PPRuNe Forums - View Single Post - Lift

Jetstream Rider · 28th June 2008, 11:59

Lift usually means downwash.

However, I think pressure distribution is more important. We were taught in ATPL exams that a third of the lift comes from downwash and 2 thirds from pressure distribution. While this is necessarily a gross simplification, there may be a grain of truth in it.

Certainly the lower surface accounts for more lift than upper surface only theories would have you believe.

I think what I am seeing with no downwash lift is purely the pressure distribution, and with flat plates turning the flow is almost purely downwash created lift. A real wing being a mixture of the two. It still means "lift is produced by deflecting the air downward" is no the right way to describe lift.

28th June 2008, 11:59	#16 (permalink)
Jetstream Rider Join Date: Oct 2002 Location: Heathrow Posts: 289	Lift usually means downwash. However, I think pressure distribution is more important. We were taught in ATPL exams that a third of the lift comes from downwash and 2 thirds from pressure distribution. While this is necessarily a gross simplification, there may be a grain of truth in it. Certainly the lower surface accounts for more lift than upper surface only theories would have you believe. I think what I am seeing with no downwash lift is purely the pressure distribution, and with flat plates turning the flow is almost purely downwash created lift. A real wing being a mixture of the two. It still means "lift is produced by deflecting the air downward" is no the right way to describe lift. Last edited by Jetstream Rider : 28th June 2008 at 13:11.