The first manned electric helicopter has taken off. On August 12, this year, the aviation world wrote history with electrical/aerospace engineer Pascal Chretien piloting a fully electric manned helicopter flight he himself designed and built. The manned electric flying machine set a record of 2 minutes and 10 seconds during the test flight.
The prototype almost took 12 months of development to reach realization. Along with his technical know-how, Pascal took substantial risk for this endeavor, as he puts it: “in case of crash I stand good chances to end up in kebab form.”
Though research and development has been in full strength, it is a wonder as to why electric helicopters have not yet been successfully made. The main reason being pointed out is that helicopter flight dynamics demand more energy consumption consistently, which does not quite go with the way conventional batteries perform.
Helicopters require strong power delivery throughout the takeoff, hovering and landing phases. On the other hand, electric planes require a lot of power only in the takeoff phase as they can glide and land on fairly less power.
This was the challenge before Pascal Chretien when French company Solution F asked him to manufacture first manned electric helicopter. He was convinced that he would want to make a unique design – an ultra-light, super simple helicopter prototype that could fly on the available battery power.
So by bringing in tweaks to the conventional design, Chretien modeled a coaxial design with two counter-rotating rotors on top – a torque-balanced design which can be controlled with a lightweight tail fin. Chretien put to use simple weight-shifting over the typical cyclic control, which uses variable blade tilting system to control which way the helicopter tilts and advances.
The new steering system has a big set of handlebars that handle overall control. This helps to tilt the main weight of the aircraft underneath the rotors. And, in fact, that meant a reversal in control systems from the conventional systems.
The frame was made from 7020 aluminium tubing. The target proposed by Solution F was 10 to 12 minutes, and that proved to be a challenge for Chretien to work out ways to store enough power to efficiently fly this one.
He chose brushed DC motors for the rotor shafts that have 87.5% energy efficiency between the battery terminals and the rotor shafts. Rechargeable lithium ion polymer pouch cells, with an energy density of 160 watt-hours per kg were used.
The result is a successful flight, though not fully adhering to what Solution F wanted. Chretien, not fully satisfied with his work, now plans to make suitable modifications to meet his target of 10 – 12 minutes. Stay tuned as we wait and watch what Chretien does next.