New Rolls-Royce turbogenerator upgrades any eVTOL's range and payload
Battery-electric VTOL aircraft should do a superb job as short-range cross-town air taxis, but there are a whole lot of other trips they could handle quicker and more conveniently than existing transport options if they could just fly a bit further. Several companies are now planning low-emission hybrid eVTOLs, and Rolls-Royce has stepped up to develop a turbogenerator specifically designed to act as a compact, efficient range-extender for this emerging class of aircraft.
Most of the benefits of battery-only VTOLs will remain; the powertrains will remain fully electric and they'll continue to carry decent-sized battery packs, so they can be just as quiet on takeoff and landing, and shorter missions can be flown emissions-free, without ever switching the generator on. Indeed, even flying out toward their maximum range, these hybrid eVTOLs should be able to considerably reduce emissions as compared to ICE-powered planes or helicopters.
Rolls-Royce plans to service a wide range of aircraft, offering its new turbogenerator in outputs ranging between 500-1,200 kW. The company is developing its own power distribution systems, such that the power from these generators can either be directed to charge up the battery pack or power the electric motors directly, depending on the circumstances. Thus, not only can they boost range, they can also potentially boost the peak power of the entire propulsion system, instantly upgrading an aircraft to handle heavier payloads if desired.
As a well-established player in aviation, Rolls-Royce plans to certify these generators with aviation authorities. That'll take a bunch of risk out of the hands of the eVTOL companies, making this a highly accessible way to offer a long-range version of just about any eVTOL design.
What kind of range boost are we talking about here? Well, it'll depend on the size of the fuel tank, but for the sake of comparison, we might start with the fully-electric Joby S4, which promises one of the longer ranges in the eVTOL class at 150 miles (240 km). How does that compare to some of the hybrid concepts we've seen? Well, the Zuri 2.0 promises 435 miles (700 km), and Odys Aviation says its nine-seat diamond box-wing design could handle a whopping 1,000 miles (1,600 km). So the gains are not insignificant.
Rolls-Royce announced its own hybrid-electric VTOL design back in 2018, promising a range around 500 miles (805 km) – although the concept doesn't seem to have gone much further at this stage.
These new turbogenerators will add to the company's portfolio of offerings for eVTOL manufacturers. Rolls-Royce might be best known to the layman for its luxury cars, but it's a huge force in aerospace as the world's second-largest manufacturer of aircraft engines. It's certainly not sitting on its hands as the sector moves to decarbonize; it's already making electric propulsion systems for the CityAirbus and Vertical Aerospace eVTOL projects, and its all-electric Spirit of Innovation plane holds the world record as the world's fastest electric plane.
A new, fully-certified, compact and efficient turbogenerator specifically designed to radically boost the range of any eVTOL aircraft with minimal friction? This kind of thing could well help establish Rolls-Royce as a major player in the next phase of human flight.
Check out a video below.