strength demo of the GRCS 6/5/04

[rbtree]

Thanks for the report, frans! I look forward to more test details..and video, for sure.

Wow, that is a lot of lift, 4400 lb or whatever the car actually weighed!! Must mean that when we lifted that cedar off the house, our line angles meant we were applying close to that much force, as it was all we could do to crank 'er up. But we were standing on a ladder, so lost some power I'm sure.

Some time ago, I noticed the Hobbs capstan was bent down a few degrees. The deformation is in the backing plate, so the parts all still work fine. Someone, possibly myself, must have dropped a chunk of wood onto it, perhaps on that big 2 day pine tree removal we did. I may have it heated and bend it back, but not if it will weaken the metal.

 

[glens]

Roger, you may be best to leave it if the old rule of thumb about "using the same amount of heat to put it back as was used to move it the first time" is correct.

Frans, "GVWR" is what the vehicle is rated to weigh when loaded to full design capacity.  In my guestimated example above, if 1300 pounds load makes the GVWR attainable, then empty it would weigh 3000 pounds.  I guess maybe that wasn't clearly what I was saying (heck, maybe it still ain't).  I apologize if you knew that, but it seemed as though you were thinking you were working with the gross vehicle weight in your tests with what I assume was an empty car.  Did you have half a dozen full-grown men strapped in it?  haha!

Glen

 

[TheTreeSpyder]

Excellent!

on a 12/1 it'd taske about 360# of cranking force to lift a 4400# vehichle. ~250# cranking to lift 3000? Was JP on it?

 

[rbtree]

Harken calls the winch 22 and 44 to one.......I did a very inexact guess as to rope travel versus crank handle, and came up with figures a bit less than that.....but it is a lot more powerful than the 17-1 ratio (?) of the Hobbs.

I think there would be slightly more power with a smaller diameter line, as it's center would be closer to the drum center, and thus move less.
Also, it may bite better, as more wraps can be used...another reason why I'm in love with our 9/16th high tech line, rated at over 20,000 average break strength.

 

[Frans]

We have not weighed the car or the log yet but wanted to let folks have some idea at least what the weight was so I took the gvwr info. off the door jamb.
I am kinda mad I did'nt test the bollard on the GRCS. But I really wanted to test the pawls on both devices. We all know what the shear strengh is for both devices but what has'nt been revealed is the pawl or ratcheting shock load strengths.
I could rigg the setup again and bring on the bollard but am kinda behind with work so I'll give it a rest for awhile. This stuff is a lotta work to set up.
Gerry donated a 120lb. yarding block w'3/4 choker cable, to drop the car into. Not too much call for the heavier blocks these days with the logging industry dieing out...
spyder:
It was alot of work cranking up the car. But after I noticed we were going around and behind a stub and rethreaded the take up line things got alot easier-duh
rbtree:
The new proto-type Hobbs we used seems to be fairly beefy. The base plate is channel iron and the capstan itself is "dished" slightly to minimize wrapping.
Frans