Ever since early man could walk upright, we've dreamed of flying. And you can bet homo erectus wasn't imagining a cramped middle-seat next to a fussy baby on a 747; the personal-flight freedom of birds has always been the goal, however distant. Daredevils among you will be happy to learn that in recent years, humans have been drawing ever closer to achieving it -- by a variety of methods, some crazier than others -- and here are our faves.

1. The Wingsuit

Batman jokes aside, the wingsuit is pretty darn cool, and probably approximates personal flight more accurately than any of our other examples. It's also scary as all get-out: to make it work, you've got to jump off of something really high, like a cliff or an airplane. The jumper wears a special suit with fabric sewn between the arms and the body and between the legs to create an airfoil shape, not unlike that of a flying squirrel. Once adequate air speed relative to the jumper is created -- this happens more or less instantly when skydiving, but takes a little longer if BASE jumping -- air speed is converted to lift.

This is where the magic happens: the jumper's body essentially becomes a wing, and rather than falling toward the ground at around 120 mph, a good portion of that vertical momentum is converted into horizontal momentum; wingsuiters often travel 2.5 feet forward for every 1 foot down (that's called the "glide ratio,") slowing their descent to between 60-90 mph, and quieting the wind rush around them to a degree that they can hold casual conversations with one another while traveling in formation. Here's a video.

Unlike birds, however, most wingsuiters don't try to land on their feet -- you need special, expensive landing strips for that sort of thing -- they wear parachutes, deployed once they're within a few thousand feet of the ground.

2. Human-powered helicopter

Humans have been trying to power their own helicopters since at least the 50s, and seriously attempting it since 1980, when the Sikorsky Prize was introduced. To claim the prize, one has to develop and fly a human-powered helicopter at an altitude of at least 10 feet for at least 60 seconds, and though many have tried, no one's come close yet. The current record is held by a group of Japanese university students, whose HPH Yuri I flew for 19.46 seconds in 1994 at a barely-measurable altitude of 2 centimeters. Somewhat more impressive was the Da Vinci III, which got all of eight inches off the ground, though for only 7 seconds, in 1989. Here's a photo of their feat, and their contraption:

As you can probably tell, it's pedal-powered, and features very light construction in its body and its enormous wings. The challenge all these pioneers have faced is creating an HPH with a super-efficient power-to-weight ratio; they must create a lot of lift but not much drag, since drag consumes power. (Sounds like an exhausting pedal.)

3. The Personal Jet Wing

jet man.jpgThis is distinct from the jet back or rocket belt, which as Miss C pointed out in a blog earlier today, are fairly impractical methods of flight that use a great deal of fuel and don't allow for more than 30-60 seconds in the air. The only personal jet wing we know of was developed and built by a Swiss daredevil named Yves Rossy, and is essentially a winged modification of the jet pack designed for use during skydiving. The carbon wings unfold from Rossy's pack when he jumps, and with a hand throttle he controls the wings and four small jet engines connected to it. A former Swiss Air Force fighter pilot, Rossy in 2006 became the first person to fly horizontally for more than six minutes with just a pair of wings strapped to his back. Check out this video of one of his flights:

4. The Backpack Helicopter

pentecost_strapon.jpgMilitary contractors in the US, Britain and the Soviet Union have been trying to develop a backpack helicopter since the 1940s, with mixed results. The first breakthrough of any note was the US military's Hoppycopter in 1945, which didn't actually fly -- it hopped, hence the name. (Hoppycopter pictured at right.) The project eventually faded away, but recently there's been a resurgence of interest in the personal copter. The most successful (and accessible) one we've heard about is Japan's GEN H-4, which has a seat, landing gear, and supposedly requires only two hours' training to use. Here are some specs, courtesy Newlaunches, and a video:

Unlike traditional helicopters it has 2 sets of coaxial, contra-rotating rotors (KA-52 Hokum for all you military buffs) which eliminates the need of a tail rotor for balancing. The rotors have a length of only 4 meters (118 inches) so no parking problems too. It is powered by 4 lightweight 125 cc 2 cylinder engines which use standard gasoline. The GEN H-4 can fly to a maximum altitude of 1000 meters at a top speed of 90 km/hr (59 mph) for up to 30 minutes.

This one's definitely on my Christmas list.