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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 June 21, 2004First available on the US market:
The Maule M-9-230 with the SMA diesel SR305 is tested in AOPA Magazine. It is proposed in the Experimental category while waiting for the final STC. Expected price: $ 200,000. The M-9-230 is the diesel equivalent of the M-7-235 equipped with a Lycoming I-540. First remark: The engine, 3-blade propeller, exchangers (intercooler, oil cooler and fuel cooler) and cowling change are responbile for a 70 Lbs. share in the total 300 Lbs. increase in total weight. Alton Marsk, who flew the plane, reports a fuel economy of 1 to 3 gallons/hour according to the cruise power: He burned during his test 9.6 gal/hour against 12 estimated for the gasoline plane. He observed a speed of 135.5 knots at 8,000 feet, but did not test the speed at 10,000 ft which should show the maximal speed, since a 200HP power is available with the diesel upto that altitude. Tested that way, the Cessna 182-SMA demonstrated 150 knots... The Maule may be disadvantaged by a drag from the huge cowling designed to cope with CHT requirements: CHT must stay below or equal to 358F against 500F for the Lycoming. Service ceiling is limited to 12,500 ft for the time being: Although the engine has flown successfully at 25,000 ft., SMA engineers fear that above 12,500ft. ram air forces might not be sufficient to keep the propeller running in case of engine loss, in case of attempt to restart. It is expected that within a few months 18,000 ft. will be authorized. Time between overhaul is 2,000 hours for the time being, expected to increase to 3,000 as for all diesel when more experience is acquired. It is then expected that the engine overhaul would cost no more than $15,000: The SMA is only 4 cylinder, and only 305 cubic inch... At this time the Maule SMA only burns Jetfuel which is priced in the US very close to Avgas. Maule expects future settings on the engine, allowing to run on auto diesel fuel, which Maule knows to be a plus with many of their US rural customers. Outside the US, the Maule SMA with Jetfuel is highly attractive either because of very high price of Avgas or because of lack of availability of Avgas, or both. It is expected that the SMA305 will soone be authorized to run at full power of 230HP instead of the present setting at 200HP constant power up to 10,000 ft. This will generally improve performance. When will other diesel planes and retrofits be available?At this time it is expected that the SMA STC for the Cessna 182 will be approved some time this summer and available for $77,000 including a complete aircraft overhaul from the firewall to front. The one for the Piper Dakota (developed by Aero Diesel Propulsion in Fort Lauderdale, FL.), the Diamond DA40 and 42 (Thielert) and the Socata Trinidad (SMA again) at the end of the year, and the one for the Cirrus SR20 (SMA) early nest year. With the Thielert, we expect the 172 and Cherokee retrofits to be available late this yearbut stay tuned. Remark from Alton Marsk: on any diesel retrofit such as the 172 Thielert or the 182SMA or other, diesel conversion means new mount, new propeller, added heat exchangers, new cowling. A new O-540 costs around $50,000 naked. Once the plane is designed for diesel, whether already retrofitted or new plane, the cost of the diesel component will be less, possibly much less than the equivalent gasoline engine. What about a Wankel diesel?The Swiss company Mistral Engines plans to obtain certification for a Wankel 230HP in 2006. They plan to develop a full range of rotary engines from 180 to 360HP, including a compression-ignition (diesel) cycle running on Jetfuel. Embry-Riddle Aeronautical university announced the first flight of a Pier Arrow III equipped with the Mistral 230HP, with Avgas for the time being. With which plane will diesel pay the most?Go to our CDRom on aerodiesel market or if you are stingy, look for planes with low market value because of high maintenance costs, and high flying time per year. You will notice that such planes are generally twins in the 250-350HP range. They are waiting for a 300HP diesel which will be offered by SMA, Thielert and DeltaHawk. Any fleet operator owning Piper Dakotas, Cessna 400 series, Aero Twin Commanders, Beech QueenAir and the like will then find it more cost effective to retrofit their planes with diesels than to replace them by Cessna Caravans. posted at 3:08 AM |
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