Electroflight Team Aims To Fly 300 MPH On Batteries

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Electroflight Team Aims To Fly 300 MPH On Batteries

By Mary Grady | September 1, 2014

Electroflight http://www.electro-flight.co.uk/aeroplane.html, a team of
British glider builders, recently announced it has teamed up with Williams
Advanced Engineering to build a single-seat airplane that will set a new speed
record for electric aircraft of 300 mph. Team Electroflight has built a mock-up
of its design, and said it will be powered by a "unique contra-rotating
electric propulsion system." Williams is affiliated with the Williams Martini
Formula One car-racing team, which is developing technology to compete in a new
fully electric car-racing series, called Formula E, that is set to debut this
month. "We are certain that the combined expertise of the teams will enable us
to achieve our goal and break the world speed record for electric aircraft,"
said Roger Targett, of Electroflight. The current speed record for electric
flight is 220 mph.

Electroflight exhibited its mock-up of the new design at the recent Red Bull
Air Races in Ascot, England. "There was a huge amount of interest and large
numbers of people, mainly children, queuing to sit in the cockpit of our space
allocation fuselage," said Targett. According to the Electroflight website:
"Our aircraft design combines advances in carbon composite materials and
construction methods with emerging electric motor, control system and
energy-storage technologies. Its twin propeller contra-rotating propulsion
offers unique maneuvering capabilities. … Two fixed-pitch propellers have been
designed and engineered specifically to the rotational and torque
characteristics of the motors, together with thrust and acceleration bearing
assemblies that far exceed the loads presented during aggressive 10 G
aerobatics and air racing.

"The carbon composite airframe is fitted with a whole aircraft ballistic
parachute system and incorporates a separate pilot safety cell, similar to that
in F1 racing cars. The airframe has extremely low form drag and incorporates
purpose designed compartments to carry batteries, controllers and electronic
equipment. The result is a completely new type of race plane and technology
demonstrator that is light, fast and capable of maneuvers impossible for
single-propeller piston or gas-turbine-driven aircraft."

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Propulsion System
The propulsion system is a wholly new generation of an electric contra-rotating
unit. The high torque of the electric motors allows the propeller shafts to be
directly driven without gearing or other speed reduction devices and achieves
simplicity unknown in non-electric forms of contra-rotating propeller
propulsion. Except for the shaft bearings, the motor rotors, propeller shafts
and propellers form the only two rotating assemblies in the system.

This allows for almost maintenance free operation for the life of the system. A
unique feature of electric propulsion is the ability to apply full power almost
instantly with no spool up or inertial lag time found in piston or turbine
types. The system's thrust to take-off weight ratio is greater than one and
allows the aircraft to accelerate vertically (vertical take-off) and to operate
at extreme altitudes far above oxygen dependant engines in unpiloted
conditions.

Two fixed pitch propellers have been designed and engineered specifically to
the rotational and torque characteristics of the motors, together with thrust
and acceleration bearing assemblies that far exceed the loads presented during
aggressive 10 G aerobatics and air racing.

The carbon composite airframe is fitted with a whole aircraft ballistic
parachute system and incorporates a separate pilot safety cell, similar to that
in F1 racing cars. The airframe has extremely low form drag and incorporates
purpose designed compartments to carry batteries, controllers and electronic
equipment. The result is a completely new type of race plane and technology
demonstrator that is light, fast and capable of manoeuvres impossible for
single propeller piston or gas turbine driven aircraft.

Facts
The single seat prototype aircraft is designed to demonstrate the advantages of
pure electric flight.

All Up Weight (excluding pilot); 345 kgs.
Maximum Power (3400rpm): 225 kW
Thrust 500 Kgs
Maximum level Speed (sea level) 250 kts
Climb rate (vertical) 9,000 ft/min
Battery power (720 volts) 15 kW