Questions & Answers

Is a tilt-wing in vertical position susceptible to side wind or wind gusts?

As the wing is fully energized by the prop wash of the propellers, the aircraft is well protected against most of the influence of side wind or wind gusts from all sides. This has been demonstrated in challenging conditions by many pilots in various test flights of the CL-84 and other tilt-wing aircrafts. We were able to confirm this outstanding behaviour during our own test flights with the eVTOL demonstrator. The fully washed vertical wing provides excellent stability even in gusty conditions. The prop-wash is harnessed by the ailerons for yaw control. This, coupled with excellent roll and pitch control from the propellers, makes the aircraft very controllable even compared to other aircraft designs including helicopters.

How much noise will Aero3 make?

Noise is hard to gauge, as every individual has their own perception of noise. What can be quantitatively measured is the intensity of the sound wave (in Decibels (dB)). Aero3 will produce significantly less sound than today's helicopters, for a significantly shorter exposure time. There are multiple reasons for this: i. electric propulsion systems do not need a long warm-up time (e.g. on a hospital roof) before take-off. ii. during transition (tilting the wing to forward flight) the power of the motors can be reduced significantly, thus reducing the noise level. iii. Finally, due to the impressive climb performance of Aero3, the aircraft will gain altitude very quickly and therefore sound level will dissipate quickly.

What is the purpose of Aero3?

Aero3 is an eVTOL aircraft built to perform most tasks of today's helicopters at higher efficiency and lower cost. While it is specifically designed to meet the requirements of the Emergency Medical Services (EMS) markets, it will also be capable to serve as an air taxi or VIP transport vehicle and as a versatile platform for public safety applications. Its tilt-wing design combines the best of the worlds of helicopters and conventional airplanes: Vertical take-off and landing capability using existing helicopter landing pads, while cruising as efficiently and at similar speeds as an airplane. Its unique design allows for redundancy and provides for a safe operation.

To what aviation standards will Aero3 be certified?

Aero3 is designed to meet EASA's SC-VTOL (Special Condition for VTOL) standards.

Will aEro 3 be capable to operate in instrument meteorological conditions (IMC)?

Aero3 is designed to allow operations according to instrument flight rules (IFR) in instrument meteorological conditions (IFR).

Is the certification of such a design possible in today's world?

Certification authorities are aware of the need to develop the necessary standards to enable certification of eVTOL aircraft. The first relevant documents have already been published (e.g. the EASA Special Conditions for VTOL), so the certification requirements are becoming clearer. While certification processes always carry certain risks of delay or cost overruns, we have no reason at all to doubt a successful certification.

What happens if a motor stops functioning?

Due to its unique design, in case of a motor malfunction, Aero3 will be able to continue its flight safely and to perform a safe landing. This is also the case in the extremely unlikely event of loss of two motors (one on each side).

What happens if the tilt-wing mechanism malfunctions?

One of the big advantages of a tilt-wing aircraft is that it can fly and land safely in every wing position as the wing remains energized, thus allowing for continuous manoeuvrability of the aircraft. The angle of the wing defines the length of the runway needed to land the plane. In the extremely unlikely case of a malfunction of the tilt-wing mechanism, a vertical landing may not be possible, in which case a conventional landing on an airfield must be performed. Pilots will be trained for this kind of scenario.

Will Aero3 be capable to fly in known icing conditions?

Aero3 will be fitted with de-icing capabilities.

Will Aero3 feature skis or floats for operation on snow or water?

The initial product will not feature skis or floats.

Will winch operations be possible with Aero3?

The initial product will not be winch capable. The aircraft structure will be designed so that a winch can be installed at a later stage.

How easy will it be to switch from passenger to cargo or combi configuration?

Aero3 is designed to be modular with respect to the different available configurations, with seats easily removable to provide additional cargo space.

For what temperature range is the aircraft designed?

The aircraft including the electric and hybrid systems are designed to be operated between -30° C and +50° C.

Will the design of Aero3 include the possibility to dismantle the wings for easy shipping overseas?

es. Aero3 is designed to be easily transportable in standard EU freight trailers (13.6 m length). A jig can locate the wing, tail, and propellers in one trailer with the fuselage transported in a second trailer.

How will the design of Aero3 prevent wing stall?

Aero3 features synchronized wing, flap, and tail tilt actuation. This has been tuned to provide the safest (widest) transition corridor possible. The wing is fully washed by the propellers which provides the safest stall protection for the aircraft. The combination of the wide transition corridor and the fully washed wing make the aircraft extremely safe from stall in all modes of operation.

Will Aero3 feature variable pitch propellers?

Yes, Aero3 will have the ability to vary both the pitch and the RPM of each prop to efficiently deliver the thrust in the time interval required and to maximize efficiency in hover and in cruise flight.

How safe and fail-proof is the tilt-wing mechanism?

The structural hinges of both the wing and tail tilting mechanism are designed to be fully multi load-path damage tolerant, such that any primary failure of any single component does not result in the failure or separation of the joint and that any secondary failure does not become critical within the inspection interval defined for the joint.

What is the main purpose of Aero1?

Aero1 is the first all-electric aerobatic plane in the world, built by Dufour Aerospace in 2015-2016. The base is a Silence Twister that was heavily modified to integrate an electric propulsion system. Within six months we performed a flight test campaign with 80 hours flight time. We flew up to eight flights per day, reaching altitudes up to 13'000 ft. We performed test flights in a temperature envelope +30 °C to -10 °C. Aero1 has the power of a conventional aerobatic plane at 10% of the cost per flight hour. Dufour Aerospace was among the first to prove the real-world viability of electric flight, and to learn about the performance of batteries in aerobatic flight, which is one of the most demanding applications. Currently we are rebuilding a second iteration of Aero1, known as "NG". The purpose is to have a flying testbed to test the latest technologies that Dufour Aerospace is developing, such as flight computers, battery packs, telemetry systems and more in realistic flight conditions. This is not only in a lab or test environment. We believe it is important that our engineers not only watch electric planes take off, but also get as much first-hand experience as possible in the pilot's seat. Therefore Aero1 NG will be flown and tested regularly by all the licensed pilots in our team.

How are the activities of Dufour Aerospace funded?

Dufour Aerospace is funded by professional investors who believe in the future of tilt-wing aircraft in modern aviation.

Why does Dufour Aerospace use electric propulsion?

Electric propulsion has many advantages over combustion engines: electric motors are more efficient at converting energy to power (efficiency factor). They are mechanically less complex; have fewer parts and are therefore generally less costly to maintain. Although they may be heavier than a comparable combustion motor, electric motors take less space and are more compact. And they have advantages in noise and local pollution, as they do not emit any exhaust gases locally. Electric propulsion also has some disadvantages, mainly the comparatively low energy density of today's batteries compared with liquid fuels such as kerosene. Dufour Aerospace compensates this by using a hybrid approach.

Why does Dufour Aerospace follow a hybrid approach?

There are several particularly good reasons leading to the hybrid approach: electric aircrafts have many advantages, but there are still limitations. Currently available battery technology does not provide the energy density necessary for long-range missions. Using a hybrid approach and charging batteries while in flight compensates for this deficit. It is especially important not only to take-off, but also to land with full or almost full batteries, as in the eventuality of a go-around the most lift power is needed. The hybrid approach also allows for appropriate reserve flight time and for an efficient load-unload battery management – finally resulting in longer battery life.

What are the advantages of the tilt-wing concept? Why does Dufour Aerospace believe in its success? Is it safe?

Dufour Aerospace strongly believes in the tilt-wing approach because it allows for building an extremely versatile, efficient, and safe aircraft. A tilt-wing aircraft combines the best features of the worlds of both helicopters and airplanes. It is capable of taking off and landing like a helicopter while being as energy efficient and fast as an airplane in cruise flight. Compared to many other designs in advanced air mobility, the tilt-wing is a proven aerodynamic concept and has already successfully been flown 60 years ago. As an example, in the Canadian CL-84 "Dynavert" programme, over 40 pilots have flown as many as 1'000 flight hours and have demonstrated the enormous operational flexibility of the tilt-wing design. At Dufour Aerospace we strongly believe that the tilt-wing is such an inspiring concept that it deserves a revival using today's state-of-the-art technology. The structural hinges of both the wing and tail tilting mechanism are designed to be fully multi load path damage tolerant, such that any primary failure of any single component does not result in the failure or separation of the joint and that any secondary failure does not become critical within the inspection interval defined for the joint.

Why is the company called Dufour Aerospace?

The highest mountain peak in Switzerland is called "Dufourspitze". It is named after Guillaume Henri Dufour (1787-1875), a well-known and respected Swiss engineer, topographer, and army officer. Dufour presided the first Geneva Convention in 1864, which established the International Red Cross and the standards of international law for humanitarian treatment in war. Both the Dufourspitze and the life and work of Guillaume Henri Dufour inspire our work at Dufour Aerospace.

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ABOUT:
With over 30 years of experience in Swiss commercial helicopter operations, we understand the real world requirements of VTOL aircraft. Our engineering team with years of aircraft construction experience is building aircrafts for rugged operations in harsh environments. Our patented combination of proven aerodynamic concepts with the latest technology makes our aircraft rock solid with unparalleled performance.