MTU Aero Engines

2^nd Generation Geared Turbofan^TM

In its Clean Air Engine (Claire) technology agenda, MTU lays out its goals as well as the options for sustainable commercial engine concepts that will pave the way for emissions- free flight. In the first stage, the introduction of a geared turbofan reduced fuel consumption and hence CO2 emissions by 16 percent each and the noise footprint by 75 percent. This is above the target of 15 percent. The next stages will focus on the further development of the geared turbofan in order to exploit its full potential. Which means: lower fan pressure ratios and high bypass and over-all pressure ratios.

Sustainable fuels

MTU is also focusing on alternative, sustainable fuels known as sustainable aviation fuels (SAFs) that can be used at once. The company wants to shift away from burning fossil fuels because the only way to achieve the ambitious climate protection goals for 2050 is through the use of sustainable, renewable alternatives. The future is likely to belong to power-to-liq-uid (PtL) and sun-toliquid (StL) fuels, which are produced using green electricity and solar energy, respectively. In the long term, hydrogen is also a viable option.

Parallel hybrid-electric systems

Aircraft with a parallel hybrid-electric powertrain have the potential to serve longer routes. They combine electric and conventional propulsion systems, opening up new degrees of freedom in aircraft and engine design. One advantage of hybrid concepts is that they enable the aircraft to have distributed propulsion systems to reduce drag. Another is that engine operating points can be optimized. However, these are offset by disadvantages such as the weight of the systems and additional losses as a result of energy conversion.

Batteries

With their promise of emissions-free flight, battery-powered all-electric engines that run on renewable energy could catapult aviation into a new era. However, these systems come up hard against the limits of physics, because the batteries and the propulsion systems connected to them are much too heavy: batteries available today can supply about 1/25 as much usable energy as kerosene. A new operating segment would open the door to all-electric flight: carrying a small number of passengers over short distances by air taxi.

Fuel cells

Fuel cells emit nothing but water, meaning they enable virtually climate-neutral and pollutant-free flight. With hydrogen as its energy source, the electric motor drives the propulsors. Whether for short- medium or long-haul flight, this technology could be used to power almost any application.