Rotax 447 UL
Rotax 503 UL
Rotax 582 UL
Rotax 912 UL
Rotax 912 ULS
Rotax 914 UL

Shown here with external alternator, hydraulic propeller governor and air guide baffles.

Rotax 912 UL DCDI 81HP

  • 4-stroke engine specially developed for recreational aircraft. Also exists in certified versions: Rotax 912 A, Rotax 912 F.
  • 4 horizontally opposed cylinders, "boxer" configuration
  • Free air cooled cylinders, liquid cooled cylinder heads with integrated pump and expansion tank
  • Dry sump forced lubrication with integrated pump and separate oil tank
  • 8 valves, automatic adjustment by hydraulic valve tappet
  • Dual Capacitor Discharge Ignition (DCDI) with RFI noise suppression
  • Two Bing Constant Depression (CD) carburetors
  • Mechanically driven diaphragm fuel pump
  • Integrated electric starter
  • Integrated reduction gearbox, ratio of 2.27:1 or 2.43:1 with optional slipper clutch
  • Various liquid and oil radiators available
  • Many option available such as: Vacuum pump, external alternator, hydraulic propeller governor
  • Operates on automotive fuel with a minimum octane rating of 87 (Canadian standards)
  • Time Between Overhauls (TBO): 1500 hours*


Maximum Power
(5 minutes)
81HP / 59.6KW @ 5800 RPM
Maximum Power (sustained) 79HP / 58.9KW @ 5500 RPM
Maximum Torque 75.9ft-lb / 103NM @ 4800 RPM

Combustion Chambers

Bore 3.13" / 79.5mm
Stroke 2.40" / 61.0mm
Displacement / 1211.2cm
Compression ratio 9.0:1


Engine with carburetors 121.2lbs / 55.0Kg
Exhaust System 8.8lbs / 4.0Kg
Air Filter 0.7lbs / 0.3Kg
Liquid Radiator 2.2lbs / 1.0Kg
Oil Radiator 1.1lbs / 0.5Kg
Regulator-Rectifier 0.2lbs / 0.1Kg
Installed Weight 134.2lbs / 60.9Kg
Weight/power ratio 1.66lbs/HP / 1.0Kg/KW


Information Sheet 912info.pdf / 429Kb / Adobe Acrobat format
Performance Graphs 912perf.pdf / 14Kb / Adobe Acrobat format
Technical Drawings 912draw.pdf / 438Kb / Adobe Acrobat format
Manuals Visit
Service Documentation Visit