dbp@dataio.UUCP (Dave Pellerin) (08/05/85)
(Flame me if I'm wrong, I only know what I read on TV...) >A small point, but isn't the "action-reaction" lift referred to >known as planar lift? Seems to me I've read figures as high as 30% for >planar lift. > Yeah, that's the word for it -- the percentage of lift provided by each of the factors will vary depending on aircraft configuration, angle of attack, etc. In general, the lower the angle of attack, the lower the contribution of planar ('newton') lift. Also, while the lift curve drops off dramatically at the stall (seperation) point, planar lift continues to increase (but not enough to save your ass). >Question: does planar lift account for the low speed effectiveness of >fuselage strakes placed near the intakes of high performance a/c? >I refer to types like the F-16, F-20, and SR-71 in particular. > I think the 'strakes' are placed to disrupt the airflow so that it enters the engine at sub-sonic speeds. Supersonic shock waves would destroy the engine in short order. >Is planar lift a significant factor in delta winged aircraft? The most >extreme exaple I can think of here is the homebuilt Dyke Delta, which >has a lot of wing area for its size. > I doubt that wing planform has much to do with it. By the way, the Dyke Delta actually has less wing area than most aircraft that size. There is no advantage to the delta wing for low speed aircraft, witness the redesign of the Vari-Viggen (delta wing canard) into the Vari-Eze. - Dave Pellerin - uw-beaver!entropy!dataio!dbp