The SMA SR305-230 is an air/oil-cooled, horizontally opposed, four-cylinder, four-stroke, diesel piston aircraft engine producing 170 kW (227 hp).

The engine installation includes an electronic central processing unit (CPU) that continually calculates the proper fuel/air mixture.

[1] The STC conversion on the Cessna 182 includes a new cowl, both to accommodate the different engine dimensions and to provide the required cooling airflow.

[citation needed] The cost of conversion may be justified in areas where aviation gasoline 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.

[citation needed] 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 330 to 400 hp (246 to 298 kW).