During the month of June, the Slovenian company Pipistrel announced that it had certified the world’s first electric aircraft: the Velis Electro. It is a plane that can be recharged in one hour, allowing 5 hours of autonomy at 250 km/h and ensuring the comfort and safety of its 2 passengers.

This gives specialists the opportunity to examine the interest and feasibility of electric aviation. Let’s come back to the words of Bruno Guimbal, aeronautical engineer, creator of “Hélicoptères Guimbal” and Gilles Rosenberg, co-founder and CEO of Faraday Aerospace.

Velis Electro, Pipistrel
The Velis Electro, the first electric aircraft certified by EASA. ©Pipistrel

WHAT’S THE STATUS OF ELECTRIC AVIATION?

First of all, the two scientists agree on the obvious point that everything possible must be done to reduce greenhouse gas (GHG) emissions, particularly in aviation. Indeed, transport accounts for a quarter of these emissions, 12% of which is due to aviation.

Electric aviation then seems a runway, even if, as Gilles Rosenberg says, it is for the moment very little developed, in particular because of its lack of maturity compared to thermal aviation.

BATTERIES WILL NOT REPLACE KEROSENE.

Both contractors agree that electric aviation has very important limitations and will not be able to replace kerosene aviation. Indeed, with his company Faraday, Gilles Rosenberg analyses all the technologies under development to have a 10-year vision. The results show that the density of electric cells will double while their price will decrease by 50% or that safety and chemical stability will be improved. But for him, it is totally impossible to think that 100% electric airplanes will be able to fly with 10 people on board within 10 years. Moreover, as Bruno Guimbel reminds us, the certification of airliners is not comparable to that of small aircraft such as the Velis Electro.

Electric Propulsion, Bristell Energic
Electric propulsion system of the Bristell Energic of BRM aero, intended for pilot training. © RTS

DIFFERENCES OF OPINION

However, unlike Bruno Guimbel, who is more measured on the subject, he maintains that electric planes have a role to play. Indeed, he believes that, as of today, the cost per hour of electric aircraft is among the lowest with an 80 kW engine. In addition, the price of batteries is falling steadily while the cost of oil is unstable. The profitability of electric aviation will therefore increase in the coming years.

Velis Electro, Pipistrel
Velis Electro Recharging System. ©Pipistrel

Their divergence on this subject can be explained in particular by the question of maintenance, which is a source of debate between the two men. Indeed, the founder of “Helicopteres Guimbel” states that the maintenance of the electric motor is very demanding, especially because of its cooling system. On the contrary, Faraday’s CEO replies that, as in cars, built-in monitoring and diagnostic devices are much easier to operate than for internal combustion engines. He therefore estimates that the total cost of the electric propulsion system is 75% lower than its thermal equivalent due to cheaper components and simplified maintenance.

A PLACE TO BE FOUND FOR ELECTRIC AVIATION

For Gilles Rosenberg, electric planes will be able to make a place for themselves. First of all, 60% of single-engine aircraft flights are made with no more than 2 passengers and have a flight time of less than one hour (according to the FFA and the FAA), which corresponds to the capacities of an aircraft like the Velis Electro. Training flights are therefore quite possible with electric aircraft, especially as the capacity of the batteries will increase in the coming years. Within 10 years, he also finds it feasible that, thanks to the investments that already exist, electric aircraft can be used for very short journeys as well as for flying taxis. There will then remain the question of the profitability of flight, which will depend on low-carbon regulations.

Taxi volant
3D image of a flying taxi. © Andrey_I

OTHER SOLUTIONS

To reduce the carbon impact of aeronautics, there are other solutions. As with batteries, hydrogen fuel cells can reduce GHG emissions in the case of decarbonized or low-carbon production (which corresponds to only 4% at the global level today) but there are also many limitations, particularly in terms of storage and transport costs.

While hydrogen planes do not seem to have unanimous support either, despite the research that has been done on the subject, the two scientists argue that the hybrid may be an interesting solution to explore. Indeed, the proportionality between power and mass for electric motors (20 motors of 25 kW have the total mass that only one of 500 kW) allows new possibilities. As engineers have known for a long time, distributing the engines in the aircraft improves its lift and reduces its drag, but this was not possible with an internal combustion engine. Adding electric motors to the internal combustion engine would then make it possible to use an electric boost during takeoff and climb, thus reducing the aircraft’s GHG emissions.

WHAT CONCLUSION?

According to Gilles Rosenberg, research on electric aviation should therefore be continued so that it can be used for very short trips and for learning to fly. However, as Bruno Guimbel explains, it will be impossible to use 100% electric for longer flights.

We also have to think about the fact that, like hydrogen, electricity needs to be produced. Nuclear power plants, wind turbines or solar panels would have to be installed in airfields in order to have carbon-free aviation.

Velis Electro
Velis Electro. ©Pipistrel

Electric aviation therefore seems to have the potential to play a role in reducing GHGs, but this will only be on a small scale. Indeed, light aviation, which could become electric, consumes 300 times less fuel than airliners, according to Total.

The two scientists nevertheless congratulate the Pipistrel engineers who have achieved a technical feat even if, according to Bruno Guimbel, it will have little impact on air transport.

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