Thielert Centurion 1.7
The Thielert Centurion is a series of Diesel cycle aircraft engines for general aviation built by Thielert. They are based on heavily modified Mercedes-Benz automotive engines.
All Centurion engines are water-cooled, turbocharged and employ a single-lever digital engine management system (FADEC). This simplifies engine management for the pilot, as well as improving reliability, as it prevents the engine being operated improperly. The series utilizes either jet fuel or diesel fuel. The high compression ratio of the engine combined with the digitally controlled fuel injection system mirrors similar advances in automotive technology.
Centurion series engines are always fitted with constant speed propellers driven through a reduction gearbox. The constant speed propeller and reduction gear result in a propeller tip speed that is 10-15% lower than comparable conventional avgas engines, reducing propeller noise.
The Diesel engine's high compression results in better fuel efficiency and the higher operating rpm of the Centurion allows higher power to be developed from a smaller displacement, in comparison to conventional aircraft piston engines.
A Centurion engine complete with CSU, reduction gearbox, turbocharger and FADEC engine management system is considerably heavier than the more conventional Continental and Lycoming engines with which it competes, but this weight disadvantage is compensated for by the Centurion's lower fuel consumption. Even though it lacks the magnetos and spark plugs of the conventional piston engines, the Centurion engines are considerably more complex.
The first product introduced by Thielert, the Centurion 1.7 is a 1689 cc (103 cu.in) engine producing 135 hp (101 kW) is based on the Mercedes-Benz OM668 engine from Mercedes-Benz A-Class A 170 CDI (W168) with 80 mm bore and 84 mm stroke. Until the end of 2006, when production ceased in favor of the Centurion 2.0, more than 1,500 Centurion 1.7 had been built. The in-service record of the 1.7 has been poor, with a combination of design, service and support issues causing widespread customer dissatisfaction, and resulting in Diamond designing its own engines to compete with Thielert.