I have been working on the wing struts for a few days now and I have the wings perfect 0 incidence as the plans call for but the right lower wing wich I can't seem to get rid of a +.5 degree pitch. Anyone have any tricks or tips. I want to move on. Its a 1/5 Pico waco. The lower wing is bolted to the fuse and I've tried to sand it out. It seems to improve but the problem is still there. I don't want to take anymore meet from the fuse or wing. Do you guys think .5 degrees is a problem. Of coarse not perfect.
Donnie

If the lower left wing is 0, but the lower right is +.5, then the wings were not joined straight or the right wing is warped. Sanding will not cure either condition. If the wings were joined twisted, then you're looking at cutting the wing in half and rejoining it straight. If the wing is warped, you may be able to twist it back with some ammonia sprayed onto the wing and a lot of weight to hold it straight while it dries. Do a search here on the site for warps and you will find a lot of info on how to deal with them.

John

The wing isn't warped. I was just getting frustrated last night. Just want to make it perfect. I'll figure it out. Just wanted to know if anyone knew a trick.
Donnie

Not warped is good. But, the fact remains. If the left is correct and the right is wrong, then the two panels were not joined straight.

John

I think it might be just the humidity change in Houston Tx. When I built the inner struts it was dead nuts. I built the outer struts and was aligning again when I noticed the +5 difference. I don't think that it is that much to be concerned about but I will get it perfect befor I cover. A little pressure on the outer N strut corrects it but I don't want to do that. I will look at it again today. Thanks for the help
Donnie

Be ing the pica kit, you could have sanded the leading edge a little different and the incedence meter is picking that up. The difference is so little on that bird that I think it should be fine. Plus, after you cover the bird, you can always twist it back.
Heres how you figure out what is going on, write down the numbers as you go.
1- bolt the lower wing in place and take a measurement from ground to wing tips (make sure the fuselage is level in the horizontal plane)
2- bolt the upper wing in position and take your measurements from ground to tips and between the two tips.
3- put your interplane struts in and recheck your measurements, if they have changed, the interplane struts are inducing the twist.
If it is showing up in the lower wing, then it means the the top wing it torsionally stiffer than the bottom wing. But if when you take your measurements and find out that the lower wing is off, and nothing else is attached to it, then that will confirm that the wing has a slight twist to it, providing the saddle is even and true.

O yeah,
Here's another tip, if the meter reads 0 at the root and +.5 at the tip, then it is warped, if it is +.5 all the way across, then the panels are joined crooked or the saddle is inducing the warp. I always check it at 3 points along each half, 6 per a wing and 12 points all together on a typical bipe.

Check the wing by itself. IE, not mounted to the fuse. If the panels are different not even bolted to the fuse, they were joined crooked.

John

Do you realy think .5 not 5 is realy something to wory about. I think I can take that out in the covering. Have'nt had time to work on it yesterday or today. I hope to tonight. Just bought a RC flight sim by great planes. call realflight r2. Its awsome!!!
Donnie

I realy dont believe that .5 deg. will cause a problem on a Bipe . Maybe on a more efficient airfoil monoplane , but not a problem on a Bipe .
I try to be a perfectionist when I build and set up an airframe (mostly bipes and Cap 232 ), but I wouldnt waist a lot of time on only .5 (1/2 degree)
on one panel only....
Now if you have .5 + on one panel and .5 - on the other I would try reduce the warp .
More than likely your concern is in the leading edge sanding , this will effect incidense measurements ,not necessarily the actual incidence itself..

[quote]ORIGINAL: CK1

Thanks Guys. Been a lot of help. I will check the leading edge.
Hey CK1, Have you flown that Cap 232, I bet it is a handfull!!
Donnie

Donnie7 , Actually the Cap is a ***** cat . Its a 30% Carden .. very gentle and friendly until you you switch it to high rates and then it turns on like a Lion... Good Luck with your Bipe !!!