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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.In 1998, one diesel engine flew on a converted airplane for the first time since 1945. Today, close to 4,000 singles and twins are flying. This is the beginning of a worldwide trend which will eventually allow a rebirth of the piston-engined aircraft, around new specs and new missions. DieselAir Research, Inc., the publisher of The DieselAir Newsletter, offers strategic intelligence services to the aircraft industry, its suppliers and its customers who ambition to benefit from this global change of paradigm which will mean new markets, new concepts, new services, new materials and components… You may be interested in our services if your firm designs and/or manufactures aircraft and components, aero engines, avionics, propellers and engine components, fuel systems or additives, advanced materials, or industry specific machinery for manufacturing of these; or provides aviation services such as fuel production or distribution; flight training, aircraft chartering, maintenance and operations (FBO’s); or airport management and design, traffic control, hangar, materials handling and storage equipment; or consulting and financial services for these industries; or advertising, sales promotion, trade shows, specialized publications. To know more, send a confidential email inquiry to Dr. Eng. André Teissier-duCros at atc@geanoverseas.com News of January 22, 2006Why a diesel rather than a turboprop or jet?This question often comes in my mail. It seems to make sense: without question, a turbine, whether turbojet or turboprop, gives much more power per weight than either a gasoline engine or a diesel, and is also much smaller in volume. And turbine costs and sizes have been going down. Several manufacturers offer mini-turboprops around 200HP at very attractive prices. So, where’s the catch? Basically the same than with a turbine for automobiles and vehicles, which has also been tried again and again. I already explained why a diesel has the advantage over a gasoline engine of a much more constant specific power at very different rpm’s. In practice it means that, with your aero diesel plane, when you pull back the power the fuel flow drops much more dramatically than with a gasoline engine. Go back to my papers of November 5, 16 and 22 (Diesel saga) to read why. With a turbine, it is the exact opposite. A turbine is remarkably efficient at full, constant, high speed. A 747 cruising with 350 passengers at 530 mph is achieving over 50 miles to the gallon per passenger. But if you deviate from that ideal rpm, the power drops while the fuel flow changes very little. So, for instance, at slow speed, on final approach or at take off, your turbine acts like a real gas guzzler. And with most small airplanes that is a problem: Safety commands that you would have plenty of time to fight a head wind, fly to an alternate or simply to go around another missed approach. This was so true in the late forties that the US Navy seriously discarded the jet aircraft for many years and played with hybrids instead: Planes with a piston engine in front and a turbojet in the back. Without much success of course. This defect of the turbine is less important in two cases: a). If the plane is big enough to carry a lot of extra fuel. A Pilatus or King Air 200, for instance, compared with a Piper Meridien. b). If the plane doesn’t need much range but does need extra performance: an aerobatics plane or a racer are the typical examples. This is why you may notice that most commercial turbos are of 600HP and over, and also experimental aerobatics planes with a 200HP mini turbo. And this is why we say that the future of aero diesel is in the 100-450HP range. posted at 2:53 PM |
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Cessna 182 SMA conversion: FAA STC is imminent
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