Lancair Legacy Design Flaw?

"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

"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
,
BobR wrote:

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.

The one thing not quite right is that there is no important difference
between tractor vs. pusher configurations with respect to directional
stability.

Like some of the early rocket designers (e.g. Goddard), you are falling
into the fallacy that somehow pulling is more stable than pushing. This
is not so.

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

On Oct 31, 2:09*pm, Alan Baker wrote:
In article
,





*BobR wrote:
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.

The one thing not quite right is that there is no important difference
between tractor vs. pusher configurations with respect to directional
stability.


Not sure what you are replying to but I never said anything about
directional stability. The discussion was regarding pitch forces.

Like some of the early rocket designers (e.g. Goddard), you are falling
into the fallacy that somehow pulling is more stable than pushing. This
is not so.

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

- Show quoted text -

In article
,
BobR wrote:

On Oct 31, 2:09*pm, Alan Baker wrote:
In article
,





*BobR wrote:
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.

The one thing not quite right is that there is no important difference
between tractor vs. pusher configurations with respect to directional
stability.


Not sure what you are replying to but I never said anything about
directional stability. The discussion was regarding pitch forces.

Which is essentially the same thing.

Pusher or puller doesn't affect pitch forces. What affects pitch forces
is the length of the moment arm between the centre of mass and the
thrust line.


Like some of the early rocket designers (e.g. Goddard), you are falling
into the fallacy that somehow pulling is more stable than pushing. This
is not so.

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

- Show quoted text -

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

In article
,
Alan Baker wrote:

Pusher or puller doesn't affect pitch forces. What affects pitch forces
is the length of the moment arm between the centre of mass and the
thrust line.

Or center of drag vs thrust line?

On Oct 31, 2:59*pm, Alan Baker wrote:
In article
,





*BobR wrote:
On Oct 31, 2:09*pm, Alan Baker wrote:
In article
,

*BobR wrote:
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.

The one thing not quite right is that there is no important difference
between tractor vs. pusher configurations with respect to directional
stability.

Not sure what you are replying to but I never said anything about
directional stability. *The discussion was regarding pitch forces.

Which is essentially the same thing.

Pusher or puller doesn't affect pitch forces. What affects pitch forces
is the length of the moment arm between the centre of mass and the
thrust line.



Like some of the early rocket designers (e.g. Goddard), you are falling
into the fallacy that somehow pulling is more stable than pushing. This
is not so.

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

- Show quoted text -

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

- Show quoted text -

Again Alan, I never indicated any issue with pusher vs tractor. The
layout of the two planes being discussed is totally different. One
involved a tractor configuration with the thrust line being very near
the vertical center of gravity. The second involved an plane with the
engine mounted on a pylon with a thrust line well above the vertical
center of gravity. This configuration, rather it be a tractor or
pusher will induce nose down forces that must be countered by the
horizontal stabilizer with an upward force. This is contrary to the
standard configuration which requires a downward force to counter the
weight of the engine. The post I was replying to was trying to link
the characteristic of the pylon mounted configuration to the Legacy.

Alan Baker wrote:


The one thing not quite right is that there is no important difference
between tractor vs. pusher configurations with respect to directional
stability.

Like some of the early rocket designers (e.g. Goddard), you are falling
into the fallacy that somehow pulling is more stable than pushing. This
is not so.


Actually, there is some difference in stability between tractor and pusher.

It's because of the volumn necesary to envlose the engine.
And the propeller disk.

Area (volumn) ahead of the CG should be considered destabalizing.

Conversly, (expecially propellers) aft of the CG contribute to better
stability.


--

Richard

(remove the X to email)

In article ,
cavelamb himself wrote:

Alan Baker wrote:


The one thing not quite right is that there is no important difference
between tractor vs. pusher configurations with respect to directional
stability.

Like some of the early rocket designers (e.g. Goddard), you are falling
into the fallacy that somehow pulling is more stable than pushing. This
is not so.


Actually, there is some difference in stability between tractor and pusher.

It's because of the volumn necesary to envlose the engine.
And the propeller disk.

Area (volumn) ahead of the CG should be considered destabalizing.

Conversly, (expecially propellers) aft of the CG contribute to better
stability.

That's a separate issue from tractor vs. pusher. True, the layout can
influence the volume question, but one is not a function of the other.

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