did you make removable? The 'triangle' between the flap and aileron? And what do you mean by a 'tube' I see the pockets are just kind of in thin air but I was thinking of putting some balsa blocks in to mount the pockets into.

Little progress today, brought both the ailerons up to speed with the third hinge and vpoxied the horns in place. Hopefully tomorrow I will be able to add the second skin to them as long as I'm not suffering to much from barrel fever!

Turbine Tinkerer

Decided to add a carbon spar to stiffen up the thin trailing edge above the flap. Looks to have done the trick and I now have a dead straight trailing edge

PhilH

If it works then there should be a couple of pictures as to the removable panel for aileron fitting & removal.

I used the Robart hinge pockets because the hinge line is recessed into the control surface leading edge, and apart from making it easy to mount the aileron it also supports the wing part of the hinge without the use of blocks.

Turbine Tinkerer

Thats a great idea Phil I think I'll do the same.

I plan on using the hinge pockets too mounted in the wing with the hinge permanently glued into the aileron. How did you mount the pockets? There's a hole in the rear spar for the inboard one but thats it. I'm thinking of balsa blocks between the skins or some vertical balsa to make like another spar further back that the rear spar if this makes sense?

PhilH

Yes I fitted blocks to support the hinge pockets which were also bonded to the adjacent ribs and skins.  This I did before applying the lower wing sheeting, as it made it easier to achieve the correct alignment as well as gluing the blocks and pockets in place.

Turbine Tinkerer

Managed to get the upper skin on both ailerons today and started hinging one of them. Drilled some balsa blocks and tacked them on to the upper wing skin. After some adjustments I'm quite pleased with the hinging. I think I'll give them a healthy bond with vpoxy to the ribs and make them up to the level of the lower wing surface so I can bond them to that too.

Thinking about adding some balsa behind the rear spar to box the aileron pockets of and stiffen up the skin.




Turbine Tinkerer

January 04, 2014, 17:44:01 pm #23 Last Edit: January 04, 2014, 19:04:17 pm by Turbine Tinkerer
Progress has slowed somewhat with the return to work but managed a little time today. Both the ailerons are now hinged and I've started looking at hinging the flaps. I think I'm going with Micks original design on these and going with the small plastic pinned hinges. Provisions have been made for these by the way of small rebates on the rear spar of the wing and flap leading edge allowing the hinges to slip under the proskin. I've added some blocks to give the hinges a little more support under the skin. I will either use the small screws available from Mick Reeves or small pieces of cocktail sticks to pin the hinges in place through the lower skin and into the blocks I've added. I've done away with the small pins that should hold the hinges together and replaced it with one length of piano wire through all the hinges so the flaps are removable. The wire is same diameter as the pins that came with the hinges. Looking at mounting the under cart and wing servos next. The wing tip is a plastic vac forming I'll probably leave that until the lower skin is on as it looks like it could be fiddly.


Turbine Tinkerer

Been thinking about what servos I can use. Downloaded the manual for the ripmax hunter and that suggests 4.5kg on elevator 6.5kg on aileron and 10kg on flap. I would have thought 4.5kg would be sufficient on aileron? 4.5kg is a little underpowered on the elevator? 10kg on the flap would be overkill? Opinions please, what have/would you use/deem sufficient? I was looking at the new thin wing alloy cased servos. Metal geared and 7kg of pull at 6v. Really easy to mount too with the 3 mounting lugs.

STORM

Imo  the DS821 @6.5kg never let me down on Elans, Sprints etc, not sure if you can still get them though.
I'd be happier with a 10ish on the tail though.

Turbine Tinkerer

10kg on each side or 10kg in total?

Fisty

I had the Ripmax Flying Legends Hunter which was based on the Mick Reeves kit, i had JR DS3401 on each elevator and the rudder which is 4.3 kilo at 4.8 volts, i was running through a Powerbox Cockpit which was regulating at 5.9 volts so you will have increased torque, DS8321 on ailerons and flaps. 10k each side is excessive, 8321's are more than adequate for ailerons and flaps.


STORM


HarryC

Jets usually need very little torque from servos apart from the flaps. However they are more prone to flutter due to tbe large speed range and that's when power and beefy gears count. Thin  or small servos often have plenty power but I am wary of their small gear teeth withstanding flutter or g load shocks.

Thommo

Quote from: Turbine Tinkerer on January 04, 2014, 22:31:34 pm
Been thinking about what servos I can use. Downloaded the manual for the ripmax hunter and that suggests 4.5kg on elevator 6.5kg on aileron and 10kg on flap. I would have thought 4.5kg would be sufficient on aileron? 4.5kg is a little underpowered on the elevator? 10kg on the flap would be overkill? Opinions please, what have/would you use/deem sufficient? I was looking at the new thin wing alloy cased servos. Metal geared and 7kg of pull at 6v. Really easy to mount too with the 3 mounting lugs.


There's a thread here by Pat Barnes who was scratch building a 1/6th Hunter and he used those slim metal cased servos:
http://www.rcmf.co.uk/4um/index.php/topic,84630.msg1034533.html#msg1034533



Turbine Tinkerer

I have the hitec thin metal geared wing servos on tbe ailerons on my f16 and that has been fine for the 18 months or so I've been flying it. My new hawk has hitec 5245's on aileron which seem ok although it's only had 2 flights. Thinking of going with the thin servos for aileron and elevators with standard sized servos o  the flap. I understand flutter can be a problem on  jets but I'm not planning on overpowering the hunter thinking about either a p80, one of the new small sized 100 engines or possibly a 120 but definitely no bigger.

Turbine Tinkerer

Started looking at mounting the retracts this morning as the flap servo is mounted in this area. The retracts I have for it are robart units with special trunnions for the hunter angles. Because these are not the Mick Reeves units I'm not sure if I have made myself extra work! The retracts fit in the slot ok but the wheel and leg seems way of to the cut outs in the ribs. I also have had to shim one end of the retract to allow it to lock up without the wheel coming out the top of the wing! Anyway I've removed a portion of the ribs to allow the wheel to retract and added some balsa to the other side if that makes sense. Basically the wheel is around 1/2" forward of where it looked lkke it would be with the cut outs in the ribs. This gives more room for the flap servo. There is a cut out it the rib for this but I plan to mount it square to the hinge line not at the angle of the rib.

PhilH

Just had a look at mine and the main wheel is more rearward than yours looking at the pictures.  Checked the plan as well and confirms the position.  The wheel centre should be about 135mm measured back at 90 deg to the wing trailing edge at the flap, if that makes sense.  I has been a while since I built her, but I do seem to remember having to adjust the retract mounts to get the correct position for the wheel as per the plan.

Turbine Tinkerer

Thanks for that Phil.

I'll have a look when I get chance. I seem to remember the position of the gear door outlines are different on either side of the fuz? I hope it doesn't cause ground handling problems? Its only about half inch so do I alter the retract mounts and the ribs on the wing I've modified or just go with what I've done to the second wing?

PhilH

The moulding lines for the inner gear doors on mine were in the wrong place as well.  Don't cut them out until the lower wing is sheeted and the skin cut for the lower leg door, this comes from someone along the moulding lines and it was wrong!  Had to re-bond the doors to fuselage and have another go!!
As to what to do about the wheel position you now have, well that is your choice.  I personally would change it back to how its shown on the plan, you haven't gone that far as yet to make the job difficult, just annoying.

Turbine Tinkerer

Just had a look and my wheels are a little over 1/4 of a inch forward from the plan. The problem seems to be with the angle that the trunnions have been drilled. It does put the wheels closer to the C of G so could affect ground handling.  I'll have a think before I make my final decision.

IB

Those look like the trunions I had made up for the Robart 635LP retracts. I built my own Hunter based on the MR fuselage but with redesigned wings and tail which on the MR Hunter were way off scale. I used the angles and retract position as per the full size which is probably why you are having an issue here as they are a compromise on the MR Hunter. With some fettling they will work correctly as one or two others have built the MR Hunter using the Robart units with the modified trunions.

Ian B
A womans mind is cleaner than a mans.
She changes it more often.

Turbine Tinkerer

Thanks for your input Ian.

Well after much delabriation I've decided to bite the bullet and move the retracts. Luckily I can do this with adding strength rather than removing it due to the amount of room between the stock bearers. In short I've doubled up the front mount and added a 'wedge' shapped piece to the edge of the original mount to correct the angle. Difficult to see with the clamps in place. The small notch in the egde of the bearer in for the pin that goes through the trunnion.

Can anyone post a picture of the cut outs in the lower wing and the gear doors as the cut outs on the drawings look rather large for the size of the gear.

PhilH

A couple of shots of my wheel wells Terry.  If you need any more just shout.

Phil