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Old October 30th 08, 09:32 PM posted to rec.aviation.homebuilt
Steve Hix
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Posts: 340
Default Lancair Legacy Design Flaw?

In article ,
"Gregory Hall" wrote:

"Dennis Johnson" wrote in message
. ..

I find your strange posting to be quite offensive in its serious charges
which are totally unfounded. As others have already pointed out, you are
fundamentally incorrect about the purpose of the horizontal stabilizer.
The horizontal tail holds the nose up, not down. Your assertion about the
Legacy's stall recovery just makes no sense at all.


I think it makes good sense.


It makes absolutely backwards sense.

You need to do a bit more handwaving. Really.

Better, go find a local park and play on the teeter-totter for a while.

I'm serious.

Look at the size of that engine up front. Looks
like a P-51 Mustang for pity sake.


For fairly vague, and small, values of "P-51".

When you're being pulled along by that
big prop and heavy, powerful engine it pulls the nose of the aircraft down.


Even when the engine is not running, it's pulling the nose down. It's
called "weight", and it's constant.

The horizontal stabilizers have to counteract this force by putting an
upward force on the nose by pushing the tail down.


Good so far.

If and when the engine suddenly dies the aircraft will pitch up suddenly


Nope. It will pitch *down* as the aircraft decelerates.

Think about it; the airflow over the stabilizer/stabilator/tail feathers
provides the down force at one end of the lever to compensate for the
downforce (engine/prop) at the other end of the lever.

Slow down and the down force at the tail end decreases, so that the down
force provided by the engine/prop is no longer exactly counterbalanced.

The aircraft will begin to accelerate downward as it pitches down (*not*
up). Given time and altitude, it will eventually stabilize in a descent,
at whatever speed it was trimmed for at the time the engine quit.

and since the size of the
stabilizers are so puny they might easily stall and be unable to counteract
the upward pitch at the nose resulting in a tail down death spiral.


How in the world do you get this upward pitch? The engine is heavy, not
lighter than air, you know.

By the way, the Lancair Legacy is the most fun civilian airplane I've
flown and is the main reason I returned to general aviation after a
decades-long absence. I'm sure there is a Legacy near you and I'll bet
its pilot would be happy to take you for a ride. You can see for yourself
what a great airplane it is.


It looks too much like an irresponsible, hot rod, stunt plane to me.


Looks like an aircraft designed for moderately high cruise speeds.

Is it any wonder so many companies offering homebuilt aircraft have gone out of
business?

http://www.homebuilt.org/aircraft/nolonger.html


They mostly failed due to not enough customers, or by being inadequately
capitalized, and for other business reasons.

Or are you arguing that aircraft similar to the old Aeronca 7AC, Chief
or Sedan are gone now because they were all "irresponsible, hot rod,
stunt planes"?

[ Say, you're not related to the fellow who was trying to drum up
support for closing down airpark housing developments for being too
dangerous, are you? ]

This is the safest homebuilt IMO.(VariEze ). The canard makes it foolproof.

http://video.google.com.au/videoplay...77166441&hl=en


Tell it to some users of that type of aircraft who found more excitement
than they'd bargained for if they flew into light rain...

Or, say, John Denver, who was killed flying one a couple years back.

The canard didn't save him, did it?

As for your movie, do you have any idea what the aircraft's sink rate
might be while it isn't stalling there?