30 years ago the American Helicopter Society (AHS) set up the Sikorsky human-powered helicopter competition. The AHS named the prize in honour of Igor Sikorsky, who designed the world’s first mass-produced Helicopter, the Sikorsky R-4, in 1942. To this day no one has won the challenge but with the prize money now standing at $250,000 people are certainly still trying.
The criteria
The team who is most likely to win the prize is a group of science undergraduates and postgraduates from Maryland University. We spoke to one of the team’s pilots, Colin Gore, to find out how it all works. But first, Gore explains the criteria that need to be met to win the quarter of a million dollar prize.
He says, “There are three criteria: the first is that the flight needs to have a duration greater than 60 seconds; the second is that during that 60 second flight you need to reach further than 3m into the air (but that only needs to happen for a brief moment); thirdly, for the duration of 60 seconds the helicopter must not drift – the point beneath the cockpit must stay within a 10×10 metre box.”
So far no one has achieved this but Gore’s helicopter, the Gamera II, has come close. On one test they kept the helicopter aloft for 65 seconds and on a separate occassion they managed to raise it just shy of 3 metres
In July, they plan to go for the prize and Gore believes they will meet the criteria.
He says, “I’m confident that, if the technical challenges are worked out, I’ve got the power and the profile to give us the energy we need for the prize winning flight. To cut a long story short, I know I’ve got the juice, we just have to make sure that everything is right with the craft which has so many components and there are 50 people working on it – there is always a chance that some little thing will creep up and eat into our time.”
Flying the aircraft requires a lot of energy. Gore says, “If we’re going all out, I’m pretty much drained by the end of a minute and a half. I stuck the heart rate monitor on and I went from a resting rate of just over 60bpm all the way up to 190bpm.” To power the helicopter Gore has to pedal with both hands and feet, which draws the string in from 4 rotors that rotate incredibly large, but light, blades. And light is the key word here: the helicopter is 105ft in length but only weighs 75lb. One of the main challenges behind making a human-powered helicopter is to make such a large and light structure strong enough.
Carbon fibre
Gore says, “When the Sikorsky prize started 30 years ago, I don’t know if it would have been possible because the lightest thing you could really use was balsa wood but now that carbon fibre has come a long way, it’s easy to work with in your garage or workshop, and our team has done a lot of custom carbon fibre work for this craft. “One of our engineers has developed a lathe system that makes carbon fibre trusses that are half the weight of a carbon fibre tube but six times stronger so by being so immensely strong for their weight we can build this craft which has the strength to hold the pilot. At one point we were flying a helicopter with only 70lb of material total, which is a little more than half the weight of the pilot.” We wish them luck for their July attempt and will keep you posted on the outcome.
