Interview with David Glover
David Glover is the past President of the United States Hang Gliding Association. He holds a world record for distance hang gliding and has taken more people up for their first flight than almost anyone in the world. Glover is among the fewer than ten tandem hang gliding instructors who have more than 5000 flights with a passenger. Today, there are fewer tandem hang gliding instructors than astronauts.
|Flying around the terrestrial biosphere
For many years, Glover trained hang glider pilots near the spot where a century-ago, two bicycle shop owners, Orville and Wilbur Wright, first achieved powered flight on the Outer Banks, North Carolina. Their first powered aircraft under pilot control flew four times in 1903, covering a distance of 852 feet (or about one football field) and staying aloft just shy of a minute (59 seconds). Orville later became a founding member of the aeronautical society that eventually became NASA, and saw in his lifetime the speed of air travel rocket from zero to a thousand miles per hour.
Flying flexible wing designs has a rich history among forward-thinking planetary explorers. The first flex wing hang glider patent by Dr. Francis Rogallo (NASA Langley wind tunnels, Virginia) dates all the way back to the late forties. Rogallo is considered "The Father of Hang Gliding", and his design is often hailed as a kind of original, not having any model in nature.
In contrast to other flexible aerial devices like parachutes, a load-bearing Rogallo wing produces more lift than drag, though not as much as a conventional wing. But rigid wings could not be folded neatly away when not in use, and they were inherently far heavier. Rogallo first realized what this might mean in 1952, when he chanced across an article on space travel: "with beautiful illustrations depicting rigid-winged gliders mounted on top of huge rockets. I thought that the rigid-winged gliders might better be replaced by vehicles with flexible wings that could be folded into small packages during the launching."
Although the light materials like bamboo and thin, strong cloth have been available for thousands of years, a practical design for human soaring was missing: the dream of foot-launched flight particularly seemed dauntingly difficult. Indeed, the Egyptians had all the items necessary to create a glider capable of carrying a person, but only the latter half of the twentieth century saw the full concept take shape.
As part of its Century of Flight commemoration, Astrobiology Magazine had the opportunity to talk with David Glover about human flight, on the one-hundredth anniversary of the Wright Brothers' famous first lift-off.
Astrobiology Magazine (AM): Since before Da Vinci, the idea of human flight has been such a powerful dream. What makes a modern hang glider the answer to this quest? Is it the weight-shiftable A-frame, the quarter-bubble wing, the glider's low total weight--as new materials and designs came, what has made the biggest difference?
David Glover (DG): Materials and design have made the biggest difference.
When some photos of Rogallo's design were published in the mid 1960's a few Americans and Australians seized on the idea and started creating their own foot launch versions out of bamboo and plastic. The Aussies developed their kites originally for water ski shows. The Americans were experimenting with foot launch down hills.
AM: The original Rogallo work took shape as an alternative to landing space capsules without a passive parachute.
DG: The Mercury spacecraft finally chose parachutes instead owing to their simplicity. The Ryan Aircraft Corporation kept work up on the design for many years.
AM: Around 1970, when hang gliders became popular, their cost was mostly materials and could be built for around 20-30 dollars. What is the cost of a modern sport glider?
DG: Gliders cost between $3,000 and $6,000 for flex wing gliders and $7,500 to $11,000 for more advanced carbon-fiber, rigid wing hang gliders.
AM: NASA has glider plans for some Mars planes, and has done some prototype flights. One problem is how to navigate long distances in low martian (1/1000th) air pressure compared to Earth. From your experience as a pilot, is it more difficult or easier to fly at higher altitudes where the pressure is lower? Is it the pressure or the low temperature that makes it challenging?
|Mars airplane design
DG: The glider performs better at high altitude, but the need for oxygen and cold weather clothing is a hassle. It is much easier to launch and land at low altitude where the air is thicker.
One of the project managers on the Mars' glider is a hang glider pilot, Juan Cruz.
Juan was the structures guy on the Daedalus project at MIT - that plane still holds the record for the longest human powered flight.
Using human pedal power, they pumped and flapped their way 72 miles over ocean from the island of Crete to the Greek mainland.
Daedalus, the archetypal engineer of Greek mythology, escaped the labyrinth of King Midas by flying out with wings he built himself. He was the only mortal in ancient mythology to fly without divine assistance.
AM: In 1999, you wrote about one of your own unique 95-mile flights, doing something called skyfloating, or flying in a paragliding harness: "I didn't even plan on flying that day and little did I know that in a few hours I would be dehydrated, hypoxic [oxygen deprived], and on my way to the Falcon World Distance Record." What are some of these milestones in the sport, and where are the best places to glide for these kinds of records from a weather perspective?
DG: There are much more impressive world records than the one I have, which is for 'Distance to a Goal on a Rigid-wing' hang glider. The Open distance record for hang gliding is 432 miles from Zapata, Texas. Zapata was discovered about 5 years ago by one of my best friends, Gary Osoba.
We have organized a World Record Encampment every year since and the pilots we have invited have broken every distance record in hang gliding and paragliding.
AM: What is the moment of 'glass-off', in hang-gliding terminology?
DG: The sun can be down and you still are floating far above the ground. So 'glass-off' denotes an end of the day phenomenon where the latent heat trapped in a valley, usually in front of a mountain, releases a rush of rising air and provides buoyant lift for a pilot.
It is a very descriptive phrase, 'glass-off', because at the end of the day, over a valley, the air can become all lift. It gives the pilot a very smooth ride.
AM: A lot of pilots working on the Rogallo principle used tows or aquatic starts. Now with the rising popularity of kite-boarding, is this history coming back to the beginning, by combining the best parts of para-sailing, wind-surfing, wave-surfing and snow-boarding?
DG: The fusion of sports is interesting. Everyone wants to fly - many people choose different methods, but hang gliding and paragliding are still the best to really achieve man's age old dream of flight.
AM: Of all the extreme sports you have done, which is the most thrilling for you today?
DG: There is nothing like hang gliding. It can be very dangerous if a pilot has the wrong stuff (attitude). Or altitude. [Laughs].
The instruction, equipment and places to fly have all gotten much better. One of the best places to learn in the world right now is in Florida using aerotow techniques.
AM: Orville Wright wrote about their original flight design: "Our machine was designed to be flown as a kite, with a man on board, in winds of from fifteen to twenty miles an hour. But, upon trial, it was found that much stronger winds were required to lift it." In bucking a trend, they finally selected "a peculiar shape; which in the lateral balance, by arching the surfaces from tip to tip, [was] just the reverse of what our predecessors had done."
Credit: Wright archives
If you could time-travel on the 100th anniversary of the Wright Brothers back to Kitty Hawk, and watch their many failures, what one piece of advice could you offer to speed them up with what you know about flight today?
DG: I was just back on the Outer Banks and was able to witness a group trying to fly the 1902 and 1903 gliders at Jockey's Ridge/Kitty Hawk Kites.
The plane they had was a brick.
But it was the first of its kind. I would just stand there in awe of what they were doing. Everything was stacked against them. The plane was too heavy and underpowered. Thank God they had a stiff breeze.
AM: The extreme sports have a dare-devil popularity. What is the opinion within the seasoned pilot community about the safety of unpowered flight these days?
DG: It is still perceived as one of the craziest sports there is. In the wrong hands, it is dangerous.
Done correctly, with a good attitude, it can be one of the best feelings anyone can experience.
But aviation is unforgiving. You cannot screw around and stay alive.
AM: You are known to say to first-time pilots that what they are about to achieve, was the life-long but unfulfilled dream of da Vinci. If you could time travel back to Florence, and have dinner with da Vinci, what advice would you give him from what you know about the experience of being a human bird?
DG: I would show him the basic Rogallo wing. All the materials to produce the craft were available.
AM: What is the average hang gliding pilot like these days, more like the sixties' surfer culture or airline pilots?
DG: The sport attracts a cross-spectra of personalities. I have seen all kinds. I can't think of a stereotype. We do fly for logical reasons.
|Tandem flying with David Glover
Credit: Wallaby Ranch, FL
AM: What is the most stunning scenery from the air you have flown over? Your perfect flight day?
DG: Anytime I am above the ground it is stunning. I flew for a few hours over Big Sur, that was beautiful.
Flying over the beach dunes that are just a few feet high also gets your attention.
One time I got a call from my mother who said: "I don't like seeing my son on the Today Show, flying a hang glider on the beach when a hurricane is just a day from landfall."
AM: You have worked with the satellite global positioning system (GPS) for tracking flight competitions. Are there plans to put internet tracking into play?
DG: A few years ago we used a system called APRS, which uses ham radios and GPS to show real time tracking on the internet - it was quite a feat to put all the components together to make it work.
Most cell phones will soon have a GPS in them and provide the real-time service.
AM: Nobel laureatte, Herbert Simon, was an economist and father of some of the earliest chess-playing computer programs at Carnegie Mellon. He preceded Sir Arthur C. Clarke's description of humans as 'carbon-based bipeds' by the more zoological classification of humans as the 'featherless bipeds', since humans and birds are the naturally upright species [excluding outliers like kangaroos]. For an X-sport enthusiast, is there another way to describe us bipeds?
Homo sapiens. What an inventive, invincible species. It's only been a few million years since they crawled up out of the mud and learned to walk. Puny, defenseless bipeds. ...And now, here they are, out among the stars, waiting to begin a new life. Ready to outsit eternity.
Dr. Who, 1963
DG: Wow, what a question. "I have no response to that" (A line from the film, Joe vs. the Volcano)
AM: From you experience, what do you think most causes hesitation among first-time fliers when you begin to teach them: safety, cost, heights generally, speed, or just the challenges of the new vertical spatial dimension? What is the first-time fear?
DG: Lack of understanding of the risks. People fear what they don't understand.
Height doesn't hurt you. Falling and hitting the ground from a height is what kills you.
The more altitude the safer you are. As a tandem instructor-- if I wanted to-- I could make everyone who goes up flying vomit.
My desire is to have everyone who flies with me come down and say that was the coolest experience of their life. Almost everyone comes down saying that.
There is a national organization of pilots [the US Hang Gliding Association] which is run by my girlfriend, Jayne DePanfilis. You can find an instructor in your area by clicking around on this site.
AM: What do you think the seasoned pilots could do to popularize unpowered human flight? ESPN coverage of flying competitions, or a Tiger Woods character to connect with us land-bound bipeds?
DG: So few people in the general public think they can handle hang gliding. If they knew what the sport has evolved into, we would not be able to handle the onslaught. Aerotowing provides one of the best ways to try hang gliding.
A tandem hang gliding flight is what everyone should try one time in their life.
New and exotic models for gliding on other planets are even in the works. A future Mars' plane has received preliminary testing. On August 9, 2001, soaring gracefully down to Earth from a balloon floating high above Oregon, a NASA prototype of an airplane that someday may fly over Mars successfully completed a high-altitude flight test. The NASA 731 glider was dropped from a helium-filled balloon that towed it up to an altitude of 101,000 feet - the highest ever for such a test - before releasing it. At that altitude, on the brink of space travel, the curve of the Earth's horizon is easily visible.
Conventional in appearance, the Mars airplane concept developed by Ames engineers features a long, straight wing and twin tails in the rear. The remote-controlled glider tested in Oregon featured an approximately four-foot-long fuselage and an eight-foot wing span. According to Larry Lemke, an aerospace engineer at NASA Ames , a Mars airplane is an idea whose time has come. "The Mars airplane is an idea that has been around for about 25 years, and over the past five years or so, it has been growing in popularity," he said. "I think a Mars airplane will play a role in exploring the Red Planet."
The Wright Brothers are credited with demonstrating controlled, powered flight: they themselves gave credit to Hiram Maxim for making the first takeoff in 1893. Hiram however couldn't control his aircraft, and it crashed without much direction, scraping along through the English countryside, going where it wanted to-- until Hiram shut down the steam engine.
Related Web Pages
Wright State Special Collections
Flying the 1902 Glider in 2002: NASA Ames
NASA's Wright Brothers' Info