Andrew Doyle/MUNICH

B&F Technik Vertriebs is offering its FK-9 Mk3 two-seat kit plane with the Suprex turbo-charged piston engine that powers DaimlerChysler's "smart car" vehicle.


The German aircraft manufacturer says it has completed flight tests and gained approval to begin selling the high-wing monoplane with the 600cc three-cylinder engine in place of the previously recommended 60kW (80hp) Rotax 912. The 40kW Suprex petrol engine is claimed to be the first aircraft engine to incorporate a three-way catalytic converter.

According to engine developer and DaimlerChrysler subsidiary Micro Compact Car (MCC), "further decisive points in favour of using the smart engine above street level" include significantly lower noise and fuel consumption levels compared with competing products, and the inclusion of an advanced control system.

The Suprex engine can deliver 80Nm of torque between 2,000 and 4,000rpm, and provides maximum power output at 5,250rpm. The engine control is designed to adjust boost pressure, injection and ignition automatically to deliver a constant power output regardless of altitude.

"Traditional aircraft powerplants lag at least 10 years behind the engineering standard of car engines," says B&F senior design engineer Otto Funk. "You won't find modern design features like a map-controlled ignition and injection system or even a catalytic converter in those," he adds.

The Suprex engine weighs 66kg and burns around nine litres of premium-grade unleaded petrol per hour, giving the FK-9 Mk3 a range of 850km (450nm) with two standard 22 litre tanks. This can be extended to more than 1,000km with an auxiliary tank.

The only technical changes to the powerplant, compared with its automotive specification, concern "peripheral equipment", says MCC, with the installation of a 2.1:1 toothed belt transmission in place of the sequential six-speed transmission. The belt drives the aircraft's Junkers composite three-blade propeller, which is mounted on a separate shaft.

The FK-9 Mk3, which has a maximum take-off weight of 450kg and full-throttle speed of 98kt (180km/h) with the Suprex engine, was unveiled at the Aero general aviation show in Friedrichshafenin 1997.

Source: Flight International