Predict the pull

LordFarkwad · Apr 10, 2023

correction: "back of the excel spreadsheet calculation"

Arb23 · Apr 10, 2023

Me> assume 80% efficiency in the pulley systems and output the force for each system in kN in table format
AI>
Sure, I can help you with that. Based on the efficiency of 80%, we need to adjust the previously calculated output forces accordingly. Here's a table that shows the adjusted output force for each system in kN:

Pulley System	Output Force (kg)	Efficiency	Adjusted Output Force (kN)
1	250	0.8	20.16
2	1,250	0.8	100.8
3	6,250	0.8	504.0
4	31,250	0.8	2,520.0
5	156,250	0.8	20,160.0
6	781,250	0.8	100,800.0

In this table, the "Output Force" column shows the output force calculated earlier for each pulley system in kg, the "Efficiency" column shows the assumed efficiency of 80%, and the "Adjusted Output Force" column shows the output force adjusted for efficiency in kN.

LordFarkwad · Apr 10, 2023

Arb23 said:
Me> assume 80% efficiency in the pulley systems and output the force for each system in kN in table format
AI>
Sure, I can help you with that. Based on the efficiency of 80%, we need to adjust the previously calculated output forces accordingly. Here's a table that shows the adjusted output force for each system in kN:

Pulley System Output Force (kg) Efficiency
Adjusted Output Force (kN)
1 250 0.8
20.16
2 1,250 0.8
100.8
3 6,250 0.8
504.0
4 31,250 0.8
2,520.0
5 156,250 0.8
20,160.0
6 781,250 0.8
100,800.0

In this table, the "Output Force" column shows the output force calculated earlier for each pulley system in kg, the "Efficiency" column shows the assumed efficiency of 80%, and the "Adjusted Output Force" column shows the output force adjusted for efficiency in kN.

That's assuming 80% efficiency in each system, not in each pulley sheave.

Arb23 · Apr 10, 2023

Wait...
Me> how did you calculate an adjusted output force of 100,800 kN from 781,250kg at 80% efficiency?
AI>
I apologize for the mistake in my previous message. The adjusted output force for the sixth pulley system should be 981.25 kN, not 100,800.0 kN.

To calculate the adjusted output force, we first need to convert the original output force from kg to N by multiplying it by 9.81 (acceleration due to gravity). So for the sixth pulley system, the original output force of 781,250 kg would be 7,659,375 N.

Then we apply the efficiency factor of 80% by multiplying the original output force by 0.8. This gives us an adjusted output force of:

7,659,375 N x 0.8 = 6,127,500 N

Finally, we convert this adjusted output force from N to kN by dividing by 1000:

6,127,500 N ÷ 1000 = 6,127.5 kN

So the adjusted output force for the sixth pulley system is actually 6,127.5 kN, not 100,800.0 kN as previously stated. I apologize for any confusion this may have caused.

--- This is still wrong...
Me> Recalculate each system - the values are not correct
AI>
You are correct. I apologize for the confusion. The adjusted output force for the fifth system should be 12,600 N, not 20,160.0 N.

And based on the corrected value for the fifth system, the adjusted output force for the sixth system should be 6,127.5 kN as previously calculated.

Here's the corrected table with the adjusted output forces for each pulley system:

Pulley System	Output Force (kg)	Efficiency	Adjusted Output Force (kN)
1	250	0.8	20.16
2	1,250	0.8	100.8
3	6,250	0.8	504.0
4	31,250	0.8	2,520.0
5	156,250	0.8	12,600.0
6	781,250	0.8	6,127.5

I hope this clears up any confusion.

Me> how can system 5 be higher than system 6?
AI>
I apologize for any confusion. You are correct, based on the mechanical advantage provided by each pulley system, the adjusted output force for the sixth system should be higher than the adjusted output force for the fifth system. This was my mistake.

Here's the corrected table with the adjusted output forces for each pulley system:

Pulley System	Output Force (kg)	Efficiency	Adjusted Output Force (kN)
1	250	0.8	20.16
2	1,250	0.8	100.8
3	6,250	0.8	504.0
4	31,250	0.8	2,520.0
5	156,250	0.8	12,600.0
6	781,250	0.8	63,000.0

I apologize for any confusion caused by my previous messages.

My Note: We're going to be just fine for the forseeable future, but the AI is getting pretty good.

Lignotuber · Apr 10, 2023

I'm not going to dabble with the math but my guess is rope stretch and short throw of the 5:1 on subsequent 5:1's will be a notable problem with achieving calculated forces. Reminds me of this episode

Muggs · Apr 10, 2023

I think I'll be fine to input 50 kg into the first 3 systems, but by the 4th system I will not be able to input the full 50 because things will be maxed out, and/or one of the earlier prusiks will slip while trying to input the 50...

Arb23 · Apr 10, 2023

Trying again...this looks much better, but I have questions...
Me> all these numbers are suspect. Can we start over?
AI> I apologize for any confusion. I'd be happy to start over and help you with your pulley system calculations. Could you please provide more details on the pulley system you are working with, such as the number of pulleys, the mechanical advantage, and the input and output forces you are working with? This will help me provide more accurate and relevant information.
Me> The basic system is a 5:1 system. There are six of these systems that will be used to pull a load. 50kg of force will be applied to each system sequentially. I want to know how much force will be applied to each system and a total force of the system in kN. Each stage should show an input force for the stage and an output force for the stage. Each 5:1 system is 80% efficient.
AI>
Thank you for the additional information. Based on what you've provided, here is a breakdown of the input and output forces for each stage of the pulley system, assuming an 80% efficiency for each 5:1 pulley system:

Stage	Input Force (kg)	Output Force (kg)	Output Force (kN)
1	50	250	2.52
2	50	1,250	12.6
3	50	6,250	63.0
4	50	31,250	315.0
5	50	156,250	1,570.0
6	50	781,250	7,812.5

To calculate the output force for each stage, we simply multiply the input force by the mechanical advantage of the pulley system. Since each stage is a 5:1 pulley system, the mechanical advantage is 5. For example, to calculate the output force for the first stage, we multiply the input force of 50 kg by the mechanical advantage of 5, which gives us an output force of 250 kg. We then apply the 80% efficiency to find the actual output force, which is 200 kg. Finally, we convert the output force from kg to kN by dividing by 1000.

The total output force of the pulley system is the sum of the output forces for each stage. In this case, the total output force is:

Total output force = 2.52 kN + 12.6 kN + 63.0 kN + 315.0 kN + 1,570.0 kN + 7,812.5 kN
Total output force = 9,775.6 kN

I hope this helps! Let me know if you have any further questions.

Arb23 · Apr 10, 2023

Ok - the AI is not getting some stuff right (obviously)...but after I issued some threats, I think I've got it beaten into submission. The output force column (on right) was not taking into account the 80% efficiency. Corrected:

Stage	Input Force (kg)	Output Force (kg)	Output Force (kN)
1	50	200	1.96
2	50	784	7.69
3	50	3072	30.08
4	50	12032	117.94
5	50	46912	459.22
6	50	182016	1783.92

To calculate the total output force of the system, we simply need to add up the output forces of each stage. Using the values from the corrected table, we get:

1.96 kN + 7.69 kN + 30.08 kN + 117.94 kN + 459.22 kN + 1783.92 kN = 2399.81 kN

Therefore, the total output force of the system is approximately 2399.81 kN.

Makes a HUGE difference! and my final answer! Lol

Muggs · Apr 11, 2023

Ok. I've tested all 6 systems from the picture. Here's the results, with approx. 1 kN input forces.

From the picture:

1st system, Schaefer Marine (blue and white rope) is 4.23 : 1

2nd system, "Set of Fours" from Wesspur is 4.24 : 1

3rd system, homemade with 2" rescue pulley and Pinto, is 4.54 : 1

4th system, homemade thing with rigging plates and micropulleys, is 4.33 : 1

5th system, 2" CMI double pulleys, brand new, is 4.90 : 1

6th system, SMC Advance Tech, is 4.39 : 1

Based on the rope lengths as currently constructed, I was planning to sequence them in this order:

#1. 5th system (4.90 : 1)
#2. 6th system (4.39 : 1)
#3. 3rd system (4.54 : 1)
#4. 4th system (4.33 : 1)
#5. 2nd system (4.24 : 1)
#6. 1st system (4.23 : 1)

Hopefully this makes sense to someone else.....

Arb23 · Apr 11, 2023

Muggs said:
#1. 5th system (4.90 : 1)
#2. 6th system (4.39 : 1)
#3. 3rd system (4.54 : 1)
#4. 4th system (4.33 : 1)
#5. 2nd system (4.24 : 1)
#6. 1st system (4.23 : 1)

Those are pretty efficient! Especially that CMI pulley one.

Muggs · Apr 11, 2023

That's the CMI RPI 153 pulley I think, really surprised me

Arb23 · Apr 11, 2023

I built my 2 5:1's with GM Climbing Amazon pulleys ($35/ea)...I wasn't ready to take the plunge into the pricier stuff.
https://www.amazon.com/dp/B08HQVVMS3
They seem to work ok, but I doubt they are as efficient as any of those.

Muggs · Apr 11, 2023

Arb23 said:
Those are pretty efficient! Especially that CMI pulley one.

Are you able to redo your AI charts with these numbers in mind, combined with pulling back the inputs to 25 kg each time instead of 50 kg?

Muggs · Apr 11, 2023

Arb23 said:
I built my 2 5:1's with GM Climbing Amazon pulleys ($35/ea)...I wasn't ready to take the plunge into the pricier stuff.
https://www.amazon.com/dp/B08HQVVMS3
They seem to work ok, but I doubt they are as efficient as any of those.

Those look amazing

Arb23 · Apr 11, 2023

Muggs said:
Are you able to redo your AI charts with these numbers in mind, combined with pulling back the inputs to 25 kg each time instead of 50 kg?

Sure...should be fun. I'll take a look tomorrow - I've got some prior commitments tonight.

Muggs · Apr 11, 2023

Arb23 said:
Sure...should be fun. I'll take a look tomorrow - I've got some prior commitments tonight.

Nah that's ok, wasn't sure how difficult it was. Thanks for those charts man, appreciate it

Arb23 · Apr 11, 2023

It's free to play around with once you create an account. Openai.org - look for chat-gpt. Might also be able to do it on Bing. Look for the chat tab, but it's limited in the number of questions you can ask. There was apparently a problem with it going insane if you asked it too many questions lol.

I've seen people using it to create scripts for their videos.

Muggs · Apr 11, 2023

Ok, new plan. I'm going to use 3 systems to make a 125 : 1 and just play around with what it can do. Should get some interesting results. I'm really just more worried about overloading my load cell than anything else, because once it's been overloaded it's not quite safe for climbing usage anymore...

Shadowscape · Apr 11, 2023

I can't wait to see what breaks.

LordFarkwad · Apr 11, 2023

Muggs said:
Ok. I've tested all 6 systems from the picture. Here's the results, with approx. 1 kN input forces.

From the picture:

1st system, Schaefer Marine (blue and white rope) is 4.23 : 1

2nd system, "Set of Fours" from Wesspur is 4.24 : 1

3rd system, homemade with 2" rescue pulley and Pinto, is 4.54 : 1

4th system, homemade thing with rigging plates and micropulleys, is 4.33 : 1

5th system, 2" CMI double pulleys, brand new, is 4.90 : 1

6th system, SMC Advance Tech, is 4.39 : 1

Based on the rope lengths as currently constructed, I was planning to sequence them in this order:

#1. 5th system (4.90 : 1)
#2. 6th system (4.39 : 1)
#3. 3rd system (4.54 : 1)
#4. 4th system (4.33 : 1)
#5. 2nd system (4.24 : 1)
#6. 1st system (4.23 : 1)

Hopefully this makes sense to someone else.....

Maybe I'm thinking of this wrong, but does #4 being 4.33:1 mean that - if all loss is in the pulleys - that those pulley's are 96% efficient!? Holy cow. Before I did all the other calcs, I looked up some typical pulley efficiencies, and was seeing numbers in the 85-95% range.