Dufour Aerospace this week announced the completion of the first phase of flight testing for the technology demonstrator it is using to develop its planned Aero family of eVTOL aircraft. The Swiss company has been experimenting with a tiltwing configuration but has yet to indicate what form the full-scale prototype will take.
In a statement issued on July 27, Dufour said that it has conducted 550 test flights, expanding the flight envelope incrementally to demonstrate, “a high degree of stability and control in all conditions, including transitions from hover to cruise and back again.”
According to Dufour co-founder and chief technology officer Jasmine Kent, the company is now focused on developing a five- to seven-seat eVTOL designated the aEro 3, having for shelved plans for a two-seat aEro 2 model. She said that the aEro 3 is intended as a replacement for existing helicopters in a variety of roles, including passenger transportation and emergency medical services.
The aircraft will have a hybrid-electric propulsion system, with batteries providing power for vertical takeoff and landing and an unspecified conventional engine powering cruise flight to support longer-range missions. Projected speed for the tiltwing design is around 220 mph.
The company’s engineering team said they have drawn inspiration from Canadair’s work back in the 1960s to develop the CL-84 as a V/STOL turbine tiltwing, which never achieved commercial traction. The program is also building on experience Dufour has gained in developing the Aero 1 fixed-wing aerobatic aircraft.
Dufour has not revealed any timeline for the development or service entry of either the Aero 2 or 3 models, but is currently recruiting more staff. Very limited performance information is available, but the company website does show a sample use case of air taxi flights from Milan in northern Italy to the Swiss Alps resort of Zermatt. According to Dufour, this 79-mile flight could be accomplished in 22 minutes, compared with a 144-mile drive that would take more than three hours.
According to Dufour’s lead aerodynamics engineer, Felix Rubin, the flight tests on the technology demonstrator focused on challenges such as ensuring that slipstream airflows over the technology demonstrator’s tiltwing were sufficiently stable. The company says that the performance and stability results exceeded its expectations.