Bird brained birdman - human-powered aircrafts

Materials World magazine
,
4 Jun 2012

Man has long endeavoured to master selfpropelled flight. Are we simply feeding our fascination with flying, or could human-powered aircrafts be the transport of the future?

So video footage purportedly showing Dutch ‘engineer’ Jarno Smeets launching himself into the air by flapping a set of wings has proved to be a hoax. It was, in fact, the work of amateur film-maker Floris Kaayk, who spliced the whole thing together using some basic CGI to create a reasonably convincing two-minute sequence on YouTube. He managed to provide a semblance of credibility by explaining how the design worked, using motion sensors from a Nintendo Wii to transfer a flapping arm movement to high-torque motors in the wings, which he claimed made it possible to flap wings that would otherwise be far too large for a person to manoeuvre. Kaayk justified the hoax not in the interests of aeronautical science, but instead as an experiment to show how quickly online media can flash a story around the world – a phenomena I would have thought was rather obvious by now.

In that respect he chose a subject bound to capture interest, since most people have a fascination with flying and, in particular, self-propelled flight. Indeed, humans have mythologised and dreamed of self-propelled flight since Icarus flew too close to the sun with his wings of wax and feathers, and Leonardo da Vinci sketched his rudimentary flying machines. From Peter Pan to Mary Poppins, the thought of being able to soar above the crowds in free flight has always fired the imagination. The annual International Bognor Birdman competition, known for the Heath Robinson contraptions judged more on entertainment value than flying ability, has been around since 1971 and has recorded ‘flights’ of up to 100 metres – although strictly speaking this is free-falling gliding, or sometimes just free fall. So just how feasible is genuine human-powered flight?  

The true definition of a human-powered aircraft is that it must be able to take off solely under the pilot’s power – no tows, pushes, catapults, ramps, free-fall launches or any other external source of thrust. The first officially authenticated take-off and flight was made on 9 November 1961 by the Southampton University man-powered aircraft (SUMPAC) team, attempting to claim the Kremer prize to complete a one-mile figure of eight course with a human-powered aircraft. The most famous flight was the crossing of the English Channel in June 1979 by the Gossamer Albatross, piloted by cyclist Bryan Allen. The empty weight of the Albatross was only 32kg, although with pilot this increased to nearly 100kg. Like its namesake, the Albatross had long, tapered wings similar to a glider, allowing the flight to be undertaken with minimum power. In still air this was of the order of 0.4 horsepower, low but close to the limits for a human nonetheless.

Most recently the concept of human-powered flight was demonstrated by the BBC’s Bang Goes the Theory team, which succeeded in a brief pedal-powered flight in April this year. All of these projects have been excellent demonstrations of the physics of flight rather than a serious attempt to develop a new form of transportation, but all have been done to educate rather than joke.

So to any other bird-brained hoaxers who try to deceive us, I say ‘On yer bike’.