Swiss start-up Dufour Aerospace gave a detailed insight into their aEro3 project for the medical supply transportation market, as part of the Vertical Flight Society’s latest Writers’ Group session.

The discussions regularly feature a host of companies from across the industry, and this webinar on 9th September featured Thomas Pfammatter, Dufour Aerospace’s CEO, and Jasmine Kent, who is the company’s Chief Technology Officer.

Moderated by Nicholas Zart, Pfammatter started by talking about his experience as a helicopter pilot, which he says is where Dufour Aerospace gets its expertise from. To date, he has completed more than 11,000 flight spans and over 3,000 rescue missions.

He said: “This is where our expertise comes from. Instead of just building technology, we have the approach of how do we use these aircraft of today and how is this going to lead electric VTOLs. So we decided that first, we have to develop the technology.

“First was the electric propulsion system: does electric flight really work? I didn’t think so, until Dominique [Steffen, Co-Founder of Dufour Aerospace] convinced me that we should build an electric aerobatic plane. This is one of the most useable applications for electric propulsion because you make noise at the same place – not just for take off and landing – and you normally have short flights.

“So that was our baseline: to build an electric aerobatic aircraft that can not only fly for five to 10 minutes, but 25 to 30 minutes and then have another 15 minutes reserve so you can fly around if something happens on the airfield.”

This led to Dufour Aerospace’s first project in 2015, which saw it design, build and test an electric aerobatic aircraft. Within six months, the company completed 70 flight hours in the cockpit, which at the time was more than aerospace giants Airbus and Boeing.

Because of the electric propulsion system, Dufour were able to conduct eight 30-minute flights a day and charge the aircraft quickly in between – allowing for a 15-minute turnaround.

“It’s super cool to fly electric planes and way better than anything I’ve ever flown,” Pfammatter said. “It’s like a glider plane with aerobatic power, and you have instant acceleration. We knew then that we wanted to make electric propulsion a reality, as well for VTOLs, so we began to look at the concepts.

“One thing we learnt is that efficiency is very important. If you have a conventional helicopter – electric propulsion will not suit. We did not want to develop something new because we would have to check what is acceptable and what has already been flown in that way.”

Kent then introduced Dufour’s latest VTOL tilt-wing demonstrator, which started flight testing earlier this year. It has a wingspan of almost four and a half metres and already completed more than 500 test flights.

She said: “We’ve been able to really prove all of our models and simulations, and demonstrate that we do understand the aerodynamics of these aircraft. And the performance has been better than we expected. We’re using the data to feed into our design programme for our flagship project, aEro3.”

This project consists of a large, manned tilt-wing aircraft with five to seven seats, and will be designed for the medical transport market.

A concept rendering of what the aEro3 could look like was shared with the audience, with Kent adding: “The design that we have now been fleshing out is not quite the same as this, but we are still making sure we have done our homework and what we have will meet the operational requirements of EMS (emergency medical service) air operators and also be certifiable.

“From Thomas’ background, we really understand what these operators need to have in their aircraft and believe it makes sense as a path to entering the market.”

“We are firm believes in urban air mobility, and regional air mobility,” Pfammatter said.

Dufour Aerospace showcased its rendering of its aEro3 project during this Writers’ Group Session by the Vertical Flight Society.

“We want to change the way helicopters are operated today and believe we can build an aircraft that can take over more than 80 per cent of today’s helicopter operations.”

Dufour Aerospace says there is another big reason why these helicopters will become the standard in search and rescue and EMS transportation, and mentioned the ‘Golden Hour’ – which refers to the window of time a patient needs to receive treatment following an serious accident to have the best chance of survival.

Pfammatter said there is an estimated 50 million people in the USA who do not live in this ‘Golden Hour’ circle, and also mentioned that eastern Germany has a shortage of emergency doctors, who would be on emergency air vehicles when attending accidents.

He explained: “In Europe there are always emergency and medical doctors on board a helicopter, but we don’t have the influx any more to offer help when it is needed.

“As these aircraft will be dramatically faster and more efficient, they will be able to provide more help and enable more people to survive.”

In terms of costs, Dufour Aerospace says its aEro3 aircraft will be much less expensive than a conventional helicopter – about three times cheaper and nearly two times faster. In Switzerland, the company said the aEro3 will also be competitive against a ground ambulance – and up to four times faster.

And in the final point, Pfammatter showed a heatmap of the eastern side of the USA which split up journeys made either by car, an aEro3 aircraft, or a commercial airliner.

The company did a commercial calculation based on 10,00 journeys to reach Boston’s Massachussetts Institute of Technology (MIT), to see if there was a business case based on the number of helipads that currently exist on the East Coast.

“We focus on existing operations and want to build something that can be used for life-saving operations, and for today’s helicopter operators. I would like to give them and my colleagues the best tool to potentially fly around, with the advantages of eVTOL.”

To watch the full discussion, visit