912 Flexwing Engines
For a Flexwing student or Pilot who is looking for their first 4 stroke engined (912) Flexwing, it can be a bit confusing what the differences are. Here is a brief overview of 912 engines.
Engines have multiple areas of redundancy. The engines have 4 x cylinders, and each cylinder has 2 spark plugs. There are 2 x banks of electronic ignition, each capable of keeping the engine going. The Carburetors are known for the connecting rubbers perishing from inside, and should be checked on a regular basis, by removal and thorough inspection for damage. Any damage should mean replacement of these rubbers.
Service sheets can be downloaded from ROTAX :
912 Engine overview
- The original 80HP Rotax is a 1,200cc Engine with twin carburetors. This is often described as the 912 UL.
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
The latter 912S Rotax engine was slightly bigger at 1,300cc, and produces 100HP. This engine has Fuel injection and an electronic fuel engine management system. This is often described as the 912ULS
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Rotax 912 ULS DCDI 100HP*
- 4-stroke engine specially developed for recreational aircraft. Also exists in a certified version: Rotax 912 S.
- 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 heavy duty electric starter
- Integrated reduction gearbox, ratio of 2.43:1 with slipper clutch standard
- 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 91 (Canadian standards)
- Time Between Overhauls (TBO): 1500 hours
These engines are found on:
- Mainair Blade
- Pegasus Quantum
- Pegasus Quik
- P&M GT-450