[Charlie C]

Right then everyone.

The first hacking and bashing session for the shop is a Hangar 9 Hellcat ARTF.

Click Here

You may think that its a strange choice for a shop show model, however, there is a twist.

This model is designed for glow motors of .60 to .78 two stoke and .91 to 1.00 four strokes.

You could electrocute it I suppose, is such was you wish, however, we have decided to stick a petrol engine in.

Yayyy a proper engine 

All will be revealed very shortly, suffice to say, the shop has acqured a cracking little petrol to try out and you will see what it is and how it peforms next week.

The plan is to have it ready for the Osbournby fly-in on the 25th Sepember 

Hope this will be of interest to you.

Charlie C

[capt2724]

I have one of these fine models almost finished with a DLE 20 and a neat pitts style silencer installed, only needs nicads and switched fitting for first flight.

[ringo]

I was flying the Hellcat with a Dle 20 installed and it flew very well indeed until I had radio failure . It was very easy to install with the supplied silencer and required no addition of church roof anywhere because it weighed more or less the same as the OS91 fourstroke that was in it.The ignition system went above the tank and the ignition battery and receiver battery either side of the tank. If I could afford it I would buy another Hellcat but I am waiting for the Hangar 9 Bluenose Mustang to be distributed to shops which might be the end of September apparently

[capt2724]

Hi Ringo,

Thats more or less where I have my gear fitted, did you have a seperate Nicad for the retracts? As i shall fit 3 nicads for retracts, avionics and CDI, although having the CDI and retracts on 1 nicad might work.

[Charlie C]

Hi Ringo,

Thats more or less where I have my gear fitted, did you have a seperate Nicad for the retracts? As i shall fit 3 nicads for retracts, avionics and CDI, although having the CDI and retracts on 1 nicad might work.

Don't know if it helps, but I shall be running the retracts and ignition off the same battery pack.

Charlie C

[ringo]

I have always ran my retract servo from the receiver pack. I always ensure there is no binding of the retracts before every flight so as not to run the battery down with a stalled servo. i have been doing this for many years with no problems

[steamysheep]

Don't know if it helps, but I shall be running the retracts and ignition off the same battery pack.

Charlie C

Are they mechanical retracts like on my Hangar Shine P-47 Charie? I will now only use a separate retract servo battery after what happened to the servo at Barkston Heath... It ain't worth the risk given the unreliability of retracts units...

[styk]

Hi
Im just about to fit retract servos to my World models Mustang and was going to just run them off the Rx battery but i notice you are saying to use a seperate battery pack to run them Can anybody tell me how you go about using a seperate battery. Do you need a seperate Rx and switch Any help much appreciated
Regards
Styk

[steamysheep]

Hi
Im just about to fit retract servos to my World models Mustang and was going to just run them off the Rx battery but i notice you are saying to use a seperate battery pack to run them Can anybody tell me how you go about using a seperate battery. Do you need a seperate Rx and switch Any help much appreciated
Regards
Styk

See here for more on separate batteries...

http://www.rcmf.co.uk/4um/index.php/topic,78636.msg891860.html#msg891860

I had an undercarriage leg hang up on my P47 on it's 15th flight...  As the leg freed up with use it got slightly longer and obstructed the wheel well when retracted, the servo tried very hard to complete the reatraction and melted itself trying to do it! You could smell the burning after I landed. I had a separate retract battery fitted and sure this saved the model... For that reason no mechanical servos will ever share a receiver battery on any of my planes...

[capt2724]

Thanks Charlie C, now I shall go and fit all thats needed to complete the Hellcat. I shall post a picture once ready.

[styk]

Thanks for that Stueysheep but i have the retracts on seperate channels. Does that make a difference. Sorry for my lack of knowledge but it's the first time i've come across this
Regards
Styk

[Mudders]

Thanks for that Stueysheep but i have the retracts on seperate channels. Does that make a difference. Sorry for my lack of knowledge but it's the first time i've come across this
Regards
Styk

The signal will still come from your RX, you will need to split the wires and run the servo pos and neg from a seperate battery.

Mud

[steamysheep]

Thanks for that Stueysheep but i have the retracts on seperate channels. Does that make a difference. Regards
Styk

Me too, works just the same... 

[Charlie C]

OK chaps,

whilst waiting for the glass cloth resin to go off on my Bearcat wing, and having sneaked into the workshop I wanted to stay in there, I dug out the box and started 

As mentioned, tis one of these little beasties.



Naturally, the first job is to pull all the bits out and see if I can lose anything before I can get started:



To be fair, everything is well packed, bagged and wrapped, even I couldn't be hamfisted enough to drop anything straight off.

The hardware pack seems to be comprehensive enough.



And the manual is written in proper English as seems comprehensive.



Sooooooooo,

First job is to install the retract servo, and get the undercart all working. The whole job, from gluing the first former in to fully functioning legs took about 2 1/2 hoursincluding tea breaks 







Although they are twist n turns, I followed the manual, (Now there's a novelty) and once installed and the appropriate measurements adhered to they worked first time.

I am two minds about the leg covers though. They look more like lollipops that parts of an airplane 

Right, off outside to do a bit more 

Charlie C

[capt2724]

Before you get too far, many members on various forums have said that the elevator pushrod is a little flexible and many have had theirs crash or loose elevator control because of flex in pushrod. Because of this I have put my elevator servo under the tail and direct drive via 3mm pushrod to elevator. I located the elevator pushrod exit and placed a pre-cut servo mount from 3mm light ply on the outside, centre it so the original pushrod exit was right in the middle of the new mount and cut the centre out. Its a little fiddly getting the new mount in place but it can be done using a small length of dowel tack glued to the rear of new mount. This enabled me to pull it into place and CA it in. Braking the dowel off once dry.

[Charlie C]

Ohhhhh,

Thanks Capt, I will look into that.

The idea behind doing this is that if it woks out with the petrol engine, the shop might, it has to be only a might a this stage offer the Hellcat, and others as a petrol engined package, replacing the glow engine bits in the box as appropriate.

The elevator rod issue is something we would definitely need to know before hand.

Thanks for that, its much appreciated 

Charlie C

[capt2724]

If you are looking for a petrol/airframe package then look at the Seagull Edge 540 in black and yellow scheme. I have one which first flew on a Saito 125a, although it flew something was missing, a bit of sparkle. I re-engined with a DLE 20 and 16x7 prop and its soooooooooooooooooo good now that it goes out every time with me.

[Pup Cam]

If you are looking for a petrol/airframe package then look at the Seagull Edge 540 in black and yellow scheme.

Yes, but where would the guns go?  You've gotta have guns!

[capt2724]

Hi Charlie c,

The only thing I have changed from the original kit parts is the tank, I changed it for a bubro 10oz and a petrol bung. This lasts for a good 10min flight with fuel to spare.

[Charlie C]

If you are looking for a petrol/airframe package then look at the Seagull Edge 540 in black and yellow scheme. I have one which first flew on a Saito 125a, although it flew something was missing, a bit of sparkle. I re-engined with a DLE 20 and 16x7 prop and its soooooooooooooooooo good now that it goes out every time with me.

Thanks for that. 

Charlie C

[ringo]

Don't stick the elevator servo out the side of the fuselage. It looks terrible on a scalish type of aircraft.Just make up a good stong carbon rod type pushrod instead. Also I cut my canopy in half and glued it on in the open position and it looks great

[Charlie C]

Don't stick the elevator servo out the side of the fuselage. It looks terrible on a scalish type of aircraft.Just make up a good stong carbon rod type pushrod instead. Also I cut my canopy in half and glued it on in the open position and it looks great

I will probably beef up the elevator linkage as I don't want to put the servo at the back either 

Remember, this build is basically a trial so although all suggestions are gratfully recieved, I also need to conssider that any modifications needed will have to be "In the box!" if it were to be released as a package.

Charlie C

[Charlie C]

I am doing this as well as repairing my Bearcat at the same time so I glued the wing panels together this evening, then hid it away whilst attacking the Bearcat wing with a sanding block.

I had to install the aileron extension leads before the larg wad of epoxy was applied so i covered the plugs with heatshrink before I started glueing.



Its all very straight forward, two dihedral braced and locating pegs on the centre wing section. Aplly loads of epoxy and slide it all together.

These are the wing panels, ready for the glue:



I have taped it all together and will inspect it tomorrow evening.

If all is well, its onto the engine installation 

Charlie C

[capt2724]

You might find that the belly pan under the wing at the trailing edge is a  different size, mine is. But you wont see it once flying, I only need to cut some cooling holes in the bottom of the cowl and fit it and mine is complete. Does look good though

[nickr100]

You might find that the belly pan under the wing at the trailing edge is a  different size, mine is. But you wont see it once flying, I only need to cut some cooling holes in the bottom of the cowl and fit it and mine is complete. Does look good though

question is when will you fly it???  ;-)

[capt2724]

When its finished my boy.

[capt2724]

Hi all, just to wet your appetites mine is now finished and looking good. 

[nickr100]

does look good. did you manage to get the prop balanced?

[Charlie C]

Hi all, just to wet your appetites mine is now finished and looking good. 

Yup, it certainly does look good. When's it going to fly?

I have done a bit more this evening. The wing is finished so its time to strap the engine in. Sooooooo, all I gotta do is get that little lot bolted onto the front:





It has taken a little bit of figuring out, only because I wanted to use the engine position as quoted in the manual.

However, for this little petrol engine the positions given are not possible, so in time honoured tradition, it gets mounted inverted which is just a case of the drilling four holes to suit and bolting it all together, everything in the box works OK and the engine is now fitted.





Still, it looks OK , and there is load of room to hide everything, just going to need some silicone tube to get rid of the exhaust gasses underneath.

That's all for now. 

Charlie C

[rogerandout]

just going to need some silicone tube to get rid of the exhaust gasses underneath.

petrol engines and silicone don't mix

[Charlie C]

I know its been a bit quiet for a few days, but I have done some work on the Hellcat.

Finally got the cowl to fit this evening and drilled and attached properly.

I know its not the perfect way of doing things but I did it this way.

Attach a length of masking tape to cover the mounting block. Draw a straight line with a reference point at both ends, in this case 80mm apart:

Its a bit blurry, sorry.



Slide the cowl on and tape it into the position you requires and then measure back down your reference line by the requisite amount and drill cowl screw size hole through the cowl only.

Assuming you have grilled into the right point on the mounting block, drill into the block the appropriate size for the screw you are using. In this case 2mm dia screw, drill 1.5mm hole and Bobs your auntie, cowl mountings perfectly lined up:



I have installed more "bits" but I will take further piccies tomorrow evening 

Charlie C

[Charlie C]

Had a bit of time this evening so got the engine and fuel tank installation finished and the throttle set up.

Not much you can say about the fuel tank, except, the tank comes pre assembled for glow fuel, soooooooo, off with the glow stuff and on with the petrol stuff, as in Tygon tubing and a Dubro red tank bung.



I have decided to mount the  ignition unit in a light ply box with foam inserts on the firewall. You could, if you wanted mount it inside the fuselage, behind the firewall as there is probably plenty of room but I wanted to keep that area clear for the two battery packs. (One for flight and one for ignition/retract servo).





I thought I would refit the cowl to give you an idea of the fit of this engine.As you van see, I have had to cur away the bottom two cylinders of the plastic "Radial engine" insert, but I don't think its to bad a fit.

img]http://www.rcmf.co.uk/RCMFLive/albums/userpics13671/Hellcat_31_Aug_4.jpg[/img]



The only job left is to make up an exhaust extension pipe with I am doing out of thin wall steel pipe.

I'll do photo's of that tomorrow.

Charlie C

[Steve Mitchell]

Looking good Mr C.

When do I get to have a go then 

[steamysheep]

Looking good Mr C.

When do I get to have a go then 

Just after the American ground crew bugger up the carby settings... 

[Charlie C]

Looking good Mr C.

When do I get to have a go then 

Patience Mr M, patience.

CC

[Charlie C]

Hi All,

Been away for a week with SWMBO hence no progress.

However, having got back earlier than planned yesterday  I managed to get a few hours on the Hellcat in the workshop 

I fitted the stab, elevators rudder and tail wheel. I haven't taken any photos and told you how I did it as it would be an insult to your intelligence.

Read instructions, locate part, fit in hole and glue, even I can do it.

Same with servos and bits, its nearly all in and I will take some photo's tomorrow to show the installation.

Sooooo, now, it looks not unlike this:



One of the more important parts of this little project is the fitting and running of small petrol engine and any changes or additions to the kit needed to make it happen, and just as importantly, is it worth it 

Well, the engine is in and in my opinion fits rather well:



I have a 2" extension tube to fit to the exhaust to get all the cruddy stuff out of the cowl.

I have carried out a trial balance of the model and with two battery backs fitted at the rear of the bulkhead the balance point is 1/4" in front of the manuals recommendation.

I shall leave it there and see how it flies, unless anyone has flown one and has any recommendations 

I intend finishing off the fitting out this week and flying it next weekend  but I will add some more piccies this week.

Charlie C

[Charlie C]

As promised, another update with a piccie of the radio installation.

Not much to it to be honest. The flight pack is under the receiver and the ignition/undercarriage battery is under the fuel tank and all the wiring is under the foam you see between the servo tray and the tank.

It took a bit of thought on how to wire up the undercarriage/ ignition battery using only Y leads available off the shelf, but we (Stueysheep and myself) sussed it.



The engine installation is complete. I used a thin wall steel tube extension onto the exhaust header. Nice and simple and again, bits off the shelf.



A few little jobs to do and she will be ready for running and flying 

I was hoping to get it done this weekend ready for the Osbournby bash the weekend after next, but the weather isn't looking to helpful this weekend.

Still, keep the fingers crossed 

Charlie C

[steamysheep]

I was hoping to get it done this weekend ready for the Osbournby bash the weekend after next, but the weather isn't looking to helpful this weekend.

Still, keep the fingers crossed 

Charlie C

Not crossed enough CC.... Weather looks worser-er! 

[steamysheep]

 

[Charlie C]

The smiles in the previous post are for a reason, sadly, Stuey got here before I did.

Its flown 

I would like to say it flew like a dream and exceeded expectations in all areas..

But I can't.

Only because I didn't fly it. In case you hadn't guessed Mr Sheep of this parish did, so he can tell ewe all about it.

I'll just tell you about the bits he broke   

First off, some pictures:









The flying shots are not very good as they were taken with my point and click, but I'm sure you get the idea.

OK, good bits:

It all works and once the engine is primed starts OK. I used a starter but once we get to know it and its run an hour or so, I am confident it will start by hand.
It seems to pull really well and was probably a bit under propped on a 16X8. Might try a 16X10 next.
The legs look a bit spindly but work OK so I think I will put the leg fairings in to stiffen then up a bit and to get rid of the anorexic look.

It seemed to fly OK, but when I came to fly it we found a couple of issues.

The bad bits:

The silencer came loose in flight and the extended down pipe has bashed the cowling. easily sorted.
The brand new, off the shelf last week retract servo has seized solid 
No idea why as it wasn't stalled and was perfectly quiet with the wheels up or down. There is a servo tester in the shop so I will whack it on there tomorrow.

Thats it 

All in all, happy, just need to get those bits sorted out then fly it myself 

I'll let Stuey tell you about the flying bit

Charlie C