Editor's note: "Jarno Smeet" has gone on Dutch TV exposing the entire affair as an elaborate hoax. Gizmodo has the full story. I left the story as it was previously as the information is relevant, regardless of the Jarno Smeet incident's status as a hoax.--WS
The video of Jarno Smeets' flight is cool, and I don't see evidence that it was faked. It seems reasonable to accomplish, and is something I have wanted to try for a long time. I am suspicious because there is not much detail shown of the actual machine, but that does not mean anything other than they don't show it all.
The still photos of the parts on a table are helpful and the components are appropriate to what the item does in the air. The motors are rare earth magnet low RPM, high torque, outrunners that look in the neighborhood of 3000 watts or so each (like this one). So you could have an output of just under 10hp there. The speed controllers look to be appropriate to those motors, and the batteries are lithium ion. This is all appropriate. I don't see any gear reductions for those motors or other sturdy components in the photo, and gear reductions will likely be the heaviest components in the mechanism.
The gear reductions appear in a YouTube video linked from their site. This is the most helpful thing, as it shows a mechanism with everything working and of appropriate scale and sturdiness (probably carbon fiber tubes over an inch in diameter), with the haptic attachments in the appropriate place on the person's arm. The mechanism is simple and appropriate in that it appears to be just a crank that the motors are operating.
The flight itself is not as impressive as it may seem, given a bit of a headwind and or a very slight incline; running and gliding close to that height and distance might be possible without any flapping or motors. My guess is that the motors are in fact helping, but that 10 hp would likely have made such a glider go much further by using conventional propellers. The battery packs the guy is using may also not last more than a few minutes--but we don't see how many he has on him.
The device is also something that is only possible in recent times, given proliferation of these types of high torque, high power density brushless motors, high voltage speed controllers and lithium batteries, off the shelf carbon fiber components and so on. I like that the attempt and could see such a design mainly being used as a relatively quiet and compact way of hang gliding. I could also see being able to stay up in the air a bit longer by having the ability to move forward into helpful currents--much like large soaring birds do. These guys could likely improve performance at some point by having hollow wings, which can be done at similar weight but without losses associated with loose fabric.