Flexwing Aircraft – Engines
2 stroke or 4 stroke?
Microlight aircraft have 2 different types of engines: 2 stroke and 4 stroke, the same as motorbikes. 2 stroke engines are smaller, use more fuel, and generally require more maintenance, but are a lot cheaper.
SSDR flexwings use 2 strokes, because they are lighter.
The various 2-stroke rotax engines are the 447 (40 bhp), 503 (47 bhp), 462 (48 bhp), and 582 (65 bhp). The 447 & 503 are air cooled, and the 462 & 582 are water cooled. The air cooled ones are simpler, but less efficient.
The 582 comes in a silvertop and bluetop version with the bluetop supposedly being more reliable as a result of updates to the cooling system. The Bluetop has a bigger and stronger crank than the older silvertop.
General characteristics- 582
- Type: two-cylinder, two-stroke, rotary valve, oil-in-fuel or oil-injected lubrication, dual carburetors, electronic dual ignition
- Bore: 76 mm (2.99 in)
- Stroke: 64 mm (2.52 in)
- Displacement: 580.7 cm³ (35.44 cu in)
- Dry weight: 50 kg (110 lb) with electric starter, carburetors, fuel pump, air filters and reduction gear
- Fuel type: premium unleaded: RON 90 octane or higher leaded or unleaded or AVGAS 100 LL
- Oil system: oil-in-fuel (pre-mix) or oil injection
- Cooling system: liquid cooled
The 4 stroke engines cone in 3 variants: 912UL (80 bhp) , 912ULS (100 bhp) and the 914 has 115 bhp
General characteristics of a 912 ULS (80 BHP)
- Type: four-cylinder, four-stroke liquid / air-cooled engine with opposed cylinders, dry sump forced lubrication with separate oil tank, automatic adjustment by hydraulic valve tappet, dual CD carburetors, mechanical diaphragm pump, electronic dual ignition, electric starter, integrated reduction gear 1 : 2.273 or 1 : 2.43
- Bore: 79.5 mm (3.13 in)
- Stroke: 61 mm (2.40 in)
- Displacement: 1,211.2 cm3 (73.91 in3)
- Length: 561 mm (22.1 in)
- Width: 576 mm (22.7 in)
- Dry weight: 60 kg (132.3 lb) with electric starter, carburetors, fuel pump, air filters and oil system
- Valvetrain: OHV, hydraulic lifters, pushrods, rocker arms
- Fuel type: Unleaded: 87 octane AKI (Canada/USA) / 90 octane RON (European) or higher. Leaded fuel and AVGAS 100 LL can be used but are not recommended.
- Oil system: Dry sump with trochoid pump, camshaft driven
- Cooling system: Liquid-cooled cylinder heads, air-cooled cylinders
- Power output: 59.6 kW (79.9 hp) at 5,800 rpm
- Specific power: 48.71 kW/L
- Compression ratio: 9:1
- Fuel consumption: 15.0 liters/h at 5,000 rpm (75% power)
- Specific fuel consumption: 285 g/(kW·h) at 5,500 rpm (maximum continuous power)
- Power-to-weight ratio: 980 W/kg
Click HERE to find out more in depth information about 912 Engines