Pilot concepts for military applications: Turboshaft and other engines

In MTU’s military product portfolio, the spectrum of pilot concepts is delineated by various applications. On the one hand, they include the conventional low-bypass turbofan engine to power combat aircraft, which is currently being tailored to suit the peculiarities of unmanned applications, and pilot concepts for advanced turboshaft engines to power turboprop airplanes and helicopters on the other.

Turboshaft engines for helicopters

For turboshaft engines powering helicopters, the rules are basically the same as for turbofan engines, the challenge being to boost performance while reducing weight and fuel consumption. Much like the geared turbofan, the turboshaft engine has a high-speed low-pressure turbine.

The transfer of technologies from existing large commercial and military engines is subject to particular constraints. Turboshaft engines for helicopters need to be rather compact, which necessitates very high speeds and involves enormous mechanical stresses.

Heavy-duty turboprop engines

Heavy-duty turboprop engines are typically found on large airlifters like the Airbus A400M. They burn less fuel than a turbofan and behave better during extreme flight maneuvers which are frequently encountered during military missions.

The engine architecture is basically comparable to that of turboshaft engines for helicopters, except that much more power is needed. The propeller is normally driven by a separate power turbine, the power being provided by a gas generator.

Apart from turboshaft concepts, engines for unmanned aerial vehicles (UAV) are presently taking center stage in military technology development in Europe. For long-range cruise applications, they need to be fuel-thrifty, but for low-level operations also should generate substantial thrust.

The variable cycle engine concept uses so-called active systems to individually adapt the engine to suit changing operating modes. What needs to be developed for such engines are variable modules (bypass duct, fan or exhaust nozzle) or variable components (stator vanes).