Dutch mechanical engineer Jarno Smeets created a stir on YouTube recently with a video that shows him flying by flapping a set of wings attached to his back — without any connection between the wings and his arms.
However, many questions have been raised regarding the authenticity of the video, which is on Smeets’ blog.
Smeets claims to have used two Nintendo Wii controllers held in his hands to transmit his arm motions to accelerometers via Bluetooth. These signals were in turn directed to two electric motors that flapped the wings.
“Putting wings on a human has been a dream going all the way back to Icarus,” Rob Enderle, principal analyst at the Enderle Group, remarked. “This is the closest we’ve come to winged flight.”
Smeets’ flight “was probably closer to the way pterodactyls flew than birds do,” Enderle told TechNewsWorld. “They were mostly gliders.”
Smeets did not respond to our request for comment for this story.
Peering at Smeets’ Contraption
Smeets used a pair of flexible wings made from material from his old Slingshot Fuel kite. These were attached to a carbon windsurf mast and a pair of ribs fixed at right angles to the mast.
The wingspan was about 40 feet, and the wings’ surface totaled about 162 square feet.
Smeets used Turnigy motors, which are normally used by hobbyists in powered model craft, to power his wings.
He connected the accelerometers of an HTC Wildfire S smartphone and Wii controller. These measured arm speed.
Smeets wrote an app that combined acceleration data from both sets of accelerometers. This data was sent to his electronic speed controllers and outrunner motors. This let him move the wings by flapping his arms, although they were not physically connected.
Is It Magic?
With a span of 40 feet or so, Smeets’ wings were relatively small for his weight. An Andean condor, for example, which weighs up to 33 pounds has a wingspan of about 10.5 feet.
Doubt has also been raised regarding the video’s authenticity. Experts at George Lucas’ CGI computer special effects firm have opined that the video of Smeets’ flight was faked, Gizmodo reported.
However, it’s possible that Smeets did really fly by leveraging the ground effect, Enderle suggested. “The aerodynamics of being close to the ground gives a lot more efficiency than if he flew higher,” Enderle said. “A hovercraft doesn’t need much power to lift off the ground, and ground effects exist for up to 15 feet in height.”
Once he was off the ground, Smeets possibly used air currents to remain aloft, Enderle surmised.
Smeets’ flight indicates that human-powered flight is doable, Enderle stated. “The first step is using the ground effect; then, with the improvements we’re making in energy density and batteries and power-to-weight ratio in small motors, we could be a decade away from human-powered birdlike flight.”
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Mr. Enderle comments about ground effect are partially right.
Relating to winged flight, ground effect exists up to approximately the wingspan of the aircraft. A 747 will be flying in ground effect to a much greater altitude than a Piper Cub would.
Even the Piper remains in ground effect well above 15 feet.
With a 40′ wingspan Smeets’ ‘aircraft’ would have been able to rise to about 40 feet within ground effect.
As Enderle stated, it takes much less effort to attain and maintain flight within this realm. All the successful man-powered flights were conducted in ground effect.