Blaine writes: >You can see from this that you want to locate the inboard edge of the >spoilers someplace between the centerline and the stabilzer tips >in order to balance the two effects described above.
I think you're unduly worried about the spoiler's effect on trim. The spoiler->elevator mixing works quite well, and it's adjustable! The mechanical simplicity of having one center spoiler wins here. >A second factor in this is the pitch stability of the airplane. I don't think that's the case. I fly my Allegro-Lite close to neutral stability -- 10% margin at low speed, less than 5% margin at high speed. When the spoiler is deployed the glider becomes more stable in pitch, not less -- it solidly "locks on" to a particular pitch trim, and the elevator's influence on pitch trim is diminished. These are sure signs of an increased stability margin. This increased stability also makes the spoiler->elevator mixing gain not so critical. I'm not totally sure why the spoiler increases pitch stability. One possibility is that the spoiler decreases the wing's dCl/dalpha because of the massive separation. - Mark RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
