The Allison Model 250 Engine: A Case for the Small Turboprop

Allison has developed and obtained FAA type certificate for the Model 250 turboprop engine rated at 317 shaft horsepower. This engine has been flight tested in several experimental installations. Development of the engine to 400 shp is continuing.

Weight savings from the lighter turboprop engine result in increased aircraft useful load; the reduced drag of the smaller turbine engine coupled with ram recovery and higher continuous ratings provide higher performance at comparable reciprocating engine power levels. These factors result in increased aircraft productivity and net worth to offset the higher price associated with the turbine engine.