Skydiving

 

“Go!” yelled the instructor.

Over strenuous objections from brain and body, I let go of the airplane’s strut and stepped sideways into 3,500 feet of air.

I fell: two simple words that don’t do the experience justice. I’d been training all day. I was supposed to arch and count to five. I didn’t. Every thought dissolved in a sensation far greater than fear. Gripped by forces beyond my control, I flipped and twirled like a leaf in a hurricane.

Then suddenly I felt a solid tug, and floating instead of falling, I looked up at the most wonderful thing I’d ever seen: my parachute, glowing serenely blue in the sunshine.

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Parachutes have been around a long time. A Chinese history from around 90 B.C. says the emperor Shun tied straw hats together and jumped from a burning tower. Leonardo da Vinci sketched a pyramid-shaped parachute in 1495, but it’s a good thing he didn’t try it: it was only six feet across, whereas modern chutes are 28 feet across.

J. P. Blanchard invented the collapsible silk parachute in 1785. He may even have tried it out — he broke his leg about that time. But the first person to jump regularly was Andre-Jacque Garnerin, who amazed audiences by leaping from balloons, swinging wildly from side to side as he descended, and throwing up when he landed.

A parachute slows a fall by trapping air, but eventually it fills up and has to let some escape. Garnerin’s chute could only release air around its edges, first on one side, then the other, with nauseating results. A small vent in the canopy eventually alleviated this problem.

Early parachutes were attached to the aircraft and pulled free by the jumper’s weight. Floyd Smith invented the modern personal parachute for the U.S. Army Air Service in 1919. In his chute-and-pack combination a ripcord, pulled by the jumper, opens flaps that release a small pilot chute. The air rushing into the pilot chute then yanks the main chute free.

Nowadays the pilot chute is often pulled out of a package on the jumper’s leg and tossed into the airstream manually, but Smith’s system survives in the obligatory reserve chute, the classic umbrella-shaped parachute whose one problem is that it’s almost impossible to steer, which can land you in trouble.

Domina Jalbert relegated round chutes primarily to reserve duty in 1964 when he invented a parachute with a curved top and flat bottom, like a wing. The slower-moving air beneath the wing has a higher pressure than the air rushing over the top, generating lift.

How do you make a wing out of thin nylon? Easy: use two layers, open at the front and closed at the back, and cross-sew additional fabric between them to form ribs. The parachute’s forward momentum rams air into the space between the two layers, giving it the required rigidity.

Today’s parachutes can be steered by pulling down on handles attached to lines which flex the back of the chute like the ailerons on an airplane. Pull the right handle to turn right, pull the left handle to turn left, and pull both to “flare,” or brake (this tilts the wing up, momentarily slowing its forward and downward motion). If you time your final flare just right, you touch down as gently as stepping off a curb.

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Once it sank in that I was still alive, I finally remembered that I was supposed to “flare twice and aim for the target.”

I looked around: I could have been over Mars for all I could tell. Fortunately, radioed instructions from a spotter on the ground (those I could decipher) guided me reasonably close to the target; and as the ground swept up, I flared and dropped gently to Earth. (Well, actually, I flared too high and dropped heavily to Earth, but considering how hard I COULD have hit, I didn’t complain.)

I’d like to say that throughout my jump I ruminated on the wonderful interplay of physical forces acting on me, and marvelled at how Jalbert’s invention put aerodynamics and gravity under my control, but in truth, at jump’s end, only one word came to mind:

Wow!

Permanent link to this article: https://edwardwillett.com/1992/07/skydiving/

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