IMissPiedmont From United States of America, joined May 2001, 6294 posts, RR: 33
Reply 1, posted (12 years 5 months 4 weeks 10 hours ago) and read 1435 times:
If it weren't from the Boeing site, I would declare this pure insanity. I'd have thought that this would cause insurmontable fatigue problems. But, since I don't get paid massive dollars to design aircraft, I defer to the experts.
Thinking about it though, it really wouldn't take much movement to affect directional control. I'm just a bit curious as to how they plan to activate this system.
Areopagus From United States of America, joined Sep 2001, 1369 posts, RR: 1
Reply 2, posted (12 years 5 months 4 weeks 8 hours ago) and read 1418 times:
I'm just a bit curious as to how they plan to activate this system.
Well, rereading the news release, it's the existing controls themselves. The plan on the F-18 testbed is to use the forces applied to the wing by the ailerons and leading-edge flaps to warp the wing. An aircraft wing designed from scratch to use this technique would use relatively small hinged controls to aerodynamically effect the wing warping.
This basically makes a virtue of an effect that conventional wings must be strengthened against. The pilot tries to raise a wing by lowering its aileron; that wing experiences more lift at the outer trailing edge, twisting the outer trailing edge up. This reduces the angle of attack of the outer wing (if it's not stiff enough), causing the aircraft to roll opposite the commanded direction. This control reversal doesn't happen on modern, competently-designed aircraft, because the designer accounts for it. Now, designers want to let the effect work for them instead of against them.