Lancair Legacy Design Flaw?

"Vaughn Simon" wrote in message
...

"Gregory Hall" wrote in message
...


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

Well, you sucked me in at first, so on a troll scale of zero-to-10 you
rate at least a five. How are things in France?

Vaughn


France? I don't live in France. I built and used to fly a Rotec Rally 2B
many years ago. It was a tail dragger with a high wing and the motor was
mounted atop the wind with a pusher prop.

When I got it trimmed out correctly at cruise speeds I could lean forward in
the seat to nose it down and lean back in the seat to nose it up. Even as
well-balanced as it was at about half throttle, when the engine quit it
would pitch up immediately and drastically because the high engine placement
and pusher prop had enough leverage so that the proper trim at the tail
counteracted the nose down force of the engine and prop. If you didn't
immediately push the stick way forward when the engine quit it was a matter
of seconds before it would nose up fast and stall and then you would have no
control at all from the stick until it fell for a while and the nose dropped
(thank god for that) so you could gain speed provided you had enough
altitude to get control of it again. But it didn't glide too well being a
single surface wing with wire bracing. Perhaps 2:1 glide ratio. But it was
easy to land with no power but you had to come in hot and steep and at the
last second pull back on the stick and flare it.

It looks to me like the Legacy would act pretty much the same if the engine
quit.

--
Gregory Hall

On Oct 30, 5:12*pm, "Gregory Hall" wrote:
"Vaughn Simon" wrote in message

...



"Gregory Hall" wrote in message
...

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

* Well, you sucked me in at first, so on a troll scale of zero-to-10 you
rate at least a five. *How are things in France?

Vaughn

France? *I don't live in France. I built and used to fly a Rotec Rally 2B
many years ago. It was a tail dragger with a high wing and the motor was
mounted atop the wind with a pusher prop.

When I got it trimmed out correctly at cruise speeds I could lean forward in
the seat to nose it down and lean back in the seat to nose it up. Even as
well-balanced as it was at about half throttle, when the engine quit it
would pitch up immediately and drastically because the high engine placement
and pusher prop had enough leverage so that the proper trim at the tail
counteracted the nose down force of the engine and prop. If you didn't
immediately push the stick way forward when the engine quit it was a matter
of seconds before it would nose up fast and stall and then you would have no
control at all from the stick until it fell for a while and the nose dropped
(thank god for that) so you could gain speed provided you had enough
altitude to get control of it again. But it didn't glide too well being a
single surface wing with wire bracing. Perhaps 2:1 glide ratio. But it was
easy to land with no power but you had to come in hot and steep and at the
last second pull back on the stick and flare it.

It looks to me like the Legacy would act pretty much the same if the engine
quit.

--
Gregory Hall

Oh for gawd sake, you are talking about two totally different designs
and the aerodynamics of the two are totally different. The Lancair is
NOT a pusher and the engine is mounted forward of the CG instead of on
top of it. When the engine quits it will not pitch upward. The plane
you flew had the engine well above the center of gravity with a pusher
prop and as a result produced a force that pushed the nose of the
aircraft down. The two planes would not act pretty much the same at
all. The weight of the engine on the Legacy is forward of the CG and
as a result always pulling the nose of the plane down. The counter to
the nose down is the horizontal stabilizer and the elevator. Look at
the angle of incedence on the Horizontal Stabilizer and you will find
a slight downward angle, not an upward angle as is common on the
wing. This counteracts the force from the weight of the engine. An
engine out condition will not have a significant effect on pitch until
the airspeed changes and that will result in a nose down, not nose up
pull.

In article ,
"Gregory Hall" wrote:

France? I don't live in France. I built and used to fly a Rotec Rally 2B
many years ago. It was a tail dragger with a high wing and the motor was
mounted atop the win[g] with a pusher prop.

When I got it trimmed out correctly at cruise speeds I could lean forward in
the seat to nose it down and lean back in the seat to nose it up.

Sort of like a Taylorcraft or Cessna 140 or similar small aircraft.

Even as
well-balanced as it was at about half throttle, when the engine quit it
would pitch up immediately and drastically because the high engine placement

.... Placed the thrust line enough above the center of drag that adding
power caused a downward pitch moment, and reducing power resulted in a
upward pitch.

and pusher prop had enough leverage so that the proper trim at the tail
counteracted the nose down force of the engine and prop.

Which is what the horizontal stab/stabilator is for.

If you didn't
immediately push the stick way forward when the engine quit it was a matter
of seconds before it would nose up fast and stall and then you would have no
control at all from the stick until it fell for a while and the nose dropped
(thank god for that) so you could gain speed provided you had enough
altitude to get control of it again. But it didn't glide too well being a
single surface wing with wire bracing. Perhaps 2:1 glide ratio. But it was
easy to land with no power but you had to come in hot and steep and at the
last second pull back on the stick and flare it.

It looks to me like the Legacy would act pretty much the same if the engine
quit.

Except for the Legacy not incorporating those design elements that
result in the pitch/power response of the Rotec Rally. The Rally needs a
lot of upward pitch dialed in for level cruise (which ought to be
contributing a lot of drag as an added bonus), giving you some nasty
response to losing power.

In particular, both thrust and drag components in the Legacy are much
closer in alignment, resulting in much less pitch change when power
changes.

The two aircraft behave very differently in many aspects, and the Legacy
not much at all as you've asserted.

In article ,
"Gregory Hall" wrote:

"Vaughn Simon" wrote in message
...

"Gregory Hall" wrote in message
...


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

Well, you sucked me in at first, so on a troll scale of zero-to-10 you
rate at least a five. How are things in France?

Vaughn


France? I don't live in France. I built and used to fly a Rotec Rally 2B
many years ago. It was a tail dragger with a high wing and the motor was
mounted atop the wind with a pusher prop.

When I got it trimmed out correctly at cruise speeds I could lean forward in
the seat to nose it down and lean back in the seat to nose it up. Even as
well-balanced as it was at about half throttle, when the engine quit it
would pitch up immediately and drastically because the high engine placement
and pusher prop had enough leverage so that the proper trim at the tail
counteracted the nose down force of the engine and prop. If you didn't
immediately push the stick way forward when the engine quit it was a matter
of seconds before it would nose up fast and stall and then you would have no
control at all from the stick until it fell for a while and the nose dropped
(thank god for that) so you could gain speed provided you had enough
altitude to get control of it again. But it didn't glide too well being a
single surface wing with wire bracing. Perhaps 2:1 glide ratio. But it was
easy to land with no power but you had to come in hot and steep and at the
last second pull back on the stick and flare it.

It looks to me like the Legacy would act pretty much the same if the engine
quit.

Greg,

What was happening to you was not caused by the *weight* of the engine,
but the change from higher than CoM thrust creating a pitch down torque,
to higher than CoM drag creating a pitch up torque.

Congratulations: you've just rediscovered one disadvantage of having a
thrust line that doesn't go through the centre of mass.

--
Alan Baker
Vancouver, British Columbia
http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg

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?

In article ,
"Gregory Hall" wrote:

"Dennis Johnson" wrote in message
. ..

"Gregory Hall" wrote in message
...
http://www.youngeagles.org/photos/ga...Legacy2000.jpg


Look at the picture. It's easy to see why the Lancair is dangerous. The
horizontal stabilizers appear to be on the too small side. This would
result in their stalling before the wing. Then the aircraft would pitch
up making the main wing stall. Ill-conceived, IMO.

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. Look at the size of that engine up front. Looks
like a P-51 Mustang for pity sake. When you're being pulled along by that
big prop and heavy, powerful engine it pulls the nose of the aircraft down.
The horizontal stabilizers have to counteract this force by putting an
upward force on the nose by pushing the tail down. If and when the engine
suddenly dies the aircraft will pitch up suddenly 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.

More nonsense. The loss of thrust won't result in a sudden pitch-up. The
engines mass and the force of gravity acting on that mass don't
disappear when it stops producing power.


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

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

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

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

Anyone who thinks an aircraft can be made "foolproof" is a fool who
shouldn't be flying.

--
Alan Baker
Vancouver, British Columbia
http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg

Alan Baker wrote:

Anyone who thinks an aircraft can be made "foolproof" is a fool who
shouldn't be flying.


You won this round, Alan!

--

Richard

(remove the X to email)

In article ,
cavelamb himself wrote:

Alan Baker wrote:

Anyone who thinks an aircraft can be made "foolproof" is a fool who
shouldn't be flying.


You won this round, Alan!

Thanks, I guess. But I prefer to win against an opponent who's a little
tougher than that...

:-)

--
Alan Baker
Vancouver, British Columbia
http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg

In article
,
Alan Baker wrote:


Anyone who thinks an aircraft can be made "foolproof" is a fool who
shouldn't be flying.

Like Mignet and his Pou-du-Ciel (Flying Flea).

Everything going swimmingly, unless you manage to somehow get it
inverted.

At which point it becomes so stable that it would stooge about until it
ran out of fuel, no way to bring it upright again.

"Steve Hix" wrote
Like Mignet and his Pou-du-Ciel (Flying Flea).

Everything going swimmingly, unless you manage to somehow get it
inverted.

At which point it becomes so stable that it would stooge about until it
ran out of fuel, no way to bring it upright again.

How about half of an outside loop?
--
Jim in NC