Date:27 February 2014
Pilots of pedal-powered airplanes defy physics to compete in aviation’s most obscure contest. Welcome to the Icarus Cup; no engines allowed. By Jeff Wise
“Dad! Hold the tail down!” David Barford shouts to his 73-year-old father, Paul, who shuffles along the grass while supporting a slender spar that connects the rear stabilisers to the cockpit and wings of Betterfly, a fragile aircraft that balances on two inline wheels. David’s 20-year-old daughter, Charlotte, supports the starboard-wing spar with his best friend, Paul Wales. David’s 17-year-old son, Chris, marches alongside the port wing, while David, 44, co-ordinates the action from the nose of the plane.
Team Betterfly’s sense of urgency grows as the summer daylight fades and the sky west of Sywell Aerodrome, a rural airstrip 120 km north of London, darkens prematurely with thunderclouds. It’s the second day of the week-long Icarus Cup, the world’s most challenging human-powered-aircraft competition, and Barford wants to make a first attempt at the speed-course event. Two dozen spectators also anxiously monitor the weather, hoping the threatening rain doesn’t ground the pilots.
The team gently sets Betterfly on the centre line at the end of Sywell’s lone paved runway. To shed weight, Barford strips down to his underwear and bike shoes, then eases into a red fabric pilot’s seat made from two aluminium folding chairs. The only controls in the transparent cockpit are bike pedals and a handle for the rudder.
Barford calls out “Three, two, one – rolling!” and begins to pedal furiously. The front-mounted propeller claws the air and Betterfly starts gathering speed as it rolls down the runway. The crew supporting the aircraft walk, then jog, then sprint as the wings rise from their hands. Betterfly floats off the runway, oh-so-slowly. Barford’s legs churn. “Go, go!” Wales shouts. The nose dips precariously, sinking to within centimetres of the asphalt before slowly rising to an altitude of under two metres. Barford flutters down the runway at an airspeed of 29 km/h. “The experience is quite odd,” he says later. “You feel like you’re just pedalling a bike, and then everything goes quiet because you’re no longer in contact with the ground.”
When Betterfly settles back on to the asphalt, the crew race up to support the wings, trailed by spectators on foot and bicycles. Barford has completed the 200 m course in 42 seconds. He also earns duration points for remaining aloft a total of 62 seconds. With 1 438 points, he’s risen to second place, a mere 30 points behind the leader, who’s flying Betterfly’s nemesis, Airglow.
Human-powered flight, dreamed of since the days of the ancient Greeks, was long considered to be impossible. Aeronautical engineers assumed that no aircraft could be light enough to fly on such a limited power source – a pair of legs – and still be sturdy enough to carry a pilot.
Then, in 1977, American aeronautical engineer Paul MacCready, capitalising on breakthroughs in strong, lightweight materials, built a human-powered plane called the Gossamer Condor. After take-off, MacCready’s pilot cleared an altitude of 3 m, then flew a figure-eight pattern around pylons 800 m apart in Shafter, California. The feat earned MacCready the £50 000 (about R890 000) Kremer Prize, established in 1959 by British industrialist Henry Kremer. In 1979, MacCready’s Gossamer Albatross, which used carbon fibre instead of aluminium, flew 35 km across the English Channel in 2 hours 49 minutes.
After those accomplishments, the public lost interest in this esoteric corner of aviation. But David Barford did not. As a boy growing up in the town of Northampton, just 32 km southwest of Sywell Aerodrome, he built model Gossamer Albatrosses out of cellophane and drinking straws. He left school at 15 to become an apprentice machinist at a race engine-manufacturing company but never lost his fascination with human-powered aircraft. “They are a pure challenge,” he says. “They demonstrate what can be done with so little power and the human mind.”
With encouragement from other enthusiasts and support from his family, Barford decided to build his own pedal-powered aircraft. He milled aluminium parts in the garage of his suburban home and made rib assemblies out of balsa and Depron foam in his living room, sheathing them with Dacron and Mylar.
He cannibalised the chain and bearings from a mountain bike and the wheels from his daughter’s childhood bicycle. It took nearly eight years and R136 000 to complete the 40-kg Betterfly,
which can fly on just 300 watts of power, compared with the 400 watts required by most human-powered aircraft – a power-to-weight ratio well suited to the middle-aged, 1,73 m-tall Barford, who holds no pilot’s licence. “I wanted to build it,” he says, “purely so I could fly.”
As Barford was completing his plane, another enthusiast, Bill Brooks, chairman of Britain’s Human Powered Aircraft Group of the Royal Aeronautical Society, was organising a competition to showcase the country’s pedal-powered fleet. He named it the Icarus Cup, after the Greek mythological figure who plunged into the sea after flying too close to the Sun and melting his man-made wings.
Brooks devised arcanely scored events to demonstrate the strengths of different designs: speed on straights, endurance on long hauls and manoeuvrability on a tricky triangular course.
His real goal was to demonstrate that flying human-powered aircraft competitively could become an international sport. “I don’t see that we’ll all be flying to work in the mornings by pedal power,” he says. “But what’s wrong with a fascinating and interesting new sport? We hope to be in the Olympics one day.”
The first Icarus Cup was held in 2012 at the home of the Lasham Gliding Society, 88 km southwest of London, with five aircraft in competition: Betterfly, two craft built by universities, a plane built by professional aircraft designer John Edgley, and Airglow. Multiple pilots flew each plane; the pilot with the most cumulative points earned R36 000 and a small silver cup.
Clearly, glory, not fortune, was the motivation.
Although Airglow flew four times as far as Betterfly and topped the field, Barford had proved he could compete. His 460 m flights were 10 times further than he had expected. This second edition of the Icarus Cup has been sanctioned by the International Air Sports Federation, and federation officials are mulling over the creation of a world championship in 2015.
If that occurs, Brooks will have achieved his ambitious goal in a remarkably short time.
Meanwhile, back among Sywell’s patchwork of wheat fields, hedgerows and sheep meadows, Barford may be the hometown favourite, but the odds are against him. The same professional glider pilots who triumphed in Airglow at Lasham are keen to repeat last year’s victory – Robin Kraike, who has logged 1 000 hours in microlight aircraft; and Mike Truelove, who is a flight instructor. Both are in their 40s, lean, athletic and a head taller than Barford.
“I felt on top of the world,” Kraike says. “That’s what we came here to do… to win.” The previous day, while Kraike and Truelove were racking up points for precise take-offs, Barford was replacing adhesive tape and foam that mice had gnawed off his aircraft while it was stored in its travel trailer.
Physics does not favour human-powered flight. To lift a 68 kg pilot, an aircraft with Betterfly’s 33 m² airfoil and 22,8 m wing- span requires around 0,41 kW to take off and about 0,335 kW to fly. Even well-trained athletes can manage only up to 0,37 kW in bursts, and 0,22 kW for extended efforts.
The aircraft competing for the Icarus Cup have comically long wings, but they need the length to fly. All wingtips generate swirls of air, or vortices, that disrupt airflow and produce drag. The longer the flight surface, the smaller the effect of the vortices, and the less a pilot has to pedal to overcome drag and stay aloft.
Yet long wings also make an aircraft heavier, which demands more power from the pilot. Every ounce saved from the design counts for more air time and longer distances. That’s why Barford flies in just his underwear in an aircraft made of balsa, foam and thin plastic. Another weight-saving omission: safety belts and harnesses.
Betterfly’s wings, however, have tapered tips, “like a Spitfire airplane from World War II”, Barford says. This wing shape minimises induced drag and decreases the chance that air will separate at the wingtip during a turn, causing a stall.
All Icarus Cup entrants, even Betterfly, have trouble steering. Control surfaces on wings generate very little force at these sluggish speeds. Everyone crashes, and even low-velocity impacts produce major damage for these fragile aircraft. Airglow veers off King Air; Betterfly bungles a take-off and cracks a cowling.
Barford’s son, Chris, steps on a wing and forces a night-time repair to fix cracked spars, which is performed at Sywell under car headlights.
The real Icarus competition becomes the repair marathon. Tool kits here contain spanners and files for working with aluminium tubing, blue extruded Styrofoam, balsa and resin. Around the tents and recreational vehicles of the team encampments stand large spools of replacement Dacron and Mylar that look like oversize rolls of clingfilm. Betterfly is not exactly the same aircraft that flew in the first Icarus Cup. The team has added fixtures to the wings that enable them to move forward on the fuselage, changing the plane’s centre of gravity. “That should allow us to fly slower, with less drag,” Barford says. But the first days of the competition are windy and the team doesn’t risk using the new design.
On the fifth day, when conditions are calm, Barford changes the wings’ location and notches an impressive 102-second flight. But that achievement is quickly overshadowed by a successful 200 m run by Airglow’s Truelove, which raises his score to within 26 points of Barford’s first-place total.
Barford is visibly exhausted. His good-sportsman, we’re-all-just- here-to-have-fun spirit has been overtaken by a gritty determination to win. The day ends with a lacklustre 7-second flight. After Team Betterfly rolls the plane into the hangar, Barford slumps to the ground. “It’s just not worth it,” he says.
At dawn, Brooks announces that high winds and more rain will probably make this sixth morning’s flights the last of the Icarus Cup. At 7:30 am, Truelove takes off, rises quickly and glides above the runway for more than a minute and a half, a personal best. The flight puts him in first place with a comfortable margin of nearly 200 points.
Now it’s all up to Barford. His friends and family push Betterfly to the starting point and wait for the officials’ all-clear signal. When it comes, Barford shouts to his crew, “Three, two, one!”. Betterfly rises smartly but then drifts worryingly to the right. Barford straightens and stabilises about 1,8 m off the deck. He’s never flown so smoothly.
Then, halfway down the airstrip, the plane once again veers sharply. No pilot in the competition has made this kind of turn on purpose. The crowd stills, then cheers. Barford is heading into the intimidating triangle course. The crowd is shouting, “Go, David! Go, David!” Even Team Airglow is rooting loudly.
Barford completes the first leg of the triangle, then makes the 60-degree turn. The course’s tight corners are the ultimate test for Betterfly’s elliptical wings. The plane dips, rises a fraction, then settles on the grass 102 seconds after lift-off.
The nose is practically resting on the white chalk line that marks the end of the second leg. “He’s done it!” a marshal announces over the PA system. Grinning, Barford climbs out of the cockpit and collapses on the grass as his team and spectators surround the aircraft. “I gave it everything I had,” he pants.
After he pushes himself to his feet, Barford’s father lets go of the wing spar long enough to give his son a hug. “I’ve only cried twice,” Paul Barford says. “Once when you were born, and just now when you made that turn.”
It will be hours before the rules committee awards 500 points to Barford, securing his position in first place. But with family, friends and human-powered flight fans celebrating at his side, he’s already won.
Betterfly human-powered aircraft takes to the air
Airglow human-powered flying machine