TW200 Forum banner

1 - 3 of 3 Posts

1,928 Posts
Discussion Starter #1
In the mid-60s when our Amarillo Skydivers club was jumping from local TV weatherman Dan True's big ol' 1923 Fairchild 71, we made a very interesting jump!

There had been a monster hail storm in the "Golden Spread" and a wheat farmer's crop was destroyed by the very large big hale, much of it 4-6 inches in diameter. He saved a couple of the really big ones, packed them in dry ice and mailed them to Dan to show on his TV weathercast. And he asked how fast they can fall. Nobody had a clue!
Dan decided he would ask a couple of us, both Expert licensed jumpers to appear on his show, display the hailstones, and "make a plan".
The plan was for Bob Hulsey & I to make a 60-second free-fall jump with the hailstones.
I think he even got the TV station to pay for the gas cost of the jump...bonus time for us!

We knew the terminal-velocity speed of a falling body is ~120MPH.
So we jumped from 12,500 ft. for a 60-second free-fall, each carrying a stone.
After about 20 seconds, we had stabilized, reached terminal velocity and were facing each other, about 15 yards apart. We released our stones 10 seconds apart and observed their behavior.
They actually "fell up", relative to us!
After we opened our 'chutes & landed, we discussed it with Dan. The consensus was that while we were travelling ~120MPH, the hailstones were falling ~100-110MPH, give or take.
Now Dan True is an expert on everything that happens in the air...from Hummingbirds to Eagles to jet aircraft to weather phenomenon and now, hailstones.
It seems hailstones do not all fall the same speed, influenced by their size, shape, density, winds & updrafts, atmospheric pressure, etc.
An interesting and fun experience!

PS - It did not occur to us at the time, but if the falling hailstones had impacted our parachute canopies after we "opened", in all likelihood, they would have blown a hole in the nylon and passed right on through!
A hole that size would had no significant effect of our descent speed, but would have required an expensive repair.
And the odds against such an occurrence were about a million to one.
Damn, I miss those days...

That's my story and I'm sticking with it! 😎
1 - 3 of 3 Posts