The Brave New World of VTOL vehicles

April 26, 2019 / Comments (0)

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/ By Gabriel Accascina

Sometimes you stare at the future and you know it will happen. That’s what I heard people looking at VTOL and eVTOL at Heli-Expo in Atlanta this month saying. Vertical Take Off and Landing and their electric-powered counterparts are that future. How do we know? Uber is investing heavily in urban air mobility through its project Elevate. At its next Elevate Summit in May, Uber will bring together industry leaders to try to induce more collaboration across manufacturers, researchers, academia and regulators. Bell, Airbus, Joby, University of Maryland, Georgia Tech, NASA, among others, are already on board.

We asked Prof. Anubhav Datta, one of the true pioneers of eVTOL research and currently an assistant professor at the University of Maryland how these companies are getting along: “There should be a lot more collaboration but the reality is that most companies are very secretive about their work. We see the prototypes, but only a few are really flying and, if so, just for a few minutes. So far we do not yet have a marketable unit out of the 150 companies active in this field.”

Several experimental designs have been flight tested either in model or in full scale. Joby, one of the most engaged companies, has already demonstrated a battery electric VTOL. The Workhorse Group, has tested a prototype of their SureFly hybrid in the open and posted its very short flight on YouTube. SureFly is a VTOL with “e” capabilities. While the eight rotors are powered by a generator driven by a 600cc Honda engine, there are 5 minutes of lithium battery power available in case of emergency.

SureFly is certificated as “Experimental” by the FAA. While this is the same type of acknowledgment that is given to home-built aircraft kits, it still undergoes very specific testing. Datta adds: “The regulators are watching. This is all new and it will require new rules. And not only for the vehicles themselves but also for the infrastructure around them.”

So, we asked, how is simulation helping to design the controls of these vehicles? Essentially, one could design any fly-by-wire type of controls with ergonomics that would work. The computer manages the rotors’ speed and tilt. Where do we draw lessons from, or is it a blank slate? We asked Allen Brittain at Bell: “We went in an unusual direction. We asked gamers how would they want to control these vehicles. These are kids whose hands are fast on joysticks and really get a sense of how to move things around. The development of our NEXUS is being informed by a much larger group of experts, not only helicopter pilots.”

Bell indeed should know how to develop new and complex aircraft. We recently flew the simulator of the V-280 tiltrotor, which uses a set of controls that are half rotary, half airplane, plus some extra unusual bits, like a small rocking switch to transition from vertical to horizontal flight. Robert Freeland, Bell’s Director of Business Development gave us a simulator demo of the V-280 and noted: “The computer does it all. You have to tell it where to point and how fast you want to go and it manages the intricacies of controlling two very large propellers, tilt them as needed and send you on your way.” The simulator ride was indeed impressive and so was the entire design of the machine.

Robert Freeland flies the Bell V-280 tilt-rotor simulator at I/ITSEC 2018.

Datta seems to be more cautious about gigantic leaps to completely different control setups: “We need to keep at least the same vertical handling qualities as today’s VTOL aircraft while augmenting agility, gust tolerance, and autonomy for obstacle avoidance. The pilot interface of these platforms should have the functionalities to encourage existing pilots to want to move to them but simpler and more intuitive features suitable for the average learner. The missions are simple so flying should be simple.” Datta is organizing and teaching a four-hour short course on eVTOL on May 14. Attendees will look at a number of issues related to eVTOL construction including hybrid-electric power plants.

We asked some of our members how they would see a new set of controls evolving. Gary Olden, a simulator veteran told us: “I would love to see a conventional cyclic joystick on the right side, to adjust forward speed and rate of turn, and a collective on the left but with a detente position that the computer will recognize as ‘I want to fly level and maintain current altitude.’ Then the pilot would lower the collective, say, to increase the rate of descent by a varying amount of ft/sec and raise it to climb.”

Then again, accommodating the pilot may be an irrelevant consideration in the future.  These could be totally unmanned vehicles like the trains at the airport. Ergonomics may not apply at all a few years from now. Priorities will be energy consumption, passengers’ loading and recharging point locations, traffic conflicts (that humans may not be able to manage), and above all, safety.

With major companies like Airbus, Sikorsky, Boeing and others bringing their brainpower into this development sprint, Datta seems to think that a generic model will emerge which will drive the standard thereafter. In the meantime, we can imagine that many manufacturers will experiment and test a number of controls solutions. The SureFly video offers a glimpse of fairly conventional arrangement but, of course, ultimately it is all about the software controlling the flight and engine parameters.

Like we did for the V-280, we are looking forward to seeing the upcoming generation of VTOL simulators, which will be on the front-line of training and in this case, very likely, will be instrumental in getting this brave new world to become reality.


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