Ed wrote

>All of my conclusions were based on actual model tests.

Sure, but you didnt actually measure the drag on any of them. On virtually any full scale airplane (i.e. where performance is worth money) drag is important, and tip plates are actually very draggy. Yes, you will get some aileron effectiveness, and you can cut the stall speed, but you can get the same results with less drag by other methods.

Winglets can be thought of as tip plates "done right", but even then, its usually better to just increase the wing span a bit. The problem with winglets is that they work well at only one flight condition. Fine for retrofitting airliners, but marginal on sailplanes.

As for the Reynolds Number comments, yes we have sort of low RN, but for most RC power planes, its not THAT low and the basic principles still apply. (FWIW, I do a lot of engineering work on Mars airplanes, and there the RN is pretty low.. 1/5 to 1/10 of your typical RC .40 sport plane, but transonic Mach and things are pretty different there).

bob