SeanKroll
Treehouser
Are you differentiating between 1000 pounds of static weight, and the force of catching something that weighs 1000 of static weight?
The Art and Science of Practical Rigging vs. TCIA Best Practices for Rigging in Arboriculture.
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theTreeSpyder
TreeHouser
- Joined
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YES
E=MCsquared.
M is the amount to take from static to dynamic, the static weight.
Csquared is the speed squared a geometric expansion by comparison.
I reached view naming cuz in parallel in electric force
Watts total power = resistance to get past statically X amps(speed once again) squared.
Same formulae from that view! Force is force, same rule just expressed in physical, then electrical languages..
.
Rule of thumb is 1unit for static, lift 1' and drop 1' is 2units force.
Starts not being so accurate about 8-10' when starts picking up speed more and speed squared leaves thumbrule behind.
1000# drop 3' look for 4000 total etc.
Higher SWL ratio is a macho strength, but loses the softer(feminine?) elastic response in trade.
>> even if put pulley on load as 2/1 for greater SWL, drops elastic dampening.
i look at everything as having a Goldilocks rule of too little or much or in the powerband of just right for the shituation, hard to paint all the way across with just 1sided rule.
.
TrueBlue very long wearing, i think Samathane coating some trick stuff!
Very solid, good knotting rope.
12 strand very Nubby easier hand grab, not as smooth thru friction hitch so not as fast, perhaps beginner climber rope for that. Rounder 16 then 24 strands rounder like stop sign rounder than square, and flows thru friction hitch smoother for that to me.
.
i try to throw minimal examples.
i try to keep it light, is very key, always figure some brains shut down on this as mine once did.
i do have own modelled views as tree guy, and personal wonder of it all.
Step-son has Master's in Engineering and sent many questions with him to school over time..
i have to cross verify everything from different aspects, to fit inside something larger.
Will start other thread, been always meaning to..will expect questions
.
To me cos/sin are measuring tapes/sticks and tan the ratio between.
To me cos is measurement of 1D inline alignment of minimal distance as a benchmark.
sin as the deflection from that benchmark
If no potential to be inline nor deflected, then is not connected to scenario.
>> therefore cos/sin covers whole scenario.
.
Quite fairly whole books and series, courses dedicated to this.
Euclid's Elements was quoted by some as 2nd most published book for millenniums.
Best description of yoga studied is that yoga traces (mostly) the animate stages of existence.
Giving back, awakening things lost in suppleness as snake, swan, cat etc. by assuming same postures stretches etc. in quietness lending to other things coming across so. Some inanimates named as asanas too but usually of things of deeper meaning in that culture like lotus, mountain, tree, wheel, boat etc.
Scouting etc. to me would/should give similar aspect of path walking for yes as Gary notes lessons beyond transference by writing etc. Martial Arts, gymnastics , tree work etc. can be seen as pushing self over edge to find what it takes to flip the binary from can't to can, to find way thru even when exhausted etc. find place to reach down into empty bucket and come back with something repetitively in series. Team sports replace wars etc. to run etc. as the strongest w/o killing the strongest, but all the same path to better.
E=MCsquared.
M is the amount to take from static to dynamic, the static weight.
Csquared is the speed squared a geometric expansion by comparison.
I reached view naming cuz in parallel in electric force
Watts total power = resistance to get past statically X amps(speed once again) squared.
Same formulae from that view! Force is force, same rule just expressed in physical, then electrical languages..
.
Rule of thumb is 1unit for static, lift 1' and drop 1' is 2units force.
Starts not being so accurate about 8-10' when starts picking up speed more and speed squared leaves thumbrule behind.
1000# drop 3' look for 4000 total etc.
Higher SWL ratio is a macho strength, but loses the softer(feminine?) elastic response in trade.
>> even if put pulley on load as 2/1 for greater SWL, drops elastic dampening.
i look at everything as having a Goldilocks rule of too little or much or in the powerband of just right for the shituation, hard to paint all the way across with just 1sided rule.
.
TrueBlue very long wearing, i think Samathane coating some trick stuff!
Very solid, good knotting rope.
12 strand very Nubby easier hand grab, not as smooth thru friction hitch so not as fast, perhaps beginner climber rope for that. Rounder 16 then 24 strands rounder like stop sign rounder than square, and flows thru friction hitch smoother for that to me.
.
Scratched head on this very long time,
i try to throw minimal examples.
i try to keep it light, is very key, always figure some brains shut down on this as mine once did.
i do have own modelled views as tree guy, and personal wonder of it all.
Step-son has Master's in Engineering and sent many questions with him to school over time..
i have to cross verify everything from different aspects, to fit inside something larger.
Will start other thread, been always meaning to..will expect questions
.
To me cos/sin are measuring tapes/sticks and tan the ratio between.
To me cos is measurement of 1D inline alignment of minimal distance as a benchmark.
sin as the deflection from that benchmark
If no potential to be inline nor deflected, then is not connected to scenario.
>> therefore cos/sin covers whole scenario.
.
Quite fairly whole books and series, courses dedicated to this.
Euclid's Elements was quoted by some as 2nd most published book for millenniums.
Best description of yoga studied is that yoga traces (mostly) the animate stages of existence.
Giving back, awakening things lost in suppleness as snake, swan, cat etc. by assuming same postures stretches etc. in quietness lending to other things coming across so. Some inanimates named as asanas too but usually of things of deeper meaning in that culture like lotus, mountain, tree, wheel, boat etc.
Scouting etc. to me would/should give similar aspect of path walking for yes as Gary notes lessons beyond transference by writing etc. Martial Arts, gymnastics , tree work etc. can be seen as pushing self over edge to find what it takes to flip the binary from can't to can, to find way thru even when exhausted etc. find place to reach down into empty bucket and come back with something repetitively in series. Team sports replace wars etc. to run etc. as the strongest w/o killing the strongest, but all the same path to better.
Last edited:
Kenny,
"Rule of thumb is 1unit for static, lift 1' and drop 1' is 2units force."
I humbly submit that do the catch on undersized rope and the slowdown is slow with smaller force, do the catch on a stout chain and the stop force spike is huge. How the motion is stopped completely affects the answer.
It perhaps shouldn't be perpetuated in so simple form as a rule of thumb with any meaning. It may also have been debunked in the HSE report.
A more meaningful version has been posted by me previously. The distance the log CofG falls = distance over which a constant braking force is applied to stop the downward motion, that force will be 2G's at the log attachment point to the rope. 1.20 tension ratio going over the rig pulley, 83% tension in the down rope leg means 2G + 0.83 x 2G in the down leg = 3.66G load on the rig pulley tip. Intuitive baseline based in physics and measurements.
Always appreciate your writings
By the way, 1.0/0.83 = 1.20, that's where 83% came from
"Rule of thumb is 1unit for static, lift 1' and drop 1' is 2units force."
I humbly submit that do the catch on undersized rope and the slowdown is slow with smaller force, do the catch on a stout chain and the stop force spike is huge. How the motion is stopped completely affects the answer.
It perhaps shouldn't be perpetuated in so simple form as a rule of thumb with any meaning. It may also have been debunked in the HSE report.
A more meaningful version has been posted by me previously. The distance the log CofG falls = distance over which a constant braking force is applied to stop the downward motion, that force will be 2G's at the log attachment point to the rope. 1.20 tension ratio going over the rig pulley, 83% tension in the down rope leg means 2G + 0.83 x 2G in the down leg = 3.66G load on the rig pulley tip. Intuitive baseline based in physics and measurements.
Always appreciate your writings
By the way, 1.0/0.83 = 1.20, that's where 83% came from
murphy4trees
TreeHouser
then of course when taking over a large top with foliage, you need to calculate wind resistance..Kenny,
"Rule of thumb is 1unit for static, lift 1' and drop 1' is 2units force."
I humbly submit that do the catch on undersized rope and the slowdown is slow with smaller force, do the catch on a stout chain and the stop force spike is huge. How the motion is stopped completely affects the answer.
It perhaps shouldn't be perpetuated in so simple form as a rule of thumb with any meaning. It may also have been debunked in the HSE report.
A more meaningful version has been posted by me previously. The distance the log CofG falls = distance over which a constant braking force is applied to stop the downward motion, that force will be 2G's at the log attachment point to the rope. 1.20 tension ratio going over the rig pulley, 83% tension in the down rope leg means 2G + 0.83 x 2G in the down leg = 3.66G load on the rig pulley tip. Intuitive baseline based in physics and measurements.
Always appreciate your writings
By the way, 1.0/0.83 = 1.20, that's where 83% came from
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