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Tier 1 Engineering e-R44 3rd Generation

Tier 1 Engineering e-R44 3rd Generation electric helicopter with a magniX electric motors, Tier 1 Engineering photo credit


e-R44 3rd Generation
Tier 1 Engineering
Santa Ana, California, USA

Founded in 2009 by Glen Dromgoole, Tier 1 Engineering is a provider of engineering and manufacturing services, specializing in the development of lightweight structures. The company offers engineering design, analysis, fabrication, material cutting, testing documentation, research and development and more, to the aerospace, energy, marine, medical and the consumer product sectors.

The e-R44 3rd Generation is a two passenger electric experimental helicopter (N3115T) using a modified Robinson Helicopter R44 for the aircraft. The e-R44 has one main rotorblade, one tail rotor, two electric motors, battery packs, control systems and has fixed skid landing gear. The major improvement to this 3rd model was changing to a high-tech and more powerful magniX magni250 electric motors.

On June 4, 2022 at 8:00 a.m., the e-R44 3rd Generation electric helicopter made a historic three minute flight at Los Alamitos Army Airfield (California, USA). The aircraft was flown by test pilot Ric Webb and co-pilot Dr. Martine Rothblatt, CEO of United Therapeutics, which is both the primary sponsor and launch customer for the battery-electric retrofit helicopter program.

“This historic flight of an all-electric helicopter with a certifiable electric engine was an important step towards obtaining aircraft certification,” said Glen Dromgoole, president of Tier 1 Engineering. “We are excited to expand the flight tests to greater distances and demonstrate safe reliable all-electric flight.”

The initial ground runs of the e-R44 3rd Generation helicopter began behind the Tier 1 Engineering offices in Santa Ana on Mar. 31, 2022 with Martine Rothblatt and Ric Webb performing system checks to validate the cooling system and engine controls of the magni250 electric motors.

Dromgoole said the company conducted more than 50 ground tests before the e-R44 3rd Generation helicopter was ready to make its first hover flight and perform traffic patterns at the airport. The tests included low and high-power runs with the aircraft anchored firmly to the ground.

Some of the tests simulated various engine fault scenarios and the pilot response. The magni250 has two motor segments which are powered by separate inverters. This means the helicopter can keep flying if one inverter or motor segment fails.

The next step in the program is to upgrade the engines to a more powerful magniX magni350 electric motor and its systems, and this will usher in the e-R44 4th Generation electric helicopter.

Tier 1 Engineering is developing the all-electric helicopter for Lung Biotechnology PBC. Lung Biotechnology PBC is pioneering techniques to address the acute national shortage of transplantable lungs and other organs. The company focuses on lung perfusion to develop new advanced technologies to preserve lungs for transplant and increase the availability of lung transplants for end-stage lung disease, including PAH.

Lung Biotechnology's work includes innovative methods that can stabilize and improve lungs that would otherwise be discarded. Xenotransplantation (the process of grafting or transplanting organs or tissues between members of different species) could potentially provide a limitless supply of organs. The company intends to acquire a fleet of electric helicopters and will use them to provide urgent hospital-to-hospital transportation for time-critical transplant operations.

Tier 1 Engineering is in discussions with the Federal Aviation Administration (FAA) aircraft certification office in Los Angeles to acquired a supplemental type certificate for the e-R44 program.


  • Aircraft type: Electric helicopter demonstrator
  • Piloting: 1 pilot, 1 passenger
  • Cruise speed: Unknown
  • Range: Unknown
  • Estimated flight time: Unknown
  • Cruise altitude: Unknown
  • Rotorblades: 1 main rotor blade, 1 tail rotor
  • Electric Motors: 2 magniX magni250 electric motors
  • Power source: Lithium polymer batteries
  • Fuselage: Welded steel tubing and riveted aluminum sheet
  • Windows: Panoramic helicopter windows in the cockpit
  • Landing gear: Fixed skid helicopter landing gear
  • Safety features: The helicopter can autorotate in case of power failure

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