Volta reaches for the sky
By François Blanc,
Copyright : F.Blanc
The first official flight of the all-electric Volta helicopter took place in Paris on October 19, an event attended by France’s Minister of the Environment. Behind the symbolic and press relations aspects of the event, the flight signals France’s civil aviation authorities’ full support for the creators of the device. Quite a rare feat in the world of civil aircraft.
HELICOPTER INDUSTRY (OR AS IT WAS PREVIOUSLY NAMED AT THE TIME HELICOPTERMAGAZINE EUROPE) ALREADY DEVOTED A FEW PAGES TO THE FIRST CONVENTIONAL ALL ELECTRIC HELICOPTER CREATED BY FRENCH BASED AQUINEA AND CO–DEVELOPED FROM 2015 ONWARDS WITH THE ENAC (FRENCH NATIONAL SCHOOL OF CIVIL AVIATION), IN ISSUE 76, PUBLISHED AT THE BEGINNING OF THE YEAR. SINCE THEN, THE TEAMS INVOLVED IN THE PROJECT HAVE MADE GREAT PROGRESS WHICH HAS LED TO THE OCTOBER 19 EVENT. THE FIRST OFFICIAL FLIGHT OF THE AIRCRAFT TOOK PLACE AT THE PARIS HELIPORT AND WAS ATTENDED BY A FLURRY OF REPRESENTATIVES FROM THE INDUSTRY AS WELL AS BY THE FRENCHMINISTER OF THE ENVIRONMENT, ENERGY AND MARINE AFFAIRS SÉGOLÈNE ROYAL.
Ten years of hard work
It is way back towards the end of the 1990s that Philippe Antoine first put pen to paper to invent what would become the Volta, his aim being at the time to develop a leisure aircraft propelled by a heat engine. The project started anew in 2007 around the concept of an electric engine but that is history as well. The ENAC became involved in 2015 which considerably sped up the project leading up to the first take off of the Volta aircraft on February 17, behind closed doors. That’s why the October 19 event is much more than a token demonstration. It’s the result of ten years of hard graft, with a lot of patience and the solving of all sorts of equations thrown in. The technical data may be of interest to many observers but the partnership between Aquinea and the ENAC is a quite a milestone in itself, as Philippe Antione describes: “We signed the partnership with the school in 2015 and it has no time limit. To summarise the agreement, the ENAC is to supply us with engineering means, especially relating to software developments and human/computer interaction. It also helps us to follow up the trial runs and lets us use its lab and some of the lab materials. “
The future two-seater Volta 2
As it is set out, the plan means that the costs resulting from the research work as well as the device building and trial expenses “will be shared by both parties”. Both will also “own the copyright of each of their contributions” when the demonstrator will have enabled them to develop viable applications from the technology. A virtuous circle, which is expected to lead to a product which can eventually be mass produced. However, even if the proof is there that the all-electric helicopter can safely take off and fly, the end of the tunnel is quite a long way off. Innovations and new concepts will have to be protected by patents. And the Volta 2 helicopter which was talked about during the October 19 event, and even mentioned by the Minister of the Environment, “will be another demonstrator and not a certified aircraft”, Philippe Antoine cautions. The Volta 1 will continue to provide bench testing, but will eventually be replaced by the new model which is a two-seater aircraft with an in- flight autonomy of 30 minutes (with some to spare), improving on the Volta 1’s 15 minutes. The batteries of the Volta 2 will be removable, a feature designed to make maintenance easier if it does become operational.
The aim ever since Philippe Antoine first embarked on such an adventure has always been to build and certify an all- electric two-seater helicopter which is able to fly for half an hour and with a full load. The target market is leisure on the one hand and training schools for novice pilots on the other, including in areas close to urban zones. “One of the aspects we have to improve in order to be able to access the market for training schools are the noise levels,” admits the Volta inventor. In other words “a more silent type of aircraft and blades will have to be designed and tested”, even if the Volta 1 is clearly an improvement compared to previous heat engine propelled devices which were used in the same sort of context. A project which calls for the skills of another French state-owned institution, the Onera (the National Office of Aerospace Research), which Philippe Antoine has always thought of partnering with. Once the specifications agreed for Volta 2 will enable it to be built “technology will be transferred to those chosen partners,” Philippe Antoine predicts, as he admits that his company Aquinea is not big enough to move the concept onto the next stage. For the ENAC, the partnership perfectly fits within its remit of applied research.
Batteries of the future
As Philippe Crebassa, the deputy director of the ENAC, mentioned in a document given to those who attended the October 19 event, “We are proud to have been able to take part in the creation of Volta, thank to our researchers, who were able to work in synergy with the staff in our different facilities and invent new solutions adapted to the device and its technical constraints.” The different facilities he alludes to are based in Castelnaudary, for the more technical aspects and Le Muret for the trial side of things. The ENAC’s main concrete contribution was to develop the avionics interfaces through its interactive computer lab or, as teacher and researcher at the ENAC Stéphane Conversy, describes “the computer technology which addresses the interaction between the pilot and the systems inside the cockpit.” “The avionics display measurement tools such as rotor speed, battery usage levels and temperature which the pilot wishing to fly the device must know how to read,” he adds. The future of the concept, from a technical standpoint, does depend a lot on which battery will be used for the demonstrator in the next three to five years. Says Philippe Antoine: “Today the propulsive power of Volta is 22kW/h (which is about the same as a Zoé Renault first generation car). The power required by a helicopter to take-off is very high especially when you compare it with what is required for a plane of around the same weight. Volta will need 65 to 70 kW to leave the ground. This means the battery will gets used up in a very short time.
The more the battery gets used up quickly, the shorter the aircraft’s lifespan. The question of how to reduce its temperature and its weight must also be answered. It is all linked together. In the future we should be able to reach the goals we have fixed by using a lighter battery, which has a longer lifespan.” According to the inventor of the Volta, that prospect is not pie in the sky but then again one would expect such a pioneer to be optimistic.