Voltage in the wind
The “Spirit of Innovation” measuring a length of around 7 meters (23 feet) is propelled by a 400-kW electric motor and the most power-dense propulsion battery pack ever assembled in aerospace, according to ACCEL (Accelerating the Electrification of Flight), the project’s development partnership. The development project has also incorporated know-how from Formula E, including the same 750-volt on-board voltage, among other things.
The powerful battery pack consisting of 6,480 individual cells enables speeds of more than 500 km/h (310 mph) and ranges beyond 160 kilometers (100 miles) to be achieved in the air space. A cork lining ensures stable thermal conditions, making the powertrain package of the record-breaking aircraft suitable for air taxis (eVOTL) as well. “Our next step is to adapt this pioneering technology so it can be applied across the wider aerospace industry to deliver a more sustainable way to fly,” says Stjohn Youngman, Managing Director of Electroflight, one of the ACCEL project partners that include engine specialist Rolls-Royce.
ACCEL names hybrid-electric powertrains that can be used on propeller-powered aircraft of the type currently known, such as the so-called city hopper with 19 and more seats, as examples of potentially related fields of application. In that case, the plane’s propeller can be driven directly by an internal combustion engine, an electric motor or both simultaneously, depending on the flight situation. The objective is to reduce fuel consumption while retaining or even increasing the aircraft’s range.
A complete or at least partial electrification of the powertrain is essential in view of the assumed passenger growth potential, combined with the concurrently required reduction of emissions from aviation. Rolls-Royce expects passenger volumes to increase globally to 6 billion just by the end of the decade. In addition, vertical mobility is playing an increasingly important role in view of the unbroken growth trend in global conurbations. Battery-electric powertrains can score especially in this context, also in terms of noise emissions.