World-Record eVTOL Is 1.5 Miles Closer to Getting Certified for Commercial Service

AutoFlight is one of the early promoters of the aerial solution for future mobility. Recently, their most advanced prototype set a world record for electric-only continuous flight: 155 miles (250 kilometers) over a period of just under 1h38min.

The aircraft that achieved the new record in the fourth generation of the company’s Prosperity I design, and the attempt from February 23, 2023 – announced just recently – was the first time the prototype was showcased to the general public. You can see it in action in the video below. The company's first air taxi concept was built in 2021 and announced in January of last year.

The crewless test flight took place at the aviation enterprise proving grounds, taking the vehicle on a predefined course. The Prosperity I aircraft circled on its trajectory for twenty laps, with the on-ground test team controlling the record-setting eVTOL remotely.

A third-party company – ForeFlight - provided the telemetry for monitoring the flying machine, both for redundancy checks and for confirming the accuracy and correctness of AutoFlight’s proprietary systems. The record broke the previous landmark by over two kilometers (some 1.5 miles) – Joby Aviation managed a 248-km (151-mile) flight distance in 2021.

While it may not sound imposing, the record set by AutoFlight was obtained with a single charge of the lithium-ion batteries. It also demonstrated the viability of the Gen 4 variation of the Prosperity I eVTOL. The aircraft has a set of ten lift propellers and three push-screws at the back.

The high-wing design allows for sustained horizontal flight, thanks to the large surface area, while the quad-boom architecture houses the takeoff and landing motors (all ten of them.) The two central main booms are the mounting structure for six lift props and two of the three push-propellers. The smaller, outboard half-booms hold another four motors. At the same time, the last horizontal-motion propeller sits on the back of the cockpit.

The ten lift props get the vehicle off and on the ground during takeoff and landing. Once the aircraft reaches the altitude and position for long-distance travel, the trio of push-propellers takes over and finishes the transition from vertical to horizontal. While the sleek flying craft moves from one point to another, the array of ten electric motors used for hovering shut off, with the blades locked parallel to the booms.

The Prosperity I is a four-passenger-capable autonomous vehicle with a wingspan of 12.8 meters (42 feet) and a height of 3.3 meters (4.25 feet). Under ideal atmospheric conditions, the maximum achievable speed exceeds 124 mph (200 kph) – around the same velocity as most helicopters. The range is battery capacity-dependent, but it is safe to affirm that the autonomy extends to “beyond 155 miles.” The recently published test results back this assumption.

Although the exact technical specifications of the prototype tested this past February are not disclosed, we can get a general picture of what those are by looking at its predecessors. Powered solely by lithium-ion battery packs, the Prosperity I’s fuselage is made of lightweight carbon fiber composite. The total weight of a previous generation aircraft ranged around 1.5 tons (3,300 lbs.), with a payload capacity of approximately 408 kg / 900 lbs.

Although the number of propellers might seem like overengineering, the strength of numbers allows AutoFlight to offer a safe transportation solution. Dubbed “Distributed Electric Propulsion” (DEP), the concept centers around fail-safe redundancy. DEP means that if one or several propellers cut off mid-air, the others can take over and ensure landing maneuvers are carried on flawlessly.

An early model of the Prosperity I air taxi was used to demonstrate the seamless transition maneuver between the two distinct flight patterns. The second video (shot twelve months before the record flight) details how this change of phases is achieved and why it is a critical aspect of eVTOL design and construction. Remember that the vehicle in this older footage differs from the record-setting prototype, but the general architecture is unchanged.

The latest iteration of Prosperity I has an extra pair of electric motors, and the vertical-flight thrusters are arranged differently. Also, the landing gear has been modified: the struts on early models were replaced with skids. Regardless of these engineering improvements, the video shows that both concept vehicles accomplished the transition operations faultlessly.

The shifting from perpendicular motion (relative to the ground) to parallel implies a series of simultaneous operations. If performed correctly, the passengers won’t feel anything in the cockpit. This is why aerodynamics and avionics are paramount, and the Prosperity I bears the styling signature of Frank Stephenson. (If the name doesn’t click any links to streamlined creativity, think McLaren, Maserati, Ferrari, MINI, or BMW. All these brands have Frank’s penning on their automobiles).

The February 23 result is claimed to be “the longest fully electric aircraft flight in history, where the aircraft both takes off and lands vertically.” The test is an important step forward for the eVTOL manufacturer that now aims to obtain the airworthiness certification in 2025. The all-important document – issued by the European Union Aviation Safety Agency - will allow the introduction of Prosperity I in regular service.