Battery-Powered R44 Flies in California
Historic 1st Electric Helicopter Flight
By S.L. Fuller
September was a successful month for Tier 1 Engineering as its battery-powered manned helicopter reached three milestones, according to a company news release. On Sept. 13, the modified Robinson Helicopter R44 performed its first hover; the next day saw its first hover taxi; and a record 5-min cruise flight to 400 ft with a peak speed of 80 kts occurred on Sept. 21.
These flights took place at the Los Alamitos Army Airfield in southern California under a contract with Lung Biotechnology PCB. The goal of the project is to produce an electrically powered semi-autonomous rotorcraft for organ delivery. To Tier 1 Engineering's knowledge, this is the first rotorcraft in its weight class to fly solely on electricity.
Subsystems in the modified R44 include 1,100 lb of Brammo lithium polymer batteries, twin electric motors and a control system from Rinehart Motion Systems. Approximately 20% of the battery was drained during the helicopter's Sept. 21 flight. Glen Dromgoole, president of Tier 1, led design, build and installation efforts.
Designing started in January of this year, with installation processes completed by July. The company said that the biggest challenge was designing around the need for a takeoff weight of 2,500 lb. The R44 was chosen for its heavy engine, even though the internal engine was removed. The retrofit with electric motors, which weighed 100 lb provided useful load for batteries, according to Tier 1. The batteries, supported by a composite panel, are attached to the landing gear.