See more in our gallery: “Highs and lows from 50 years of human-powered flight“
“AIM for that big tree,” someone shouts, pointing at a large oak in the distance. David Barford sits back, takes a deep breath and starts pedalling as fast as his legs will let him. Within seconds, the wheels of his bicycle start to lift off the ground.
Barford is riding no ordinary two-wheeler. Built from scratch, it is a chimerical creation, part bike, part ultra-lightweight wing. The pedals drive a large propeller, and with luck and enough airspeed, the thing should take to the air.
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, as Barford has christened it, might sound like a death trap, but it is proving something of a sensation here at Lasham gliding club, 80 kilometres south-west of London. It is mid July and after days of wind and rain, the clouds have lifted and about 50 enthusiasts have gathered to watch what promises to be a nail-biting aviation competition, albeit in slow-motion.
The event is the inaugural , a sort of Wacky Races for human-powered aircraft. Barford is pitting his machine’s gravity-defying abilities against four other equally flimsy craft and their pedalling pilots in sprints, duration flying, slalom courses and challenges to test take-off and landing accuracy. Unlike the other competitors, however, Barford has no formal training in aircraft design and has never even learned to fly. Yet that hasn’t deterred him. And now, after eight years of work, he is ready. So will Betterfly take wing, or crash in a splintered heap?
There’s more than just pride and a £2000 pot at stake. The 1980s were the heyday for record-breaking human-powered aircraft, and the field has since become something of a backwater, says Bill Brooks, who . So last year he and the decided to do something about it. With the London Olympics looming, they set up a novel flying competition as a way to reinvigorate human-powered aviation and perhaps even turn it into an extreme sport. “You won’t see people commuting to work on these things,” Brooks admits, “but what we’d really like is for it to become a new sport. It’s a marriage of human ingenuity and physical ability that requires a team effort to succeed. Ultimately, it would be great if it became an Olympic event.”
Judging by the history of human-powered flight, today’s enthusiasts certainly deserve gold medals for perseverance. Since Leonardo da Vinci’s 15th-century designs, there have been many attempts at human-powered flight, with daredevils strapping all kinds of wings to their backs. None generated sufficient lift to fly, however, mostly because the designers had no clue about aerodynamics, in particular the importance of the ratio of wing surface area to craft weight. Things began to change when the Wright brothers proved that machine-powered flight was possible. Yet it wasn’t until the 1960s that human-powered flight finally came of age.
In 1961, glider pilot Derek Piggot became the first person to make a verified human-powered flight in a craft made by a team of students at the University of Southampton in the UK. It was what aficionados call a short hop – Piggot flew a grand total of 64 metres and reached the giddy altitude of 1.8 metres – but it was a giant leap in the field (see “Into the blue”).
A burst of interest followed, partly spurred by the Kremer prize, a jackpot worth £50,000 set up by industrialist Henry Kremer and administered by the Royal Aeronautical Society. The prize would go to the first craft to fly 1.6 kilometres on a figure-of-eight course, and in 1977 it was won by the , built by Paul MacCready, an aeronautics engineer at a company called Aerovironment. MacCready went on to win the second Kremer prize of £100,000 when his improved aircraft, the , flew across the English Channel in 1979 piloted by Bryan Allen.
The next decade saw further leaps in human-powered flight. Several new designs emerged, and as lightweight materials became more affordable, carbon fibre and styrofoam frames began to replace metal and balsa wood, providing increased strength while reducing overall weight.
The climax came in 1988 with the record-setting flight by an aircraft called Daedalus 88. Built by a team at the Massachusetts Institute of Technology, flew 115 kilometres from Heraklion on the Greek island of Crete to the island of Santorini in 3 hours and 54 minutes, piloted by the Greek Olympic cyclist Kanellos Kanellopoulos. Although the craft crashed in the sea just metres short of the beach, the distance record stands to this day. “Daedalus proved we can build something that can fly all day,” says Brooks. “The limit is the supply of food and water to the pilot.”
Sadly MIT’s machine seemed to mark the zenith in the design of human-powered aircraft. The next big challenge was to make them faster, says Brooks, but in most cases this proved a step too far. And despite a continuing trickle of new projects, interest in the field began to wane in Europe and North America.
Then came the 50th anniversary of Piggot’s pioneering flight. In 2011, Brooks and a team of enthusiasts decided to mark the event by dusting off a veteran craft called Airglow and restoring it to . Airglow was built in 1990 and had spent years in storage, yet with some adjustments the craft flew , Brooks says. With the London Olympics approaching, he began to think about competitive flying and a year later he and the Royal Aeronautical Society convinced the Kremer Foundation to support their idea for the Icarus Cup. The plan was to encourage a new generation of designers by showing that human-powered aircraft can be flown competitively, and that these events are fun to watch. “Most people imagine it takes huge budgets and Olympic-quality cyclists to fly successfully, but it doesn’t,” says Brooks.
Balancing act
Constructing such an aircraft is not simple, however. Success requires a deft balancing act between three factors: the total weight of the craft plus pilot; the power the pilot can produce; and the aerodynamic performance of the wing. These factors pull in different directions, so compromises must be made. A heavier aircraft requires lift from a larger wing, which in turn adds to the weight, for example, whereas a smaller wing offers less lift so requires faster pedalling from the pilot. An average person’s power output is about 250 watts, equivalent to cycling at 20 kilometres per hour on level ground with no headwind. That means these craft must be ultralight: Daedalus 88, for instance, weighed a feathery 31 kilograms.
Although the latest lightweight materials tend to weigh heavily on the wallet, a human-powered plane doesn’t have to break the bank. Last year, Jem Stansfield, a television presenter with a background in aeronautics, decided to build one for the BBC show . “We had three months and a budget of about £8000,” he recalls, “and at first I didn’t think it could be done.” But by copying an existing design, and by taking other shortcuts, including using ready-made carbon-fibre struts, he hit his targets. “We had no test flights,” he says. “I just had to get on the thing on the morning of the shoot and hope that it would fly.” To his delight, .
Betterfly, on the other hand, was made to measure. Barford designed it from scratch with himself in mind, which meant using a larger wing than had been built before. He kept weight down by shaving off every gram that he could, and by turning to lightweight but expensive materials. “For my 40th birthday, my wife bought me a fridge full of carbon-fibre sheets,” he says.
Barford sandwiched a layer of foam between two layers of carbon fibre to create a light but flexible frame for his plane. The resulting structure is extremely strong. “It’s almost too strong,” he says. “You can’t afford any excess weight, so I drilled holes in any part that I thought was stronger than it needed to be.” Eventually he managed to whittle Betterfly down to 40 kilograms. “I wanted to build something that I could fly myself, not some Olympic athlete,” he says.
Back at Lasham gliding club, Barford is facing determined opposition. His competitors are university teams from and , plus a group led by aeronautical engineer John Edgley with an unusual canard or . Finally, there is the team behind , who hope their veteran flier can teach the newbies a thing or two.
When I arrive at the airfield, Brooks is busy trying to get the University of Southampton’s craft off the ground for the first time. With years of experience, he is the informal chief test pilot for new craft at the event and manages a wheelie before being blown gently off course and planting one wing tip into the ground. Damage is slight, but it was a different story a few days earlier.
On a test flight on Betterfly, Brooks narrowly avoided disaster. He had just become airborne when the handle of the control stick came off in his hand. He tried to maintain control, but the craft took an unexpected nose dive and crashed into the ground. “The fuselage broke in nine places and we lost chunks of the carbon-fibre tube,” says Barford. To repair the damage, Barford worked long into the night replacing the broken sections with aluminium tubing wrapped in carbon fibre. “It’s a bit of a high-tech bandage really,” he says. Just 24 hours later it was flying again. And with the weather improving, the competition was finally under way.
“He had just become airborne when the handle of the control stick came off in his hand”
On the first full day of flying, Airglow showed its pedigree by covering 200 metres in just 26 seconds, and all aircraft, bar the one from the University of Bath, make it into the air. Over the some 16 flights are made but by the close of the competition, Airglow has the cup sewn up. And much to Barford’s delight, Betterfly takes second place. “Ever since I was a boy, I have wanted to build my own human-powered plane that could fly 100 metres,” says Barford.
Brooks has nothing but praise for Betterfly. One of the aims of the event was to develop more practical craft that can cope with windier conditions and Barford’s machine was easy and intuitive to pilot, he says. Brooks suggests it might even make a suitable mount for future events such as pursuit races around a triangular course. “Almost anyone could fly it.”
Aircraft designer and retired architect Fred To is also looking for ways to make human-powered craft more accessible. In the 1980s, he designed Phoenix, a prototype human-powered aircraft with an , but he is now working on a more conventional flyer that could be assembled easily like flat-packed furniture. He still hasn’t ruled out inflatable wings. If people are to own these things, he says, you have to think about how they will be stored and transported.
As for Barford, he plans to take a rest from flying. But if the Icarus Cup runs next year, it might see competitors from Asia, where there is growing interest in the challenge. In July, the Japan International Birdman Rally attracted about a dozen human-powered aircraft to Lake Biwa, near Kyoto. The winning entry from Tohoku University flew 14 kilometres.
Even among the crowd at Lasham gliding club, potential competitors are already hatching plans for new flying machines. During the afternoon To sidles up to me. “Isn’t it amazing what these guys have achieved?” he says. “Next year I think I’ll have a go myself.”
Hauling up the helicycle
The is the most bizarre helicopter you will ever see. Spanning 33 metres and made entirely from carbon-fibre struts, it looks a bit like a giant metal spider. Built at the University of Maryland, this human-powered chopper set a new – but as yet unconfirmed – record in June when it became the first device of its kind to maintain a hover for 50 seconds, albeit at a modest height of 1.3 metres. The aircraft just missed out on winning the $250,000 , a jackpot offered by the American Helicopter Society to the first human-powered helicopter to hover for 1 minute, achieving a momentary maximum height of 3 metres.
The shape is not the only peculiar part of this helicopter. Its four rotors – attached to each end of a cross – are driven by a long length of line that is hauled in by the pilot with the help of hand and foot pedals, in the same way you yank a string to spin a yo-yo. The length of cord on Gamera II is enough to fly it for about 60 seconds, a significant limitation, but it does make the system much lighter than a normal chain-driven design. The team now plans to make improvements to increase its hover height and expects to fly again later this year.
