Zippy De Do Da Line

[trees4life]

Ok all of you experts... Im installing a zip line that will take you from zero to terminal velocity in 4.2 seconds. Question is I would like to stop before I hit the other tree without putting a tremendous amount of shock load on the system, anyway the only two ways I can think of is a stopper knot(shock load to the pully, hardware, saddle) or a seperate line that runs along with you as your zipping along but is shorter the the one your one(Shock load) Any ideas how I can stop and avoid shock load?

 

[JesseHuffman]

I hope there will be video

 

[jim454]

Throw a line over the top of the zip line so that it crosses it. Tie it to two anchor points.

Does that make sense?

Actually there is a chance that the block could slide under the cross line, haven't had a problem with it though.

You may want to girth hitch a biner into the cross line and clip it to the zip line.

 

[JesseHuffman]

Jim, is that to change the trajectory of the line so its not so steep at the point where the lines cross?

 

[jim454]

It kind of works like a reverse sling shot.

Hmmmm......... just had a thought, but that could be kinda dangerous

 

[trees4life]

Thats funny...terminal velocity...agggghhhhhhh.......I see the whole the concept but have you actually used it??? If you anchored it with a dynamic line you would have the stretch to your advantage too. Sound like a start

 

[easyphloem]

I saw a home-made zip line today that had a pretty creative braking system, which could be modified to a larger scale.


The zip line was steel cable, and it ran about 70 feet or so. At about 15 feet from the terminal anchor point on a tree, a small rubber tire was bisected by the zip line cable (the cable going through the middle of the tread). The tire was secured to a bungee type rope running perpendicular to the zip line cable.

As the pulley runs down the cable, it hits the tire, compresses the rubber and the bungee rope absorbs the rest of the force.


Pretty cool, and I should have taken a picture. I hope I described it clearly.


SZ

 

[jim454]

trees4life,

Yes, I have.

Hopefuly tophopper will chime in on this one, we set up a 500 ft zip line off a cliff, maybe it was 300 ft. Did that years ago and can't quite remember what we used for a brake.

I have used the system I wrote about on smaller set ups though, worked fine.

 

[SumoClimber]

I've made a few zip lines in the past, with the boy scouts. The best brake I've found used bungee cords, a steel rigging ring, and a Dog's kong chewtoy. Setup was pretty similar to what easy did with the tire. The bungee cords connected to the rigging ring and the kong (large, black, 6.5" model) rested on the rigging ring. The zip line was threaded through the center of the kong/ring assembly. The rubber kong toy provided some compressible cushion, and the stretch of the bungees provided the braking.

[link]
http://www.petsmart.com/product/index.jsp?productId=2750604#prodTab1[/link]

 

[JesseHuffman]

What kind of bungees are safe to use for something like this?

 

[trees4life]

I think that by the time I want to start coming to a stop Ill have hit mach 5. I was thinking last night that any other type of brake system that stretches has the potential of snapping at that speed. I wouldn't want to be in the way of a line, bungee or anything else when it snaps under that kind of pressure.

 

[trees4life]

I guess we would be talking about some professional grade bungees.

 

[JesseHuffman]

ok ok, I will google it myself. such a hassle.