In Part I of this post, we discussed current developments in fixed-wing electric aircraft and the current state of aircraft battery technology, followed by current developments in transport category hybrid-electric aircraft. Today, we switch to what might be the next evolution in aviation transportation – the all-electric vertical take-off and landing aircraft, otherwise referred to as the eVTOL.
According to the Electric VTOL News website, there are currently 217 electric and hybrid-electric Vertical Take-Off and Landing (VTOL) concepts in various stages of development from the automotive, aviation, and the tech industries. According to the below chart – which tracks 190 eVTOL and 5 eSSTOL (SS = super short) concepts, the majority of the projects are originating from the United States (48%) and Europe (32%).
Major aviation industry players – including Aurora Flight Sciences (Boeing), Bell, EmbraerX, Karem Aircraft, Pipistrel Vertical Solutions, and Jaunt Air Mobility — are partnering with Uber Elevate on developing eVTOL designs. The aircraft vary in performance, (depending on their mission type), but will meet Uber’s specific Urban Air Mobility (UAM) vehicle requirements found here, which includes a 150 mph cruise speed, 60-mile sizing range, a 3-hour sprint of 25-mile trips, VTOL capable, and capacity for one pilot and 4 riders.
For eVTOLs, safety, battery efficiency, and speed are at the top of the must have list in design, which make Multirotor and Tilt-X VTOL configurations the favorites. The Multirotor design provides increased safety due to its redundant systems, while the Tilt-X provides a superior energy efficient design that maximizes battery life, speed, and range by relying wing-born lift during cruise flight.
Certain eVTOL designs such as the Bell Nexus with its six overhead ducted fans will be ideal for short flights in and around the city due to its multi-rotor configuration. On the other end, the Pipistrel 801 will be better suited for long haul flights due to its ability to transition after take-off to wing-born lift for cruise flight with the use of just one pusher propeller.
By 2023, Uber expects to have aerial ridesharing networks in Dallas, Los Angeles, and Melbourne Australia, with demonstrator flights planned for as early as 2020, according to the Uber Elevate website. For Dallas, Uber plans on at least six vertiports, with the first of them being built at Frisco Station. According to a recent article, additional vertiport locations will be in downtown Dallas, Plano, Fort Worth, and at Dallas Fort Worth (DFW) International Airport.
Outside the U.S., companies like Volocopter and Lilium are not far from commercial production of their ultra-redundant eVTOL air taxis. Volocopter, a German based startup incorporates 18 electric motors/rotors in its 2 passenger eVTOL design. In August 2019, Volocopter revealed its first commercial air taxi called the VoloCity, which meets the European Aviation Safety Agency’s (EASA) SC-VTOL certification standards. For flight testing, Volocopter is still using its earlier “2X” eVTOL and has scheduled a public test flight in Singapore for some time in Q4 2019.
Lilium, another German startup expects its 5-seater eVTOL aircraft – powered by 36 all-electric turbines – to be operational by 2025. The Lilium concept was awarded the 2019 Red Dot: Best of the Best Design Award, which is not surprising considering Lilium’s design team includes Frank Stephenson, the world-renowned designer of the BMW X5, the Ferrari F430 and the McLaren P1. Lilium intends to use off-the-shelf battery technology to reach its 300 kilometer per hour speed and 300km projected range on just one battery charge. Lilium, however, isn’t disclosing the aircraft’s weight or battery specs (maybe they haven’t quite settled on a battery design?).
Although it is clear that electric aircraft are in full development, much is yet to be accomplished. A concept in of itself is a significant accomplishment, but it’s still a concept. In Part III, we will discuss the certification rules and how we go from concept to aircraft certification, and then to full production and commercial operations.