Archived posting to the Leica Users Group, 2002/03/06

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Subject: RE: upside-down airplanes (was: [Leica] Optical Question)
From: Rolfe Tessem <rolfe@ldp.com>
Date: Wed, 06 Mar 2002 14:39:11 -0500
References: <20020306191420.7847.qmail@earthlink.net>

- --On Thursday, March 07, 2002 03:14:19 AM +0800 Douglas Herr 
<telyt@earthlink.net> wrote:

> Ernest Nitka wrote:
>
>> why is that airplanes can fly upside down - if
>> flying upright caused a vacuum just above the wing
>> creating lift then flying upside down should cause
>> the wing to move down. This has bothered me for
>> near on 2 decades.  I get bothered easily
>>
>> ernie
>>
>
> The airplane's wing is designed to produce lift efficiently at it's
> normal angle of attack but it can produce additional lift inefficiently
> by increasing the angle of attack (until it stalls).  The upside-down
> airfoil relies on a high angle of attack to produce lift but does so very
> inefficiently.


All true.

However, airplanes designed for aerobatic use have a so-called "symetrical" 
wing, such that both top and bottom are lifting airfoils.

In fact, when doing four-point rolls -- where the airplane is in knife-edge 
flight for two of the points -- the fuselage itself is the "wing" and is 
providing significant lift at those moments.

To keep this on topic, I personally always carry one of my Leicas when 
doing this kind of thing. :-)


Rolfe

- --
Rolfe Tessem
rolfe@ldp.com
Lucky Duck Productions, Inc.

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In reply to: Message from "Douglas Herr" <telyt@earthlink.net> (RE: upside-down airplanes (was: [Leica] Optical Question))