Exciting news for aviation enthusiasts: A major step towards electric powered air travel was achieved with the power-up of the world’s most powerful hybrid electric powertrain for aviation in a project led by Pipistrel. Hybrid-electric powertrains are a new breed of aviation propulsion, which extend the range of all-electric aircraft while being environmentally friendly and quiet. The 200 kW propulsor developed during the project HYPSTAIR delivers the power equivalent to a typical general aviation piston engine and can run in three modalities: electric-only mode using batteries, generator-only mode or hybrid mode combining both power sources.
Pipistrel’s powertrain components were developed by Siemens during the project and represent the state of the art of electric flight propulsion. The drive motor, delivering 200 kW take off power and 150 kW continuous, and the generator, delivering 100 kW feature a power density exceeding 5 kW/kg and dual windings with four power controllers to provide unprecedented reliability. Further element of innovation is the Human-Machine-Interface designed to simplify the operation of a complex powertrain. A single lever with haptic feedback is used to apply power and a new integrated cockpit display to monitor the powertrain status and performance.
After the extensive laboratory testing of components and the integration on a representative airframe at the Pipistrel aviation factory in Slovenia, the successful power up managed all propulsion modes at low and high powers, driving a specially developed five blade low rpm, low noise propeller. Tests of take-off power were performed using combined output of the generator driven by a turbonormalised engine and the high-performance battery custom developed to support high discharge rates.
Pipistrel CEO, Ivo Boscarol, says: “We are proud of what HYPSTAIR represents for the development of electric flight. It demonstrates the possibility for general aviation class aircraft to be electrically powered and it confirms the vision of Pipistrel – we were the first to design a four seat aircraft, the Panthera, which can be alternatively equipped with three different propulsion types: piston engine, electric motor or hybrid powertrain. Project HYPSTAIR represents a major step in the direction of a hybrid aircraft and an opportunity for Pipistrel and other general aviation aircraft manufacturers.”
Frank Anton, Head of e-Aircraft and the initiator of electric aircraft development at Siemens AG: “Siemens is developing electric drive systems with highest power-to-weight ratio for aircraft propulsion. Only with innovation we can solve the problems of rising fuel costs, rising passenger demand and rising environmental regulation. Innovations developed for the HYPSTAIR hybrid-electric powertrain will be instrumental in making aviation more sustainable in the long run. As electric drives are scalable, we can expect that in the future also larger aircraft will use electric propulsion. The world is becoming electric, whether in the air, on land or at sea.”
During the next few months, extensive testing will continue to simulate typical mission profiles covered in the performance study and to validate the hybrid drive concept and performance. This pioneering achievement was first unveiled at the E2 Fliegen Symposium 2016 in Stuttgart, Germany.
Interestingly, HYPSTAIR has received funding from the European Union’s Seventh Framework Program for research, technological development and demonstration under grant agreement no. 605305. Project partners are Pipistrel d.o.o. Ajdovščina, Siemens AG, MBVision, University of Pisa and University of Maribor.