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From:    Bill Lais
Date:    Wed, 11 Mar 1998 14:56:06 EST
To:      rickhave@juno.com, cavers@www.geek.com
Subject: Re: Bungee Wings: A Real Drag?
Excellent example of the Scientific Method in action.  I would be concerned
that the flow characteristics of water would be different from that of air,
due to the vast differences in viscosity and specific weight.  But I'm sure
the same result would be observed nonetheless...

In a message dated 98-03-11 14:42:13 EST, you write:

<< Recently, myself and several  engineering colleagues were performing wind
 tunnel tests on a new airfoil, under design within our division at
 Grumman Aerospace.  Somehow the subject of technical diving and buoyancy
 compensation systems came up.  We got to talking about the drag profiles
 on certain manufacturers brands of BCs and one of the guys suggested that
 we run some actual aerodynamics tests.  A couple of the engineers are big
 time mixed gas wreck divers with lots of experience on deep wrecks such
 as the Doria and Republic. They were touting the benefits of the OMS
 bungeed wings and I was arguing that the Dive Rite wings provided a
 vastly improved knife edge profile with far less drag.

 A simple surface area calculation showed that the bungeed wings had an
 area of over  12 square feet inflated.  This is over 4 times the area of
 the Dive Rite wings.  The huge box like profile caused immense drag and
 horrendous turbulence when we observed it in the wind tunnel.  The bungee
 cords caused massive vorticial eddies all along the wings.  It was very
 interesting to observe the colored smoke trails streaming in chaotic
 cyclonic patterns  around the brightly colored bungees. It was almost
 psychedelic. These results were in stark contrast to the Dive Rite wings
 which showed very little turbulence and almost hydrodynamic behavior such
 that the wings probably generate lift when there is current flow across
 them. Needless to say, the extra inflator assembly on the OMS wings
 created marked disturbances in the laminar flow field of the trace smoke.
  When the wings were in the collapsed state the turbulent patterns were
 even more spectacular, clearly discrediting  the myth that the bungees
 reduce drag by supposedly decreasing the surface area.

 After the tests there were no more arguments except about what other uses
 these wings might be put to.  One of the guys suggested we employ them as
 portable cushions for homeless people, another suggestion involved using
 them as toxic waste storage containers.

 There was much discussion and speculation about the personality and
 physical characteristics of the rocket scientist who had designed these
 wings.  I suspect that the same individual carries a fire extinguisher in
 the front seat of his car along with the spare gas can.

 Rick >>
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