Adjustable Daisy: Bad math, wild gyrations, and no answer?

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deuce4

Big Wall climber

the Southwest

Aug 27, 2005 - 04:02pm PT

Well, from Russ's second test, then clearly, using the adjustable daisy means more work to get yourself up each foot of vertical travel. Obviously ridiculous in the case of using the daisy only to gain vertical. There would be some chance of interesting calculations if the opposing force was less than twice the load, but not in this case of exceesive added frictional forces from the cam buckle.

If you wanted to follow in Pete's aiders, so to speak, you would want some sort of hauling pulley instead of a narrow edged cam buckle. It might begin to make sense if the opposing load was on the order of 110lbs to pull 100 lbs., due to the human efficiency of pulling smaller loads as opposed to one big load.

The reality is that Pete is also pushing up with his feet in the aiders. If he pushes up completely with his feet, the "2:1" daisy wouldn't affect any energy calculations, only in the ease of shortening the daisy. So the percentage mix would have to be figured.

In any case, the mechanical advantage of the daisy appears to be completely eliminated by the frictional forces, if we are to trust Russ's data, and the only way it can be helping is that the immediate anchoring of the adjustable daisy may be saving some energy.

that is all.

ps: check out this link for some data on pulleys:
http://oberon.ses.nsw.gov.au/resources/Vertical%20Rescue%20Friction%20Testing.pdf

mark miller

Social climber

Reno

Aug 27, 2005 - 04:46pm PT

Sometimes you just have to believe, can you prove the tooth fairy? No, but I always had a quarter under my pillow. Can you prove Santa Claus? No, but there where always gifts on Christmas morning. Can you disprove the effectiveness of adj. daisys? Well it appears so but I still like them.
I wonder if you used a petzel traxion( not the mini) with the larger pulley and a peice of cord tied to your waste if the reduction in drag would make it a viable alternative to the adj.daisy. Your carrying the pulley with you anyways. That cord could be part of your "zed" line 3 to 1 hauling system also. This Idea needs some fine tuning but it could be a better way. Problem 1.. do you carry 2 traxions or improvise something else. Problem 2 can you release the traxion under a load.ie. you sucked all the 'daisy' in and have to high step and extend your daisy to reach that next Gerberding rivet 8' away.

Ed Hartouni

Trad climber

Livermore, CA

Aug 27, 2005 - 05:07pm PT

yikes, saving energy isn't the same thing as gaining mechanical advantage...

the minimum energy you will expend going up something is just E=mgh, where m is the mass you are lifting, h is the distance you lift it and g is the gravitational constant. Divide this by the efficiency and you get the total energy...

...if you use some mechanical contrivence to lift then you are probably going to suffer in the efficiency department... e.g. friction creates heat which disipates energy, you loose it to your mechanical task at hand: lifting. At best you can brake even (2nd law of thermodynamics) but in practice efficiencies of 30% are very good... most devices are much less.

As far as I can see, the adjustable daisy is being used as a sort of ratchet, with the difference between the static and dynamic coefficients of friction providing the ratchet action.

Karl Baba

Trad climber

Yosemite, Ca

Aug 27, 2005 - 05:34pm PT

Oh the humanity!

Math and physics geek threads always manage to prove something that's plainly not true in practical experience.

First of all, one thing that the Fish line tests don't replicate is that when you pull on one end of an adjustable daisy, you are taking weight off the load end at the same time you are applying force on the pull end. Russ's test keep the weight being pulled up the same.

But also, nobody is actually advocating that you should pull yourself up El Cap by arm-hauling yourself up with an adjustable daisy. Let's say you use them in basically the same way as you would use a pocketed daisy, only they have the following advantages:

1. You can immediately and with one hand cinch yourself up to the high point that you've climbed in your aiders instead of fiddling to clip a biner or fifi to find approximately that high point.

2. If you need to let slack out on the daisy, at least with the Yates system, you just push the button instead of having to unweight yourself enough to unclip. You are also able to let yourself out gradually rather than cut loose.

3. If you placed your next piece very high, and can't reach it to clip with your aiders, it is possible to rachet yourself up into stricking distance by clipping your aiders to the ring at the pull end of the adjustable daisy. You won't find any more questions regarding the "mechanical advantage vs distance traveled upwards" once you try this. It's pretty obvious that it's far easier than climbing your aiders straightway but that you have to climb twice as far to get the same upward travel.

I only recommend this once in awhile for convenience to reach the piece. If you do it all the time, you'll wear your daisy out.

But nobody is going to calculate how much energy is saved or lost in a wall by using adjustable daisies any more than you could figure out how much extra energy would be required if you jammed thumb down all the time versus thumbs up. It's an indefinable and cumulative gain or loss depending on the efficiency of your total technique and judgement about how and when to use your gear

peace

Karl

deuce4

Big Wall climber

the Southwest

Aug 27, 2005 - 06:09pm PT

Karl, you're right in the fact that the whole theoretical aspect becomes kind of moot. Somewhat of an interesting analysis, but in the end, it just comes down to personal preference and if you don't mind resetting an adjustable daisy a thousand times per route.

Shack

Social climber

So. Cal.

Aug 27, 2005 - 06:54pm PT

Karl, you hit the nail on the head with every point.
Once you use adjustables on overhanging rock,
the benefits become glaringly obvious.

Ed Hartouni

Trad climber

Livermore, CA

Aug 27, 2005 - 07:19pm PT

Karl, with all due respect, Fish was asking about the forces, efficiencies and such... you provided a "good old practical American" response... complete with the cultural disdain for any higher understanding then "it works".

Sort of like the old gold panning 49er's who didn't much believe that geology or geologists had anything to do with finding gold...

Perhaps Chris should also ban any explanation which deviates from "common wisdom" so that we can avoid flaming each other as either ignorant hicks or over-educated idiots....

Ed Hartouni

Trad climber

Livermore, CA

Aug 27, 2005 - 07:24pm PT

that really is funny klaus....

Karl Baba

Trad climber

Yosemite, Ca

Aug 27, 2005 - 07:27pm PT

Daisies have a lot of uses besides resting. Like saving your gear and aiders when the piece that you haven't clipped rips.

But Ed, I appreciate what Russ went out and did. He is the freakin greatest.

But his test was totally screwed up up because it doesn't account for the aspect of losing weight on one side as force is applied by the counterweight itself, rather than by weights added on the other side. Get it?

Peace

karl

Shack

Social climber

So. Cal.

Aug 27, 2005 - 08:08pm PT

Chris!!!...
Klaus infered that were homos for using adjustable daisies!
Ban him!!!Ban Him!!!

Just kidding! hehe

deuce4

Big Wall climber

the Southwest

Aug 27, 2005 - 08:29pm PT

Actually, Fish's test does show that it requires 250 pounds of force to lift a 100 pounds through an adjustable daisy. The fact that in typical use the weight is distributed through pushing up with your feet (with no mechanical advantage there) just emphasizes that most of the work is done the traditional way, by a combination of stepping and pulling your own weight, without much mechanical advantage. The argument about the weight on the other side of the "pulley system" lessening is a non-issue, from an ideal-world mechanical perspective. It's not like your mass suddenly decreases.

In short, if it was a more efficient pulley, there could be some advantages in the 2:1 system in terms of effort.

In terms of the preference factor, thinking of all the thrashing I've done on overhangs, I can see the benefit there, but still prefer regular moving like a butterfly dancing in my aiders (yeah, right) with regular (simpler) daisies on general vertical.

On a side note, sorry to see you go, Klaus..

Shack

Social climber

So. Cal.

Aug 27, 2005 - 08:38pm PT

Sport climbers have rights too!
Bwahahahahahaha!!!

Chris...
It's probably already too late but,
please don't ban Klaus, that was too funny!!!!

Karl Baba

Trad climber

Yosemite, Ca

Aug 27, 2005 - 09:56pm PT

Deuce wrote:

"The argument about the weight on the other side of the "pulley system" lessening is a non-issue, from an ideal-world mechanical perspective. It's not like your mass suddenly decreases."

But I believe you're wrong, you're weight on the load side does decrease. If I pull down 100 lbs on the far side, my weight at the load side on the system decreases by 100 lbs minus friction.

Try this, hang on an adjustable daisy and try to pull yourself up just using your arms on the far side. Now reset, hang in your daisy and let somebody else try to pull you up using their arms. HUGE difference

Peace

Karl

ChrisW

Trad climber

boulder, co

Aug 27, 2005 - 10:01pm PT

I agree with Klaus.

Adjustable daisys rule and I am a wuss.

Russ Walling

Social climber

This space for rent.

Topic Author's Reply - Aug 27, 2005 - 11:22pm PT

I hate to reiterate, but here is what Russ was really saying. It is in the first post that sent PTPP over the side.

Nutshell: Pete says adjsutable daisys are 2:1.

I say, they ain't 1:1, but they sure ain't 2:1.

Pete bases his on pure numerical theory, and is correct. I sorta knew the theory, and also knew the real world. I guessed you would never get a real 2:1 out of the things. I also said most of the magic is due to gyrations and such, which of course is standing up, moving weight from side to side and applying a downward pull. I also said then that with these "gyrations" you could effectively make the friction at the buckle near zero. Because you have stood up, arched your body in and pulled on the free end there is no real weight on your side anymore. Or you are pulling on an object (your standing up body) that is already in motion.

So, back to what Russ was really saying: It ain't 2:1 except on paper, and it ain't 1:1. As my everyman tests showed to me at least, it seems to be 1.266 : 1 if you are just sitting there and pulling your fat ass up.

Seems good to me. But to flat out say you get a 2:1 mechanical advantage with an adjustable daisy is misleading and wrong, because we don't live on paper.