Aerosport LH-10

On Dec 20, 12:53*am, "Flash" wrote:
"Richard" wrote in message

Was the craft pictured above flown in to that show or trucked in?

Flash

ha ha, maybe they pieced it together like a leggo. But
seriously, I have built a database of every image and article
on that bird, including 2 videos of it in flight.

There are numerous reviews from several reputable
sources, and the company also produces a small plane
similar to a little cessna.

The test pilot is an experienced airman from the
military, with an extensive track record.

All indications are, it *will* hit 200 kts, and a cruise
of 120kts is a comfortable rate, using a pittance of
gas.
Considering the alternatives, to get that kind of
performance in a composite plane,you're gonna pay
200 grand for a diamond star, 400k Cirrus SR series,
or 600K for the Lancair/Columbia/Cessna 400.

Heres my criteria:

1) Range- 1000 miles
2) Max speed- 200 kts minimum
3) Low wing profile
4) Modernistic technology
5) 2 leather seats
6) Low spin/stall speed

I just like the way it looks. It takes the concept
of the "Bedee" minijet and brings it beyond the
unrealistic toy to possibly practical transportation.
Some have tagged it for military applications.

Mark

"Mark" wrote

I just like the way it looks. It takes the concept
of the "Bedee" minijet and brings it beyond the
unrealistic toy to possibly practical transportation.
Some have tagged it for military applications.

I just want to see how they deal with the harmonic resonance issues of a
long drive shaft to the propeller (longer than the BD-6, thus with more
complexities present) and how they succeeded where Bede (and others) failed.

Unless they can show you a craft where the same engine, PSRU bearings, and
prop shaft and prop have ALL gone more than 500 hours with all the same
original components still intact, there should be warning flags going off,
there.

People bought the BD-5 after seeing some videos of a flying model, not
knowing that the engine, or speed reducer or bearings or mounting, or
_something_ tore itself apart after every few flights. Those same failures
due to the resonance issues are what eventually killed the concept. They
could not make it work, because when one part was beefed up, another failed,
and so on. It is a subject of such complexity, that few fully understand
it, and even fewer know how to deal with it.

If you have not read up on these problems, you owe it to yourself to get
educated. There are volumes of work on the subject, with some fascinating
reading. Someone else will have to point you to it, because I don't have
the references bookmarked. (I'm sure some do.)

So for now, I'm going to have to be like a person from Okalahoma. Show me.
Convince me.

I would love to see it triumph. It is cool looking. But if it was easy,
there would be a few dozen look a likes buzzing around out there.
--
Jim in NC

On Sun, 21 Dec 2008 00:14:22 -0500, "Morgans" wrote:

If you have not read up on these problems, you owe it to yourself to get
educated. There are volumes of work on the subject, with some fascinating
reading. Someone else will have to point you to it, because I don't have
the references bookmarked. (I'm sure some do.)






So for now, I'm going to have to be like a person from Okalahoma. Show me.
Convince me.

--
Jim in NC

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

OKLAHOMA?

Last I heard...
MISSOURI was the SHOW ME state!
When did it change and who did it?



Baryard BOb - Kansas City, MO.

"Barnyard BOb" wrote


Last I heard...
MISSOURI was the SHOW ME state!
When did it change and who did it?

****.

OK, one of them there damn states way West from here!

So what the hell is Oklahoma's motto/excuse from keeping the East Coast
further away from California? g
--
Jim in NC

"Morgans" wrote in message
...

"Mark" wrote

I just like the way it looks. It takes the concept
of the "Bedee" minijet and brings it beyond the
unrealistic toy to possibly practical transportation.
Some have tagged it for military applications.

I just want to see how they deal with the harmonic resonance issues of a
long drive shaft to the propeller (longer than the BD-6, thus with more
complexities present) and how they succeeded where Bede (and others)
failed.

Unless they can show you a craft where the same engine, PSRU bearings, and
prop shaft and prop have ALL gone more than 500 hours with all the same
original components still intact, there should be warning flags going off,
there.

People bought the BD-5 after seeing some videos of a flying model, not
knowing that the engine, or speed reducer or bearings or mounting, or
_something_ tore itself apart after every few flights. Those same
failures due to the resonance issues are what eventually killed the
concept. They could not make it work, because when one part was beefed
up, another failed, and so on. It is a subject of such complexity, that
few fully understand it, and even fewer know how to deal with it.

If you have not read up on these problems, you owe it to yourself to get
educated. There are volumes of work on the subject, with some fascinating
reading. Someone else will have to point you to it, because I don't have
the references bookmarked. (I'm sure some do.)

So for now, I'm going to have to be like a person from Okalahoma. Show
me. Convince me.

I would love to see it triumph. It is cool looking. But if it was easy,
there would be a few dozen look a likes buzzing around out there.
--
Jim in NC

These problems have been solved many times in the past and all of the
successfull solutions add both weight and complexity--although usually only
to a modest degree.

The development of the BD-5 was certainly an excellent cautionary tale of
how things can go wrong, and fail to improve with the wrong solutions
applied. There was an excellent article from Contact! Magazine, which used
to be available on the web and may still be available as a reprint.
Basically, in the case of the original BD-5 prototype, there was a resonance
just below idle speed which affected both the startup and the shutdown of
the engine. I no longer recall whether any other resonant frequencies, or
unusual wear conditions, became evident at a later time.

In any case, to the best of my knowledge, Molt Taylor was successfull in
solving all of these sorts of problems with his AirCar, IMP, and Mini-IMP.
The Leone brothers also solved some interesting bearing wear problems with
the twin-engine power pack in their highly modified Cozy-IV.

IIRC, all of the successfull solutions have involved 3 elements:
1) non linear rates--because resonance requires a linear spring rate,
2) more compliance, and
3) a propeller that is not bolted directly to the engine is NOT a flywheel.

All of those elements of the solution tend to add cost, weight, and
complexity--and then there are also the issues directly related to the
reduction drive.

Really, the more I learn about the alternatives, the more attractive the
"standard" solution becomes.

Peter

On Dec 21, 9:35*am, "Peter Dohm" wrote:
"Morgans" wrote in message

...





"Mark" wrote

I just like the way it looks. It takes the concept
of the "Bedee" minijet and brings it beyond the
unrealistic toy to possibly practical transportation.
Some have tagged it for military applications.

I just want to see how they deal with the harmonic resonance issues of a
long drive shaft to the propeller (longer than the BD-6, thus with more

Thank you for your input.

Just yesterday I watched a video of an aerocar in mint
condition rolling to a stop, and when asked, they tell the
interviewer that it's a 1955 model and they love it. (early
pusher propeller).

A couple of brothers did a home-built pusher propeller
to show their neighbors. They were the first on their block.
Orville and Wilbur I think they were called.

Today seems Cirrus is all the rage with their SR series,
but look at their very first plane, the prototype introduction
of the VK-30. It looks like a jet! But out of my price range.


For me these are probably some of the considerations for
a conventional tractor propelled verses a push propeller:


ADVANTAGES

Efficiency can be gained by mounting a propeller behind the fuselage,
because it re-energizes the boundary layer developed on the body, and
reduces the form drag by keeping the flow attached. However, this
effect is not nearly as pronounced on a small airplane as it is on a
submarine or ship, where it is quite important due to the much higher
Reynolds number at which they operate.

Wing efficiency increases due to the absence of prop-wash over any
section of the wing.

Rear thrust is somewhat less stable in flight than with a tractor
configuration. This has the potential to make an aircraft more
maneuverable.

Visibility of a single-engined airplane is improved because the engine
does not block forward vision. Consequently, this configuration was
widely used for early combat reconnaissance aircraft, and remains
popular today among ultralight aircraft.

The propeller of a single-engined airplane can be placed closer to the
elevators and rudder. This increases the speed of the air flowing over
the control surfaces, improving pitch and yaw control at low speed,
particularly during takeoff when the engine is at full power. This can
be beneficial while bush flying, especially when taking off and
landing on airstrips bounded by obstacles that must be avoided while
the airplane is moving slowly.

The engine is mounted behind the crew and passenger compartments, so
fuel does not have to flow past personnel, any leak will vent behind
the aircraft, and any engine fire will be directed behind the aircraft
(however, this arrangement puts the empennage at greater risk, if
there is one -- but this is less of an issue if the fire occurs on, or
as a consequence of, landing). Similarly, propeller failure is
unlikely to directly endanger the crew.

And then we have the DISADVANTAGES-


The pusher configuration can endanger the aircraft's occupants in a
crash or crash-landing[citation needed]. If the engine is placed
behind the cabin, it may drive forward under its own momentum during a
crash, entering the cabin and injuring the occupants; however there is
no case where this has been reported to have occurred (in the US and
UK accident records). Conversely, if the engine is placed in front of
the cabin, it might act as a battering ram and plow through obstacles
in the airplane's path, providing an additional measure of safety.

Crew members may strike the propeller while attempting to bail out of
a single-engined airplane with a pusher prop. This potentially
gruesome scenario helps to explain why pusher props have rarely been
used on post-WWI fighters despite the theoretical increase in
maneuverability.

A less dire but more practical concern is foreign object damage. The
pusher configuration generally places the propeller(s) aft of the main
landing gear, but often placed above the wing. Rocks, dirt or other
objects on the ground kicked up by the wheels can find their way into
the prop, causing damage or accelerated wear to the blades. As a
result, pusher aircraft such as the canard homebuilts are not usually
operated from unimproved runways. Also, a few centreline pusher
designs place the propeller arc very close to the ground while flying
nose-high during takeoff or landing, making the prop more likely to
strike vegetation when the airplane operates from a turf airstrip.

When an airplane flies in icing conditions, a layer of ice can
accumulate on the wings. If an airplane with wing-mounted pusher
engines experiences wing icing and subsequently flies into warmer air,
the pusher props may ingest pieces of ice as they shed, posing a
hazard to the propeller blades and other parts of the airframe that
can be struck by chunks of ice flung by the props.

The propeller increases airflow around an air-cooled engine in the
tractor configuration, but does not provide this same benefit to an
engine mounted in the pusher configuration. Some aviation engines
experience cooling problems when used as pushers. Likewise, the pusher
configuration can exacerbate carburettor icing. Some air-cooled
aviation engines depend on air heated by the cylinders to warm the
carburettor(s) and discourage icing; the pusher configuration can
reduce the flow of warm air, facilitating the formation of ice.

Propeller noise often increases because the engine exhaust flows
through the props. This effect is particularly pronounced when using
turboprop engines due to the large volume of exhaust they produce.
Aviation enthusiasts can often hear a Piaggio P180 Avanti approach due
to the loud high-pitched wail produced by the engine exhaust blowing
through the props.

Vibration can be induced by the propeller passing through the wing
downwash, causing it to move asymmetrically through air of differing
energies and directions.

Problems may emerge when using wing flaps on a pusher airplane. First,
the absence of prop-wash over the wings can slow the airflow across
the flaps, making them less effective. Second, wing-mounted pusher
engines block the installation of flaps along portions of the trailing
edges of the wings, reducing the total available flap area.

Placement of the propeller in front of the tail (as referenced in
Advantages) can have a negative side effect: strong pitch and yaw
changes may occur as the engine's power setting changes and the
airflow over the tail correspondingly speeds up or slows down.
Aggressive pilot corrections may be required to maintain the desired
flight path after changing the power setting.

Still, I think the possibility of my having to bail out in flight
are minimal.

Do you or anyone know the approximate "drive-out" price
for an Aerosport LH-10 Ellipse?

Thanks, Mark

"Mark" wrote

Thank you for your input.

Just yesterday I watched a video of an aerocar in mint
condition rolling to a stop, and when asked, they tell the
interviewer that it's a 1955 model and they love it. (early
pusher propeller).

Yes, I would be interested in seeing a detailed drawing of the drive system.
It does seem to not have the resonance problems, but from what I have read,
it deals with problems with more weight. It is fair to call it a "sluggish,
underpowered performer."

A couple of brothers did a home-built pusher propeller
to show their neighbors. They were the first on their block.
Orville and Wilbur I think they were called.

Ahh, but big diferences, in their design. No long drive shaft. The speed
of the very long, slow turning props mean that resonance will probably be in
such a low frequency as to not be a problem.

All work was done for low speed flight. Sluggish performer, with that one,
too.

Today seems Cirrus is all the rage with their SR series,
but look at their very first plane, the prototype introduction
of the VK-30. It looks like a jet! But out of my price range.

Another interesting plane, and interesting drive system. I would like to
see into that one, too.

I have helped push that one, so I can qualify it as very heavy indeed. Add
enough weight, and there is a good chance to kill the resonance problems.

Surely someone out there can provide some of the links to the readings I did
a few years back, as to all of the developmental problems that they had,
dealing with the BD-5. There were volumes written, very detailed, some very
technical pages written on the case, and studies on the problem in a very
scientific study, as I recall.

Someone?

I am not saying that the problems are impossible to overcome. I am saying
that the problems are significant, and are to be expected with a drive
system of this type, and are more likely, than not, to show up in such a
system.

If you are thinking about a plane with that configuration, the writings
should be manditory reading, or if you are just interested in all things
mechanical, they are also very interesting.

You might be able to surf and find the studies yourself. Someone did give
me some good starting places way back, to explore. It would be nice to get
some clues provided for you, this time.

Have a good one!
--
Jim in NC


For me these are probably some of the considerations for
a conventional tractor propelled verses a push propeller:


ADVANTAGES

Efficiency can be gained by mounting a propeller behind the fuselage,
because it re-energizes the boundary layer developed on the body, and
reduces the form drag by keeping the flow attached. However, this
effect is not nearly as pronounced on a small airplane as it is on a
submarine or ship, where it is quite important due to the much higher
Reynolds number at which they operate.

Wing efficiency increases due to the absence of prop-wash over any
section of the wing.

Rear thrust is somewhat less stable in flight than with a tractor
configuration. This has the potential to make an aircraft more
maneuverable.

Visibility of a single-engined airplane is improved because the engine
does not block forward vision. Consequently, this configuration was
widely used for early combat reconnaissance aircraft, and remains
popular today among ultralight aircraft.

The propeller of a single-engined airplane can be placed closer to the
elevators and rudder. This increases the speed of the air flowing over
the control surfaces, improving pitch and yaw control at low speed,
particularly during takeoff when the engine is at full power. This can
be beneficial while bush flying, especially when taking off and
landing on airstrips bounded by obstacles that must be avoided while
the airplane is moving slowly.

The engine is mounted behind the crew and passenger compartments, so
fuel does not have to flow past personnel, any leak will vent behind
the aircraft, and any engine fire will be directed behind the aircraft
(however, this arrangement puts the empennage at greater risk, if
there is one -- but this is less of an issue if the fire occurs on, or
as a consequence of, landing). Similarly, propeller failure is
unlikely to directly endanger the crew.

And then we have the DISADVANTAGES-


The pusher configuration can endanger the aircraft's occupants in a
crash or crash-landing[citation needed]. If the engine is placed
behind the cabin, it may drive forward under its own momentum during a
crash, entering the cabin and injuring the occupants; however there is
no case where this has been reported to have occurred (in the US and
UK accident records). Conversely, if the engine is placed in front of
the cabin, it might act as a battering ram and plow through obstacles
in the airplane's path, providing an additional measure of safety.

Crew members may strike the propeller while attempting to bail out of
a single-engined airplane with a pusher prop. This potentially
gruesome scenario helps to explain why pusher props have rarely been
used on post-WWI fighters despite the theoretical increase in
maneuverability.

A less dire but more practical concern is foreign object damage. The
pusher configuration generally places the propeller(s) aft of the main
landing gear, but often placed above the wing. Rocks, dirt or other
objects on the ground kicked up by the wheels can find their way into
the prop, causing damage or accelerated wear to the blades. As a
result, pusher aircraft such as the canard homebuilts are not usually
operated from unimproved runways. Also, a few centreline pusher
designs place the propeller arc very close to the ground while flying
nose-high during takeoff or landing, making the prop more likely to
strike vegetation when the airplane operates from a turf airstrip.

When an airplane flies in icing conditions, a layer of ice can
accumulate on the wings. If an airplane with wing-mounted pusher
engines experiences wing icing and subsequently flies into warmer air,
the pusher props may ingest pieces of ice as they shed, posing a
hazard to the propeller blades and other parts of the airframe that
can be struck by chunks of ice flung by the props.

The propeller increases airflow around an air-cooled engine in the
tractor configuration, but does not provide this same benefit to an
engine mounted in the pusher configuration. Some aviation engines
experience cooling problems when used as pushers. Likewise, the pusher
configuration can exacerbate carburettor icing. Some air-cooled
aviation engines depend on air heated by the cylinders to warm the
carburettor(s) and discourage icing; the pusher configuration can
reduce the flow of warm air, facilitating the formation of ice.

Propeller noise often increases because the engine exhaust flows
through the props. This effect is particularly pronounced when using
turboprop engines due to the large volume of exhaust they produce.
Aviation enthusiasts can often hear a Piaggio P180 Avanti approach due
to the loud high-pitched wail produced by the engine exhaust blowing
through the props.

Vibration can be induced by the propeller passing through the wing
downwash, causing it to move asymmetrically through air of differing
energies and directions.

Problems may emerge when using wing flaps on a pusher airplane. First,
the absence of prop-wash over the wings can slow the airflow across
the flaps, making them less effective. Second, wing-mounted pusher
engines block the installation of flaps along portions of the trailing
edges of the wings, reducing the total available flap area.

Placement of the propeller in front of the tail (as referenced in
Advantages) can have a negative side effect: strong pitch and yaw
changes may occur as the engine's power setting changes and the
airflow over the tail correspondingly speeds up or slows down.
Aggressive pilot corrections may be required to maintain the desired
flight path after changing the power setting.

Still, I think the possibility of my having to bail out in flight
are minimal.

Do you or anyone know the approximate "drive-out" price
for an Aerosport LH-10 Ellipse?

Thanks, Mark

Here you go:

http://ibis.experimentals.de/downloa...lvibration.pdf



"Morgans" wrote in message ...
.....

Surely someone out there can provide some of the links to the readings I did
a few years back, as to all of the developmental problems that they had,
dealing with the BD-5. There were volumes written, very detailed, some very
technical pages written on the case, and studies on the problem in a very
scientific study, as I recall.

Someone?

I am not saying that the problems are impossible to overcome. I am saying
that the problems are significant, and are to be expected with a drive
system of this type, and are more likely, than not, to show up in such a
system.

If you are thinking about a plane with that configuration, the writings
should be manditory reading, or if you are just interested in all things
mechanical, they are also very interesting.

You might be able to surf and find the studies yourself. Someone did give
me some good starting places way back, to explore. It would be nice to get
some clues provided for you, this time.

Have a good one!
--
Jim in NC


For me these are probably some of the considerations for
a conventional tractor propelled verses a push propeller:


ADVANTAGES

Efficiency can be gained by mounting a propeller behind the fuselage,
because it re-energizes the boundary layer developed on the body, and
reduces the form drag by keeping the flow attached. However, this
effect is not nearly as pronounced on a small airplane as it is on a
submarine or ship, where it is quite important due to the much higher
Reynolds number at which they operate.

Wing efficiency increases due to the absence of prop-wash over any
section of the wing.

Rear thrust is somewhat less stable in flight than with a tractor
configuration. This has the potential to make an aircraft more
maneuverable.

Visibility of a single-engined airplane is improved because the engine
does not block forward vision. Consequently, this configuration was
widely used for early combat reconnaissance aircraft, and remains
popular today among ultralight aircraft.

The propeller of a single-engined airplane can be placed closer to the
elevators and rudder. This increases the speed of the air flowing over
the control surfaces, improving pitch and yaw control at low speed,
particularly during takeoff when the engine is at full power. This can
be beneficial while bush flying, especially when taking off and
landing on airstrips bounded by obstacles that must be avoided while
the airplane is moving slowly.

The engine is mounted behind the crew and passenger compartments, so
fuel does not have to flow past personnel, any leak will vent behind
the aircraft, and any engine fire will be directed behind the aircraft
(however, this arrangement puts the empennage at greater risk, if
there is one -- but this is less of an issue if the fire occurs on, or
as a consequence of, landing). Similarly, propeller failure is
unlikely to directly endanger the crew.

And then we have the DISADVANTAGES-


The pusher configuration can endanger the aircraft's occupants in a
crash or crash-landing[citation needed]. If the engine is placed
behind the cabin, it may drive forward under its own momentum during a
crash, entering the cabin and injuring the occupants; however there is
no case where this has been reported to have occurred (in the US and
UK accident records). Conversely, if the engine is placed in front of
the cabin, it might act as a battering ram and plow through obstacles
in the airplane's path, providing an additional measure of safety.

Crew members may strike the propeller while attempting to bail out of
a single-engined airplane with a pusher prop. This potentially
gruesome scenario helps to explain why pusher props have rarely been
used on post-WWI fighters despite the theoretical increase in
maneuverability.

A less dire but more practical concern is foreign object damage. The
pusher configuration generally places the propeller(s) aft of the main
landing gear, but often placed above the wing. Rocks, dirt or other
objects on the ground kicked up by the wheels can find their way into
the prop, causing damage or accelerated wear to the blades. As a
result, pusher aircraft such as the canard homebuilts are not usually
operated from unimproved runways. Also, a few centreline pusher
designs place the propeller arc very close to the ground while flying
nose-high during takeoff or landing, making the prop more likely to
strike vegetation when the airplane operates from a turf airstrip.

When an airplane flies in icing conditions, a layer of ice can
accumulate on the wings. If an airplane with wing-mounted pusher
engines experiences wing icing and subsequently flies into warmer air,
the pusher props may ingest pieces of ice as they shed, posing a
hazard to the propeller blades and other parts of the airframe that
can be struck by chunks of ice flung by the props.

The propeller increases airflow around an air-cooled engine in the
tractor configuration, but does not provide this same benefit to an
engine mounted in the pusher configuration. Some aviation engines
experience cooling problems when used as pushers. Likewise, the pusher
configuration can exacerbate carburettor icing. Some air-cooled
aviation engines depend on air heated by the cylinders to warm the
carburettor(s) and discourage icing; the pusher configuration can
reduce the flow of warm air, facilitating the formation of ice.

Propeller noise often increases because the engine exhaust flows
through the props. This effect is particularly pronounced when using
turboprop engines due to the large volume of exhaust they produce.
Aviation enthusiasts can often hear a Piaggio P180 Avanti approach due
to the loud high-pitched wail produced by the engine exhaust blowing
through the props.

Vibration can be induced by the propeller passing through the wing
downwash, causing it to move asymmetrically through air of differing
energies and directions.

Problems may emerge when using wing flaps on a pusher airplane. First,
the absence of prop-wash over the wings can slow the airflow across
the flaps, making them less effective. Second, wing-mounted pusher
engines block the installation of flaps along portions of the trailing
edges of the wings, reducing the total available flap area.

Placement of the propeller in front of the tail (as referenced in
Advantages) can have a negative side effect: strong pitch and yaw
changes may occur as the engine's power setting changes and the
airflow over the tail correspondingly speeds up or slows down.
Aggressive pilot corrections may be required to maintain the desired
flight path after changing the power setting.

Still, I think the possibility of my having to bail out in flight
are minimal.

Do you or anyone know the approximate "drive-out" price
for an Aerosport LH-10 Ellipse?

Thanks, Mark

"Blueskies" wrote in message
news
Here you go:

http://ibis.experimentals.de/downloa...lvibration.pdf

Yep, that was the primer to the whole treatise.

Anyone who likes mechanical things, at all, NEEDS to read this. If you are
considering something that has a PSRU, or especially a long driveshaft, then
you really need to read it.

Download it, and read it a little at a time, if you don't have a little
while to digest it. To me, it is fascinating reading.
--
Jim in NC