The eVTOL aeromobility industry may be a product of Silicon Valley, but conventional aerospace players have been quick to pile on board.
These include, of course, major airframe manufacturers like Bell and Airbus, which have been developing high-profile vehicle concepts. But the industry is also starting to attract an increasing number of suppliers — notably Honeywell, which is aggressively positioning itself to serve the full spectrum of eVTOL aircraft developers.
“In the early days there was a lot of skepticism about whether it was going to be possible to do these small vehicles, and whether the public would accept them,” acknowledged Mike Ingram, Honeywell’s VP and general manager of cockpit systems, in a recent interview with eVTOL.com.
Now, he said, “with the amount of money, with the amount of investment that’s going into this market, and just the excitement around it, we see that there’s huge potential. It’s going to happen, and we need to be a part of it.”
Honeywell is betting that its experience with air transport levels of certification will give it an advantage in the emerging aeromobility market, where safety and reliability will be paramount. That’s a big part of its pitch for the new, compact fly-by-wire system it announced on June 3.
Targeted specifically at the eVTOL market, the flight control computer is derived from Honeywell’s existing, certified fly-by-wire systems for airplanes. Fly-by-wire systems use electric actuators to replace conventional mechanical flight controls, yielding weight savings that will be especially critical in small, power-limited electric aircraft.
According to Honeywell, its product features a triplex flight control computer architecture for redundancy. Each computer uses lockstep processing, with two processing channels that constantly check each other’s work.
“What we did was we took the concepts and the safety levels of our flight controls and fly-by-wire [systems] from our air transport products and redesigned them down into a smaller package — smaller scale, lower power, all the things you would need to do to go onto a much smaller vehicle,” Ingram explained.
“We did all of that while maintaining the same level of safety and reliability that you would have in that larger aircraft that’s carrying 200 people, versus these [eVTOL aircraft], which will carry about four to six people.”
Honeywell has already announced a memorandum of understanding with U.K.-based eVTOL developer Vertical Aerospace to incorporate the fly-by-wire system and other Honeywell technologies onto the company’s future eVTOL aircraft. Vertical Aerospace successfully flew one full-scale eVTOL prototype in 2018 and plans to launch its next aircraft later this year, a company spokesperson told eVTOL.com.
The MoU with Vertical Aerospace is one of several such agreements that Honeywell has revealed so far, including an agreement with Volocopter to develop navigation and automatic landing systems for its eponymous multicopter, and one with Pipistrel to provide avionics, radios, navigation, flight control systems, connectivity, and other products for the eVTOL concept that Pipistrel is developing under the Uber Elevate framework.
Honeywell is also a supplier for Eviation’s fully electric, nine-passenger Alice airplane, which is being developed for commuter and on-demand operations. And on June 10, Honeywell announced an agreement with an unnamed air taxi developer to supply multiple units of its new IntuView RDR-84K band radar system for the developer’s prototype aircraft.
Ingram pointed out that many of the more than 100 companies currently developing eVTOL aircraft have taken a bottom-up approach, adapting software and technologies used in small drones for their passenger-carrying designs. As a consequence, he said, “they’re now realizing that that’s very difficult to certify. They need a high level of reliability, they need more safety included, and they’re now looking to Honeywell and probably to some other larger aerospace companies to help figure out that problem.”
Of course, that higher level of safety and reliability comes at a financial cost — one that is much more difficult to accommodate in an inexpensive five-passenger aircraft than in a transport category airplane that retails for tens of millions of dollars. Ingram acknowledged that the aeromobility business model is “very different,” and that keeping costs manageable will be key to Honeywell’s success as well as that of its customers.
Here, Honeywell thinks it can meet customer expectations through new-generation technology and mass production. For example, Honeywell’s new fly-by-wire system will be delivered as a generic product that can be adapted for many different vehicles, not just those being developed by its announced customers so far.
“We know we have to bring that price point down, we have to lower cost in the development of our system — not only non-recurring engineering but the recurring price to our future customers,” Ingram said. “We [also] recognize that we have to move faster, and we’ve heard a lot of feedback from Eviation and Pipistrel that they’re very surprised that Honeywell can move as fast as we can.”
Honeywell is more than just a supplier of avionics and flight control systems; it’s also a major manufacturer of gas turbine engines. While the company is actively supporting developers of fully electric aircraft, it is also expecting a strong market for hybrid electric applications.
Earlier this year, Honeywell revealed a version of its HTS900 turboshaft engine modified with two compact 200-kilowatt generators, pitched as a solution for aircraft developers who are seeking greater range and endurance than can be achieved through battery power today. Honeywell has already confirmed one hybrid electric application for the HTS900, XTI Aircraft Company’s TriFan 600.
According to Bryan Wood, senior director of Honeywell’s hybrid electric and electric propulsion programs, the company annually manufactures around 4,000 gas turbine engines in the 600- to 1,700-shaft-horsepower range, more than any of its competitors. That range is nicely compatible with the 5,500-pound (2,500-kilogram) to 7,500-lb. (3,400-kg) vehicle concepts that have been floated to date.
Among its engine models, the new-generation HTS900 — certified for helicopter applications in 2011 — stood out as an ideal one to adapt for its first entry into the hybrid electric market.
“When we took a look at all the options that we had, we essentially stacked that up against what the OEs [original equipment manufacturers] are asking for,” he told eVTOL.com in February. “This engine seemed like it was in the sweet spot, and had the best power density and the best specific fuel consumption of all the other engines that we have in this size class offering range.”
Besides adding the two new generators, Wood’s team modified the engine control unit and gearbox for the hybrid electric prototype.
“We’re also working on motors, motor controllers, as well as distribution and other things that relate to conversion as well as energy storage,” he added. “So we don’t plan to stop here; our ultimate goal is to put together a demo that integrates all of the components within the powerplant.”
Wood said that Honeywell’s confirmed and potential customers are contemplating different ways of using the turbogenerator in hybrid electric VTOL applications. Some are looking to run it full time. Others intend to take off and land solely on battery power for noise mitigation purposes, then run the turbogenerator in cruise flight to recharge the batteries.
“Honestly we’re getting quite a few ideas from aircraft OEs, and I can tell you there hasn’t really been a convergence yet on where they’ll end up,” he said.
Based on today’s battery technology and Federal Aviation Administration fuel reserve requirements — currently 20 minutes for most helicopter flights — Woods suspects that hybrid, rather than fully electric, VTOL aircraft will dominate the UAM market for at least the next 15 years. Even beyond that timeframe, he said, hybrid electric will make sense for longer intercity missions like the ones that XTI Aircraft is targeting with its TriFan 600.
Moreover, he said, “we’ve talked to quite a few OEs that are interested in doing not quite the XTI hop — where you’re going from New York to Boston — but like San Diego to L.A., or Silicon Valley to San Francisco, for example. And that will be very difficult to do that with an all-electric vehicle. So I think there will always be a market for hybrid.”
According to Ingram, Honeywell’s growing focus on electric and hybrid electric aircraft reflects not only a desire to profit from aeromobility, but to actively influence the regulatory and safety standards for this emerging space.
“We feel we want to be helping to define the future of this market from a regulatory perspective; from what products, safety levels, and functionality can be in this market,” he said. “It’s our obligation from a Honeywell perspective, [because] we have the right products, we have the right people, we have the experience when it comes to certifying and providing a higher level of safety than we think people coming in from the lower part of the market can provide.”