Flapper (oz8728)

About this Plan

Flapper. Rubber powered ornithopter model.

Quote: "Ever since we began designing model planes, we've wanted to develop a flapping-wing model (ornithopter) that would be more practical structurally and look less like the weird contraptions we'd seen on flying fields. Our first few attempts failed miserably, and for a long while we completely forget about the whole idea. Then, about a year ago we again attempted the project, and taking up where we stopped, worked out what we felt was a more efficient flapping mechanism.

Its final evolution was similar in many respects to the standard type of mechanism in general use, with several very important additions; most important being the 'Angle of Attack Changer' the idea behind this was to use a more rigid wing frame.

In doing this we were aware that, with the standard type of mechanism, lift and thrust were achieved through the use of a highly flexible wing, made up of a thin leading edge which was lightly braced, with the remainder of the wing pattern made up of tissue paper. When the wing would flap on the up-stroke the trailing edge would be depressed downward, which would in effect raise the angle of attack of the wing; when the wing would flap on the down-stroke the trailing edge would be pushed upwards, which in effect decreased the angle of attack of the wing. Our 'Angle of Attack Changer' is designed to do some of the work that originally had to be done by an extremely flexible wing.

The wing we used can be truly considered as being semi-rigid and capable of supporting a useful load even when the wings are not flapping. The leading edge we used, is very rigid..."

Direct submission to Outerzone.

Hey, Something a little different? So, here is the PDG "Flapper", an ornithopter of course. Flying Models, October 1955. Dave

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