Electric Propulsion – Certified E-811

E-811: The first type-certified electric engine for use on General Aviation aircraft

The E-811 is the first electric engine certified for use in General Aviation by the European Union Aviation Safety Agency (EASA). Enjoy the benefits of a type-certified electric engine or boost the development process of your powered sailplane, UL, LSA, VLA or Part‑23 Level-1 aircraft.

The E-811 engine combines a liquid-cooled electric motor and a liquid-cooled power controller. Offering 57.6 kW (77 hp) of peak power, and 49.2 kW (66 hp) of maximum continuous power, the E-811 is the ideal powerplant for powered sailplanes, UL, LSA and VLA aircraft, where a Type Certified Engine is required. It may also be installed on Part-23 Level 1 aircraft and other distributed propulsion applications by applying the corresponding special conditions.

The propulsion motor is a state-of-the-art axial flux synchronous permanent magnet electric motor. Lighter and more compact, these motors are also more powerful than radial flux motors, making them ideal for their application in aviation. 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.

Flexibility

The motor’s rotation direction is not factory selected and can be easily adapted to any given application as part of the installation. The motor can turn clockwise or counter-clockwise as the default direction of rotation.

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 propeller should have a maximum moment of inertia of 3245 kg-cm² (7.7 lb-ft²) and weigh less than 5.5 kg. Maximum engine speed is 2500 rpm. A propeller that meets the E-811 engine technical specifications and limitations is available to order or can be specially designed at Pipistrel.

Cooling system and additional installation equipment

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: a coolant pump; a radiator; an expansion tank; an overflow bottle; inlet, outlet and intermediate hoses; and the coolant itself. The circuit shall ensure a coolant temperature at either component of less than 60°C.

In order to control the engine power output, an auxiliary control system should be provided. This can be ensured either by a power lever or a flight control computer, while cockpit indication such as an RPM indicator shall be provided as well. Different solutions are available to complement your installation, please inquire about different options which Pipistrel can deliver.

The engine requires high-voltage DC power to be supplied 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.

Installation of the additional equipment depends on the aircraft configuration. Its suitability for the E-811 engine must be demonstrated within the scope of the type certification of the aircraft.