alt fuels?
Joined: Jan 2001
Posts: 1,365
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From: UK
1. In principle, yes. That is if you put bio-diesel in the tank it would run. Turbines will run on a variety of fuels.
2. However, it isn't approved. so it wouldn't be legal (I imagine). In my experience, AFMs almost always limit use to certain fuels.
3. It would also be sensible for some bench testing (i.e. on the ground to be done). I am sure this would be needed in order to get 2.
4. I also wonder whether you might get problems with water in the fuel, like you do if you use ordinary motor fuel (MOGAS) in a piston engine. When you go to altitude (i.e. cold) the water freezes and can cause all sorts of problems.
Quality control of your alternative fuel has to be a priority for flight safety, if you value your life.
2. However, it isn't approved. so it wouldn't be legal (I imagine). In my experience, AFMs almost always limit use to certain fuels.
3. It would also be sensible for some bench testing (i.e. on the ground to be done). I am sure this would be needed in order to get 2.
4. I also wonder whether you might get problems with water in the fuel, like you do if you use ordinary motor fuel (MOGAS) in a piston engine. When you go to altitude (i.e. cold) the water freezes and can cause all sorts of problems.
Quality control of your alternative fuel has to be a priority for flight safety, if you value your life.
Thread Starter
Joined: Nov 2004
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From: the great white north
i agree, that quality control is essential, and i wasn't going to try this myself. i just wondered if anyone had any experience testing modern engines with alternative fuels and if so, might we see it in the future?
Joined: Nov 2000
Posts: 4,330
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From: White Waltham, Prestwick & Calgary
One big problem here is that the engine fuel pump(s) are lubricated by the fuel itself - this doen't happen with alternatives, which is why there is usually an hours restriction
Phil
Phil
Joined: Apr 2003
Posts: 3,012
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From: USA
Other than that it is not approved, if a fuel is liquid and it burns, a turbine will burn it, and run ok, for a while. The fuel control automatically makes up for the volumetric density differences, and all fuels have about the same heat/energy per pound, so the engine will run nicely.
The problem isn't water, or pump lube, it is the crud that is left on the hot section when the fuel burns away. Worst fuel is car gas with lead or anti-knock compounds, which coat the turbine blades and make an awful mess in just a few hours.
If the gas is pure and has no lead/antiknock, it is fine.
Another concern is the fuel pump and suction system. Thin fuels like gasoline with low vapor pressures will bubble out at lower altitudes than regular kerosene, and starve the engine after a few "low fuel pressure" light blinks.
The problem isn't water, or pump lube, it is the crud that is left on the hot section when the fuel burns away. Worst fuel is car gas with lead or anti-knock compounds, which coat the turbine blades and make an awful mess in just a few hours.
If the gas is pure and has no lead/antiknock, it is fine.
Another concern is the fuel pump and suction system. Thin fuels like gasoline with low vapor pressures will bubble out at lower altitudes than regular kerosene, and starve the engine after a few "low fuel pressure" light blinks.
Joined: Jul 2003
Posts: 464
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From: UK
The RAF Puma (Turmo engines) had alt fuels that included forms of diesel and petrol but there were time limitations on use, 25 hours total during the life of the engine for petrol comes to mind. Also the PTIT / ITT may be considerably higher and of course the fuel may be more volatile so the were restrictions on OAT and usage. Believe they used petrol once during earthquake relief ops in mexico.
Joined: Jul 2001
Posts: 1,383
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From: ...in view of the 'Southern Cross' ...
I think you must also be cautious of the waxes/oils solidifying and blocking the fuel filters if used at too low a temperature.
I remember, I think the Allouette/Lama series being able to burn just about anything (except coal perhaps) due the use of a fuel slinger arrangement rather than a fuel nozzle ??? can't rem the details though .... getting old I guess!
Cheers
I remember, I think the Allouette/Lama series being able to burn just about anything (except coal perhaps) due the use of a fuel slinger arrangement rather than a fuel nozzle ??? can't rem the details though .... getting old I guess!
Cheers
