Taking the Sky

Pedalling himself airborne, an alumnus raises the limits of human endurance.

• If Glenn Tremml were a dozen different people, each one would probably qualify for an article in this magazine. A story in The Washington Post lists some of the accomplishments of the 1982 graduate of Dartmouth:

"Tremml is an author of 'Effects of Ascorbic Acid on Prostaglandis Synthesis in Human Lung Tissue.' He has surveyed the interdependency between ant colonies and acacia trees in the Costa Rican jungle, has investigated bluefish cardiovascular response during studies at Woods Hole Oceanographic Institute, is an Eagle Scout and a student of judo, was a yachtracing champion as a teenager, a competitive diver, a windsurfing instructor, a show horseman (dressage), and a ballroom dancer."

He also happens to hold the world's record for flying an airplane with himself as the power plant. For two and a half hours last January, Tremml pedalled the human-powered craft Michelob Light Eagle several feet above the barren high desert of California and went 36.5 miles almost twice the distance set over the English Channel by the sky cycle Gossamer Albatross.

Now, Tremml has a chance at an even greater challenge, one that mingles science with legend: to follow the course flown in myth four millennia ago by the Greek craftsman Daedalus from the island of Crete to the mainland of Greece. The 80-mile flight, which is scheduled for March or April of next year, will take six hours, requiring an effort equal to running two back-to-back three-hour marathons without a single letup in effort.

This extraordinary attempt, initiated by a group of MIT scientists, is an unprecedented study in aerodynamics, materials science and human endurance. Last month scientist-athlete-pilot Tremml, who is one of the team members, told the story of his role in Project Daedalus to this magazine.-Ed.

On January 10, 1987, I am as nervous as I have ever been in my life. Yesterday, as a second-year medical student, I took a final exam at the University of Connecticut. Today I am sitting in a strange aircraft at Edwards Air Force Base, California, on a lake bed where the Space Shuttle lands and where Chuck Yeager first broke the sound barrier.

I am nervous because I have never flown this plane before. Some of the nation's finest engineers, along with a host of student volunteers, have spent 15,000 hours building it. Any crash will be fatal; they'll make sure of that.

The cockpit does not add to my comfort. My arms and shoulders touch both sides. An instrument panel lies 12 inches ahead of me, level with my face. The windshield is clear plastic, allowing me fairly good vision; the back is plastic covered with an opaque silver film. It helps keep the sun from adding to the kilowatt of heat produced by my own body when I pedal. The effect on the cockpit environment is that of a plastic bag with a hair dryer blowing in it for a couple of hours. This heating problem may be especially acute in Greece, where interior Temperatures may exceed 90 degrees for six hours.

I am sitting back in a nylon web chair, my feet attached to pedals, my arms dangling. On either side of me is a small control stick. The one on my right moves the rudder to control direction left and right, up and down. The stick in my left hand helps stabilize the plane during a turn. Crew members hold each wing to keep the plane from tipping over. Another holds the tail behind me.

After a seemingly endless series of instrument checks, I hear a voice over my headset: "Okay, Eagle, whenever you are ready."

"Let's go!" I holler to the man on the tail boom, and he begins pushing me at a trot.

I pedal furiously, making the 11-foot propeller spin. It gets noisy in the cockpit as the small plastic wheels beneath me grind against the frost-covered runway. At 12 miles an hour the plane suddenly surges forward: liftoff. In less than two seconds I accelerate to 15 miles an hour or Mach .03, as the project director likes to say. The cockpit gets quiet as soon as the wheels leave the ground, and the only sound I hear is the faint whistling of the propeller with every stroke of the pedals. I am floating down the runway. The feeling is hard to describe: it is like skiing down the beginner's slope with my feet off the ground.

"My God," I think. "I'm in the air, it's just my legs doing this."

Ten days later we broke the world record for human-powered flight, and I had the good fortune of being the pilot.

My joining the team in the first place was the result of a long string of coincidences. After I graduated from Dartmouth in 1982 I went to work at the John B. Pierce Foundation, a physiology laboratory which is affiliated with the Yale Medical School. While working there I flew in an eight-seat commercial plane to give a paper in respiratory physiology at a conference, and enjoyed the flight so much I decided then and there to get my pilot's license. Two days after I got back I began taking lessons.

A second coincidence: I stopped swimming, because there wasn't good access to a pool. At Dartmouth I had been a junior-varsity diver and swimmer. Now I started jogging during lunch with an exercise physiologist. Within a year I had picked up two new avocations: flying and running.

A third coincidence: I started medical school and met Stan Moraski, a local triathlon hero. His worst event was swimming, so he convinced me to do laps with him at 7 in the morning before class. It wasn't long before Stan also talked me into buying a bicycle. In June of 1986, before starting the rigorous second year of med school, I returned to my old job at the Pierce Foundation and began competing in triathlons. I planned to retire from serious competition in the fall; little did I know that the biggest physical challenge of my life lay beyond the summer.

About the middle of August, I was running with my physiologist friend when he told me about a group of world-class triathletes and bicyclists who were being tested upstairs from our lab. The researchers were trying to find someone who would pedal a plane farther than anyone had ever flown under his own power. And that was just the first challenge they were trying to meet. The ultimate goal of the Daedalus Project, as the group called themselves, was to fly a human-powered plane from Crete to Greece. The project had already completed one phase: a feasibility study in which the engineers convinced themselves that the task was possible.

Phase II was to design and build a prototype plane and then fly it 30 miles. If the craft could go that distance a task that would take about two hours then the flight from Crete to Greece would seem possible. The difference between pedalling for two hours and for double or triple that amount is relatively slight, in physiological terms. Small improvements in the plane would increase its range by several hours. Or so the team thought; the truth was, research had not yet shown that such a human effort was possible.

The project director is John Langford, a cheerful, effusive engineer on leave from the Institute for Defense Analyses in Alexandria, Virginia. Steve Bussolari is director of flight operations. He is a slim, no-nonsense MIT aerospace engineer in his midthirties. A dozen or so other crew members included a remarkable diversity of backgrounds. There was a meteorological researcher, a material scientist, aerodynamic engineers, Electronics engineer, classicist, physiologist, mechanical engineer, and computer simulation expert, along with assorted MIT undergraduates who assisted in the work.

The team also had recruited Ethan Nadel, a Yale physiologist who is a pioneer in physiological control of energy exchanges in humans the essence of endurance. Nadel was testing the athletes at the Pierce laboratory. I wanted very much to talk to him. I was just getting into flying various kinds of planes; at the same time, I was as fit as I had ever been in my life, training two and a half to three hours a day. Most importantly, I wanted a chance to help researchers understand the limits of human endurance. If the team let me be their pilot, I could serve as both scientist and subject.

At first, I didn't seriously consider applying. They had national athletes trying out what did they want with me? Out of the 25 or so athletes the group had tested, however, none could fly. So I told them I was a licensed pilot. That very afternoon the team brought me up to the lab for a test.

To their surprise (and mine), my oxygen consumption and power output in relation to body weight ranked me about tenth among the 25 athletes tested. Body weight was important: the way the plane was designed, it worked best with a pilot who weighed between 140 and 150 pounds. At that time my 5-9 frame weighed 149 (the rigors of training have since dropped my weight several pounds). I finagled permission to take January off from med school for the record attempt. Now just one obstacle was in the way of my becoming a member of the Daedalus team: for four hours I had to pedal a stationary bicycle the equivalent of 23 miles an hour.

Electrodes were stuck all over my chest. I breathed through a tube in my mouth; every hour, technicians tested the gases I exhaled to determine how much oxygen I was using. From a catheter sticking out of my arm they drew samples of blood every half hour.

The feeling of pedalling that cycle was like sitting in a car for four hours while running a marathon and a half. After two and a half hours, my rear end became distinctly uncomfortable. Toward the end of the test, I began to get weaker. I felt cold, and the hair stood up on the back of my neck. My body began to steal energy from storage areas outside the legs my liver, my arms every corner of my body.

This was more than an athletic event: it was also part of a scientific experiment that fascinated me as a physiologist. We were concerned about how much fuel the muscles could hold, and for how long. After rigorous exercise for more than two or two and a half hours, the body must replenish its energy.

One of the main obstacles to the Crete-to-mainland flight is that it will last considerably longer than that. In order to endure the flight, the body must take on some sort of fuel. The problem is, if you eat, your stomach takes time to digest the food and pass it on to the intestines. In the meantime, water can't get through. So researchers devised a synthetic food, an extremely long chain of sugar molecules that can "sneak" undetected through the stomach. The organ recognizes only the few molecules suspended in water, allowing the solution to go straight to the intestines where it is quickly converted into thousands of sugar molecules. Though the version I tried tasted sickeningly sweet, this glucose polymer had seemed to work on long bike rides. To determine my ultimate endurance, however, the technicians had fooled me, giving me only colored, artificially sweetened water for the test.

After three and a half hours, my body did not want me to go on but my mind did. If I passed the test I was in I would get to go to California and possibly set a world record. If I failed, I would go back to school, weeks of intense training wasted, and hear about some other pilot on the news. It is amazing what you can do when you want to badly enough. I passed the test and became a member of the team.

I was one of two pilots. The other was Lois McCallum, a systems analyst from Belmont, Massachusetts, who was also a triathlete and licensed pilot. Each of us would fly every other day so that someone was always fresh. Although Lois is not as strong as I am, she can put out a comparable amount of power per kilogram of body weight, and she also successfully underwent the four-hour torture test. Both of us would break the world record.

FROM the end of August until January 9, while attending medical school, I trained for the flight. My bike rides got longer and more intense in the ice, cold and darkness around Hartford, totalling ten hours a week at an average of more than 20 miles an hour. To supplement my flying experience I practiced hang gliding in Claremont, New Hampshire, not far from Hanover. I also had a few rides in an ultralight, which is a hang glider with a motor on it. On weekends I flew sail planes at an airport outside of Hartford, flying as slowly as the planes could go before stalling.

But none of that could prepare me adequately for flying the pedal-powered plane dubbed Michelob Light Eagle for its corporate sponsor. Its wing span was greater than that of a DC-9 airliner. From tip to tip it was a few feet shorter than the Wright Brothers' first flight. As a result, the craft was very slow to respond to controls. If I wanted to turn to the right, for instance, I would add rudder with my right hand, holding it while counting "one one thousand, two one thousand." Then I would return the stick to its neutral position. After another two seconds the plane would slowly begin to turn to the right. I had to get used to this big time delay.

Another problem was the delicacy of the controls combined with rigorous pedalling. It is not easy to pump the legs while gently fondling a joystick-like running and trying to thread a needle all at once.

To help us get the feel of the plane, the engineers adapted a sophisticated flight simulator from the one used to teach pilots to fly the F-15 fighter jet. We trained often on the machine. I would pedal while watching on a television screen the instrument panel and the view out the Light Eagle's front window. The engineers liked the simulator very much; crashing it left the plane intact.

Finally, in January, we got to fly the real thing. For ten days, Lois and I went on short flights of eight to ten minutes apiece. Heart rate monitors took a reading every 15 seconds, revealing that we were close to breaking the anaerobic threshold. At first, our heartbeats were just a bit too fast to allow us to endure for much more than half an hour. If we could pedal with a heart rate just several fewer beats per minute, this would prevent lactic acid from building up in our muscles-allowing us to exercise for hours instead of minutes. With the test and safety equipment off the plane, I was suddenly below threshold. We were ready to go for the record book.

Lois was the first to try, however. On January 21 she flew for 37 minutes and went 9.9 miles, setting the Wornen's record for duration and setting the world record for distance around a triangular course. The problem was, she was still working slightly above her an aerobic threshold.

The next day, at 8 a.m., Steve Bussolari walked me out through the Space Shuttle hangar and a voice came over loudspeakers all over the base. "Attention," it said. "This morning, Glenn Tremml will be flying on Rogers Dry Lake in an attempt to break the seven-year-old world record for human-powered flight." The announcement echoed eerily across the lake bed. Steve and I climbed into a van and were driven straight to the waiting plane. A crowd of spectators, including media packed in several flat-bed trucks, watched as we approached. Ahead lay a ten-mile triangular course. I was to go for three laps a total of 30 miles.

I stripped down to cycling shorts and a tee shirt, though the desert air was still a chill 26 degrees Fahrenheit. The crew helped me squeeze into the plane. Someone reached in front of my face and checked the instruments. Several team members then took a thin piece of Mylar and taped it around the edges of the small hole that serves as a door, heat-shrinking the plastic with a hair dryer. In the cool confines of the cockpit, sweat trickled down my armpits.

After an eternity of instrument checks, I got the go-ahead. As the plane accelerated, the wing runners let go and ran along beside me. I could hear people cheering as I zoomed to the edge of the pavement and took off over the lake bed. My adrenalin was high, and I was probably pedalling much harder and making the plane fly faster than it needed to. A voice came over the radio the official observer, who was a captain in the Air Force. "You are now on the course," he said. "I am starting my stop watch and the mileage count."

The pedalling should have been easy at that point, but it wasn't. I was gasping for breath just 15 minutes into the flight; my visions of going 30 miles started dwindling. "It feels too hard," I radioed to the crew. The van pulled in just behind me. The crew noticed that the outboard wing tips were not aligned properly. "Jiggle the controls. Maybe they'll snap into place," Steve said. They did just that. I fell into a smooth pace for a while at least.

About 25 minutes into the flight I heard my right shoe rub against the fuselage. I looked down: my foot was slipping off the pedal, which is a thin bar that sticks out from the crank and is attached by a special cleat to my shoe. The device was new, and we hadn't had time to test it adequately before this flight. I tried sliding my foot back on, but the fit was too tight. There was nothing to do but yank my foot completely off the bar and reattach it correctly. I radioed my intentions to the van, pumped furiously to raise my altitude to eight feet, and jerked my foot off the pedal. I frantically worked with my left foot to stay in the air and tried to reattach the right one, all the while keeping one eye on the altimeter. Six feet, four, two, one . . . we

were dropping fast. Panicky voices came over the headset: "You're going to touch, you're going to touch!" Just as the plane descended to six inches from the ground, I managed to snap my foot into place. Gradually, I rose several feet.

An hour into the flight, I decided it was time for a drink of water. One attempted sip revealed a problem with the drinking system, a set of bags over my head with a hose that came down to my mouth. Several stop mechanisms ensured that liquid didn't leak and slosh around in the bottom of the cockpit. The device proved all too effective: the water came out in a slow dribble, and I was breathing too hard to let it fill up my mouth.

Now this was really frustrating. We had worked for months to get rid of every unnecessary ounce, and here I was carrying five pounds of useless water. To make matters worse, my feet began working their way off the pedals again. Three times I had to work to gain more altitude; three times I reattached my feet to the pedals.

Passing through the world record mark was strangely anticlimactic, because we weren't sure exactly where it was. There was no marker on the course. Besides, the rules said I had to break the record by one percent in order to establish a new one. The television networks were disappointed.

As I approached the third lap, my legs began to feel rubbery. I said little over the headset, concentrating on flying and breathing. I was starting to get thirsty. The water bag hung, tantalizing, overhead. I brought the plane down a bit to take advantage of ground effect. The air can't escape from under the wing close to the surface, making the plane relatively lighter. I'd already broken the record; if I touched down inadvertently, well, those were the breaks.

The official came over the radio: "You have just completed three laps," he said. Thirty miles. The next leg of the triangle, a short two and a half miles, went well. After another short leg was a five-mile downwind stretch. If I could just complete that long leg I would have gone 40 miles.

I made the turn and felt the wind picking me up from behind. The plane gained to several feet of altitude, and then the old pedal problem returned. I had to bring the Eagle up from three to eight feet in altitude. It takes twice as much energy to climb as it does to fly straight and level. At six feet I started hyperventilating, and my heart was pounding. I just didn't have it in me to go another two feet. And the extra climbing had worked my foot dangerously close to the edge of the pedal. When I yanked my foot out, my legs were too rubbery for good coordination. "You are losing altitude," said the van, but there was nothing I could do about it. The crew could hear me kicking the bottom of the plane. Despite several tries the altitude slipped away; after one last attempt the wheel hit the ground.

Without thinking, I turned the Eagle into the wind, leveled the wings, and looked for the wing runners. Only then did the disappointment hit me. That was quickly followed by a feeling of relief that the ordeal was over. It was only when the runners came up hollering with joy that I realized what I had done wasn't so bad after all. I had set my goal at 30 miles and had exceeded that by seven-almost double the previous world record. And I had done it while carrying five extra pounds, going more than two hours without water, and occasionally pedalling with one foot.

And now comes the hard part. Even as the media were still thinning out from the post-flight press conference, the team members stood around talking about Phase Ill: the Greece flight. The new craft, appropriately called the Daedalus, will look essentially the same, but it will weigh just 68 pounds 24 less than the Eagle. Superior materials and innovations in the control mechanisms are the main reasons. We have not changed the pedal system an outdated version of bicycle cleats had been installed accidentally during the record flight. The new ones work fine.

The water system, on the other hand, has been scrapped. I opted for an empty plastic orange juice container, which will sit by my left hand. You pick it up by the handle and drink out of it. That is what engineers like to call "appropriate technology."

Just when I thought myself capable of making the Greek flight, however, the team voted to change the route. The original course would have covered 69 miles, but there was insufficient space on the proposed takeoff site. The new flight plan runs 80 miles. From the tiny town of Maleme, Crete, we'll fly to the nearest beach on the Peloponnese Peninsula. The attempt is planned for March or April of next year. We are recruiting three more pilots, one Greek and two Americans, so that one of us can be in peak condition for the flight at all times.

I have taken a year off from medical school, working out as many as seven days a week and participating as a paid member of the Daedalus team. I'm modifying a computer program that predicts indoor environments in the hope of helping to solve the thermal heating problem in the cabin. I'm keeping up to date on my flying skills, pursuing a glider rating. I have also been lending a hand in construction and other chores, gluing, lashing, bending, sawing a task that should be done about the time you read this.

My chances of being the pilot in Greece are exactly one in four. Sometimes I dream of being the one; sometimes I fervently hope the job falls to someone else. The prospect of making the attempt is intimidating. Triathletes in the infamous Iron Man race compete for a grueling eight or nine hours. As punishing as the race is, however, they have breaks of a sort they change their activities, and stop for a short time between. If they push too hard they can back off; if they have cramps they can stop for 30 seconds and continue. The Daedalus flight will require six hours of constant effort. Because the propeller is attached directly to the pedals-it is not a free wheel, as on a bike-there's no coasting or sprinting, no change of pace, no shifting of poition on the seat.

In preparation, I have worked up to three and a half hours of 21-mile-anhour cycling. If I can get that up to five hours I will be fairly confident of succeeding in the Greek flight. But another problem worries the engineers. The pilot will sweat off two pounds of water every hour, and must replace that amount, supplemented with the glucose polymer, during the flight. The team is trying to figure out how to get 12 pounds of water on the plane after working for years to get rid of every ounce of excess weight.

We kid that the engineers do the work and the pilots get the credit, and there's a lot of truth to that. But what has excited me most about the project is the team, a group of extraordinary people all working seamlessly toward an unprecedented goal. If I am the pilot in Greece, that solidarity will be my fuel. When I get into the plane and take off, what will drive me to the other shore will not be the chance for personal satisfaction but the sense of responsibility to the team. When I take off, the engineers' job will done. Mine will be just beginning.

Soaring above the California desert,Glenn Tremml '82 broke the record forhuman-powered flight. Planned nextspring is an 80-mile pedal from Crete tothe mainland of Greece, mimicking themythical aviator Daedalus.

To become a self-propelled pilot, Tremml had to pass an endurance test devised by Yale physiologist Ethan Nadel.

Dozens of athletes applied, but Tremml and triathlete Lois McCallum were the onlypilots tested who could put out sufficient power to break the record.

With wings almost as long as the Wright Brothers' first flight, the Light Eagle cruises atclose to normal altitude. Curved tips stabilize the plane for turns.

Using space-age materials to go Mach0.3, the engineers hope to get evenlighter than the prototype.