The Rotax 914 is a turbocharged four-cylinder aircraft engine developed from the Rotax 912. Work on the more powerful derivative began in 1990, and the certified 914 F versions received their original approval on 15 May 1996. The family also includes the UL version for the applicable light-aircraft market.[1][2][3]
Turbocharged layout
The 914 combines liquid-cooled cylinder heads with air-cooled cylinders. Two carburettors meter fuel, while an electronic turbocharger control unit operates the boost-control system. The engine uses a 1,211 cc displacement, a 9:1 compression ratio and a propeller reduction ratio of approximately 2.43:1. Its turbocharger allows the engine to preserve useful output as ambient pressure falls with altitude.[2]
Rotax's product specification lists automatic wastegate control, dual electronic ignition and hydraulic valve tappets. Oil circulates through a dry-sump system with a separate tank. An electric starter and reduction gearbox are included in the basic engine arrangement, with the intake and exhaust systems forming additional parts of the installation.[3]
Power ratings
The F-series certificate gives 84.5 kW at 5,800 rpm for take-off, limited to five minutes, and 73.5 kW at 5,500 rpm continuously. The corresponding critical altitudes are 8,000 feet for take-off power and 16,000 feet for maximum continuous power under the certificate's stated conditions. These are separate ratings, rather than a single unrestricted output.[2]
Propeller and equipment choices
The certified F2 is configured for a fixed-pitch propeller. The F3 adds a drive, adapter and hydraulic governor for constant-speed operation; the F4 has preparation for that equipment without the complete governor installation.[2]
Rotax lists the engine with reduction gearbox at 64 kg, while separately identifying the exhaust, mounting frame, overload clutch and optional external alternator. The complete installed weight therefore depends on which of those components the aircraft requires.[3]