3:1 Mechanical Advantage
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- Опубліковано 14 жов 2024
- This video demonstrates how to build a “theoretical” 3:1. I do not take into account the factors of friction and pulley efficiency. If you are a physics major, this is not the video for you. You are not my target audience
All these experts yet here they are looking for instructional videos... Dude, thanks for the video, I could already do 3:1 but this is just so much cleaner than mine!
Finally found the video. Saw my foreman make one of these as I’m new to tree work and we pulled whole trees over with this system. It was impressive.
Can you make a playlist of your MA videos? I often watch them for reference as a beginner. Thank you!
I would really appreciate if you could do a video explaining mechanical advantage from a climber's perspective. Like when the load does the hauling. For example, when a climber is the load, is climbing SRT, and creates a 3:1 haul back system how does this follow the rule that, if it is odd the line will be terminated at the load? I really think you do an excellent job explaining MA and was just curious if you could explain it from the climber's perspective...Thanks.
2:1 = pulley at the load and 3:1 equals end of the rope atv the load
1:43 with a longer rope.. instead of the prussic/rope grab on a carabiner..
Could you not just run the carabiner straight to the load?
Maybe add another pulley on it?
If you pull three feet of rope through that system, the tackle will move eighteen inches. It's a 2:1 set up, the final turn is only a redirect. Measure the pulled rope and the distance that the tackle moves and see for yourself - dont just take my word on it.
Your comment almost doesnt deserve a reply. I said if you pull 3 feet of rope, you will move the load 1 foot. There is a 2:1 attached to an existing 1:1 Making it a 3:1.
This is not a 2:1. A 2:1 would be a single pulley attached directly to the load. Watch other video son a 3:1 or speak with another rope rescue expert if you do not believe me.
@@dangerstall I'll ask again, have you pulled three feet of rope and then measured how much the load has moved? If you've gained one foot, then it's a 3:1. If you've gained eighteen inches, then it's 2:1.
It's not a matter of opinion - the measurement speaks for itself.
If I'm wrong I'll admit it, but please go and actually measure the gain before responding.
@@d1a1x1d1a1x I dont need to go measure it. It's a matter of science. I pull significant loads on a 3:1 all the time. Go put 100 lbs on a 3:1 system and pull it. Measure the distances, and also measure the force it takes to pull it. With 100% efficient pulleys it will take 33.3 lbs of force to move 100 lbs. That is the true reason it is called a 3:1. The distance in feet is just a way to tell what system it is. With most pulleys it will take more force because they are in the 80-90% efficiency. Anyway, I dont know your education and level of experience, but I have been doing this a long time. And this video has been viewed 26k times and you are the first person to question if it is a 3:1, so maybe that tells you that you are wrong???
@@dangerstall Either measure the distances or place each strand on a load meter and allow for friction (you'll find they corroborate) but please - measure for yourself.
Pulling significant loads all the time (and I have no doubt successfully) has no bearing on whether your description of this system is accurate. I understand the math example you've given but that doesn't prove the actual system in your video is a 3:1.
If you've stated as fact, in your video, that three feet will result in a one foot movement then the 'true reason' should support this statement, and those responsible for your 26k views will see my error.
Whether you are correct doesn't depend on the number of views and as I've stated before, I'll be the first to say so if I'm wrong. However, there's no question that a simple real-life test will produce more dependable support of your position.
All I'm asking is that you make your own measurements.
With regards to my standard of education and level of experience, why would that affect the outcome of an actual experimental test that you could carry out? Again, the science will stand on its own merit without any need of anyone's opinion.
Please measure this system yourself.
@@d1a1x1d1a1x I got 22 inches when pulling a 3:1 moving the load 1 foot. But remember that I said a 3:1 is a mechanical advantage or a force multiplier. And its theoretical. So when you account for pulleys that are working at 80-90% efficiency, you will not get 3 full feet, and it will not take only 33.3 lbs of force to move 100lbs. It will take more force because the pulleys are not 100% efficient. Regardless of that, this system has been called a 3:1 since the beginning of its use, and will continue to be, no matter what you say. It is understood that it is not 100% efficient. When I said in the video that you can measure distance pulled to figure out the MA, that is a rule of thumb or a guideline. The T method is more accurate when you know the efficiency of each pulley. With those omni blocks, the true MA would probably end up being 2.7:1. You won't be seeing anyone teaching this system as a 2.7:1 because a 3:1 or a z rig is already the common name for it, and in a perfect world with 100% pulleys it would be a true 3:1. So if I'm using crappy pulleys or carabiners to build the 3:1 do I have to change the name because its not truly a perfect 3:1? If I'm on a rescue team should I tell someone to build me a 2.7:1, or a 2.1 to 1?
I'm pretty sure the world is going to continue to call it a 3:1. Its not a 2:1. Distance pulled in rope compared to load travel is just a guide. True calculation comes through use of a dynamometer. But then, once again, the name 3:1is based off of it being theoretical because who the hell knows what type of pulley you might be using. There is no such thing as a 100% efficient pulley in this world. If I used carabiners it would be a 2:1 actual MA, but it's still considered a 3:1 due to how its constructed, rope terminated at the load, etc...
Great video! Thanks
The point of the prusik is to stop the load from dropping right?
Depends on which prusik you are talking about. There is a progress capture prusik that goes on the change of direction pulley, and a rope grab prusik that goes on the traveling pulley. The progress capture prusik stops the load from dropping.
This is the same as truckers hitch but with prusik and pulleys😁
How much is all this going to cost??
That prusik is not necessary. Just create a figure of eight or butterfly loop and hock a carabiner.
Correct. If you want to be less versatile and efficient
Yeah, but then once it reaches the pulley, you can't haul anymore. With the prussik, you can let the progress capture hold the load, move the traveling prussik, and keep hauling. With you method, you're only gonna haul something a short distance.
@@geometerfpv2804Correct me if I'm wrong, here it's a progress capture pulley not a progress capture prusik (as wrongly labelled in the video). That prusik is not for progress capture but for efficiency if the rope goes 90 degrees down as in a cliff. So you use that prusik before the rope angle down. Once the travelling pulley meets the progress capture pulley, the pull is over. You can't reset anything because the progress capture pulley is fixed. If anything that prusik while increasing efficiency in some cases shortens the haul. I would like to be corrected though.
@rapalalake Yea prusik is amazing. I use it all the time when a setting tarp system for hammock camping. I also use two modified prusiks called schwabisch to climb a rope easily using a harness. Another use of prusik people doesn't know much. If you have a tree (not too thick) and you can't reach a branch, you can make two butterfly loops as foot rest and use the same rope to make a prusik around the tree (the shorter end you don't use can actually just hang free). Once you put a foot in the loop you have tension and the prusik holds. Put your foot again in the other loop to rise further.. You can then raise yourself up to reach the branch. It's like a quick rope ladder. Works also any pole as long as it is not icy. Once you are done and the system is without tension, you can quickly undo the whole thing.
After more research, im basically certain @Dee H. is correct and this is a 2:1 with a redirect.
The cool thing is, this can be magically turned into a 6:1 by adding only one more pulley on a prusik (another traveling pulley). On the setup you have at 3:24, it would be called a drop C plus a Z
You just contradicted yourself. If you add another 2:1 into the system you could not get a 6:1 according to your logic. When combining 2 simple mechanical advantages you multiply them for the resulting mechanical advantage. Meaning if you combine a 2:1 to a 2:1 you get a 4:1. Your argument proves my point that it is a 3:1 because if you combine a 2:1 into it, you get a 6:1. Thank you.
@@jstewart627 there isn’t an invisible strand of rope. It is clearly there. Please gain more knowledge of mechanical advantages before you try and discredit my videos.
How is it a “redirect” pulley or CHANGE of direction when he is pulling the load in the SAME direction. It’s clearly a 3:1
You're right man it's only a 2:1 with cod
Thanks chisel chest!
Huh?
@@dangerstall Thanks
Your audio is terrible
Cool
Walt, why would you even bother leaving a comment saying that?