RADS Theoretical Ratio

Yes there are only four legs but if you take the spliced end of the climbing line and pull the line with the piggy backed pulley and pull it over the limb and down and fix it to the climber there are now 6 legs.


It was just a technique i was playing around with to eliminate the piggyback and make it into a simple pulley system which could be easily analyzed. Then there are six lines. 6:1 MA for the climber. You see what I am saying?
 
I'm sorry treebing, I must have missed your original description of what you set up.

Still not real clear what the set up looks like, but if you are absolutely sure the system is a simple pulley system, by the definition of a simple pulley system, then counting the lines supporting the load will give an accurate MA.

I probably got an inaccurate image of what you were doing. I took the 'piggyback' to mean you had a DdRT (a 2:1) and installed a 3:1 on the pull line of the DdRT. That's a compound system.

In any event, I'm fully convinced what you're claiming is 100% correct.

Oh, I meant to mention, I noticed the RW in your vid. I have an application that I believe it is just about the perfect solution to. I'm gonna have to get a RW one of these days and give it a try.
 
What Im trying to describe is just a way to analyze a compound system physically. It shows how the system multiplies out and though what appears to have only four lines really has six lines acting on the climber. Nothing more than a way to physically see what is going on in a the system and how to easily switch a compound system into a simple system by just moving the pulley back across the limb (or through pulleys) and attaching it directly to the load.
 
Ron, as usual your series on pulley systems is outstanding.
It occurred to me while watching them that maybe someone could persuade you to do a stand-alone video on the RADS configuration and why it can be both a 3:1 or a 2:1 pulled to advantage.
Your presentation effectiveness, both visual and oral, are second to none. It is quite possible, that you are the only one capable of shining the light of understanding.

Obi-Wan, you are our only hope.

Dave
 
OK, Dave, you're embarrassing me.
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, but thanks for the kind words - not so sure I deserve them but I do appreciate it.

I had the thought on the way to work this morning that a RADS analysis might be good, so with your encouragement, I'll try to get that done this weekend.

But it's not just the RADS that behaves differently to the climber and to a ground person - ALL systems will exhibit that change in MA between a ground referenced 'hauler' and climber referenced.
 
[ QUOTE ]
...But it's not just the RADS that behaves differently to the climber and to a ground person - ALL systems will exhibit that change in MA between a ground referenced 'hauler' and climber referenced.

[/ QUOTE ]

Thanks, Ron. We will all be waiting in eager anticipation!

I quoted your last paragraph for emphasis so that those that state it "makes no difference" who is doing the pulling can ponder the meaning of what you said.

Dave
 
[ QUOTE ]
[ QUOTE ]
...But it's not just the RADS that behaves differently to the climber and to a ground person - ALL systems will exhibit that change in MA between a ground referenced 'hauler' and climber referenced.

[/ QUOTE ]

Thanks, Ron. We will all be waiting in eager anticipation!

I quoted your last paragraph for emphasis so that those that state it "makes no difference" who is doing the pulling can ponder the meaning of what you said.

Dave

[/ QUOTE ]

Dave, please dont take what I said out of context.

In regards to output, effort (MA) or whatever you want to call it I did not say at any point that it 'makes no difference', quite the contrary in fact. But it is just so that I do not agree with the way certain mechanical concepts are worded....like the traditional double rope technique i.e the advantage is there for sure, but for there to be a suggestion that a climber pulls down 2 foot of a straight up and down line only to gain one foot of lift is nuts.

Where did the other foot go?

I can understand how a person might feel like he's pulling 2 feet by watching his pulling motion relative to his body, but that doesn't make it true.

You guys are clearly passionate about your climbing which is great, but thats no reason to get prickly about it when someone else has a different take on things.
 
I believe all this confusion stems from people using different reference points to measure the amount of rope being pulled. In drt you pull 2 feet of rope past yourself to go up one foot while you only pull down 1 foot in reference to the tree. With the RADS you pull 3 feet past yourself to move 1 foot and 1.5 feet of rope moves down the tree. Thats my take on it anyway!
 
I would say measure the amount of rope that passes through your friction hitch in order to move one foot in ddrt. That is how much rope you have to pull.
 
I agree treebing for DRT but that wont work with RADS will it? I believe if we use the climber as a reference point it will best illistrate the MA in the system as long as the climber is doing the hauling
 
[ QUOTE ]
... But it is just so that I do not agree with the way certain mechanical concepts are worded....like the traditional double rope technique i.e the advantage is there for sure, but for there to be a suggestion that a climber pulls down 2 foot of a straight up and down line only to gain one foot of lift is nuts.

Where did the other foot go?

[/ QUOTE ]

Reg, that quote was not directed at you but it is relevant. The points of rope measurement are not random and help define just what is going on. Let me try a different example than the 2 foot 1 foot thing to try and put rope "used" in perspective.

OK, a pulley is attached at the 25' mark with 50' of rope run through it. Both ends on the ground. If a worker ties a load to one side and hauls it up to the 25'high pulley he will have pulled only 25' of rope. The load will be 25' higher but there will still be 25' of rope coming down to the worker holding the load.

Now, you tie yourself to one end of the rope and start hauling yourself up. By the time you reach the top you will have pulled the entire 50' of rope.

This is not being "prickly" it is just the way it is. It is where the other foot went.

Dave
 
So I am 10ft off the ground doing my DRT acsent, with each pull one extra foot of rope hits the ground from my tail. Then my groundworker starts pulling on the tail to help me out, we are working in sync with each other. one foot of new tail hits the ground with every pull. More rope is passing my body than his as a result of my body travelling upwards at an equal rate/reaction to my arms pulling down, obviously....but for each foot that flakes on the ground I gain a foot up the tree, irespective of whether he, I or both of us are pulling at the same time.
 
Dave we must have been writting at the same time. Willy said it, we are using different references.... you prefer yours, I prefer mine. Its all good.

And I wasn't suggesting anyone had been prickly with me personally.
 
[ QUOTE ]
...but for each foot that flakes on the ground I gain a foot up the tree,...

[/ QUOTE ]

No,Reg. That is not correct.

Dave
 
[ QUOTE ]
[ QUOTE ]
...but for each foot that flakes on the ground I gain a foot up the tree,...

[/ QUOTE ]

No,Reg. That is not correct.

Dave

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I'm stood on the ground with one hand on each end of the line, my hands are both level at 4 feet. I a pull down 1 ft with my right hand so it now at 3 ft, my left hand is now at 5 ft, no?
 
I am sorry my friend, you are indeed correct. My bad.
blush.gif
For every one foot you go up there will be one foot flaked on the ground.

But does not my explanation on the 25' TIP using a full 50' of rope to reach not explain why we say it uses 2 feet rope for every one foot of rise.

Dave

PS. I think I am not awake enough for clear thought
 
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