who needs a winch (hard lean tale)

Dan Cobb said:
An Omni Block 1.5 with 11mm Bluewater tests at 93.2% efficiency in a 2:1. The make/model pulleys used and the stretch of the rope have significant bearing on how far actual MA deviates from theoretical. In general, complex systems provide better real world efficiency than simple systems. Just another reason I like the z-rig.
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Is that overall efficiency, as in 2:1 was actually 1.86:1? or were they referencing the efficiency of just the pulley?
 
Tension loss "efficiency" is always a function of both rope and pulley and angle traversed. I suspect the unknown model of Bluewater rope is a parallel lay core static line, not bending a braided or other core. 1 / .932 = 1.07 or basically 1.1 in rough numbers. The only two quantities to test are the tension on each side of the pulley, so the "efficiency" is just the tension ratio. I prefer numbers greater than 1 for easy math. 100 lbs, 107 lbs etc. My 1.2 tension ratio was across multiple arborist rope types.

My measurements were taken during motion to guarantee not undermeasuring the tension difference. I actually started the jig measuring friction. Just stopping makes the analysis indeterminate as microscopic motion can send you to equal tensions. We're talking stretch of a relatively short piece of rope. Reversing direction reverses the tension ratio after the rope starts moving. Taking points off a time recording gets rid of possible procedure errors and the consistently present ratio of forces in a single data run lead me to just adopt tension ratio, because that's what occurred. Now that the bee's in my bonnet, go read the basal SRT tip loading thread.

As for n-1, well. three pulleys each side = 6 pulleys pick either side, there's six tension lines to add up and the initial pull gets nuked around 6 bends. Seems right? The math sum formula was a look up. It's for n terms, seems similar on different web pages. Maybe practically you can't make 6:1, just 5:1 etc. 6 was arbitrarily chosen.

The biggest insight was the you can't get arbitrarily large mechanical advantage because tension loss progressively negates it. And you can know the actual value beforehand.

edit - apologies for being grumpy, bit of a bad day. I think I figured out the Bluewater anomaly. Add the two rope tensions 1.0 + 0.83 = 1.83, divide by 2 because you're expecting 2:1 -on the pulley anchor- 1.83/2= .915 or 92% system "efficiency" so the bluewater rope behaved as expected with a tension ratio of 1.2. Overall system tension losses for higher number of pulleys could be similarly reformulated. The term efficiency still makes me think of gas mileage ;)
 
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Flushcut, Are the ground anchors you can't wiggle with your mini the amon eye auger lookin things? just curious how beefy they are and what they look like? how easy are they to set... honestly, just curious
 
Stakes and pickets. Lay a stake on the ground pound in two more stakes at a 45 and tie back the top of that stake to another deadman and pound in two more stakes and repeat.
 
As the POTENTENTIAL for builds gradually in single increments, so then the inefficiency of the frictions compound at a greater rate of building against(but from Zer0). Still the inverse of the potential is needed in distance, no break there. So if 5x potential actual yield is 2.9xEffort, it still cost$ 5xDistance for input. Rotational leverage builds in multipliers of length, linear leverage(pulleys) build more nominally in the amount of lengths used to the needed length type ratio(n) instead, much more incrementally, than a multiplier for rotational leverage, then so certainly much less than COMPOUNDING frictions around pulley as a low friction capstan arc. In the end, rotational or linear leverage just exchanges distance for power less inefficiency.
But have found other trick, sitting hours in DdRT, and the 2:1 over self, less friction magic,
SaveForces_4.png

.....by even more so conserving all forces spent to be against target even more. As see above, distilled that single principle out to carry with and play it against other challenges in then even rigid or round leveraging.
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If take bodyweight out would only be left with Equal & Opposite against, so i try to do that, to dual opposing direction outputs, and add bodyweight back then against target, for more from same!
i imagine if standing on a scale, how to be as weightless as possible to the ground
(easiest for over head pull down), and then exert effort when that effort can't add nor subtract to/against bodyweight to ground(unless added handhold as shown above). All pulls directly against load(if any) are friction free then, or reduced per their position etc. As POTENTIAL increases, so does input distance, so may use normal 1 hand mode to chase out slack, then transmission switch to lower gear of more powerful 2 handing the system. i imagine some kind of go to lift legs up hard purposefully, sudden impact pulse to system, perhaps sliding wide for stability, maybe cheat to only 10-20# bodyweight on ground for stability like some kind of sudden, high impact, martial arts move, and then doing the equal/opposite opposings thru hands at same time, against 'opponent'/load.
GAME CHANGER: can be as 2nd man pulling at lesser point; within same system. As if standing at a lower leveraged input on lever to help against load fo' FREE!.
Different_ways_of_handing_a_pulley_system_to_get_different_outputs.png

The idea extends then to not arm lift as input, but leg propulsion as input instead, to really get 'jump' on it. Still receive the equal/opposite of leg input at a hand position as secondary/lesser input position.
Even to 45 degree pull etc. try to invoke as much bodyweight as possible against target, plus pulls of opposing hands at leveraged distance apart. If pull with 1 hand, the equal and opposite added to or subtracted from is bodyweight.
These also give a more flexible usage of 2 part input system, one part can hold , the other impact, both impact or 1 impact and other keep motion going etc. A multi system to orchestrate, rather than mono.
Then for tiedowns, or tweak last lil'lift or perhaps a last input:
We have made the system iron bar tight as possible LINEARILY.
Next tighter is to then bend those iron bars shearing across at 90degrees, for the tighter they are, the more/less rubbery leveraged return from the purposeful bend of sweat/swig w/o the 'purchase' (olds-cool sailor speak)of line from the loaded bank to the unloaded bank of rope; thus removing rope from the loaded system to stretch rope and/or move target load..
Anchor 1 side of rope, over motor cycle handlebar and back down to a 5x1 can give POTENTIAL 10x if legs parallel, but also can sweat/swig some over handlebar, pinch to bar, hyper tighten more, then bend centers of over bar ropes towards each other some from their centers Then do other side, looking to compress shocks to either side/if any for softer ride. Such tie downs can bend some lighter metal parts/skins. Then secure rear of bike similarly with just 1 rope(2 in front on handlebar); a chess game with just a few pieces. Like gymnastics etc. something you study and then force thru your own body to proper positions to pull of the trick.
1 co$t to note is that in these 'closed' systems BOTH non input system points are equal.
Where a 5x compersssion jig down, has 5x POTENTIAL against load, but only 4x against machine pivot postion.
Witht he tweak they are equal 8xEffort wise, then plus as the original 5xBodyweight against load and 4xBodyweight against



Picket Holdfasts:
(holdfast is old sailing term for immediate, rigid, iron strong, absolute 'bombpruf',unyielding anchor position and lashing/hold per anticipated loading).
US.mil Field Manual 5-125 is an excellent, bare bonz guide to many topics, including key anchoring(look for all these things to need a rigid 'ground' like electrical model, thus electrical ground schematic symbols in last pic above) connection to get power/light the rope with force as if wire! US.mil Field Manual 5-125 should be required reading to expand mind out of only tree mindset, to then come back to trees now deeper in own powerband of understanding of rawest workings.
Manual shows pickets (page_4-3 to 4-8 )at 45 degrees, then the high to low ropes at 90 to stake high towards load, low on next stake further away, tightened, then Spanish Burton/tourniquet type further tightening between stakes/stake plates to iron rigid. Guide goes into deadman's and numbers before going to small crane and gin poles, very good imagination stretcher for what are the real, minimal basics to watch for those that really start with much less of nothing and do magic.
Perhaps about the only place to see this nifty utility grade clean, quick release: Speir page_2-13 but figure_2-17 in their numbering.. From it have done 1" pipes as rollers to get hot top thru doorway etc. Any jewels seen on this short journey, that have to come back to and true up focus again as read again once same silhouette is sighted in field.
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edit fig_3-4 on page_3-5 is key model/reminder to me as also seen in ABoK ABoK Lesson# 3267+/pg.533: Mousing a Hook
Look at carabiner as a fancy moused hook, with only 1 solid leg to one side
After all the gate's weakest link tends to be a thin steel axle pulled not lengthwise to it's strongest axis, but rather cross wise against it's weakest axis.
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edit: absolute key(s)
pulley rolling lever is incremental additive of cos vals
rigid lever is multiplier of sine val
capstan frictions are compounding with cos+sine vals !
ALL displacements against space and/or force can be shown as cos/sine; even predict star movement and waveforms of wind, electric very accurately!!
Pulley and Capstan tools give us science of each extreme in the powerband shown
>>pulley is pulley theory + so much capstan
>>1 turn on capstan can likewise show capstan theory plus some pulley etc.
pulley and capstan are extremes, actuals in between inheriting some from each extreme border parent to the actual.
 
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I generally redirect from low on another tree as anchor, potential of 2 xTension, to high leveraged balanced pull to rigid part of target.
Then METER force from truck , not use all of overwhelming influence of truck. The low redirect has less leveraged pull against anchor AND prevents lifting up on rear traction of truck ad go forward. For pulling loads out likewise if truck run is half as much as needed, make like a 2/1 pull against truck from load. Truck will pull half as strong but 2x as fast, can really help up hills even where equipment not favored.
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Favor direction to target , to make hinge stronger, property lasts to tearoff. Tapered Hinge preferred against side lean.
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Rope/wedge force parts directionally against side lean do not make hinge stronger, nor last until tearoff. They do TEMPORARILY ballast against side lean until lifts from wedge and or rope tension relieves. At this point side force would seem to then impact back, so tree should be more at commitment speed i'd think.
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vs. Tapered forced stronger and lasting longer as hinge exercised stronger by false loading, and it in turn handling side lean. Thus I think can let go softer, not have to throw so hard into it to compensate for side force rebound not shown until tearoff.
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e=mcSQUARED ; the dynamic squared is the larger force, once speed gained, rushing forward train of inertia will want to maintain that direction; can help against the rebound of side force (d)effect I think. But Tapered would need lots less of that property until tearoff when fully expect commitment speed anyways. Also, look at feeding directly into lean as most severe potential of lean force forward, but less forward force if part of it is to the side.
 
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flushcut said:
Something similar to that. I remember, I think it was you, who posted a link to large/circus tent staking and anchoring video. That had some good info about using plates between the stakes, like your video. I didn’t watch it all.
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I've only ever used the ground anchor a few times, but sleep better at night knowing it is there when needed
 
Daniel said:
what do you haul equipment, wood and brush with etc?
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Equipment goes in my SUV. I generally don't haul wood and brush. I'm retired, not a full time tree worker. I rarely take jobs that require haul off. I may sub out haul off if the job is worthwhile or use my small trailer if it's minimal. "Just put it on the ground" are my favorite jobs. Many homes in my area have fully or partially wooded backyards large enough for debris disposal.
 
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