It's an aviation story so cool we're kind of upset we didn't hear about it a month ago when it happened. Back on August 12th electrical and aerospace engineer Pascal Chretien, working with the backing of French company Solution F, made the world's first untethered, all-electric manned helicopter flight. And it didn't even show up on our radars--probably because he only reached an altitude of about one meter.
The helicopter was one of Chretien's own design that he patched together nearly completely by himself in about 12 months. And his 2 minute and 10 second flight means he beat helicopter powerhouse Sikorsky to the prestige of being the first to get a manned, untethered electric helicopter off the ground.
But it wasn't easy. Helos aren't really great candidates for electrically-driven power plants because they are so power hungry. While airplanes and cars require a lot of juice to get moving, both of them can coast on momentum. An electric airplane sucks up a lot of power during takeoff, but once airborne it can cruise and then land with relatively little power suck.
Helicopters, on the other hand, are pretty much fighting gravity all the way through a flight. So when Solution F asked Chretien to build and fly the first manned electric helicopter, he got to work putting together the leanest, lightest, most efficient design he could conceive of.
The result is what you see above: a coaxial rotor design (that's the kind with two rotors that rotate in opposite directions--a favorite of Sikorsky) that dispenses with a weighty and inefficient tail rotor and a heavy cyclic control, opting instead for a simple tail fin and a blade tilting system that the pilot uses to manually pitch the blades one way or another to control the helo's direction of flight. He crafted a frame from sturdy, crash-worthy aluminum tubing to keep him safe in case of a rough landing, and then packed a bunch of notoriously volatile Lithium ion polymer pouch cells under the seat to make sure he wouldn't be safe in case of a rough landing. To quote Chretien: "In case of crash I stand good chances to end up in kebab form."
Gizmag has a great breakdown of the design process and the different components that came together to make this historic flight happen, as well as a thorough photo gallery of the helo and its historic flight. Click through below.
Without the tail rotor, and cyclic control I wonder what keeps this thing from spinning uncontrollably on its vertical axis.
Its because of the dual rotors, you see a tail rotor is needed because of the torque created by the spinning of the main rotor. The tail rotor compensates for this extra torque wanting to spin the helicopter out of control. In this design there are dual rotors on top of the helicopter which eliminate eachother's torque (they spin in opposite directions).
research coaxial rotors if you want more details on their operation
Davinci would be proud! This really is a nice step forward. I'm sure this technology is at early stages and that it'll probably likely never catch on. However I'm really quite impressed by it (until it hits a pigeon in mid-flight of course).
I wonder how come more helicopters aren't made like this (coaxial rotors). As far as all electric, you'd need a power source that can stack up to the challenge of a power hog such as a rotorcraft.
It's largely due to the added complexity of the mechanics regarding coax rotors. You need linkages and swash plates for two separate rotors that turn oppositely. Swash plates are used to tilt individual rotor blades in order to provide direction to the craft. It's more costly, it's more maintenance and it requires more knowledge to build therefore i need to congratulate this man.
Military wise, it is preferred to use coax rotors because of enemy fire. Attacks can result in a direct loss of the rear rotor if there is one. It is one of the best ways to bring a copter down..with a simple few bullets. Also, there is not a separate motor for the rear rotor, it is a long shaft that runs through the tail of the copter, this also can be damaged under fire.
Thanks for the insight. Sounds to me like this design is best suited for combat, peacekeeping, and humanitarian operations than general aviation use.