Peterf's 1/4 scale Falcon Models Tiger Moth

[PeterF]

Manish,

The sketch attached shows the hook up I plan. I will put a wheel or a drum in the wings connected to a disc flush to the bottom of the wing surface with the offset ball joint for the torque rod. The drum will be actuated by a closed loop wire pull pull system. One end of the wire attaches to the aileron control arm I have made from epoxy glass, the other end attaches to the aileron return arm. This is mirrored on the second side. Hence the closed loop is control arm to LHS drum to return arm to RHS drum to control arm. The aileron return arm is like an idler shaft / pulley on a drive belt, it just keeps everything running in the correct location but is not powered. The return arm is present on the full size. I have not got the details such as what the wheels / drums will be like and how to make the removable connections to the control and return arms yet. However, I do know from calcs that the drums will need to be 12.5mm, the sprocket in the full size is 2" dia for the chain centre and I will also have to make longer aileron control arms at 29mm as I believe the ones in the kit are shorter than scale.

[Manish Chandrayan]

Thanks Peter, explains the working nicely.

If I go this route, I think I will use a dual take off ball link on the actuation arm and two clevises on the return arm to make it easy for wings to be removed or attached.

[Spice Cat]

Stunning!

[cymaz]

I use the Falcon undercarriage on a Stampe, it didn't need much modification. It's a stunning piece of work....if a little expensive

[Manish Chandrayan]

Some more food for thought on actuating the aileron. How about actuating the aileron disc with a linear actuator ?

Something like this http://www.robotshop.com/en/firgelli-technologies-l12-50-100-12-i.html

[PeterF]

Manish,

I looked around for linear servos but did not find anything that was small enough, the type you have located would fit, however they are a little slow and low force. It makes you realise that our servos are cheap in comparison. I have now committed to the almost completely scale actuation, so have stopped looking for other options.

Peter.

[Manish Chandrayan]

Thanks for advice Peter. Looks like if I follow you, it would entail some surgery on the fuse floor to fit a servo to drive the ailerons.

But before that I am going to try using the thin wing servo to drive a scale disk on a mock up of the wing. If it works I would go this route or else follow your example.

[ron thornhill]

Hi Peter how is your build coming along, haven't seen any updates from anybody lately. I finally managed to get my tigy down to Shoreham today and Ian Perry was very obliging, so I had brilliant afternoon. Will be flying mine at Hastings next week hopefully. Good luck with your build. Ron

[PeterF]

Ron,

That looks good and some time at Shoreham to boot. I hope all goes well at Hastings and I am sure that you (sorry the plane) will get lots of admirers.

I have not been at home much since the last post, a lot of time travelling for work and some vacation so little shed time. What I have had has been taken up putting a new small F3A model together and flying that when I get the chance. I'll be back in the shed towards the end of the summer probably.

[Manish Chandrayan]

Both the model and the pilot look dashing

What hardware pulls the model around?

[Manish Chandrayan]

Ron, Looked at your albums to find an answer to my question regards the engine on the Tiger, a Saito petrol.

I have a few questions for you regarding your Tiger. May I please?

[ron thornhill]

Hi Capt Manish, thanks for the compliment. The engine is a Saito FG30B four stroke petrol mainly because I thought it was the easiest to configure the exhaust without any bespoke stuff also it sounds nice. The engine bearers did require quit a bit of witling to fit it in. I should have documented the build but am a bit thick with things like that, I admire people like PeterF who make wonderful job of photo documentation and meticulous building technics. How are you getting on with your build and your aileron control system, a photo would be nice. Ask away and will try and answer any thing I can.

All the best

Ron

[ron thornhill]

What you can see of the engine

[Manish Chandrayan]

Thanks Ron for those additional pictures. I have made a dummy lower wing section to try out the idea I have in my mind. Will see what comes out of it.

With regard to questions, here they are

1. That nice raised lip around the cowl intake, how did you achieve that ?

2. On the interplane struts I see nice end caps, how is that simulated?

3. Some more details on your aileron mechanism would help simulate my grey cells/

4. On both, top and bottom wings, there is a gap to facilitate fastening the wings to the fuse (like the full size). The kit has play plates to cover this gap. How did you achieve this so that it was easy to remove and refix the ply covering?

[PeterF]

Here are a few general shots of the model at the moment, as I said before, no progress since earlier in June. The engine has been removed though and has now been sold. I have decided to complete it as an electric model, I have bought a suitable 2500W motor (Hyperion ZS4035-10) and 100 Amp ESC for 6S cells, plus I already have suitable battery packs that I use in other models. Over the past year I have been flying more and more electric and my glow models have started to become hangar queens.

[ron thornhill]

Ha right here we go.

The raised lip was made by two layers masking tape laid on then cut to the shape of the lip then filled with polyfiller then sanded to shape, rivets with modellers glue as normal.

The caps on the interplane struts was thin cardboard cut to shape and glued on, (obvious now I've mentioned it, Ha).

The covers were made as per drawing but I only put them on for display I will leave them off for flying, I don't suppose anyone will notice when it's buzzing about. I can take some pics if your not sure.

I will show how I did the aileron controls in a following post, it may require a drawing.

I hope that has given you some thing to work on Manish, good luck.

Ron

[Manish Chandrayan]

Thanks Ron, now that you reveal the secret it is clear , will wait for your explanation on the aileron mechanism. From the pictures I have studied I assume you are using a bell crank and and idler from the fuse bottom to activate cables that work on the servo horns which are in turn connected to scale like discs at the wing bottom surface. That being the case a few drawings and especially the connections at the fuse bottom would be helpful.

Peter, sad to see you change to electric option, hope Trevor sticks with the glow/gas on this Tiger.

[ron thornhill]

Hi Manish this is the prototype, I did tidy it all up before covering, the return cables are connected with an expansion spring it dose work on the ground I just hope it works in the air. The servo arm is not so pretty as Peters but it does come directly off the servo hence the extension, The tubes through the ribs are ally with swaged ends. I hope that all helps, obviously there's many interpretations to all this, you could improve on the servo arm and have the clevises connected straight on the arm. Yes Peter it does seem a bit of a shame to go electric, I have gone back to IC just for this model but each to their own, it won't detract from the look of the plane. I hope you are able to get back onto it soon, and yes how are you getting on Trever. good luck all.

[Graham Wood 3]

I am loving this thread. Absolutely brilliant workmanship and photos. Many thanks to all for sharing your secrets.

Just a quick question on the above aileron setup; I take it that the offset on the servo disk to torque rod is for some up/down differential? Also as the aileron control assembly in the wings has some shear load from the wire tension, does anyone use these little bearings **LINK** which you can get as spares for small helis. I guess they can be mounted into a wooden plate instead of using fiberglass board which will eventually have the hole elongated. You can get all sorts of different size bearings for small helis. Just a thought.

Thanks again

Graham

[PeterF]

Graham,

Thanks for the bearing info, I will consider this when I come to develop mine. The offset on the disc is exactly true to scale, at neutral the control arm ball joint is at 45 degree towards the front of the wing and the disc rotates approx. 90 degree either way. This means that the ball joint moves towards the rear of the wing to give a lot of up aileron. For down aileron it moves initially until it is fully forward with 45 degree of rotation, giving about 1/5 as much down aileron as up. As the disc then continues to rotate from 45 to 90 degree, the down going aileron start to rise back to neutral as the ball joint will be trvalling back towards the rear of the wing. See attached link.

**LINK**

Manish & Ron,

I will go out and buy a hair shirt tomorrow.

[ron thornhill]

Hi Graham, yes the differential is for down and no up as in the full size, it takes a bit of working out (many holes in the disk). I thought about using bearings after I had covered the wings, I've got loads of bearing too, that's the problem when you rush something, well that's the problem when your retired, you just bang away without taking time out to think things through properly, well that's my problem anyway, and I'm still quit new at this game. Its good to see someone else interested in Peters blog, long may it continue, at least until Peter is up and flying. So Hamish go down the bearing route.

[PeterF]

Ron,

Re the differential, isnt it up and no down. The photo shows it is set up the right way on the plane.

[cymaz]

The rule of thumb is , more up than down.......here

[ron thornhill]

Yes Peter I said it all wrong but at least it is correct on the plane, brain cramp.

[ron thornhill]

Aha Cymaz using a disk on the top in that configuration would have cured my problem having to use a spring on the return cable and I assume the push rod on the lower disc would still be in the same position. As far as the bearing situation goes you would still have to key the two disks to avoid any slip, I wouldn't rely on the compression onto the inner race. although it's too late for me now, I am going to sit down and have good ole think about all this.