I finished building a GP Extra .60. I mounted the wing and surprisingly found that the stab was way off alignment with the wing when looked from behind. After investigating, I found that the problem was not in the wing mount or the assembly of either piece, wing and stab that is. I came to the conclusion that the fuse was twisted along the flight path axis. I clamped the fuse to a table using some unorthodox methods (had to) and used the engine mount to twist the fuse. I clamped all this paraphernalia in such manner that the fuse was straight. I then soaked the fuse with almost boiling water and left it overnight. It worked pretty well and I almost corrected all of the twist but there still seems to be just minimal disparity between the alignment of the wings and the stab. Should I go through all of this process again? My concern is that I used a PVA glue (White carpenter's glue) to finish a lot of the joints and when It gets wet it seems to lose some of its strength. I want to know if having just a little misalignment will change the flight characteristics of the plane. (Will post pictures tonight)

It will never fly totally right if they are out of alignment. You'll tend to roll to the side.

PVA should be pretty waterproof once dry. Heat can soften it. You may want to try the straightening again with a bit of hot gun action and the warm water again. A spray ottle of ammonia is another moistening choice for straightening balsa.

Another thought....

If you try to further straighten it, and do all your clamping again. This time, twist the fuselage just slightly beyond straight. Maybe 1/8" or so. That way, when you pull it out of the clamping, it'll spring back to straight...

This is the picture I said I'd post. When measured at the tip of the stab, it has to be depressed 1/16" to be totally in line with the wing.

The artist's worst critic is indeed himself. I'd fly that.

I know, sometimes when I think about the warp it seems like minimal but I still want to make this the best I can as it is my first build.

I would sand the wing sadle a little to get the wing and stab level. It would not take much and the plane will fly fine.

David

I've already sanded a bit off the wing saddle. I don't want to over do it. Does the misalignment seem too bad?

There was a Russian poster up on the walls of aircraft factories in WWII that translated to: "Perfection is the enemy of good enough".

There's a great deal of truth in that.

1/16" is pretty tight tolerances when dealing with balsa and glue. Here I thought you was talking one wing tip was pointing up at 45º or something.

PS - rather than sand more you can build up the opposite side with wood dust in glue or epoxy. Won't take much.

you well probly get more misalinemnt then that with the chaneg in the wether. i would not let it bother you. cover it and have fun.
c-crunch

if you will make it perfect first time, what will you improve the second time???

Looks pretty darn good but I feel your pain. What vmsguy said about over twist in op direction could help if perfection is desired but like the others said...Weather will affect it that much. After all your efforts to straighten..go over everything twice to make sure that you have no loosened glue joints, fractures etc.. GL have fun

Sand the stab mount, not the wind saddle. The stab mount is flat, smaller and much easier to sand. A thin, straight board with sand paper glued on it will work just fine, event the edge of a GP sanding bar works great as it should have more than enough reach to get the whole area. It doesn't take much sanding to get the stab angle to change.

When I build I always get the wing aligned and mounted on the fuselage first, then align and attach the horizontal - much easier to align everything that way.

Hogflyer

If you have sanded one side then add a thin strip to the other. 99% of guys flying would never feel the difference in the air. You might be that 1% though. I am not the 1% but I would fix it anyway. It would bother me just knowing and now is the time while it is in the bones stage.

David

[cough]It'sallreadygluedinplace[/cough] [&:]

(I figured that). ;-)