At a late and insomniac hour, when you can’t find a Law and Order rerun that you haven’t already seen and resuming your reading of the family’s Encyclopaedia Britannica at GUNN to HYDROX seems too arduous to contemplate, it is well to resort to YouTube, that portable and compendious ocean of funny cats, sadistic pratfalls, awful vocalists, miraculous gymnasts, instructions for dismantling your computer and fake airplanes presented as though they were real.
I wrote five years ago about one of the remarkable things that I found on YouTube: the use of wingsuits in sky diving and base jumping. A wingsuit consists basically of some fabric membranes stretched between arms and legs and between the legs. It increases the area and improves the shape of the jumper’s planform, making him or her look a bit like a flying squirrel. Some of the most startling daredevil stunts on YouTube — and there are many — involve guys in wingsuits barreling down mountainsides, seemingly inches away from some very abrasive-looking rocks. A good wingsuit can attain a glide ratio of 2:1 or so; in 2010 an Army jumper glided 11.5 miles after jumping out of a C-17 at FL 320.
Normally, wingsuit jumps end with a parachute deployment. But the last time I looked, a fellow was trying to figure out how to flare and land without a chute, just using the lifting capacity of the wingsuit. He may have given up by now. I doubt it is possible, but you could certainly get killed trying. Perhaps one could calculate a flare factor — the product of lift-drag ratio and wing loading, with suitable exponents, required to permit a given touchdown speed — in order to know what kind of wing would be required to allow a man to touch down at, say, 25 feet per second with a survivable vertical velocity. Hang gliders do it all the time, but a hang glider is a far cry from a wingsuit.
Speaking of flaring, a magnificent super-slo-mo video of an owl flaring to pounce upon a bait can — and must — be seen below. It certainly makes human attempts at “variable geometry” appear contemptible.
Another surprising example of airplane-as-clothing is Swiss pilot Yves Rossy’s jet-powered strap-on wing. Rossy has used several different wings, all more or less conventional-appearing, of about eight-foot span, somewhat swept, of carbon-fiber construction, with four model-airplane jet engines slung underneath them.
Each engine weighs five pounds, produces 50 pounds of thrust and burns a pound and a half of kerosene per minute at full throttle. The wing has ailerons, but there is no empennage, and I imagine pitch must be controlled with elevons or small fore-and-aft weight shifts. A former Swiss Air Force fighter pilot who now flies for Swiss International Air Lines, Rossy, 52, jumps out of an airplane or helicopter or balloon with the wing on his back, and is able to fly level and maneuver for some time. There is a YouTube video of him racing about among the Swiss Alps, in formation with a couple of jets, and another of him crossing the Grand Canyon. He crossed the English Channel but failed because of weather to make it across the much narrower Strait of Gibraltar, ending up in the drink.
Startling stunts can get millions of hits on YouTube. A couple of years ago there was the airplane that appeared to lose a wing during an aerobatic routine but managed to land nonetheless. This was a rather obvious fake, but it still fooled a great many people.
A less obvious fake that recently excited millions is the purported achievement of one Jarno Smeets, a Dutch engineer presented, in a series of videos, as having constructed a wing that allows him to rise, flapping, into the air. It is not clear to me that Jarno Smeets actually exists; he may just be a persona of a filmmaker named Floris Kaayk, but that is unimportant, since what is interesting to me is the project’s technical plausibility, or lack of it.
