Pepsi Super Chipmunk

An update on the Pepsi wing incidence. Flew her again last week with some hard balsa packing under the trailing edge wing seat area to add incidence. Checked CG and balances where it should do according to plans. Still needs a fair amount of up elevator for trim whilst flying. Also found that the ailerons needed some slight mechanical adjustment which I did later at home. Oh well! Maybe it is just this animal's characteristic.

When I get another chance on flying her I will follow Jon's advice that he gave some time ago under Scratch Built & Kits regarding checking wing balance.

Balancing the wing certainly minimises aileron trim, unfortunately sticking a few grams of lead on the tip causes turbulence and extra drag, so now you have to use rudder trim to fly straight. Did you check the tail plane incidence too Phil?

I will check wing balance in the near future. Tail pane cannot be altered, It sits where the plans say it is supposed to. Must not be too picky maybe. Just fly it and enjoy. :lol:

Brian wrote: Balancing the wing certainly minimises aileron trim, unfortunately sticking a few grams of lead on the tip causes turbulence and extra drag, so now you have to use rudder trim to fly straight. Did you check the tail plane incidence too Phil?

Brian

Adding wingtip weight isn't about reducing aileron trim as this can also be caused by a slight warp. It is to help trim the model to loop straight without needing to add aileron correction.

I'm reality I have never noticed any yaw inducing effect of surface mounted wingtip weight, although it will cause drag I don't think it would be noticeable. However the best thing to do when the correct amount of weight is established is to build it in, this is easily done by using nails of the same total weight, driven into the tip block, the heads can be covered over with a small circle of film if required.

Flying the Chipmunk with up elevator trim might be normal Phil. I read an article about a home built wooden Spitfire, the builder/flyer said that the most satisfying thing about the build was the fact that the Spit flew with slight down elevator..............just like a real one.