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Jan 16, 2002, 03:27 PM
Balsa to the Wall
Thread OP
Help!

Does anyone know how to get twist out of Tiger Moth wing? I'm stumped. Update


I have about 1/2 inch of twist in the wing assembly. If anyone has tackled this problem, I'd sure like to know how/if you got it fixed.
This forum has been a wealth of info and help as this is the first one of these things I have done and I want to make sure I get it right.
Thanks again for all the good info, guys.
Chuck
Last edited by Chuck; Jan 18, 2002 at 06:58 PM.
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Jan 16, 2002, 03:43 PM
Tight is Right
Darren Hintze's Avatar
Where is the twist you are talking about? Upper wing? Lower wing? Both?
Jan 16, 2002, 03:54 PM
Balsa to the Wall
Thread OP
Thanks for the reply.
I've got the wings assembled and mounted and the top and bottom have the same amount of twist. The LE of the left side wings is about 3/8 to 1/2 in. higher than the right at the wingtips..
Jan 16, 2002, 03:59 PM
G G Ghost Pirates !!!
Vyceroy's Avatar
that is strange i have not seen that in any i've built..are the wing struts in properly?.. Happy Landings... Vyceroy
Jan 16, 2002, 04:07 PM
Balsa to the Wall
Thread OP
Vyceroy:
Yes, I attached the struts in the dimples in the wings. The inner struts had no marked location points, though, so I glued them in after looking at several piv here. ??????????
Jan 16, 2002, 04:23 PM
Tight is Right
Darren Hintze's Avatar
Just the leading edges are higher? Ouch. Humm... the only thing that comes to mind is the cabane struts. Are they mounted straight onto the fusalage? If they are, perhaps you could manipulate the screw locations to remove the twist.

Let me know
Jan 16, 2002, 04:48 PM
aka: A.Roger Wilfong
gnofliwr's Avatar
If all of the struts are attached to the wings in the right place, once the wing is mounted on the plane, it has to be straight. So, if the interplane struts are seated in their respective dimples and the cabine struts are installed in the upper wing joints to the same depth, either the cabine struts are too far forward, back or askew on one side (making the upper wing crooked), or the lower wing joint reinforcement is off (making the lower wing crooked).

The cabine strut attachment at the fuse should be flush with the bottom of the reinforcement plate and even with the front and back of the plate.

The lower wing reinforcement should be centered on the dihedral break both front and back.

With the wings attached try measuring from the tail post to each lower wing tip - should be the same. Then try to each upper wing tip. One of the wings has to be on crooked.
Jan 16, 2002, 05:11 PM
Balsa to the Wall
Thread OP
gnofliwr;

Melfsmite:

Thanks guys for the tips. I shall now go and check all that stuff. Let you know what I find.
Chuck
Jan 16, 2002, 06:07 PM
Balsa to the Wall
Thread OP
OK, I measured the strut placement. They are all even, top & bottom, side to side.
Even with the wing off, there is still twist.
Moving the inner(cabane?) strut fuse mounting points only affects the center part of the top wing.
I think the the lower wing was bent when I started. Do you suppose a gentle application of the ol' blow dryer while applying a counter twist might work?
Jan 16, 2002, 06:33 PM
Registered User
Seems to me there must be something wrong with some of the struts, as a twist in the wings with the interplane struts properly installed would require the wings to bend fore and aft, which seems unlikely.

If there really is nothing wrong with the struts, then you can put in rigging wires, which the Moth kind of needs anyway. Adjustments to the wires should take out the twist. A member of our club has done this and now doesn't have to worry about loops. They can be pretty light material and still add tremendous stiffness. They look scale too.

I will admit I don't have one of these things, but everyone else in the club does!
Jan 16, 2002, 11:26 PM
Registered User
Seems to me there must be something wrong with some of the struts, as a twist in the wings with the interplane struts properly installed would require the wings to bend fore and aft, which seems unlikely.

If there really is nothing wrong with the struts, then you can put in rigging wires, which the Moth kind of needs anyway. Adjustments to the wires should take out the twist. A member of our club has done this and now doesn't have to worry about loops. They can be pretty light material and still add tremendous stiffness. They look scale too.

I will admit I don't have one of these things, but everyone else in the club does!
Jan 17, 2002, 12:18 AM
Registered User

GWS Wingwarp!


I had this problem with a litestick - one wing had enough twist (wash-IN) to cause severe twisting dives on launch. As a newly minted idiot at the time, it took several doses of E-Zone advice before I figured out the problem. A trip back to the LHS revealed that the whole shipment of Litestick had a warp in the right wing. The cure was the very careful application of a heat gun (on LOW from about 12-18") an a gentle trising in the opposite direction.
With the TM you might also be able to add some rigging to pull the offending wing into correct alignment. I've added rigging to mine, along with the Carbon Fiber reinforcement LE of the bottom wing as per the "Bleriot Endorsed- Seal of Approval" standard mod. This might straighten out your wing with out the dicey application of heat to thin foam.
Good luck!

SG
Jan 17, 2002, 12:19 AM
Registered User
Chuck,

Sounds like you "tweaked" the bottom wing when you applied the plastic joiner. Now the top wing follows the bottom. Could that be it?

Dave
Jan 17, 2002, 01:27 AM
Almost a Pilot
Mauilvr's Avatar
Provided you've checked everything suggested above, I would attempt to fix it in one of 2 ways.
  • Add flying wires and use them to adjust the wings as required. There is plenty of info on these forums - use the search function. This isn't a bad idea anyhow because it also adds a lot of strength.
  • Use the hairdryer. I had a nasty twist in my GWS Cub wing from a "tip" landing. I pinned/blocked/weighted the wing in position then SLOWLY and CAREFULLY heated it using a hairdryer, moving it back and forth to heat the wing SLOWLY. It doesn't take much heat - the foam will get soft and you can put it in any position desired.
It came out fine. Good Luck!
Jan 18, 2002, 06:56 PM
Balsa to the Wall
Thread OP
Thanks for the advice.
I tried the hairdryer and the wires. Got most of the twist out. I have attached this picture which shows the final appearance(see arrow). If this looks like too much, please let me know. I'll take the wing assembly apart(major bummer) and start over. Thanks again for all the good ideas, guys.
Chuck


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