Back in the 1970s, Paul MacCready's Gossamer Condor and Gossamer Albatross airplanes succeeded in winning the Kremer Award by successfully flying a series of flights that culminated in the crossing of the English Channel by the Albatross in 1979. MacCready's planes achieved a kind of odd status as the first truly human powered aircraft. When I say "human" I mean "pedal" powered. Accomplished amateur cyclist Bryan Allen pedaled the long-winged craft for MacCready. He was, essentially, the human motor. The pedal-driven crank drove a propeller, which provided the thrust for the endeavor.
Like many people my age, I grew up around bicycles--like many fewer people, I was fortunate enough to have grown up around airplanes, too. As a kid I had a red Schwinn single-speed with a coaster brake, and it was serious transportation for me. I rode it all over town, to friends’ houses, to the ball field, to the swimming hole. It was a great ride. And, yes, I would often bike down to LaFluer Field (now Northampton Airport) on the banks of the Connecticut River to watch the airplanes fly. When I went off to college, as a starving student I used a bike for transportation and recreation. It wasn't unusual for me and my roommates to do 100 miles or more on a weekend, pedaling our way through Southern California's beach towns. Today I ride for fun and fitness. And I love to work on bikes, too, a "hobby" I began when I was in college and couldn't afford to pay somebody else to fix my brakes.
It wasn't until recently that I started to think about how much bikes and airplanes have in common. At face value, they seem drastically different. One, the bicycle, is probably the earliest form of mechanized transportation--I am open to corrections on this point. The other, the airplane, is, with the exception of space ships, the ultimate form. Bicycles are simple. On most designs, you can see the inner workings with the naked eye, and the lowly steel chain is still the key link in changing human motion to mechanical advantage. Airplanes, on the other hand, are almost absurdly complex. Even the "simplest" designs are orders of magnitude more complicated than a bike.
But the design of the Condor and Albatross highlight the similarities between bikes and planes. The keys to design success with both bikes and airplanes are the same two things: strength and light weight. When I climb into my 3600 pound SR22 I don't necessarily think of it as being a featherweight, but it is. The airplane weights just over 2300 pounds empty. The rest of the weight is gas and people and gear. To get an airplane that goes 200 knots, carries a payload of roughly 1300 pounds that has a 310-hp engine, four 26-G seats, and a list of hundreds of components that all need to go into the airplane for it to be certified and to fly takes enormous discipline and effort. Touring the Cirrus factory a couple of years ago I was taken by the attention to weight they paid even seemingly very minor components. Weight adds up. Ignoring an extra few ounces here or there has bad consequences for the final tally. This is true for bikes, too. MacCready wouldn't have been successful without new materials, particuarly carbon fiber, and a fiendish attention to weight. The Albatross, for instance, weighed just 71 pounds, about how much the air conditioner in my Cirrus weighs. When he flew the airplanes back in the 70s, Allen weighed 137 pounds. I used to weigh 137 pounds too. I think I was 12. In any case, he had to be that light. A 180-lb pilot would have overgrossed the delicate structure.
Another thing I love about airplanes is that they, like bikes, rely on old technology to do lots of things because it's elegant and light. Cable actuated flight controls, bell cranks, tube steel landing gear, have all been around since near the dawn of flight, and they aren't going anywhere soon, just like cable actuated brakes, spoked wheels, and ball bearing cranks in bicycles. They're light, they're cheap, they're elegant and they're durable.
As with airplanes, this seemingly anachronistic technology doesn't show any lack of technological innovation but the vision and ingenuity of the early developers, who, let us remember, like MacCready, had very little horsepower at their disposal. Keep it light. Make it strong. Make it durable. Those maxims were and are at the fore in both winged and wheeled machines.
And the technology has advanced in both disciplines. Here's a riddle: What's the difference between a 20 pound bike and a 15 pound bike? The answer: about $10,000. Here's another one: What's the difference between a 150-knot airplane and a 200-knot one? I'll let you supply that figure. (Hint: It's more than $10,000.)
The dual love affair with planes and bikes goes way back. Let's not forget that the Wright Brothers' day job was building bikes. Without that experience, one might argue that they never would have had the conceptual background to make the airplane thing work. As pilots we can appreciate the elegance and simplicity that aircraft design demands. For those of us who ride bikes, that appreciation is very much the same.
MacCready's pilot, Bryan Allen, is today a software engineer at Jet Propulsion Laboratories. He recently gave a presentation to the JPL bike club about those famous airborne rides. For those of you interested in the details, check out the Google Video. Warning the sound and video quality is not good. The content, though, is fascinating.
Also, here’s a link to an episode of Scientific American Frontiers highlighting MacCready’s human-powered flight project.