One of several derivative branches from unmanned air vehicles and their technologies is electric aircraft and air-taxis. Referred to as eVTOL (electric Vertical Take-Off and Landing), a class of manned and unmanned aircraft is being developed and certified for short-hop passenger transit from down-town ‘Verti-Ports’ to classic airports, aimed at improving the economics and reducing the noise footprint of current helicopter services. Urban air transport is undergoing significant change as organizations such as United Airlines, Delta, American Airlines and others plow money into electric aircraft and the development of manned and unmanned air-taxis.
Archer Aviation is developing two such aircraft, with ‘Maker’ being the first cut flying test-bed, and ‘Midnight’ its so called ‘first production version.’ The vehicle design is similar in that they both have wings and are powered by six lift propellers and six tilting props that rotate vertically to lift for take-off and landing, then transition to horizontal for forward flight.
Image: Maker in forward flight/Archer
Image: Midnight/Archer
In the past, Archer has been somewhat secretive about its air-taxi program, but with the introduction of Midnight on Nov. 17, and with Maker achieving transition from hover to forward flight on Nov. 20, they released some useful information. Lift to forward transition is a big step for eVTOL, with the potential for a major set-back, almost like an irrecoverable stall for a fixed wing aircraft.
There are six battery ‘packs’ mounted in the wing near the engines – batteries, engines and FAA certification are key focal areas in their program, with fault tolerance and endurance being key considerations. An existing lithium battery has been selected following extensive testing, with a design objective of 10,000 average 20 mile trips, each trip with a 10 minute recharge cycle. Two similar electric motor types are used, with 95% commonality, and flight can allegedly be maintained through one complete engine or propeller failure. Each engine has redundant elements allowing one side to fail while still maintaining full operation. All these redundancies support the Archer plan for FAA certification which has now progressed through ‘Certification Basis’ and ‘Conceptual Design’ to ‘Preliminary Design’. There are many steps still to complete, with certification not anticipated until at least the second half of 2024.
Meanwhile, Joby Aviation has been making significant progress with its flying prototype and pre-production aircraft, with the objective of developing a flying rideshare platform. With space for four passengers and a pilot, the Joby aircraft is smaller than the Archer vehicle, however smaller size means less weight and complexity and requires fewer lift props. The Joby vehicle has six large props that all transition from vertical for take-off and landing to horizontal for full forward flight.
Image: Courtesy of Joby
Aviation. (c) Joby Aero, Inc.
Joby developed its own lithium-iron batteries and dual redundant electric motors and while developing flying prototype and pre-production aircraft, has also focused on teaming with key industrial partners who are assisted in key areas:
- NASA has undertaken a study with Joby on 5 potential route configurations at Dallas/Fort-Worth airport for eVTOL traffic.
- The US Department of Defence has provided flight range and facilities to enable airborne testing of the Joby prototypes. This contract has just been modified so that US Marine Corps personnel may flight test Joby’s eVTOL to evaluate DoD use-cases for the aircraft.
- The company ‘Uber Elevate’ was purchased by Joby and is now integrated as the future provider of trip access for customers.
- Toyota has not only invested in Joby, but is providing essential production facility knowledge and guidance as Joby begins its initial build out of volume manufacturing.
- Delta has invested an initial $60 million, which could increase to $200 million provided progress towards certification and service entry meets certain milestones
Other eVTOL notable companies entering this market include Jaunt Air Mobility in Dallas, Texas; Velocopter in Bruschal, Germany; Lilium in Munich, Germany; Kittyhawk in California; Wisk in California and New Zealand; Airbus in Toulouse, France; Ehang in Guangzhow, China; Vertical Aerospace in Bristol, England; Urban Aeronautics in Tel Aviv, Israel; and Eve Mobility in Melbourne Florida.
So, just a small taste of two of many eVTOL hopefuls – but two with the backing of mainline commercial airlines – who knows who will actually make it through the arduous and expensive aviation certification process before the cash runs out? However, there are many significant investors who are currently standing by their selected hopefuls and others continue to jump in – let’s hope that by 2025 we’ll begin to see home-airport air-taxi services underway.
Tony Murfin
GNSS Aerospace