I agree that pulling on a single point, such as the weight bench demonstrated here, provides 12:1 mechanical advantage. However, if you were tensioning parallel or tandem high lines, the tension on each line would only be 6:1. The true advantage of the Flying W in that case is that the tandem lines are self equalizing, as was stated in the video, and each would be supporting the same weight in the system.
it is 8:1. if you imagine the last 2 pulleys he adds as being on a separate anchor it's easier to see where the confusion is. the new "load" is on the prusik, which is a 2:1. he's not getting 3:1 out of 2 pulleys. that new 2:1 multiplies his original 4:1 to get 8:1.
Stewart; Can you describe your calculation? eg if you count the ropes tied directly to the moving load I count 4. If you count the ropes going to the prussik I count 2. 2X4=8.
@@lashlarue7924 I'm not going to argue this, the fire department guy is obviously trained in a specialized field. Either you tell him he's an idiot or you figure out where you went wrong. P.S. you did go wrong. Hint: If his logic on the 4:1 is correct, why is the 3:1 logic wrong, if he only setup a 3:1 (no 4:1 present) why would it not be 3:1?
Your first one wasn't a 4:1. It was a 3:1 with a change in direction. Then you made it into a 4:1 with the 4th pulley and joined it with a 2:1 on the prussit. You made an 8:1. Just look at the part where you announce 4:1. If you pull 3 inches of the top rope, you're getting 1 inch out of each of the other three lines.
I think you might be looking at this backwards. An even mechanical advantage sees the rope terminate at the anchor. An odd mechanical advantage sees the rope terminate at the load.
@@dangerstall you are correct. I went down a rabbit hole after this and discovered my fundamental understanding was flawed. Rope pulled vs load move distance doesn't have to equal MA.
@@whermanntx Good that you see it as 4:1 now but don't go away with a misconception... the length of rope moving through the system vs distance the load moves still relates exactly to the MA.
What is the limit of mechanical advantage one can get when you factor in the friction of the pulleys? I assume that at one point adding another pulley would put so much friction in the system that you actually remove mechanical advantage.
You could multiply the efficiencies of each pulley and get an estimate of the efficiency of the system. If the load is 100N and the efficiency is lets say .8 the ideal pulling force required would be (4:1) 25N, divide that by the efficiency of the system and you are pulling 31.25 N. Using pulleys wont get you less mechanical advantage as the efficiencies are quite high. Using carabiners instead could prove a problem as the efficiency lowers and the real force required to pull the load may be closer to the 100N.
If watchers here cannot google a reference then don't bother wasting peoples time. Prussic is a friction knot or cord used to attach a loop of cord around a rope, used in multiple areas ie rope rescue, mountaineering etc. Mainly used in progress capture situations when a loads are an issue. and yes they are very effective. I have worked at heights over 350 ft. with this knot to rescue / haul victims.
Michael Rhymer if people don't already know what a "Prusik" (correct spelling) hitch is, they don't need to be learning any type of mechanical advantage.
Ryan, What Air Force Base do you work for? I work for Cape Canaveral Air Force Base? FF/ paramedic, tech rescue. And I agree on the mechanical advantage statement. Some people just want to comment about idiotic stuff, they do not understand the NFPA requirements we deal with. in addition to the DOD requirements as well. keep doing what your doing brother, everyone thinks they are smarter than everyone else.
prusik is mainly used for progress capture systems. They can also be used for ascending a line. the klemheist isnt approved for high angle rope rescue as far as i know.
@@dangerstall I didn't know the word Prusik, but need to understand mechanical advantage so I can create a pulley system to move a shipping container. Thank you for the video. Remember, you once learned these words too.
@@anthonyd5884 Indeed, learning mechanical advantage goes beyond rescue work. For Ryan to make such a statement that you don't need to know it outside of the rescue field only shows how limited his understanding is of mechanical advantages resoucefulness.
I cant understand the words you say when referring to the red piece of rope ? My best guess is Cresent Gauntlet... Could you explain more what you did there with the red loop ?
if you used scales to measure the input force and the output force you would probably find the actual mechanical advantage to be far less than 12:1 due to friction
Yup. That’s not the point of this video. It is a theoretical 12:1. There are multiple variables to find out the true mechanical advantages, one being the efficiency of the pulleys
Good video, although the echo's undesirable. I've also taken UA-camrs to task for using uncommon words which're bastards to figure out, if you ever even do. "Prusik" was one of them. Just spell such words for viewers, the first time. Not everyone here's a certified search & rescue worker. Some of us just took UA-cam up on their suggested video & the material's reasonably new to us. Thumbs up, however, & thanks.
Same folks that own youtube offer an awesome tool for looking up words you don't know. www.google.com/?q=prusik. I don't want to take an introductory class; I just wanted to see how to make a 4:1 and 12:1 rigging. Awesome and simple video.
dalepres1: I detect some sarcasm. I'm perfectly capable of looking up "prusik" once I figure out what in the sam hell WORD the guy is actually SAYING. I've never heard the damned word before in my life, audio quality is not the best, & this is a frequent problem w/ home-made videos w/ topics that're new to me. "Cussick"? "Prussich"? F. if I knew what the hell he was talking about-- was I hearing a new word, or mis-hearing a known word?
Where would one put a progress capture prusik on this? I'm just trying to lift something heavy. Figured it out. Now how do you keep all the lines from twisting? I was using polyethylene which seems like it wants to twist easily vs climbing rope.
At the last change of direction pulley at the anchor. I pointed to where it should go, but never attached it. Re-watch the video and look for where I placed the prusik temporarily.
@@dangerstall Thanks! P.S. It worked great for my purpose which was lifting a very heavy plasma tv (little old) and I learned a ton and didn't kill anybody. The audio was a little difficult and I knew what a prusik was but still couldn't understand the word. But, still a great video overall. Also, understanding what you do makes me appreciate it all the more.
Once the prusik reaches the pulley you can reset the system by sliding the prusik back towards the load if you have a load capture device in place (which he doesn't).
I’m by no means and expert in rope rescue yet but I thought mechanical advantage only multiplied when you introduced one simple system onto another. Had he attached a rope grab to the 4:1 and then created a 3:1 using another rope, acting as if the rope grab on his 4:1 was the load, he would have made a 12:1. I wasn’t aware you could multiply mechanical advantage using one system like that.
@@johnsonjj117 Effectively, that's exactly what he's done. Everything left of the rope grab is that separate 3:1 system acting on the first 4:1 system. It just looks confusing because the 3:1 is anchored to the same plate. The 4:1 system starts where it exits the load. It doesn't have to go through a change of direction to be a 4:1 - just pull it to the left (instead of to the right through a COD).
orble h no, its a 12:1. learn the "t method" of figuring out mechanical advantages. also, when you create a complex system you multiply the systems. 3x4=12.
Yeah, it's a 3:1*4:1 = 12:1. Verifying with numbers is good (make sure you're aware of friction affecting them), but these systems are so commonplace that they're easy to analyze.
Best explanation I have EVER seen...
I agree that pulling on a single point, such as the weight bench demonstrated here, provides 12:1 mechanical advantage. However, if you were tensioning parallel or tandem high lines, the tension on each line would only be 6:1. The true advantage of the Flying W in that case is that the tandem lines are self equalizing, as was stated in the video, and each would be supporting the same weight in the system.
it is 8:1. if you imagine the last 2 pulleys he adds as being on a separate anchor it's easier to see where the confusion is. the new "load" is on the prusik, which is a 2:1. he's not getting 3:1 out of 2 pulleys. that new 2:1 multiplies his original 4:1 to get 8:1.
This is 100% a 12:1
Stewart; Can you describe your calculation? eg if you count the ropes tied directly to the moving load I count 4. If you count the ropes going to the prussik I count 2. 2X4=8.
@@BriTube007 There are 3 at the prusik. This is a 4:1 being pulled by a 3:1 so 12:1 total
@@killer2600 No. There are 2 at the prusic. The 2:1 is reeved to advantage to ONE line at the prusic; you don't count the prusic attachment itself!
@@lashlarue7924 I'm not going to argue this, the fire department guy is obviously trained in a specialized field. Either you tell him he's an idiot or you figure out where you went wrong. P.S. you did go wrong. Hint: If his logic on the 4:1 is correct, why is the 3:1 logic wrong, if he only setup a 3:1 (no 4:1 present) why would it not be 3:1?
Nice. I've been using 4 to 1's for a while. But adding that 3 to make it a 12 is pretty awesome.
My brain now hurts
WHO,S ON FIRST????????
@@anthnchav9 what’s on second?
Your first one wasn't a 4:1. It was a 3:1 with a change in direction. Then you made it into a 4:1 with the 4th pulley and joined it with a 2:1 on the prussit. You made an 8:1.
Just look at the part where you announce 4:1. If you pull 3 inches of the top rope, you're getting 1 inch out of each of the other three lines.
I think you might be looking at this backwards. An even mechanical advantage sees the rope terminate at the anchor. An odd mechanical advantage sees the rope terminate at the load.
@@dangerstall you are correct. I went down a rabbit hole after this and discovered my fundamental understanding was flawed. Rope pulled vs load move distance doesn't have to equal MA.
@@whermanntx Good that you see it as 4:1 now but don't go away with a misconception... the length of rope moving through the system vs distance the load moves still relates exactly to the MA.
Put a link(s) of where you can buy this stuff...
What is the limit of mechanical advantage one can get when you factor in the friction of the pulleys? I assume that at one point adding another pulley would put so much friction in the system that you actually remove mechanical advantage.
You could multiply the efficiencies of each pulley and get an estimate of the efficiency of the system. If the load is 100N and the efficiency is lets say .8 the ideal pulling force required would be (4:1) 25N, divide that by the efficiency of the system and you are pulling 31.25 N. Using pulleys wont get you less mechanical advantage as the efficiencies are quite high. Using carabiners instead could prove a problem as the efficiency lowers and the real force required to pull the load may be closer to the 100N.
Hey, thanks for the video, it is awesome! could you please tell me the name of that yellow unit with the holes? I wanted to find something like that
Hey Adam, the yellow device is called a rigging plate YW :)
@@austinwood9520 thank you :)
Adam Toth no problem, I am currently looking at that stuff right now 😂
Rigging plate of 31 KN capacity
What do I look up to learn about these terms and such? I had no idea this stuff existed
Just look up pulleys, block and tackles and mechanical advantage.
If watchers here cannot google a reference then don't bother wasting peoples time. Prussic is a friction knot or cord used to attach a loop of cord around a rope, used in multiple areas ie rope rescue, mountaineering etc. Mainly used in progress capture situations when a loads are an issue. and yes they are very effective. I have worked at heights over 350 ft. with this knot to rescue / haul victims.
Michael Rhymer if people don't already know what a "Prusik" (correct spelling) hitch is, they don't need to be learning any type of mechanical advantage.
Ryan, What Air Force Base do you work for? I work for Cape Canaveral Air Force Base? FF/ paramedic, tech rescue. And I agree on the mechanical advantage statement. Some people just want to comment about idiotic stuff, they do not understand the NFPA requirements we deal with. in addition to the DOD requirements as well. keep doing what your doing brother, everyone thinks they are smarter than everyone else.
prusik is mainly used for progress capture systems. They can also be used for ascending a line. the klemheist isnt approved for high angle rope rescue as far as i know.
@@dangerstall I didn't know the word Prusik, but need to understand mechanical advantage so I can create a pulley system to move a shipping container. Thank you for the video. Remember, you once learned these words too.
@@anthonyd5884 Indeed, learning mechanical advantage goes beyond rescue work. For Ryan to make such a statement that you don't need to know it outside of the rescue field only shows how limited his understanding is of mechanical advantages resoucefulness.
I cant understand the words you say when referring to the red piece of rope ? My best guess is Cresent Gauntlet... Could you explain more what you did there with the red loop ?
AH, i think i figured it out... Prusik loop.
@@PhilScordato correct that is prusik knot. the standard is 1 chord for general lifting 2 cords if life is involved.
Prusik is the name of the loop of rope, a prusik loop is basically a girth hitch but wrapped additional times. It creates a friction hold on an object
if you used scales to measure the input force and the output force you would probably find the actual mechanical advantage to be far less than 12:1 due to friction
Yup. That’s not the point of this video. It is a theoretical 12:1. There are multiple variables to find out the true mechanical advantages, one being the efficiency of the pulleys
Good video, although the echo's undesirable. I've also taken UA-camrs to task for using uncommon words which're bastards to figure out, if you ever even do. "Prusik" was one of them. Just spell such words for viewers, the first time. Not everyone here's a certified search & rescue worker. Some of us just took UA-cam up on their suggested video & the material's reasonably new to us. Thumbs up, however, & thanks.
Same folks that own youtube offer an awesome tool for looking up words you don't know. www.google.com/?q=prusik. I don't want to take an introductory class; I just wanted to see how to make a 4:1 and 12:1 rigging. Awesome and simple video.
dalepres1: I detect some sarcasm. I'm perfectly capable of looking up "prusik" once I figure out what in the sam hell WORD the guy is actually SAYING. I've never heard the damned word before in my life, audio quality is not the best, & this is a frequent problem w/ home-made videos w/ topics that're new to me. "Cussick"? "Prussich"? F. if I knew what the hell he was talking about-- was I hearing a new word, or mis-hearing a known word?
WEIRD! THE URL SAYS "bing" AS A BELL-ICON MESSAGE, BUT GOOGLE IN THE ACTUAL COMMENT!!
If you don't know what a prusik is going in to this video, this info is outside of your skill level.
@@brettd.3116 or you could be someone who uses rescue senders/rope grabs. This demo is super old school.
Where would one put a progress capture prusik on this? I'm just trying to lift something heavy.
Figured it out. Now how do you keep all the lines from twisting? I was using polyethylene which seems like it wants to twist easily vs climbing rope.
At the last change of direction pulley at the anchor. I pointed to where it should go, but never attached it. Re-watch the video and look for where I placed the prusik temporarily.
@@dangerstall Thanks! P.S. It worked great for my purpose which was lifting a very heavy plasma tv (little old) and I learned a ton and didn't kill anybody. The audio was a little difficult and I knew what a prusik was but still couldn't understand the word. But, still a great video overall. Also, understanding what you do makes me appreciate it all the more.
So isn't that complex/compound system limited by how much rope is in between the last pulley and the limit?
Once the prusik reaches the pulley you can reset the system by sliding the prusik back towards the load if you have a load capture device in place (which he doesn't).
In general more complex the mechanical advantage system the more rope you will need.
What kind of pulleys are those ?
That’s what I want to know
Rock Exotica
they are rock exotica omni blocks
You have an 8:1, not a 12:1. Your final 2:1 connected to a 4:1 = an 8:1; it does NOT magically become 12:1 by the way you rove it to advantage.
Sorry, but it is a 3:1 connected to a 4:1. 3x4=12. Study the T method for units of tension and get back to me.
I’m by no means and expert in rope rescue yet but I thought mechanical advantage only multiplied when you introduced one simple system onto another. Had he attached a rope grab to the 4:1 and then created a 3:1 using another rope, acting as if the rope grab on his 4:1 was the load, he would have made a 12:1. I wasn’t aware you could multiply mechanical advantage using one system like that.
@@johnsonjj117 Effectively, that's exactly what he's done. Everything left of the rope grab is that separate 3:1 system acting on the first 4:1 system. It just looks confusing because the 3:1 is anchored to the same plate. The 4:1 system starts where it exits the load. It doesn't have to go through a change of direction to be a 4:1 - just pull it to the left (instead of to the right through a COD).
@@dangerstall Sorry but it is a 2:1 connected to a 4:1 which makes an 8:1
@@johnsonjj117 it would be exactly the same thing whether it’s one rope or two. Think about it.
Mantab 👍👍
Kids playing with toys.
Not hardly.
that is 8:1
orble h no, its a 12:1. learn the "t method" of figuring out mechanical advantages. also, when you create a complex system you multiply the systems. 3x4=12.
you must prove it by pulling a heavy stuff up, using a meter. Anyone should trust numbers only.
And I will test this either.
Yeah, it's a 3:1*4:1 = 12:1. Verifying with numbers is good (make sure you're aware of friction affecting them), but these systems are so commonplace that they're easy to analyze.
The system is divided into the exact point where the blocker is placed.
4：1
Learn the basics of physics and you will know that this number of coloons could be better utilized