What GA needs

"Andrew Sarangan" wrote in message
oups.com...
On Sep 10, 6:28 pm, "Capt. Geoffrey Thorpe" The Sea Hawk at wow way
d0t com wrote:
...
"Small Turbine" and "Gas mileage" - you only get one - the thermodynamics
just don't support both without real exotic materials.

Other than that, though...

--

I have heard that argument many times, but I have never seen that
thermodynamic argument presented. I just borrowed the book on Aircraft
Gas Turbine Engines from the library and plan to read it to find out
what the real story is. My suspicion is that the limitation is in the
materials, not thermodynamics. It may take a significant investment,

That's why I said "without real exotic materials"

The materials limit the maximum termperatures. The maximum temperatures
limit the maximum efficiency. Also "small" (and I assume "reasonable cost")
rule out regenerators to capture some of the waste heat (common on
stationary applications)

but if the military is also interested in similar things it won't be
that hard to find the R&D suppport. I've heard that small turbines are
of interest to the Air Force for potential use in UAVs. A UAV and a
small GA airplane are not that far apart. In fact, the predator is

True, but the military tends to care less about fuel cost and more about
being able to use the same fuel in everything so if you have fuel, you have
fuel.

There were a number of programs in the 60's for turbines and direct
injection piston engines that would run on "any fuel' that was available...

...
Having said that, I know of at least two companies working on small
turbines. One is Innodyn, and the other one is M-dot. The latter one I
believe has some DoD contracts to be build turbines for UAVs. I doubt
these companies would even exist if the basic physics is flawed.


Nothing wrong with the physics. Small turbines work. And for some
applications they have big adavantages. Fuel quantity per horsepower-hour,
however, isn't one of them.

--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.

"Capt. Geoffrey Thorpe" The Sea Hawk at wow way d0t com wrote in message
news:BuCdncDCBfMie3jbnZ2dnUVZ_jadnZ2d@wideopenwest .com...
"Andrew Sarangan" wrote in message
oups.com...


Nothing wrong with the physics. Small turbines work. And for some
applications they have big adavantages. Fuel quantity per horsepower-hour,
however, isn't one of them.

The "New Wave" is much more likely to be diesel, especially given the 100LL
"crisis".

Capt. Geoffrey Thorpe wrote:


Nothing wrong with the physics. Small turbines work. And for some
applications they have big adavantages. Fuel quantity per horsepower-hour,
however, isn't one of them.


Agreed. Turbines are most efficient well above normal GA altitudes. At
common GA altitudes they suck large quantities of fuel. A turbine powered
Luscombe project used to be based at my field. The speed and climb were
slightly better than a piston powered Luscombe, but the range was
dramatically shorter.

While you can burn almost anything in them, you should plan on burning a
lot of it. That was also one of the downfalls of the early turbine powered
cars (besides the initial expense).

John Galban=====N4BQ (PA28-180)

--
Message posted via AviationKB.com
http://www.aviationkb.com/Uwe/Forums...ation/200709/1

"JGalban via AviationKB.com" u32749@uwe wrote in message
news:7814f2bf2e916@uwe...
Capt. Geoffrey Thorpe wrote:


Nothing wrong with the physics. Small turbines work. And for some
applications they have big adavantages. Fuel quantity per horsepower-hour,
however, isn't one of them.


Agreed. Turbines are most efficient well above normal GA altitudes. At
common GA altitudes they suck large quantities of fuel. A turbine
powered
Luscombe project used to be based at my field. The speed and climb were
slightly better than a piston powered Luscombe, but the range was
dramatically shorter.

A Luscombe needs a turbine engine like a carp needs an outboard motor.