Rotax 912ULS with tuned exhaust in a
Dyn'Aéro MCR01 with 3-blade hydraulic
CSU propeller.
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.
[edit] Development
The original 80 hp (60 kW) 912 engine has a capacity of 1,211 cc (73.9 cu in) and a compression ratio of 9.1:1. The later 912S is enlarged to 1,352 cubic centimetres (82.5 cu in) and has a compression ration of 10.4:1, yielding 100 hp (75 kW). The 912 A is used in certified aircraft, such as the Diamond DA20, which is quite popular in Europe. The 100 hp (75 kW) versions are used in many light sport aircraft, such as the Flight Design CTSW, the Tecnam P2002 Sierra and the Titan T-51 Mustang. The 80 hp (60 kW) versions are sufficient to overpower 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 water-cooled heads and uses a gearbox (PSRU) to reduce the engine's relative high shaft speed (5,800 rpm for 100 hp versions) to a lower speed for the propeller. Lubrication is dry sump, and fuelling is via CV carburetors. These engines have yet to become fuel injected.
The 912 series 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.[1] In addition to the lower fuel consumption they are certified to run on automotive fuel (mogas) further reducing running costs. The engines are popular in Europe due to the lower fuel consumption and lower generated noise.
[edit] Variants
The engine is available in the following versions:
- 912 A# - Certified to JAR 22, 80 hp (60 kW)
- 912 F# - Certified to FAR 33, 80 hp (60 kW)
- 912 S# - Certified to FAR 33, 100 hp (75 kW)
- 912 UL# - Uncertified, 80 hp (60 kW)
- 912 ULS# - Uncertified, 100 hp (75 kW)
- 912 ULSFR# - Uncertified French Authority specification. 100 hp (75 kW)
The # in the designation stands for:
- Shaft with flange for fixed pitch propeller, P.C.D. 100 mm
- Shaft with flange for fixed pitch propeller, P.C.D. 75 mm, P.C.D. 80 mm and P.C.D. 4 inches
- Shaft with flange for constant speed propeller P.C.D. 75 mm, P.C.D. 80 mm, P.C.D. 4 inches and drive for hydraulic governor for constant speed propeller
- Shaft with flange for constant speed propeller P.C.D. 75 mm, P.C.D. 80 mm, P.C.D. 4 inches and prepared for retrofit of a hydraulic governor for constant speed propeller
[edit] Applications
[edit] Specifications (Rotax 912 UL/A/F)
General characteristics
- Type: four-cylinder, four-stroke liquid / air-cooled engine with opposed cylinders, dry sump forced lubrication with separate oil tank, automatic adjustment by hydraulic valve tappet, dual CD carburetors, mechanical diaphragm pump, electronic dual ignition, electric starter, integrated reduction gear 1 : 2.273
- Bore: 79.5 mm (3.13 in)
- Stroke: 61 mm (2.40 in)
- Displacement: 1,211.2 cm3 (73.91 in3)
- Length: 561 mm (22.1 in)
- Width: 576 mm (22.7 in)
- Dry weight: 60 kg (132.3 lb) with electric starter, carburetors, fuel pump, air filters and oil system
Components
- Valvetrain: OHV, hydraulic lifters, pushrods, rocker arms
- Fuel type: Unleaded: 87 octane AKI (Canada/USA) / 90 octane RON (European) or higher. Leaded fuel and AVGAS 100 LL can be used but are not recommended.
- Oil system: Dry sump with trochoid pump, camshaft driven
- Cooling system: Liquid-cooled cylinder heads, air-cooled cylinders
Performance
[edit] See also
- Comparable engines
- Related lists
[edit] References
[edit] External links
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