|Type||Piston aero engine|
|Unit cost||US $18,500 (2015)|
|Developed into||D-Motor LF39|
Design and development
This direct-drive aero-engine is unusual in two respects: it is very oversquare with a bore:stroke ratio of 1.295:1, and it has a side-valve valvetrain. The designer determined that since maximum continuous power output was to be developed at only 2800 rpm, the extra weight and complexity of overhead valves would be superfluous. The resulting engine is compact and lightweight, with a dry weight of 58 kg (128 lb), with a power-to-weight ratio of 1.46 kW/kg. Coolant fluids weigh 5 kg (11 lb). The engine uses fuel injection, so carburetor heat is unnecessary. Lubrication is by dry sump, with an external oil tank. Dual ignition is used, each cylinder having twin spark plugs sited between the valves and the piston crowns.
Unlike an engine which uses ohc to be capable of high revs, a feature of the slow-revving side-valve arrangement is that the engine does not suffer high frictional losses, so the power curve is completely linear up to 3100rpm. An inherent disadvantage of the side-valve design is the relatively inefficient shape of the combustion chamber; but there remains potential for squish to promote turbulence of the fuel/air mix, and the low rpm means that the flame front is able ignite all the fuel in each power stroke.
With the aid of funding from the Belgian government, D-Motor has developed a derivative 4 litre flat-six engine,the D-Motor LF39, and this motor is claimed to produce 125 hp (93 kW) and to have dry weight of 74 kg (163 lb).
- BOT SC07 Speed Cruiser
- Foxcon Terrier 200
- Peak Aerospace Me 109
- Raj Hamsa X-Air
- Sherwood Ranger
- Type: horizontally opposed flat four
- Bore: 103.6mm ( 4.1 in)
- Stroke: 80 mm (2.91 in)
- Displacement: 2690 cm³
- Length: 611 mm
- Width: 533 mm
- Height: 382 mm
- Dry weight: 58 kg with exhaust, radiator & external oil tank
- Valvetrain: none (tappets only)
- Fuel system: fuel injection
- Fuel type: AVGAS 100/130 or Auto Gas 91 Octane Minimum
- Oil system: Dry sump
- Cooling system: liquid cooling
- Power output: 91.8 hp (68 kW) at 3,000 RPM
- Compression ratio: 8:1
- Fuel consumption: 11 litres/h at 75% power
- Power-to-weight ratio: 1.17 kW/kg
- Comparable engines
- HKS 700E
- Jabiru 2200
- KFM 112M
- Revmaster R-2300
- Rotax 912
- Sauer S 2200 UL
- Sauer S 2400 UL
- Sauer S 2100 ULT
- ULPower UL260i
- Verner 133M
- Related lists
- "Belgium firm offers Light Sport engine". AOPA Pilot: 40. March 2015.
- "Kapelstraat 198 8540 Deerlijk - Recent information". D-motor1.vpweb.be. Retrieved 2012-08-14.
- "LF26 specifications". D-motor. Retrieved 26 June 2012.
- D-motor performance graph
- "Kapelstraat 198 8540 Deerlijk - News". D-motor1.vpweb.be. Retrieved 2012-05-10.
- D-Motor publicity specification sheet, August 2014
- D-Motor (n.d.). "X-air test plane". Retrieved 2 August 2011.