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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 March 09, 2009The Tecnam twin: A promising concept.
 The Tecnam P92 Eaglet is an all aluminum airplane that combines the best features of their high wing aircraft line into one improved platform suitable for primary and advanced training as well as cross-country needs. It received its US Airworthiness Certificate on 1/11/2008. It is manufactured by Italian aircraft manufacturer Costruzioni Aeronautiche Tecnam S.r.l. in Capua Caserta, Italy. (www.tecnam.com) The Eaglet is presently equipped with the Rotax 912S. Powerplant Developments Ltd. (PPD) is supplying two samples of its Gemini 100HP 2-stroke diesel to Tecnam for flight evaluation testing. Later PPD will supply its 125HP if first results are favorable. According to PPD, the Gemini engine is very low weight for a diesel and it provides greater efficiency and higher torque than is found in current available engines. Powerplant Developments is a UK based Company of four principals located in West Sussex. Managing partner Tim Archer, PPDs CEO, is based in the United States. Their Gemini family of two-stroke diesel engines is currently in development starting with the Gemini 100HP engine which is being targeted specifically at the LSA market and certified via ASTM Standards. Other engines of the same basic two-stroke design and up to 600HP are envisioned as the line matures. Archer stressed that supplying general aviation with a reliable alternative diesel engine is the primary focus of the Company. The Gemini 100 weighs in at just over 155 pounds dry (with starter, alternator and fuel system) and 190 pounds wet with required ancillary accessories. The Gemini 125 - essentially the same engine with turbo charging added - weighs 170 pounds dry and 205 pounds wet. The Gemini 100 is a geared engine of 1.6/1 ratio. When asked if the gearbox would have time limitations as it does for a competitor, Archer stated that, 'it would not.' The Gemini 100 and 125 are two-crankshaft, two-stroke, three-cylinder, six-piston opposed designs with mechanically driven superchargers required to maintain positive pressure for induction and scavenging. The combustion chamber is formed between the opposing pistons (so the Gemini is another scaled down version of the Junkers Jumo diesel of the thirties, which was regularly demonstrating 0.345 Lb/HP-hour of Specific Fuel Consumption); inlet and exhaust ports are formed by orifices in the cylinder walls. This engine, same as the old Jumo, must be geared because the two crankshafts are connected by a gear transmission, with the propeller on an intermediate shaft. The Gemini 100 maintains sea-level performance to 5,000 feet while the Gemini 125 -- with turbo charging added -- maintains sea-level performance to 15,000 feet. As currently envisioned, all engines above the Gemini 100 will be supercharged and turbocharged and any used for aviation will be certified via FAR 33. The Tecnam twin with diesel, depending on price, can one day change completely the US professional and private twin market. One could expect a fuel consumption of 7Gal/h, and a long range. One advantage of the opposite piston design is that the gear transmission is balancing stresses on the gear driving the propeller: It is symmetrically actuated. (Aero News Network 8/08 plus DieselAir comments and update). posted at 1:40 AM |
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