Rotax 914

From Wikipedia, the free encyclopedia

Type Piston aircraft engine
National origin Austria
Manufacturer Rotax
Major applications Light aircraft, unmanned aerial vehicles
Produced 1996–present[1][2]
Developed from Rotax 912

The Rotax 914 is a turbo-charged, four-stroke, four-cylinder, horizontally opposed aircraft engine with air-cooled cylinders and water-cooled cylinder heads. It is designed and built by the Austrian company BRP-Powertrain, owned by Bombardier Recreational Products (BRP), as part of its Rotax brand.[3][4][5]

The engine commonly powers certified light aircraft, homebuilt aircraft, autogyros and military UAVs such as the MQ-1 Predator.

Design and development[edit]

Introduced in 1996, the Rotax 914 is a turbocharged development of the Rotax 912.[2]

The Rotax 914 has a turbocharger with an automatic wastegate controller and dual carburetors. It features dual capacitor discharge ignition, liquid-cooled cylinder heads and air-cooled cylinder barrels, an electric starter, a built in propeller reduction gearbox, dry sump forced oil lubrication and has a separate oil tank. It has hydraulic valves that include automatic adjustment. Rotax can provide a purpose-designed air intake, exhaust system and engine mount.[3][4][6]

The 914 oil system differs from most dry-sump designs in that lubricating oil is forced into the storage tank by crankcase pressure rather than by a separate scavenge pump. This requires a novel preflight inspection procedure: before checking the oil level with the dipstick, the engine is "burped" by removing the oil filler cap and turning the propeller until a gurgling sound is heard, which indicates that all oil has been forced into the tank and the oil level can now be checked accurately.[2]

The 914 is more fuel efficient and lighter than similarly sized traditional engines, but originally had a shorter time between overhaul (TBO), restricting its market potential. On introduction, the TBO was only 600 hours, which was double that of previous Rotax engines but far short of existing engines of comparable size and power. However, by 1999 the TBO had been increased to 1,000 hours, and it was increased again to 2,000 hours in 2010.[2]

The engine can be operated on 100LL leaded avgas or on unleaded regular automotive gasoline, with a minimum RON of 95.[4][7] If the 914 is operated using leaded fuel, lead sludge will accumulate in the oil tank and reduction gearbox, and the fuel is incompatible with the recommended synthetic oil because it cannot hold lead in suspension; consequently, using leaded fuel mandates additional maintenance, and unleaded fuel is recommended.[2]


914 F
Family of engine versions certified to US Federal Aviation Administration FAR 33 and EASA JAR-E. These include:[4][6][7][8]
914 UL
Non-certified engine version for homebuilt and ultralight aircraft.[4][6]


Specifications (914)[edit]

General characteristics

  • Type: four-cylinder, four-stroke liquid- / air-cooled engine with opposed cylinders
  • Bore: 79.5 mm (3.13 in)
  • Stroke: 61 mm (2.4 in)
  • Displacement: 1,211.2 cc (73.91 cu in)
  • Length: 561 mm (22.1 in)
  • Width: 576 mm (22.7 in)
  • Dry weight: 78 kg (172 lb) with electric starter, carburetors, fuel pump, air filters and oil system


  • Valvetrain: OHV, hydraulic lifters, pushrods, rocker arms
  • Fuel system: Dual CD carburetors, mechanical diaphragm pump
  • Fuel type: Unleaded: 91 octane AKI (Canada/USA) / 95 octane RON (European) or higher[9]
  • Oil system: Dry sump with trochoid pump, camshaft driven
  • Cooling system: Liquid-cooled cylinder heads, air-cooled cylinders
  • Reduction gear: Integrated reduction gear 1:2.273; 1:2.43 optional
  • Electronic dual ignition


  • Power output: Maximum 84 kW (115 hp) at 5,800 rpm, with 5 minute time limit; 73 kW (100 hp) continuous

See also[edit]

Related lists


  1. ^ "40 years of rotax aircraft engines". Rotax. 30 June 2015.
  2. ^ a b c d e Busch, Mike (1 June 2017). "Opinion: Savvy Maintenance – Outside the Box: The Rotax 912 is Delightfully Different". AOPA Pilot. Aircraft Owners and Pilots Association. Retrieved 10 April 2020.
  3. ^ a b Bayerl, Robby; Martin Berkemeier; et al: World Directory of Leisure Aviation 2011-12, pages 242-243. WDLA UK, Lancaster UK, 2011. ISSN 1368-485X
  4. ^ a b c d e Tacke, Willi; Marino Boric; et al: World Directory of Light Aviation 2015-16, pages 260-261. Flying Pages Europe SARL, 2015. ISSN 1368-485X
  5. ^ Rotax (2005). "Engine Models". Archived from the original on 18 March 2007. Retrieved 13 March 2020.
  6. ^ a b c Rotax. "Rotax 914 UL/F". Archived from the original on 15 September 2018. Retrieved 13 March 2020.
  7. ^ a b c d e Federal Aviation Administration (11 October 2016). "Type Certificate Data Sheet No. E00058NE Revision 4" (PDF). Archived from the original (PDF) on 13 November 2016. Retrieved 13 March 2020.
  8. ^ a b c d European Aviation Safety Agency (5 September 2016). "EASA Aircraft Type Certificates – E.122" (PDF). Archived from the original (PDF) on 14 March 2020. Retrieved 14 March 2020.
  9. ^ OM-914 Operator's Manual 914 Series

External links[edit]