I am building a kit and I'm have trouble with the wing tips kind of have to design my own any suggestions. It is a flat bottom wing and the trailing edge of the tip has to come out to some kind of a point to line up with the ailerons some one out there must know a easier way to this I have been scratching my head for a week now. Thanks for your input

Several kits have used tri-stock balsa for wing tips. This will provide a nice looking tip that is easy to install. It will result in a tip that looks like what is on the Sig Kadet (though the Kadet tip is built up instead of solid tri-stock) Once glued in place, carve/sand the top surface of the tip to the shape of the airfoil and you are done.

John

The way I make wing tips is to make a form the shape of the wing tip from a piece of thick floor tile you know the stick on vinal stuff. Then on the building board I laminate bass wood strips soaked in windex and glued togeather with yellow glue. Pull the basswood around to shape and hold in place with pins. Let it set overnight and then add a rib or what ever is needed to secure it to the wing. Very light and very tough wingtip.

I'm fond of what I call a "vortex" wingtip.

It starts out with triangle stock glued with the angle up instead of down. Then add a piece of 1/4 inch sheet on top of the tri stock to give material to carve (upper surface, and add more droop at the TE of the tip.

Round the upper surface to smoothly fair to the tip at the TE.

Use a dowel wrapped in sandpaper to hollow out the inner surface to a smooth curve.

If desired... some weght can be saved by holowing out after the tip is shaped. (tack-glue it on while shaping... remove, hollow out and then glue it on firmly.)

From the side, you see a triangular drooping "winglet."

This tip gives some suprizing results. I've been TOLD thay can't be effective due to scale of the aircraft... but they do reduce tip-vortice induced drag. They also enhance low speed performance. With this tip on a plane such as a Sig Kobra, stall speed is reduced approximately 12%. (It can almost stay in a thermal with a sailplane!)

Negative effect: Though stall speed is reduced... the plane will tend to snap violently when it does stall.

Design is for short field landings . Lowers stall speed but will stop flying all at once. Changes roll rate , will not snap roll, will not fly inverted as easy as with standard tips. Will shorten takeoff space lenght of run way.

If you can get a copy of the November 2002 Model Airplane News
there is a great article on making wingtips from scratch. If you
can't find it, go to their website and you can order back issues:

http://www.modelairplanenews.com/issues/display.asp

Good luck,

Jesse