The first issue to tackle in a discussion of how air taxis will fit into the urban landscape, their “concept of operation” as the cool kids say, is that, like conventional helicopters, they will need to take off and land vertically. The infrastructure currently envisioned for such services is likely to take the form of rooftop air terminals, or skyports, with on-demand passenger flights departing to a range of fixed destinations such as airports, resorts, convention centers, adjacent city centers, and so on. In addition, and in order to reduce the environmental impact of the service, described operations are promised to be clean, green, quiet and safe. Concepts of OPERATION Air Taxi
Up in the sky, the aircraft are shaping up into five categories or types, each designed to meet the most common mission-profiles, from short duration flights to longer, inter-city jumps, and deliver zero local emission performance. To help provide a little more detail and understanding of these five types, we’ll take a look at some real-world examples, starting with perhaps the most power-intensive design, the Vectored Thrust.
Vectored Thrust (DEVT) Vertical takeoff and landing aircraft that use the same
propulsion system for hover and cruise operations are generally referred to as
“vectored thrust” aircraft. Like the well-known Harrier jet design, they use
the same propulsion system for Liftoff, landing and forward propulsion. Lilium, a German-based enterprise and design, is a prime example of a unique form of Vectored Thrust, called a “Ducted Electric Vectored Thrust (DEVT)” aircraft. In this implementation, two banks of propellers and electric jet engines—housed in rotatable flaps in the wings—are mechanically oriented for both hover and cruise functions. Additional vectored propulsion—for a total of 36 individual jet powered electric motors and propeller systems—is housed in a forward Canard. The eponymous Lilium flagship leverages its unique DEVT system to optimize aircraft versatility for both short duration flights and longer distance city-to-city jumps. And as designed, the Lilium is configured as a 6 passenger plus pilot aircraft, making it one of the larger form-factor eVTOLs in development. QwikConnect is not rooting for winners, but we have to observe that the design aesthetics of the Lilium flight control surfaces make it one of the most compelling jet designs in the long history of aviation. And the promised efficiency of the aircraft at cruising altitude and speed make it one of the most versatile in terms of mission-profiles.
The Lilium jet shown with wings rotated in cruise orientation (above) and on the tarmac with wings in their vertical orientation (below) ready to lift and hover once passengers are boarded. Images courtesy Lilium
QwikConnect • July 2021
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