Pipistrel is to make its certified electric propulsion system available to other electric aircraft manufacturers.
The Pipistrel E-811 is the first electric engine certified for use in General Aviation by the European Union Aviation Safety Agency (EASA).
It can be used as a type-certified electric engine in various types of aircraft including powered sailplane, Ultralight (microlight), Light Sport Aircraft (LSA), Very Light Aircraft (VLA) or Part‑23 Level-1 aircraft.
The E-811 engine combines a liquid-cooled electric motor and a liquid-cooled power controller. It provides 57.6kW (77hp) of peak power, and 49.2kW (66hp) of maximum continuous power.
Now this gets a bit technical: the propulsion motor is an axial flux synchronous permanent magnet electric motor. The propeller is mounted directly on its rotor.
The associated controller converts direct current (DC) from the batteries to alternating current (AC) for the motor. The controller receives torque command via CAN bus and adjusts the motor current input accordingly through the engine’s high voltage AC bus. The motor reacts instantaneously and without hesitation. The controller also requires a 12-volts power supply.
Pipistrel says the E-811 supports a wide range of propellers. Fixed, ground-adjustable and electric variable-pitch propellers can be mounted on the engine, as long as they are compatible with the flange geometry and screw pattern (6xM8 on 75 mm diameter). Hydraulic governors are not supported.
The engine is entirely liquid-cooled through a single cooling circuit with a mixture of 50% water and 50% glycol (automotive grade G12+). The coolant inlet is located on the power controller. It then proceeds to the motor via an intermediate coolant hose. The coolant outlet is located on the motor.
The cooling system is part of the installation and can be provided by Pipistrel. It comprises the following components:
- coolant pump
- radiator
- expansion tank
- overflow bottle
- inlet, outlet and intermediate hoses
- and the coolant itself.
The circuit ensures a coolant temperature at either component of less than 60°C.
To control engine power output, an auxiliary control system is needed – either by a power lever or a flight control computer.
The engine requires high-voltage DC power for propulsive force. Depending on the chosen architecture, the engine will accept DC power from the energy source, which may be batteries connected via a battery management system (BMS), or a generator, or a fuel cell, or combinations thereof. A low-voltage (12 VDC) power connection is also needed.
Tech spec
| MOTOR – 268 MV LC VHML | |
| type | axial flux synchronous permanent magnet |
| diameter | 268 mm (10.55 in) |
| width | 91 mm (3.58 in) |
| dry weight | 22.7 kg (50 lb) |
| maximum take-off power (MTOP) up to 90 seconds | 57.6 kW (77 hp) at 2500 rpm |
| maximum continuous power (MCP) | 49.2 kW (66 hp) at 2350 rpm |
| outside air temperature range | -20°C, +40°C (-4°F, 104°F) |
| max motor temperature | 110°C (230°F) |
| speed limits | 2350 rpm (MCP), 2500 rpm (MTOP) |
| torque limits | 200 Nm (MCP), 220 Nm (MTOP) |
| CONTROLLER – H300C | |
| dimensions | 245 x 126 x 230 mm (9.65 x 4.96 x 9.05 in) |
| dry weight | 8.1 kg (17.8 lb) including cables |
| max controller temperature | 70°C (158°F) |
| input voltage range | 250 – 400 VDC |
| max controller current | 311 A |
| max continuous current | 226 A |
| COOLING SYSTEM REQUIREMENTS | |
| coolant flow | > 5.5 l/min |
| coolant temperature | < 60°C (140°F) |
| pressure drop (over the entire system) | < 1 bar |
| PROPELLER REQUIREMENTS | |
| max moment of inertia | 3245 kg-cm2 (7.7 lb-ft2) |
| max propeller mass | 5.5 kg (12.1 lb) |
| max speed | 2500 rpm |