Helicopter Electric Tail Rotor

Bell Helicopter 206B
Bell 206 A/B Helicopter

The tail rotor in a helicopter is used to balance the forces of the main rotor so that a pilot can control the aircraft azimuth or heading. Currently, the main turbine of the helicopter drives the tail rotor via a mechanical shaft and gears similar to the way power is transferred from an automobile engine to the rear wheels of a car. This mechanical linkage imposes a fixed speed relationship between the main rotor and the tail rotor, which can be detrimental in certain flying conditions. If the tail rotor can be run independently of the main rotor, improvements in the maneuverability of the helicopter can be achieved.


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LaunchPoint Halbach Array Motor

LaunchPoint Technologies has recently completed an inrunner version of their Halbach array electric motor.  This extremely lightweight and power-dense electric machine can be used both as a generator and as a motor. To drive the motor, LaunchPoint is also developing a highly-reliable and lightweight power-electronics package.  These two innovative technologies are being integrated to meet the requirements of an electric tail rotor drive for the Bell 206A/B helicopter as part of a recent Navy SBIR Phase I Award. This system will add at most a few kilograms to the helicopter and will provide highly reliable independent tail rotor operation.



Tail Rotor Assembly Using LaunchPoint Motor
Helicopter Tail Rotor Assembly Schematic

An independent electric tail rotor drive would add considerable flexibility to the operation of the helicopter and allow optimized usage of the tail rotor propeller.  Benefits include the ability to:

  • achieve more efficient forward flight.
  • help prevent tail rotor stall.
  • help compensate for the loss of tail rotor thrust and improve aircraft control in turbulent wind conditions.
  • enable azimuth control when taking off from icy surfaces or from the water with float landing gear.
  • include a hinged tail on the helicopter that could be folded for storage.
  • eliminate (usually fatal) tail rotor gearbox failures, substantially improving vehicle safety and reliabiity.