Vertical Flight Society Applauds EVTOL Innovation, Bell Nexus UAM Concept

The vision of UAM is a safe and efficient system for air passenger and cargo transportation within urban areas, including package delivery and other services via unmanned aircraft systems (UAS).

The electric vertical-takeoff-and-landing (eVTOL ) revolution is gaining momentum, as evidenced by the unveiling of the Bell Nexus hybrid-electric VTOL air taxi concept at the Consumer Electronics Show (CES), affirms Mike Hirschberg, executive director at the Vertical Flight Society (VFS), a non-profit organization working to advance vertical flight, in Fairfax, Virginia.

Bell, having delivered more than 35,000 helicopters and tiltrotor aircraft since its first helicopter took flight in 1943, is now combining its “deep understanding of vertical flight technology with hybrid-electric power to create a disruptive new VTOL air taxi for everyday use,” VFS officials say.

Learn more: Read "Bell Nexus full-scale air taxi design debuts, taps novel VTOL, hybrid propulsion, energy storage, and avionics technologies"

Innovators within and outside the aerospace industry have seized the opportunity to leverage advances in electric motors, batteries, hybrid-systems, control systems, low-cost manufacturing, and autonomy that have been developed by the automotive, aerospace, and consumer unmanned aircraft systems (UAS) industries, VFS officials continue. “These technologies have revolutionized the creative design space for VTOL innovators, resulting in an incredible breadth and depth of new electric and hybrid-electric  VTOL aircraft configurations that don’t resemble the helicopters that have dominated vertical flight for the past 75 years.”

The Bell Nexus builds on the company’s heritage, including its experience developing and producing, with Boeing, the world’s only operational tiltrotor VTOL aircraft, the V‑22 Osprey .

The Bell Nexus uses a Safran turboshaft-based hybrid propulsion and drive system to produce the electrical power for six propellers, each housed in a tilting duct — three on each side of the aircraft cabin. The use of electrical power enables revolutionary configurations that can be much quieter and environmentally friendlier than conventional helicopters. Although batteries have much lower energy density than liquid fuel, the Nexus offsets this by cruising on an airplane wing — as well as lift generated by the six ducts — for extended operational range.

The Safran turboshaft engine, which is housed on the aft fuselage above the cabin, provides additional power for vertical takeoffs and landings, as well as extended range, like a hybrid-electric automobile. The V-tail configuration reduces the noise of the engine exhaust when it is running.

Bell is also leveraging the legacy of its experimental X-22 VTOL X-Plane, which was flown from 1966 to 1988, but the complexity of its four turboshaft engines mechanical driving four tilting ducted propellers via 11 gearboxes was too challenging for the Bell X-22 to go into production, VFS officials explain.

The Vertical Flight Society is tracking more than 135 eVTOL aircraft under development in its World eVTOL Aircraft Directory ( ), including revolutionary concepts such as vectored thrust aircraft (e.g., the Bell Nexus), wingless multicopters, lift-plus-cruise configurations with both tilting and fixed propellers, electric helicopters, hover bikes, and personal flying devices.

“Fifty years ago, many innovative VTOL designs were rejected because of the complexity of their manual flight controls linkages and propulsion drive systems, but electric power today enables ‘fly-by-wire’ computerized flight control systems as well as ‘power-by-wire’ energy transmission,” Hirschberg adds. “Electric power has opened up an exciting new design space for vertical flight and the Bell Nexus takes full advantage of these advances.”

In addition to Safran , the Bell Nexus team includes Electric Power Systems  (EPS), Thales , Moog,  and Garmin .

The Vertical Flight Society will host its 6th Annual Electric VTOL Symposium  in Mesa, Arizona, on Jan. 29-31, 2019, where Bell Executive Vice President of Technology and Innovation Michael Thacker will deliver the keynote address on Nexus and the company’s other autonomous and electric VTOL aircraft; this will be the first opportunity for Bell to present its Nexus air taxi to an aerospace audience. The Symposium will be held in conjunction with the 8th Biennial Autonomous VTOL Technical Meeting. The combined event features more than 100 speakers on the promise, progress, and challenges of autonomous and electric VTOL aircraft.

Courtney E. Howard  is editorial director and content strategist at SAE International. Contact her by e-mail at This email address is being protected from spambots. You need JavaScript enabled to view it..