how to pull webbing fast, fast

[councilman24 36]

I want to do some testing to try to understand the problem of main pins penetrating the bridle and causing a PC in tow. To do it I need to pull two inches of bridle at several hundred feet per second instantaniously. Any ideas?

Thinking about an FXC 12000. If I had a junk one I might tear it apart to just use the spring and cable. Thought about a bow but even a cross bow only gets up to 300-350 fps and I don't have one. My compound is probably only 200 fps, if that.

I don't particularly want to throw PC's out of a car but may resort to that. Don't have a wind tunnel readily available.

Any othe ideas? Or a junk FXC 12000 to contribute?

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[pilotdave 0]

300 fps is over 200 MPH. What kinda test you doing, and what kinda car ya got???

Dave

[NovaTTT 1]

I have a FXC12000 you can have, Terry, if you'll please cover shipping. It's not junk, but it'll never see airtime again. Send me a PM if you're interested.

Nova

"Even in a world where perfection is unattainable, there's still a difference between excellence and mediocrity." Gary73

[councilman24 36]

Okay, so it was late (when I punched the calculator) and I did it the old fashioned way. Really only want 30-50 mph, maybe 120, 176 feet per second. So maybe tieing it to my bow would be good.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[pilotdave 0]

Damn, I was hoping this would end up making for some really cool video. It'll still be cool, but not REALLY cool.

Dave

[mjosparky 3]

Quote

I don't particularly want to throw PC's out of a car but may resort to that.

You will get more reliable results if you do it from the bed of a pick-up truck.

Sparky

My idea of a fair fight is clubbing baby seals

[Slurp56 0]

Quote

Any othe ideas?

I hate to be the un-original thinker of the bunch, but how about taking it skydiving?

________________________________________
I have proof-read this post 500 times, but I guarantee you'll still manage to find a flaw.

[theonlyski 3]

Probably wouldn't want to fire a reserve past it.

"I may be a dirty pirate hooker...but I'm not about to go stand on the corner." iluvtofly
DPH -7, TDS 578, Muff 5153, SCR 14890
I'm an asshole, and I approve this message

[councilman24 36]

I need to watch, take close up video, and do it a hundred times. Skydiving doesn't work.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[fcajump 153]

Quote

I need to watch, take close up video, and do it a hundred times. Skydiving doesn't work.

Several years ago I read where a jumper, wanting to test his bungee collapsible PC, wrapped the bridle around his forarm while his buddy drove 70+ down the road and he tossed the PC out the window...

Oh - wait... as I recall that didn't turn out too good...

Never mind,
JW

PS - If you need additional PC's, let me know and I'll send you one that I've got kicking around.

Always remember that some clouds are harder than others...

[councilman24 36]

Now known as lefty?

FXC on the way. Thanks NOVA!

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[NovaTTT 1]

It's on the way, Terry - info sent via PM.

Looking forward to seeing your experiment discussed, the data and your interpretations.

Remember to get lots of photos and video - especially if you do the "From The Vehicle" experiment!

N

"Even in a world where perfection is unattainable, there's still a difference between excellence and mediocrity." Gary73

[airtwardo 6]

Garage door spring mounted to the work bench works too...

~ If you choke a Smurf, what color does it turn? ~

[councilman24 36]

Yeah, but it's a bitch rewinding those torsion springs.

I actually installed one once and was REAL nervous winding that thing up.

But it's a thought.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[Gary73 8]

Use a standard coil spring instead of a torsion spring. You can vary the speed just by moving the attach point. Place a yardstick behind the sample and you should be able to get fairly accurate speeds from the video. (Don't forget the safety cable running through the middle of the spring!)

"Extraordinary claims require extraordinary evidence." - Carl Sagan

[airtwardo 6]

Quote

Use a standard coil spring instead of a torsion spring. You can vary the speed just by moving the attach point. Place a yardstick behind the sample and you should be able to get fairly accurate speeds from the video. (Don't forget the safety cable running through the middle of the spring!)

That's what I was talking about, did something similar a couple years ago.

Mounted it on a long board with 'peg holes' every three inches at the non anchored end...used a steel 'peg' with a QR shackle attached to it, to release the spring.

I used a dowel rod through the center as a safety guide.

BOING!

~ If you choke a Smurf, what color does it turn? ~

[JerryBaumchen 1,047]

Hi Terry,

If you are going to use a coil spring and need a quick release, see if you can build a 3-ring system for the release system. They do work.

~20 yrs ago we had to drop-test some steel drums filled with water from ~15 ft. Our Mechanical Lab had no idea of what they were going to do to release these drums; they could get them up to 15 ft but then what do ya do. So I made up a release system based upon a 3-ring and ~30 ft of line to pull and let'er go.

Lots of fun . . . .

JerryBaumchen

[hackish 8]

I was going to suggest launching a 2l pop bottle full of water out the 2nd floor window with a bridle attached. Fairly easy to repeat and we all know from experience that gravity is fairly reliable.

-Michael

[theonlyski 3]

Quote

I was going to suggest launching a 2l pop bottle full of water out the 2nd floor window with a bridle attached. Fairly easy to repeat and we all know from experience that gravity is fairly reliable.

-Michael

Fairly?

"I may be a dirty pirate hooker...but I'm not about to go stand on the corner." iluvtofly
DPH -7, TDS 578, Muff 5153, SCR 14890
I'm an asshole, and I approve this message