Re: FLYING MACHINES was physics of flight

[Ludwik Kowalski <KowalskiL@MAIL.MONTCLAIR.EDU>]

Thanks John for noticing the "typing error". The correct
sentence (the helicopter item at the end) should have been:

> The role of its spinning blades is to produce both the lift
> and the THRUST (by pushing air down and backward).

The word "drag" (instead thrust) was a mistake.

It would be useful if you could produce a better outline
for those of us who must teach the topic in the spirit of
"less is more" philosophy. Fell free to use my preliminary
outline in any way you wish (repair what you want, add
what can be helpful, delete what is not appropriate, etc.)

I know how much you know; the task is to show how
to make it meaningful in an introductory physics course.
Show how to create a "physics" explanation with the
"insights" when time and backgrounds are limited.


John Denker wrote:

> There's nothing wrong with this approach as far as it goes.  (You can
> easily repair most of the defects pointed out above.)  But it leaves out
> some important points.  In particular, there's a pretty big difference
> between lift and drag.  Real wings have *amazingly* good lift-to-drag
> ratios, and saying the airplane and the rock are "just projectiles" misses
> the point.
>
> Finally, this doesn't sound like a *physics* explanation.  It seems to say
> "the airplane flies because it flies".  It offers no particular insights --
> even qualitatively -- as to how the lift or drag should depend on size,
> airspeed, shape, angle of attack, air density, or anything else.

Ludwik Kowalski