Wankel engine will be offered for Katana motor glider after transfer to Austria and renaming of UK engine subsidiary

Diamond Aircraft is to offer a rotary combustion engine (RCE) for its DA20 Katana motor glider after completing the transfer of its Mid-West Engines subsidiary from the UK to its headquarters near Vienna, Austria.

The DA20-W fitted with the 78kW (105shp) twin-rotor GIAE 110R is to enter serial production next year. The aircraft will also include design modifications made for the C1 Eclipse basic trainer.

Diamond managing director Christian Dries says the potential of the "super-efficient engine" was not being fully exploited by Bristol, UK-based Mid-West Engines, which the company has owned since 1994.

Dries says there is demand, especially in the USA, for cheap and reliable general aviation engines capable of running on low-lead and unleaded aviation gasoline. The renamed Diamond Engines aims to certificate the GIAE 110R by the end of the year and will offer it alongside the JAR 22 certificated single rotor 37kW GIAE 50R for the retrofit market.

The twin rotary engine is based on the Wankel principle and has only four main components; a fat figure-of-eight (epitrochoid) combustion chamber, two triangular rotors with convex flanks; and an internal gear. The four-stroke engine cycles of induction, compression, expansion and exhaust are replaced by each flank exploiting the varying volume between itself and the chamber walls. Three separate power impulses for each complete revolution and individual phases of combustion take place on each flank of the rotor.

Diamond says that the simple engine design, with no cylinder liners to tear, means that only seals and bearings need ever be replaced, leading to longer periods between overhauls.

The engine offers a flat torque curve over a wide speed range due to its rotary motion and dynamic balance, ensuring that increasing speed does not significantly increase stress levels.

Source: Flight International