Warps. How Do You Get Rid Of Them?

[David Davis]

I have recently re-acquired two models which I built in the 1980s, a Junior 60 and a Telemaster 66. The models were badly stored for the last twenty years and the wings on both models are warped, substantial wash-in on the port wing in both cases.

I managed to remove the warp in the Junior 60's wing by using weights on the wing, twisting it in the opposite direction to the warp and applying heat from a heat gun. However, it appears to have come back, although it's not as bad as it was. I flew the model for the first time in twenty years today but I found that I was having to use full right trim and then to hold in some right rudder to get it to fly in a straight line.

I haven't started on the Telemaster 66 yet but the wings on both models are covered in Solartex.

Short of stripping the covering from the wings and starting again, is there anything I can do?

[Former Member]

[This posting has been removed]

[Martin Harris - Moderator]

You could try the same technique but introduce a little warp the other way - then wait and see if it returns to nearer true?

[Barrie Dav 2]

I think that to be sure to avoid a total loss of the model one day, it'd be best to strip the wings use a little, fine water spray and then weight the wings on a flat table until dry. I know that you said that you didn't want to strip the wings but it might be worth it in the long run. Using heat to rectify covered warped wings are often ok at first but then revert to the warped state when the sun gets to the wing. I have had this experience.....

Edited By Barrie Dav 2 on 17/10/2016 08:13:33

[Peter Miller]

Definitly twist the wings the other way by quite a big amount. hey should then come back to nearly true.

[Engine Doctor]

Twist the warp out further than needed and then apply heat using hot air gun on both sides of the wing until all twist or signs of stretching on the covering dissapears and covering is taught . Hold for a short while until it cools. Now iron over the covering where it touches the ribs etc ,this will help stiffen the wing by fixing the covering to the structure . It should go back to proper shape but may need a couple of goes to stay where you want it. If the adhesive on the covering has deteriorated then it s a strip off job .If the wing has a "D" box front section thats warped then you mayhave to strip it and remove the back of the D box( vertical spar bracing) to re set it. What glue did you use when you built them all those years ago ? Might be worth stripping off the covering and checking the structure anyway . Good luck with them .

Edited By Engine Doctor on 17/10/2016 09:51:56

[Braddock, VC]

I hope you've typed in the wrong words, wash in on port wing should induce a rolling tendency to the right, to correct it with right rudder....

[Braddock, VC]

Meant to add, my j60 had a similar problem, I am now resigned to stripping the covering off and gluing in some diagonal braces to remove the washin.

[J D 8]

Sometimes on an old model like the Junior 60 the addition of a trim tab [bit of ali sheet]near the wing tip to counter the unwanted turning may be the simplest answer as on my Mercury Matador.

[David Davis]

Engine Doctor, I'll try your method with the iron first to see what happens. The Junior 60's wing has a sheeted leading edge back to the main spars on the top surface only. The Telemaster, as you can probably see in the picture, is simply an open structure with a leading and trailing edge and two spruce spars. Both models have webbing between the two main spars. I would have used PVA white glue, bought from a builder's merchant all those years ago. I'm a notorious skin-flint!

Braddock, it is indeed the starboard wing which is washed-in on the Junior 60, hence its constant gentle turns to the left in flight yesterday evening. I flew it for over ten minutes and there was still half a tank of fuel left in the 4 oz tank! Very economical those little HP VTs.

If I have to, I'll recover the model over the winter. Pity really as the wing is currently the best feature of the model. Having said that, the thought of a smart new-looking Junior 60 appeals.

PS. I was a better-looking fellah in those days. .

[David Davis]

PS to the above.

While the model was in flight yesterday evening, my mate Roger Aubard, asked for a go on the sticks. He is the best pilot in the club having once participated in the French National Championships in both the glider and the i/c aerobatic cometitions. He had no trouble flying the model despite the fact that he's Mode 1 and I'm Mode 2!

[Mike Etheridge 1]

When I first constructed my junior 60 in 1962/3 I built in a slight warp to the wing with the result that if you selected right rudder for too long a spin could result, I then had to throttle back the old ED Racer and apply left rudder and pray! It finally crashed in 1976 after radio interference on Epsom Downs, so I repaired it and took the opportunity of straightening out the wing warp after removing the nylon covering and re-setting the ribs and trailing edge of one wing and then re-covering the wing with new nylon. This did the trick with the right turns, and as I have mentioned before I have nearly finished re-furbishing the plane except the wings which still have the 1976 nylon covering which is some what blotchy now but still intact. I just need to re-connect the radio equipment and then take it to my club flying field where the old crate is a standing joke with the other flyers!