PPRuNe Forums - View Single Post - Lift

Jetstream Rider · 1st July 2008, 09:36

"lift without power for infinite spans" comes from the link above

here
How Airplanes Fly: A Physical Description of Lift c

"There is a misconception held by some that lift does not require power. This comes from aeronautics in the study of the idealized theory of wing sections (airfoils). When dealing with an airfoil, the picture is actually that of a wing with infinite span. Since we have seen that the power necessary for lift is proportional to one over the length of the wing, a wing of infinite span does not require power for lift."

This is the bit I'm struggling with. The rest is quite comfortable.

I've looked again at the spinning cylinder and its clearer now.

1st July 2008, 09:36	#44 (permalink)
Jetstream Rider Join Date: Oct 2002 Location: Heathrow Posts: 289	"lift without power for infinite spans" comes from the link above here How Airplanes Fly: A Physical Description of Lift c "There is a misconception held by some that lift does not require power. This comes from aeronautics in the study of the idealized theory of wing sections (airfoils). When dealing with an airfoil, the picture is actually that of a wing with infinite span. Since we have seen that the power necessary for lift is proportional to one over the length of the wing, a wing of infinite span does not require power for lift." This is the bit I'm struggling with. The rest is quite comfortable. I've looked again at the spinning cylinder and its clearer now.