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Re: [OM] IMG: Vultures

Subject: Re: [OM] IMG: Vultures
From: "Jim Nichols" <jhnichols@xxxxxxxxxxxxx>
Date: Tue, 10 Jan 2012 15:49:02 -0600
Hi Chris,

It just takes us aero engineers a while to get our ideas across. ;~)

When I was in engineering school, late 40s-early 50s, Dr. Gus Raspett was 
the head of the Aerophysics Dept.  One of his interests was the flight of 
birds, and finding ways to adapt their techniques to manned aircraft.  Gus 
was an avid sailplane pilot, and trained a turkey vulture to allow his 
sailplane to circle in the same thermal that the vulture was using.  He made 
a lot of photos of the wing shapes and tip movements.

He was also interested in boundary layer control, and modified a Super Cub 
with a perforated wing surface, to pump off the boundary layer.  He was 
demonstrating this airplane to a British scientist when something went wrong 
at low altitude, and Gus was killed.  This was many years ago, and I can't 
recall the fate of his companion.

The tip winglet is something that should have been realized early on.  With 
low pressure on the upper wing surface, and higher pressure beneath, it is 
not too hard to realize that these pressures will try to equalize at the 
tip, causing a tip vortex to form.  The winglet minimizes the strength of 
the vortex, hence reducing drag.  This was done for years by experimenters 
using tip plates to increase effective aspect ratio and reduce vorticity, 
but the winglet is a much more elegant solution.

Jim Nichols
Tullahoma, TN USA
----- Original Message ----- 
From: "Chris Barker" <ftog@xxxxxxxxxxxxxx>
To: "Olympus Camera Discussion" <olympus@xxxxxxxxxxxxxxxxx>
Sent: Tuesday, January 10, 2012 3:24 PM
Subject: Re: [OM] IMG: Vultures


> Thanks, Jim.  I love big birds; their flight systems are easier to see and 
> to appreciate.
>
> Who would have thought, for instance, that it would take aero engineers so 
> long to emulate the tipped up wingtips so as to reduce drag?
>
> There's a TV programme called Earthflight on in the UK at present; there 
> are some fantastic shots of big birds in flight, but this evening watching 
> a fish eagle lurking over grizzlies fishing, the stance of the bird was 
> just like a fighter pilot's.
>
> Now the turkey vultures are not quite as attractive as the eagles, but 
> their abilities are just impressive.
>
> Chris
>
> On 10 Jan 2012, at 19:56, Jim Nichols wrote:
>
>> It was that kind of a day.  Even the Turkey Vultures had to take a break. 
>> Dampness, some fog, lousy light.  But, I couldn't pass up the chance for 
>> a photo.
>>
>> Three of the five vultures in a dead oak tree:
>> http://gallery.leica-users.org/v/OldNick/Turkey+Vultures+09.jpg.html
>>
>> The leader took the high ground:
>> http://gallery.leica-users.org/v/OldNick/Turkey+Vulture+13.jpg.html
>>
>> He decided it was time to leave:
>> http://gallery.leica-users.org/v/OldNick/Time+to+Leave+18.jpg.html
>>
>> Departure:
>> http://gallery.leica-users.org/v/OldNick/Departure+22.jpg.html
>>
>> Olympus E-510 with Leica Telyt-R 250/4
>
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