A true GA jet engine

[chornedsnorkack]

Fuel

- At GA speeds, piston engines are much more fuel efficient.

- But AVGAS is much more expensive than AVTUR

- As a result, you roughly break even on fuel costs per hour and on payload (the engine becomes lighter, but the amount of fuel you have to carry becomes greater).

Er, why does a piston have to burn benzine? A Wankel needs benzine (because of the geometry and compression ratio, diesel cycle does not work with Wankel engine), but what is wrong about a piston diesel engine?

[Genghis the Engineer]

Cyclone - those are Diesel engines: diesel fuel and gas turbine fuel are basically the same (kerosene).

G

[rigpiggy]

Wankels actually would make a pretty good diesel, as their closer to a 2stroke in function, ie higher power/weight ratio. The reasons why they are inefficient as a gas engine has to do with intake/exhaust overlap, and low compression ratio due to heat annealing the tip seal springs.
http://www.der-wankelmotor.de/Motore...lls-royce.html

[The Flying Pram]

rigpiggy, thanks for the link. I seem to remember that Rolls Royce made a very large Wankel diesel many years ago to power a military tank (I think). I believe it used two stages in a type of supercharger arrangement. The other cause of poor efficiency is the large surface area to volume ratio of the combustion chamber. This causes considerable heat loss, thereby wasting much of the useful energy in the fuel.

[con-pilot]

The 1963 Chrysler Turbine Car.

[Charles E Taylor]

Another Aircraft Engine

An interesting thread.

Just to prove the I.C. engine is not yet finished.

There is some very interesting work being done in the UAV engine world.

http://gltrs.grc.nasa.gov/reports/20...006-214342.pdf

C E Taylor