Training video - felling a side leaner

As far as I can see, the calculation I depicted is correct. I cannot figure what it was they were doing to come up with better than three times the value.

Which calculator are you referring to when you say it spits out wacko way off results? And what were you trying to figure?

I don't think the center of mass value is needed in my version of the calculator. What I mean is, the value is never referenced in the equation. It doesn't need a value to be input in my local copy at any rate...

Okay, I see it's not responding to a change in the height the rope is tied to the tree. Me fix. Will attach new version later.
 
Glen asked me for some comments on this in a different thread.

Here are the basic on how to analyze the first leaning beam problem. For trees you will need to use the appropriate center of mass (CM) location.

First you need to calculate the center of mass (CM) and the torque (moment/rotation force) it generates. For a uniform cylinder the CM is easy, it is located at the midpoint of the beam. Using Ekka's figure this point is 50 ft * sin(10°) = 8.7 ft to the left of the pivot point. It's exact vertical location is not of concern, but can be found with the cos() function. This horizontal offset will generate a torque (force times distance) of 10 T * 8.7 ft = 87 T-ft at the pivot point.

Next we need to calculate the force needed at the various angles. The force needed to counteract the torque is 87 T-ft / 100 ft = 0.87 T perpendicular to the pole. This equation 0.87 T/sin(angle-10°) can be used to calculate the force on the rope at various angles. An observant person would note that all this together matches the equation Chris posted earlier once you substitute (angle-10°) for alpha, 10° for theta, W = 10 T, H = 100 ft and L = 50 ft.

So after all that for the two cases we get 0.88 T for 90° and 1.51T for 45°.

For the second example Ekka posted you get 3.5 T not 5 T. Remember sin() is not a linear operator!

I didn't try the calculator, but the fundamental equation appears to be correct. If you are having problems you may not understand exactly what it is asking for.

Regards,

Cary
 
Thanks for taking a look, Cary.

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So after all that for the two cases we get 0.88 T for 90° and 1.51T for 45°.

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I had 1736 lb for the 90°; 2455 lb for the 45°.

You've got 1760 and 3020.

The online calculator has (only, for the second figure) 8585 lb!

I contend that cannot possibly be right. How / where is he getting access to / use of the sine of alpha directly in any case?
 
Glen,

I just checked it out and it does works correctly, except they are using a theta relative to the horizontal not vertical. So substitute 80° (90-10) instead of 10° to get things to work out correctly. My guess is they do a translation before the equation instead of changing the base equation to use the input directly.

Cary
 
Sorry, but I don't see needing 4-1/4 tons of pull at 45 degrees from 100 feet up to hold a 100 foot 5 ton pipe at 10 degrees from vertical. That much achieved tension would surely pull the object back over center quite rapidly. Somebody mentioned trebuchets in a recent thread elsewhere here and I believe we'd essentially be seeing one in action!
 
Glen, I'm not sure where you are getting those numbers. I thought we had always been talking about a 10 T object. The 10° from vertical is 80° from horizontal which is what the calculator wants. Also, with a 10° lean and the rope 45° from horizontal we get 35° for the tree to rope angle. Look at the example at the top of the calculator page. If you enter: 50 ft; 20,000 lb; 80°; 100 ft; 35° you will get the correct result (3,027 lb).

Cary
 
Ekka

I have watched many of your videos and applaud your efforts in not only just showing what you do but to go to the details you do to break it down so the layman can understand it.

Many unfairly have critiqued you, some challenged you, and some just shouldn't even be here but this video is a gem.

2440 views the board now sits at, that's over a 1000 in front of any other video, it's quite obvious that people have added it to their favourites and show it around.

Regarding the force on the side rope have we got a 100% accurate formula now that we can use?

Keep up the good work and I hope you ignore some of the "experts" of this board and put more videos up, after seeing some of the "bad" things done in videos by others namely one Mr Ed who constantly hounds you, you come out pretty clean so dont be put off. I'm sure I dont just speak for myself but many others.

Being new I suppose people I can say these things without a group of people jumping on me. There certainly are wings within this board that need clipping behind the ears but just ignore them.

Most likely while you are taking the time to make these videos both on the job and at home the "experts" are sitting around flapping their gums, drinking beer, and smoking pot so dont worry about them.
 
Ekkka is MOST AWESOME INDEED, and his training videos leave me agog and agape! I just hope he remembers us little guys when he becomes FAMOUS!!!

And ArborAddict, for you to realize this means you must be a wise, wise man! I look forward to learning from you!
 
I have to state right now, my good friend Ekka's video's are an educational resource extraordinaire! I am completly overwhelemed by the sheer depth of knowledge and talent that man posesses!
If only I could even aspire to be as good as the great panjandrum himself!
The best thing any budding arborist could do is settle down for an educational Ekkathon, and watch all those vids in one sitting. Why they'd learn all they need to know in one go!

Arboraddict,
are you going to be a bro for all aswell? ;-)
 
ArborAddict be leery of Ekka's two nefarious supporters Masterasster and Mr. Ed. They are closer to athletic supporters than true fans.
smirk.gif
 
I haven't got a clue what to say but just have a look at what's happened. The two "mates" of mine have answered, and TreeCo's warning is fair course.

MB, read my sig at AS, how are you going with it? I'm testing Old Monkeys theory and it appears he was wrong.

Ever tried Nuclear disarmament against a nation that has more nukes anyway... you tend to run out whilst they got spares. So unload some more MB, like the ekkka character.

I am on thin ice, well, that's how I feel anyway so I dont post much here ... go to AS and find me or see vids, I dont feel as threatened or victimized there.
 
And fix up my email address so it aint blocked or whatever you have done to it. Then I might be able to log in and kick ya butt! And same for poor ole Aussie what you done to him ya beast, he's just a bloke and had jack to do with me, that guy aint got a mean bone in his body!!!!!!!!!!!!!!!!!
 
What is going on here?

I hired a great climber once. He was fast. Really fast.

This guy would one hand a 66 and throw 500lb logs to the ground, he was different. The crew didn't like him much coz he had no consideration of the lower food chain, he would have big logs on top of brush on top of ropes etc then yell at people for not having his ropes in the clear. The guy was a tree demolition crew on his own.

Anyway, the crew belly ached and carried on till I fired the guy ... and to this day I have never had a crew that could perform as well.

A serious lesson learnt.

Have you learned it yet?

No? Yes??

Cant understand the question?

Answer is, appreciate what ya got coz the grass aint no greener. MasterBlaster and Mr Ed, Ekka is human just in case you haven't noticed.

Ekka, I'll send you a PM, I'm going to holiday not far from you soon, maybe we can see the zoo Steve Irwin was from.
 
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Dead on!!! you rock ekka.

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I've always thought that. His "training" videos are the most awesome educational vids I've ever seen.

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Thats very nice of you!
 
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