I've been wondering how those flaps worked ever since I first saw them. The
theory is that under the increased flight loads of a fast launch, the flaps
bend up, reducing the camber, the lift and the tendency to loop. But how
much force really exists on the wing? With typical loadings, there is around
0.1-0.2 gram per square inch load, most concentrated in the forward half, less
on the flap. How much force is required to move the flap? How much
difference in lift does that flap change make? The lift is also not directly
proportional to the square of the velocity. The excess lift will make the plane
loop, yes, but in looping the circular airflow reduces both the attack angle and
the decalage, both reducing lift and countering the tendency to loop.
Somewhere the glider finds a balance, and it isn't at the same attack angle as in
steady glide. What would that excess lift pull against? There is only 9
grams of airplane and it only pulls back when it is accelerated. In a steep
climb, most of the weight force is directed back toward the tail, not
perpendicular to the wing chord. The balancing around the CG that establishes attack
angle in steady glide is not at work here.
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Received on Sun Feb 11 2007 - 15:37:58 CET
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:44 CET