Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: thedoc on 10/09/2013 12:20:46

Title: How can planes do tricks?
Post by: thedoc on 10/09/2013 12:20:46

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



Asked by Cameron Thompson


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Title: Re: What produces lift during a knife-edge pass?
Post by: evan_au on 17/07/2013 10:45:01

During the knife-edge pass, the propeller/jets are angled slightly downwards, and this directs a flow of air downwards.
The body of the aeroplane is angled, and this directs a flow of air downwards.
This downwards force on the air provides an upward force on the aeroplane to keep it in the air.

Title: Re: What produces lift during a knife-edge pass?
Post by: lightarrow on 17/07/2013 12:55:52

Quote from: evan_au on 17/07/2013 10:45:01

During the knife-edge pass, the propeller/jets are angled slightly downwards, and this directs a flow of air downwards.
The body of the aeroplane is angled, and this directs a flow of air downwards.
This downwards force on the air provides an upward force on the aeroplane to keep it in the air.

I am not an expert at all, is it possible that the rudder also is used for this purpose?

Title: Re: What produces lift during a knife-edge pass?
Post by: alancalverd on 17/07/2013 13:34:24

All of the above. A true 90 degree bank produces no upward lift from the wings, but every nonvertical surface is acting to produce lift. To sustain a knifedge at constant height you need to angle the thrustline upwards or tolerate a significant loss of speed throughout the manoeuver.