Replies

https://www.thenakedscientists.com/articles/questions/what-produces-lift-during-knife-edge-pass

from link:

When an airplane does a knife-edge pass (wings vertical), where is the vertical component of lift coming from to keep it in the air?

Thanks!
Cameron
Answer

Dave - So, the plane is basically flying on its side. The wings can’t be doing anything because they’re vertical. So, the lift must be coming from somewhere else. When you watch them doing it, they’re actually quite a big angle. So, they’re not flying horizontally. They’re sort of flying at 20 or 30 degrees to the vertical. And so, you’ll be getting some lift from the side of the body of the plane, from the side of the fuselage. Some from the tail plane itself will be giving you some lift and mostly, the kind of planes which do this have got very, very large propellers which can throw an awful lot of air backwards. So, because the plane is pointing upwards, that air is being thrown downwards, and so you get an equal opposite reaction and the plane gets pushed upwards.