The SMA SR305-230 is an air/oil-cooled, horizontally opposed, four-cylinder,

four-stroke A four-stroke (also four-cycle) engine is an internal combustion (IC) engine in which the piston completes four separate strokes while turning the crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either directio ...

diesel Diesel may refer to: * Diesel engine, an internal combustion engine where ignition is caused by compression * Diesel fuel, a liquid fuel used in diesel engines * Diesel locomotive, a railway locomotive in which the prime mover is a diesel engine ...

piston aircraft engine producing . The engine is manufactured by

SMA Engines SMA Engines (Société de Motorisations Aéronautiques) is a French manufacturer of diesel engines The diesel engine, named after the German engineer Rudolf Diesel, is an internal combustion engine in which ignition of diesel fuel is cau ...

, and is currently the only product of this French company. The engine is offered as a conversion package for the

Cessna 182 The Cessna 182 Skylane is an American four-seat, single-engined light airplane built by Cessna of Wichita, Kansas. It has the option of adding two child seats in the baggage area. Introduced in 1956, the 182 has been produced in a ...

Design

The SMA SR 305-230-1 is a four-cylinder, horizontally opposed

turbocharged In an internal combustion engine, a turbocharger (also known as a turbo or a turbosupercharger) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake air, forcing more air into the ...

direct fuel injection diesel engine. The engine installation includes an electronic central processing unit (CPU) that continually calculates the proper fuel/air mixture. If this unit fails completely during flight, the mechanical backup position is selected and the pilot can control the fuel/air mixture as required to complete the flight. Full-throttle operation at sea level is of manifold pressure which is available to . Unlike some aircraft engines, which recommend the maximum power setting be used only for five minutes during the initial takeoff stage, the SR 305 can be operated indefinitely at this setting, although normal cruise is at and economy cruise at of manifold pressure. The STC conversion on the Cessna 182 includes a new

cowl A cowl is an item of clothing consisting of a long, hooded garment with wide sleeves, often worn by monks. It was developed during the Early Middle Ages. The term may have originally referred to the hooded portion of a cloak, though contempor ...

, both to accommodate the different engine dimensions and to provide the required cooling airflow. Belly-mounted cowl flaps are still used, but less cooling airflow is directed over the cylinder barrels and more cooling airflow is directed into side-mounted oil coolers. About one-third of the engine cooling is provided by airflow over the cylinders; the remainder is provided by engine oil. The engine's oil distribution system routes a large oil flow to hot zones in the cylinder heads and upper cylinder barrels, carrying the heat away to the oil coolers. As of early 2008, SMA had provided over 50 conversion packages. (The installation is usually performed by other companies, not SMA.) Most of those conversions were performed in Europe, with less than a dozen having been performed in North America. The cost of conversion may be justified in areas where

aviation gasoline Avgas (aviation gasoline, also known as aviation spirit in the UK) is an aviation fuel used in aircraft with spark-ignited internal combustion engines. ''Avgas'' is distinguished from conventional gasoline (petrol) used in motor vehicles, wh ...

costs significantly more than jet fuel, and by the fact that the diesel fuel flow at cruise is about 10 gallons (38 litres) per hour, compared to about 13.5 gallons (51 litres) per hour with the original engine. SMA expects 90 engines to be delivered in 2014, and is working on six-cylinder version called the SR460 which will have an output of .Thurber, Matt.
AirVenture Report: 2014
''AINonline'', 1 September 2014. Accessed: 4 September 2014.

Applications

* SMA SR305-230:

(STC conversion) * SMA SR305-260E:

Diamond DA50 The Diamond DA50 is a five seat, single-engine, composite aircraft designed and built by Diamond Aircraft Industries. First shown in 2006, it made its maiden flight on 4 April 2007. The project has been proposed to be powered by several differe ...

* SMA SR305-230 ATLS GS-301 Batoor In July 2012, Cessna announced it would offer the Cessna 182 with this engine as a factory option, with deliveries expected by the second quarter of 2013. Cessna also stated at that time that the SMA engine would eventually replace the current

avgas Avgas (aviation gasoline, also known as aviation spirit in the United Kingdom, UK) is an aviation fuel used in aircraft with spark-ignited internal combustion engines. ''Avgas'' is distinguished from conventional gasoline (petrol) used in moto ...

engine. This plan was abandoned and in 2023 the Cessna 182 was still being sold only with the Lycoming IO-540-AB1A5 gasoline engine.

Specifications

References

External links

* {{SMA Engines SMA aircraft engines Air-cooled aircraft piston engines Aircraft diesel engines 1990s aircraft piston engines

Design

Applications

Specifications

See also

References

External links