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The Rotax 912 is a normally aspirated, air- and water-cooled, horizontally opposed four-cylinder, four-stroke, gear reduction-drive engine commonly used on certified aircraft, light sport aircraft, ultralight aircraft and unmanned aerial vehicles. Rotax produced its 50,000th 912-series engine in 2014.〔(【引用サイトリンク】url=http://www.avweb.com/avwebflash/news/Rotax-Rolls-Out-50000-912-Series-Engine222133-1.html )〕 ==Development== The original 912 engine has a capacity of and a compression ratio of 9.1:1. The later 912S is enlarged to and has a compression ratio of 10.4:1, yielding . The 912 A and F are used in certified aircraft, such as the Diamond DA20, which is quite popular in Europe. The versions are used in many light sport aircraft, such as the Zenith STOL CH 701 and the Tecnam P2002 Sierra. The versions are sufficient to power the new generation of efficient motorgliders, such as the Pipistrel Sinus and the Urban Air Lambada. It is also fitted to some light twins, such as the Tecnam P2006T. The engine differs from conventional aircraft engines (such as the Lycoming O-235) in that it has air-cooled cylinders with liquid-cooled heads and uses a 2.43:1 gearbox (PSRU) to reduce the engine's relatively high 5,800 rpm shaft speed to a more conventional 2,400 rpm for the propeller. On the 912A, F and UL the standard reduction ratio is 2.27:1 with 2.43:1 optional. Lubrication is dry sump, and fuelling is via dual CV carburetors or fully redundant electronic fuel injection. The electronic fuel injected Rotax 912iS is a recent development.〔 A further derivative, the Rotax 915 iS was announced in July 2015.〔(【引用サイトリンク】title=Rotax-Owner.com - ROTAX 915 IS: BRP UNVEILS A NEW TURBOCHARGED ROTAX AIRCRAFT ENGINE )〕 Early 912 series engines have a shorter time between overhaul (TBO) than traditional engines, but are more fuel efficient than similarly sized engines, ''e.g.'', Continental O-200. Effective 14 December 2009, 912 engines have had their recommended Time Between Overhauls (TBO) raised from 1,200 hours to 1,500 hours, or 1,500 hours to 2,000 hours, depending on serial number. In addition to the lower fuel consumption they are certified to run on automotive fuel (mogas), further reducing running costs, especially in areas where leaded AVGAS is not readily available.〔 The engines are popular in Europe and in United States Light Sport Category aircraft due to high power-to-weight ratio, low fuel costs and relatively quiet operation. On 8 March 2012 the company displayed its 912 iS variant, a version with direct fuel injection and an electronic engine management unit. The version weighs , which is more than the standard 912S. The non-certified 912 iS targets the Light Sport and Experimental market and 912 iSc will be certified. Production started in March 2012 and the engine has a 2000-hour recommended time-between-overhaul to start. On 1 April 2014 the company announced its new 912 iS Sport upgrade with greater power and torque and reduced fuel consumption.〔(【引用サイトリンク】title=Rotax lowers fuel burn, boosts performance with 912 iS Sport )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Rotax 912」の詳細全文を読む スポンサード リンク
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