Guy Norris September 25, 2020
Aviation Week had the opportunity to sample the flight characteristics of the Joby air taxi in a company demonstration simulator. I was guided through the remarkably simple operation of the aircraft by Justin Paines, the chief test pilot for Joby who, as a military test pilot, played a key role in developing the unified flight control strategy for the Lockheed Martin F-35 Joint Strike Fighter.
My simulated flight began at San Francisco International Airport (SFO). With propellers stowed in up position, blades stationary and locked in the safe configuration, there was plenty of headroom for my imaginary passengers as they boarded the aircraft and settled into the four seats behind the pilot in the surprisingly roomy cabin.
Although the simulator is not the final version of the aircraft, it demonstrates the concept of operations and generic layout of the cockpit. I moved a switch from “load” to “taxi,” and the props began turning. There is no need to start the engines with an electric aircraft—I just switched the vehicle on and confirmed activation with a second switch.
The electric motors provide instant power and, with a slight movement of the throttle-like left-hand inceptor that controls longitudinal acceleration, all six propellers angled slightly forward, and we began to taxi like a normal aircraft. Despite the appearance of the inboard props in my peripheral vision as they pivoted forward on either side, the all-round view remained excellent from the cockpit.
A short push on the left inceptor to a soft detent started forward motion, and I let go once we were underway. Meanwhile, a simple twist of the right-hand inceptor steered the nosewheel. There is no need for rudder pedals or a separate nosewheel steering control. We taxied to a clear area, and after clearance for takeoff and preflight checks, I selected another switch that allowed me to “enable” or “disable” flight.
A press on a “confirm” button completed the two-step procedure, and we were ready for flight. To take off, I simply pulled back on the right-hand inceptor and left the left-hand inceptor alone, as I wanted to fly vertically upward without also moving forward. Although at first it seemed strange not to be concerned about adding power for vertical lift, the system automatically converted my command for takeoff into the required motor torque. “We can go up like a champagne cork and pull 2g vertically if we need to,” says Paine.
Letting go of the right inceptor brought the aircraft to a gentle stop and, with my hands off the controls, we entered a stable hover over the ramp. The integrated flight and propulsion control system will maintain position in crosswinds. In thrust-borne flight, aircraft control is through a combination of propeller RPM, pitch and nacelle tilt.
Using the twist grip, I yawed the aircraft around to face San Francisco and pushed the left inceptor through the detent to begin transitioning to wing-borne flight as we climbed to 2,000 ft. and accelerated toward the city. Speed quickly built up to the cruise maximum of 175 kt. “The idea is the pilot can push the inceptor all the way forward and they’re not going to break anything. It will just go to the maximum permittable speed,” says Paines.
En route to a rooftop landing pad, I was shown how to use an automated decelerate-to-hover “shortcut” feature Joby is developing to give pilots even simpler control options. With a press of the button—for the moment mounted on the right-hand inceptor—the control system automatically deploys flaps and other effectors to reconfigure from forward flight to a hover at whatever altitude the button is pushed. In the simulator, the landing gear also extended automatically to assist the deceleration. The aircraft initially will be certificated with fixed gear, with the intent to introduce retraction later.
The deceleration brings the vehicle from cruise speed to a complete stop in around 20 sec. with a comfortable braking force significantly less than the 0.4g load sometimes imposed on airliner passengers by heavy braking during a landing roll.
From the hover, I then pressed the second “shortcut” button to accelerate to cruise. The nacelles tilted to accelerate the aircraft to a predetermined speed. Joby is still defining the speed options for this function, which reverses the decelerate-to-hover sequence. It is also likely the buttons will be merged into a rocker-type switch and relocated to the left-hand inceptor to fit better with the intuitive feel of its acceleration function, rather than the directional control function of the right-hand inceptor.
With the city now closer, I set my sights on the landing pad. To aid the approach, a blue line on the moving map display depicts the projected flightpath ahead of the aircraft and uses airspeed to calculate where it will stop if the “decel-to-hover” button is pressed at that moment. Pilots simply have to point the aircraft so the blue line rests on the destination and, when the end of the line touches the “H” of the helipad, a press of the button will bring them to a stop over the pad.
In my caution to make a safe approach, I pushed the button too early, which brought us to a hover just in front of the pad rather than overhead. Decelerating to a hover from wing-borne flight automatically blends the controls to the transitional rate command mode used for precision hover tasks.
Pushing the left inceptor forward, we edged in at just under 10 kt., and once over the pad, I let go and we stopped in the hover. I then pushed forward on the right-hand inceptor to descend, remembering the “push forward, houses get bigger; pull backward, houses get smaller” mantra used by pilots learning to fly the short-takeoff-and-vertical-landing F-35B using essentially the same aspect of the unified control law.
With my first vertical landing accomplished, I pulled back on the inceptor and lifted off—while pushing the “accel-to-cruise” button. “You’re pointing where you want to go, and the airplane does all the flying,” says Paines. Passing over the downtown skyscrapers, I headed to Alcatraz Island, where I allowed the blue line to guide me to another precision approach and landing by the old prison walls.
The simulator experience culminated with a conventional takeoff and landing at SFO. From a standing start on the runway, I pushed the left inceptor through the detent and rotated at 70 kt. Climbing quickly, I positioned for an approach. Aiming for a touchdown point halfway down the field, I slowed until I was over the runway threshold at just 26 kt. but with no concerns over directional control or descent rate, as the nacelles pivoted to provide lift and thrust until we gently touched down.
The simulator experience showed that, just as in the F-35, developers have taken away the concerns over flying the aircraft to enable the pilot to focus on the mission. At no point had I become worried about piloting the aircraft or about issues such as stall speed or, as a rotary-wing pilot, an overwhelming workload
Guy is a Senior Editor for Aviation Week, based in Los Angeles. Before joining Aviation Week in 2007, Guy was with Flight International, first as technical editor based in the U.K. and most recently as U.S. West Coast editor. Before joining Flight, he was London correspondent for Interavia, part of Jane’s Information Group.