Why are there no small turboprops?

"Brian Burger" wrote in message
ia.tc.ca...
On Tue, 25 May 2004, Tom Sixkiller wrote:

And there's other sources for diesel...and maybe you can smoke it, too.

http://www.artistictreasure.com/learnmorecleanair.html

Smoke my fuel! grin Actually, industrial hemp - the stuff they make/will
make biodiesel, t-shirts, etc out of - has practically NO THC content. THC
is the stuff in pot that actually makes you high.

:~)

Industrial hemp is THC-free to the point where you'd have to smoke pounds
and pounds of the stuff to get enough THC into your blood - and the smoke
would kill you dead first!

I remember reading something a few years ago from the Libertarians about the
history of hemp (paper, for instance...the paper on which the Constitution,
Declaration of Independence, other... were written) and the many uses for it
today (medicine, the industrial applications that you mention, etc.) but the
anti-druggies have made it far too restrictive.

Author Stuart Woods has a Malibu with a turbo engine, and I have seen a
turbo-powered 206.

Bob Gardner

"Thomas J. Paladino Jr." wrote in message
...
I have always wondered why there are no small GA turboprops. It seems like
most of the major problems & maintenance issues associated with GA
aircraft
are related to the piston motor, and as far as I can tell, turboprops are
much more reliable, fuel efficient, smoother running and easier to
maintain.

So it begs the question, why are there no small turboprops in the
100-300hp
range for use on GA aircraft? I would think that turbine engines of this
size would be relatively easy to produce, and would be ideal for GA
applications. The smoother operation and lower vibration levels would also
ease wear and tear on the entire airframe and avionics components. So
what's
the deal? Does turbine technology not translate downwards very well? Would
it be cost prohibitive? Am I entirely missing something?

the lanceair has a turbo prop version, I saw one take off few months back, fast
little airplane

Bob Gardner wrote:

Author Stuart Woods has a Malibu with a turbo engine, and I have seen a
turbo-powered 206.

Bob Gardner

"Thomas J. Paladino Jr." wrote in message
...
I have always wondered why there are no small GA turboprops. It seems like
most of the major problems & maintenance issues associated with GA
aircraft
are related to the piston motor, and as far as I can tell, turboprops are
much more reliable, fuel efficient, smoother running and easier to
maintain.

So it begs the question, why are there no small turboprops in the
100-300hp
range for use on GA aircraft? I would think that turbine engines of this
size would be relatively easy to produce, and would be ideal for GA
applications. The smoother operation and lower vibration levels would also
ease wear and tear on the entire airframe and avionics components. So
what's
the deal? Does turbine technology not translate downwards very well? Would
it be cost prohibitive? Am I entirely missing something?

there is a company making small turbo props, I cant remember the name of them,
but they have a 200 HP one

"Thomas J. Paladino Jr." wrote:

I have always wondered why there are no small GA turboprops. It seems like
most of the major problems & maintenance issues associated with GA aircraft
are related to the piston motor, and as far as I can tell, turboprops are
much more reliable, fuel efficient, smoother running and easier to maintain.

So it begs the question, why are there no small turboprops in the 100-300hp
range for use on GA aircraft? I would think that turbine engines of this
size would be relatively easy to produce, and would be ideal for GA
applications. The smoother operation and lower vibration levels would also
ease wear and tear on the entire airframe and avionics components. So what's
the deal? Does turbine technology not translate downwards very well? Would
it be cost prohibitive? Am I entirely missing something?

A few years ago at Arlington I saw a turboprop made from an APU. 150
hp, $20,000 or so, 18 GPH. Would have gone nicely on my Jodel, but
with a 15 gallon tank I sure wouldn't have gone far. Not too many were
sold, I think, but others were converted for small homebuilt
helicopters, where the power-to weight ratio was more welcome.
A small propeller has poor efficiency, especially in takeoff and
climb, so serious propeller-driven aircraft use large, slow-turning
props to get the most out of the available horses. It's more efficient
to accelerate a large volume of air to a low speed than a small volume
to a high speed, since prop drag increases with the square of the
increase in speed.
A small turbine has the same drawbacks. That small diameter has a
tiny area, so the gases must be accelerated to a really high speed to
get any useable thrust. That same small diameter also applies more
drag to the flow, the same way a small pipe impedes flow more than a
large one for a given rate of flow. The power turbine that converts
exhaust gas flow to shaft torque is similarly handicapped, so
efficiencies fall off dramatically as diameter goes down. The most
efficient turbines are the really big ones that are driving large,
slow-turning props or large fans (which are often also geared).
So for the money a piston engine is still a better bet, and
probably will be until some totally different principle is invented. I
wish we weren't still burning stuff (1600's steam engine technology)
to get motion, whether turbines or pistons or rockets, but I don't
suppose anyone will have a workable nuclear fusion engine, built by
Lycoming, in my lifetime.
It would probably still have magnetos.

Dan

Jeff wrote in message ...
there is a company making small turbo props, I cant remember the name of them,
but they have a 200 HP one

"Thomas J. Paladino Jr." wrote:

I have always wondered why there are no small GA turboprops. It seems like
most of the major problems & maintenance issues associated with GA aircraft
are related to the piston motor, and as far as I can tell, turboprops are
much more reliable, fuel efficient, smoother running and easier to maintain.

So it begs the question, why are there no small turboprops in the 100-300hp
range for use on GA aircraft? I would think that turbine engines of this
size would be relatively easy to produce, and would be ideal for GA
applications. The smoother operation and lower vibration levels would also
ease wear and tear on the entire airframe and avionics components. So what's
the deal? Does turbine technology not translate downwards very well? Would
it be cost prohibitive? Am I entirely missing something?

here you go, they do exist
http://www.atpcoinc.com/Pages/Products.html



"Thomas J. Paladino Jr." wrote:

I have always wondered why there are no small GA turboprops. It seems like
most of the major problems & maintenance issues associated with GA aircraft
are related to the piston motor, and as far as I can tell, turboprops are
much more reliable, fuel efficient, smoother running and easier to maintain.

So it begs the question, why are there no small turboprops in the 100-300hp
range for use on GA aircraft? I would think that turbine engines of this
size would be relatively easy to produce, and would be ideal for GA
applications. The smoother operation and lower vibration levels would also
ease wear and tear on the entire airframe and avionics components. So what's
the deal? Does turbine technology not translate downwards very well? Would
it be cost prohibitive? Am I entirely missing something?