Re: Misconceptions: Physics of Flight

[brian whatcott <inet@INTELLISYS.NET>]

At 09:36 8/14/99 -0400, John Denker wrote:

> >    But people conceive that the low trailing edge lifted the
> > wing - wrongly. The low wing [*trailing edge*] dropped and slowed
> > the Flyer as it turned towards it.

> The Wrights discovered that they needed to deflect the rudder
> to overcome this adverse yaw, to keep the airplane pointing
> the same way it is going.

 As I say, this misunderstanding is very widely held.
The folks who inherited the Wright heritage (of flying an airplane
with very low power engine) realised the virtues of the Flyer when
they arranged the first really controlable MAN-powered airplane so
as to drop the trailing edge of the wing they wished to drop and
 turn towards.  Paul McCready acknowledged his debt when describing
Gossamer Condor etc.

However, if you take flying lessons in a light airplane, as other
contributors undoubtedly have, you will find that there are some
current aircraft that DO react in this orthodox way: adverse drag
provides a perverse effect when attempting to roll left using aileron
control only: the nose yaws to the right initially.
This was however NOT the Flyer's modus.

So called 'differential aileron control' can often abolish this unwanted
effect by increasing the amplitude of the up aileron's deflection over that
of the down going aileron. This increases the drag contribution of the
inside wing over that of the outside one.

   On one thing it's easy to agree with other posters here: fluid dynamics
can be complicated, and lays conceptual traps at many levels.


brian whatcott <inet@intellisys.net>
Altus OK