BMW engine approved for British DeltaJet microlight

A motorcycle engine from German manufacturer BMW has been approved as an alternative power unit for the Exodus DeltaJet 500 StingRay flex-wing microlight.

The Technical Office of the British Microlight Aircraft Association (BMAA) completed its evaluation of the two-cylinder ‘Boxer’ engine from BMW’s R1200 GS motorcycle and issued approval at the beginning of this week.

The 1170cc R1200 GS engine has been adapted for aircraft use by German company Takeoff GmbH. It is fitted with a reduction gearbox with a ratio of 3.2:1, and also incorporates Takeoff’s unique centrifugal clutch and rotary vibration absorber.

The centrifugal clutch disengages the propeller at low engine rotation speeds, automatically engaging as engine speed rises (when taxying, for example), removing load on the engine for smoother start-up and idling.

“Flight testing showed an increased climb rate and reduced take-off run in comparison to the Rotax 912ULS,” said the BMAA’s Chief Inspector Rob Mott.

The British built DeltaJet 500 StingRay has a sculpted low-drag design, fully sprung undercarriage, spacious seats, and a topless 100mph wing said to offer fast roll rates with light control.

Engine features:

• 1170cc
• 115hp at 7500rpm with max torque at 6000rpm
• Double Overhead Cam
• Fuel injected
• ECU controlled
• Thermostatic valve in oil system as standard
• 3.2:1 gearbox with centrifugal clutch and rotary vibration absorber
• 2 cylinder & 4 spark plugs
• 4 valves per head
• E10 suitable (up to 10% ethanol – like Rotax)
• Belt driven 60A alternator
• YTX14H LiFePO4 (Lithium) battery as standard
• Kiev 283/1800 3 Blade

There are some maintenance differences compared to the Rotax 912ULS alternative:

• Valve clearance checks (after first 10hrs, then every 200hrs)
• Generator belt (check 100hrs & replace 200hrs)
• Although no carburettors, the throttle body must be periodically synchronised
• Air filter clean every 500hrs
• Gearbox check every 400hrs
• Gearbox oil (after first 10hrs, then every 200hrs)
• Spark plugs replace 400hrs
• Engine oil (after first 10hrs, then every 100hrs)

Exodus Airsports