Re: Physics of Flight

[brian whatcott <inet@INTELLISYS.NET>]

At 16:28 8/17/99 -0500, P.O Johnson wrote:
> ... If the shape and attack angle of the foil are vital, how can
> an airplane remain stable while flying upside down?
>
> poj
> Collin County College

By 'stable' I expect Paul referred to 'in steady inverted flight'.

 One sees occasional flypast photos of inverted light planes with
asymmetrical foils at airshows. It is often noticeable that their
 tail is 'hanging down' quite noticeably.

 This is to overcome both the normal incidence with which wings
of non aerobatic planes are set on the fuselage - typically a few
 degrees and then to provide some angle of attack which provides
sufficient lift to balance the airplane's weight.

 This goes some way to explaining why such planes have rather high
 horse power engines for their size: an upside down profile is a
draggy object.


brian whatcott <inet@intellisys.net>
Altus OK