Other Limiting rope new version??

EXPERIMENTAL

EXPERIMENTAL

PROTOTYPES WELCOMED
Location
Jefferson City, MO
i am making a limiting rope and i finished one end. i was going to measure how long to make it, so i took it back to my dads house (where my SJ is). i showed my dad and he liked it, but he also asked me a question that got me thinking. He thought the whole rope was supposed to be made out of bungee rope material. I told him no, only the part that attaches at the base of the pole to keep things neat and tidy was supposed to be a bungee.

I left the house and went to work, which was rather slow tonight, and was thinking to myself (and being an engineer) if the whole rope was made out of bungee material, when it came time to be put to use, the bungee cord would actually be better.

with simple mechanics to back my thinking, force = mass x (velocity / time). the bungee would allow the force on your pole to react with a longer time span, thus reducing the total force applied to your pole. this could actually be a small difference that saves your pole, plus with this design you would have less stress applied to your attachment points. this would also reduce the risk (in a very serious crash) of possibly ripping your eye bolts or fracturing the fiberglass area from either the pole or "dash"

Im not trying to get technical with a simple question, but has anyone ever tried making a limiting rope with all bungee material?? does it work? is it better?

like i said, i just got bored.....let me know
 
EXPERIMENTAL

EXPERIMENTAL

PROTOTYPES WELCOMED
Location
Jefferson City, MO
for example

scenario #1: you weight 200lb, you wreck at 10 ft/sec, and it takes .5 sec for your standard nylon limiting rope to take all the force away from your pole.
F=200lb*((10ft/sec)/(.5sec))=4000 ((lb*ft)/sec^2)

scenario #2: you still weight 200 lb (imagine that), you wreck again (unfortunately) at 10 ft/sec, but this time you have your bungee limiting rope, and it takes 1 sec. for your new rope to absorb all the force away from your pole
F=200lb*((10ft/sec)/(1sec))=2000 ((lb*ft)/sec^2)

this is only made up example, but results could be more or less (haven't studied properties of bungee material), but you can see how even a small amount of time like .5 sec more could half your total force applied to your rope/hardware/fiberglass
 
1

1eyedjim

Location
Solihull, UK
i can see this working so long as the max length of the bungee is no longer than the max length of normal limiting rope and that the breaking strain is the same, its a good idea if bungee is strong enough
 
the WaTeRhAwK

the WaTeRhAwK

fryin' up a/m electrics..
Location
okc
bungee sux for a limiting strap.
if you get it short enough to be effective it becomes too much of a strain to hold up, which pretty much defeats the purpose of a pole spring.

also, when the pole flys forward and stretches the bungee, it will cause the pole to snap back to the hood with too much force, usually cracking and/or breaking something.
 
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The Penguin

The Penguin

triple secret probation
Location
down by the river
the WaTeRhAwK said:
bungee sux for a limiting strap.
if you get it short enough to be effective it becomes too much of a strain to hold up, which pretty much defeats the purpose of a pole spring.

also, when the pole flys forward and stretches the bungee, it will cause the pole to snap back to the hood with too much force, usually cracking and/or breaking something.
Click to expand...
ding ding ding

plus - to have enough tensile strength in the bungee to prevent it from breaking due to the energy of the crash - it would probable be too thick to handle easily - and add weight to the pole.

I use a 1/8" Amsteel rope for my limiting rope.
 
snowxr

snowxr

V watch your daughters V
Location
Waterford, MI
The limiter should not be a bungee of any kind. The bungee tensioner should be tight enough that it stretches and reduces shock as the pole extends.
 
EXPERIMENTAL

EXPERIMENTAL

PROTOTYPES WELCOMED
Location
Jefferson City, MO
the WaTeRhAwK said:
bungee sux for a limiting strap.
if you get it short enough to be effective it becomes too much of a strain to hold up, which pretty much defeats the purpose of a pole spring.

also, when the pole flys forward and stretches the bungee, it will cause the pole to snap back to the hood with too much force, usually cracking and/or breaking something.
Click to expand...


like i said guys, it was only an idea, and obviously i was only thinking of the goods, and didn't even think about that aftermath of the pole reacting to the bungee. i can see now although it sounded good on paper (and in my mind) it doesn't actually work. maybe a little stretch would be good, but not as much as bungee has. thanks for the replies and not ripping me to hard
 
Cannibal

Cannibal

Tasty Human
Location
Summit Lake, WA
I have thought about this as well. What I wanted to do was build a rope with a bungee inside hollow rope. Basically you'd have a shock absorbing rope that has a finite limit, which a bugee does not.
 
Waternut

Waternut

Customizing addict
Location
Macon, GA
I've over stretched a yellow nylon rope over the course of a season before but honestly, I don't think the rope will see anything close to 2000lbs. The caribeaner that we all use on the ends of the rope are typically the weakest link. On a side note, the bungee that goes between the pole base and the middle of the limiting rope does help dampen the load to a degree.

It's always good to hear of people trying to improve the sport so don't take any criticism personally.
 
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