First Jet Flight with 100% Biodiesel

Technocrat

First Jet Flight with 100% Biodiesel

zogger

Sun Dec 02 08:32:51 -0800 2007

Chemistry

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An ex Ukrainian military jet has become the world's first jet aircraft to be flown on pure biodiesel from vegetable oil. The researchers did extensive ground and flight tests first, gradually building up to pure vegetable oil biodiesel (they used canola oil as the feedstock), then the test flight, which was a perfect success. They say they got 98% efficiency compared to normal jet fuel. The particular aircraft, an L-29 fighter/trainer was chosen because it came stock with an onboard fuel pre-heater and is known as an exceptionally rugged and simple basic jet plane that was designed to be fueled with a variety of fuels.

.."The experimental test flights were conducted starting with a blend of jet fuel and biodiesel. The engine data was measured and the performance was evaluated and found acceptable for continued use, eventually resulting in the landmark flight using 100% renewable biodiesel fuel. According to Chief Pilot Carol Sugars who wrote and conducted the test program, “As we gradually increased the amount of biodiesel in the fuel blend, the data confirmed that the aircraft continued to perform well, giving me the confidence to transition to 100% biodiesel.” Flight tests were conducted up to an altitude of 17,000 feet showing no significant difference in performance compared to conventional jet fuel."..more at the links

Biggest problem with biodiesel

mcrbids

Sun Dec 02 21:24:18 -0800 2007
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Biodiesel has great energy density. It is chemically very similar to jet or diesel oils. It has just one problem - it tends to gel when it gets cold. Which it does, in a thin, flat wing (where the fuel is kept in most planes) at high altitudes. (which is where planes typically go... UP)
In General Aviation, there is a slow, gradual movement away from 100 LL AvGas (which is leaded gas, with more lead than used to be in "Leaded" car gas) towards diesel engines burning jet fuel. Diesel engines are really under-appreciated and can burn everything from light oil (EG: diesel oil or jet fuel) all the way down to coal dust.

But bio-diesel is not the "best choice" for jets until the nasty gelling problem is really solved. Which, to my knowledge, is unsolved.

Biggest problem with biodiesel

Dan Ost

Mon Dec 03 05:46:25 -0800 2007
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Doesn't regular diesel have gelling issues? I thought that's why they changed the diesel at the pump from #1 diesel to #2 diesel (or a blend of #1 and #2) during the winter.

Biggest problem with biodiesel

mcrbids

Mon Dec 03 14:31:14 -0800 2007
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Diesel fuel has gelling issues, which is why it's not used in airplanes. But diesel engines burn just about anything, including Jet fuel, which is what they burn when you have a diesel engine in a piston-driven plane.