Dear Burt

A student pilot with 5 hours bought an experimental taildragger
"midget mustang II" and proceeded to reconstruct it into a
nosedragger. When he was done, I convinced him to fly with the
old owner, and to get the former owner to train his CFI.

This happened. During the test flights the stall was 82mph IAS.
The student also mentioned the engine was "sometimes rough
or unresponsive." I mentioned quite plainly that if it failed
on takeoff, he would die. And I told him the squared business.

So he redid the leading edge. No difference. Same stall speed,
and a dramiatic, instant wing drop during stall, with a spin
entry and 500 foot recovery (if you were doing it intentionally).

I recommended avoiding full stall landings for a bit, and also
calibrating the ASI.

Turns out the stall is 56mph (48 kts?). He's working on the
calibration some more now.

And then I mentioned to him again that he would still be severely
injured. 35 knot stall in a Cessna 152 vs 48 knots in a
Mustang II means about 2 times as much energy. Then, drop
the wing at stall and cartwheel into the ground, and it's
worse.

So he's working on getting the stall speed down with fences.
Hmmmm...I hope it works.

All this because the published performance was better. 1100 NM
range. And speed. But no safety whatsoever.

I've told people the difference between a 2-33 and an ASW-20
is simple. Just take all of the built in safety for the
design and replace it with higher workload and
higher required pilot proficiency for the same level of safety.
As Bob K. is apt to say "it goes like stink." The
downside is the naked edge of safety vs. performance.

In article ,
Nyal Williams wrote:
At 17:30 05 February 2005, Vaughn wrote:

'Vaughn' wrote in message
...



the simple formula 'E= M * V^2',

Typo. Actually, the formula is 'E=.5M * V^2'
but the important thing is
the relationship between mass and velocity. Double
the mass of your glider and
you 'only' double the landing energy, double your speed
and you quadruple the
energy!

Vaughn


Thank you for that simple statement. It is clear and
concise, the way our instructions should be. Many of
us and many, many more do not 'read' formulae. I have
no personal knowledge of the meaning of the '^' symbol
in the above equation, but I know very well the truth
of what it purports to state.





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Mark J. Boyd