By: Barbara E. Lichman, Ph.D., J.D.
The concept of “on call” transportation has now moved from the Earth to the sky. As demonstrated recently at a meeting of the players in Washington, D.C., the future of aerial transportation is transitioning toward “flying cars,” i.e., electric Vertical Takeoff and Landing (eVTOL) craft that hover and glide relatively quietly and without emissions, summoned by “app,” and without the need for a pilot. To accomplish this purpose, companies including Embraer, Aurora Aircraft, Karem Aircraft, Pipistrel USA Engineering, and Bell Aircraft Corporation have launched development of requisite engines and airframes.
In order to achieve the fundamental purpose of this (hopefully) revolutionary mode of air transportation, a number of parameters must be met in developing the requisite airframe, including a cruise speed of 150 miles per hour, 60 mile range, and capacity sufficient to fly three hours’ worth of short (e.g., 25 miles) trips carrying a pilot and four passengers. In addition, the “aircraft” must be able to takeoff and land vertically, like a helicopter, but fly on wings to conserve energy.
Each of the aspiring companies touts a different concept to accomplish these purposes.
Karem Aircraft proposes rotors that point up for helicopter mode, then tilt forward for continuous flying. Embraer, instead, proposes two sets of rotors: eight on top of the wings to lift and lower the aircraft, and two in the back to push it forward.
Finally, Jaunt Air Mobility, recently formed in April, 2019, proposes an innovative “reduced rotor operating speed aircraft” (“ROSA”). Martin Peryea, Chief Technology Officer for Jaunt, explained that, unlike a gyrocopter, the main rotor is powered, but uses a simple rotor attached system and weighted rotor tips that maintain a high degree of inertia in the event of power loss. The main rotor is powered by a large electric motor. Four smaller electric motors are mounted on the wings’ leading edges, and without a tail rotor. Thus, not only does the design do away with the tail rotor, the second largest generator of noise after the main rotor, but also reduces drag, and, thus, noise by slowing the main rotor at cruise speed.
While these plans are both timely and consistent with the societal push toward the utilization of technology based solutions, at least two significant detours may lie in the way of implementation. The first is the process of regulatory approval. The proposed designs must be certified by the Federal Aviation Administration (“FAA”) under 14 C.F.R. Part 29 – Airworthiness Standards: Transport Category Rotorcraft. Regulatory constraints range from “weight limits,” 14 C.F.R. § 29.25, through “performance at minimum operating speeds,” 14 C.F.R. § 29.49, to “maximum operating altitudes,” 14 C.F.R. § 29.1527, and a myriad between. That could take a significant period for even a conventional design in the opinion of Michael Hirschberg, Executive Director of the Vertical Flight Society. Hirschberg anticipates longer for the innovative designs for, and regulatory requirements applicable to, VTOL aircraft.
Finally, although not least important, is the potential obstacle of public opposition. With VTOL aircraft comes the need for development of “vertiports,” takeoff and landing grounds for VTOLs. Even though VTOLs often create less noise that conventional aircraft because of the absence of gas powered motors, the rotors for VTOLs, particularly the tail rotor, as set forth above, and the “drag” created by the main rotor, both create a whining noise to which surrounding communities may object. Federal and state environmental laws, as well as local zoning and planning regulations, may constitute additional roadblocks to implementation than FAA regulation, or, at least, delays in implementation, especially if “vertiports” are proposed on or near residential buildings in urban settings, or in residential areas in the suburbs.
There is no doubt, however, that the VTOL “train” has left the “station.” Stay tuned to see when and how it will reach its destination.