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When will a diesel be available for my aircraft? |
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News, facts, and comments on the coming revolution for piston-engine aircraft.News of September 09, 2007Answering a frequent question regarding biodiesel fuel for aircraftAn example of questions we receive is this one from RTD in Pace, FL: 'I enjoy the newsletter very much and I have learned very much. I have an unanswered question about fuel. At least one manufacturer (I forget which one) says that BIODIESEL fuel is not approved. Why would biodiesel not be approved? Is it because of quality control issues? Or what?' DieselAir Newsletter answered: An aero diesel engine is certified for a certain fuel, typically JetA. That fuel is a certain formulation of kerosene. Calibration of the engine to a fuel consists in taking into account the density (weight per gallon), the caloric content (which gives the rated power), and the viscosity. To adapt a diesel engine to a different formulation of kerosene, in the most complex case one must: Change the setting of the injection pump, to have the right amount (weight) of fuel per injection stroke for the max. allowed power, Change the nozzle, to fit with the viscosity and still obtain the right size of droplets of fuel in the mist generated by injection. This is never very difficult. For example, some aerodiesel engines can shift from motor diesel to JetA and back with one switch of a control. Now here come the problems: If you are flying from A to B, you expect to refuel your plane at A and B. With JetA this is easy: It is the most universal aviation fuel. With Avgas it is relatively easy but getting tricky in certain areas. With biodiesel, there is none available. Your engine, to use a different fuel, must be STCd again. Here comes the FAA with a test program, at a cost. So what will happen is this: Biodiesel will be added to JetA, according to a formulation producing same density, same caloric content, same viscosity. Oil companies know how to do that. FAA will cooperate. Also engine manufacturers. FAA and JAA will have conventions to reconcile their certification processes. There will be a lot of testing, and of disagreements regarding test results. Meanwhile oil companies and farmers lobbies will resist on the grounds that biodiesel is more costly to produce. Politicians will have their say, according to whether their constituents are oil companies or farmers. This goes for foreign countries too. It will take years, and zillions of dollars (most of it to consist in legal fees.) But it is going to be FUUUN... And in the mean time you will fly your aerodiesel with JetA, and already save a lot of money and gain all kinds of advantages. posted at 2:38 PM |
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The D-Air 100 aerodiesel acquired by Howell Aero E...
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