This is one thing I've never understood.  Maybe someone can explain it to me.
Why was the descent rate so much slower than predicted for the Velocities in
the deep stall?  Like the report said, 1200 fpm, "several" times slower than
theory would predict, according to Rutan.

Is there some mysterious unkown form of lift occurring? I think Rutan was
going to investigate but I never heard what his conclusions were.

I know Nat Puffer did a lot of tests in the Cozy also.

I think there were some Long-Ez accidents that were caused by deep stall
that were fatal, unlike the Velocity incidents.  Might have to research those
incidents to be sure.

Bill Freeman, do you have any answers on this?
--
Perry J. Mick
Mick Duckt N7XR
http://www.ductedfan.com

Bill Freeman wrote:

  A Long Eze went in in a deep stall in a toilet paper cutting competition,
impacting on
hard desert.  The pilot had a serious back injury and there was no sign of
significant fwd motion at impact.  Video footage was examined by Rutan,
and it debunked the "falling slower than it should" theory.  Hitting the water
and having 2" of very stiff foam and 2-4" of seat unholstery foam apparently
mitigates the deceleration enough to survive.  Temper foam would help a lot.

Last I heard Burt doesn't believe in the 'special lift' theory for the LE
design.

The lack of lower winglets was found to substantially increase the chance of
a deep stall in the full-sized trailer-wind tunnel testing done by Puffer.

Bill

Also in the case of going into the water the main wheels and landing gear entering
the water and the ground affect of the wing in proximity of the water
mitigates the impact.

On land the failure of the fixed main landing gear also helps mitigate the impact.
Same for the ground effect.

There is a formula. As I recall it is feet per second divided by
stopping feet (height of landing gear and seat cushions) gives acceleration
somehow. One G is a change in velocity of 32 feet per second per second.
If you are sinking at 2400 FPM or 40 feet per second and you stop
on one second that is 40 feet per second per second or about 1.25 G's 
If you stop in .5 second that is 2.5 G's and so on. Translate that
to distance.

Something like that. Its late.  

There is another subtle factor and if it comes down significantly nose high
some of the vertical momentum will be converted to angular momentum as the 
nose accelerates downward when the mains touch.

These factors are far more plausible than some magical force holding up
canards.

Paul Lamar
 
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