- Location
- Bloomington, Indiana
[ QUOTE ]
As for distance of fall, I believe it's:
Distance of Fall = Distance from the Block to Center of
Gravity of the Falling Piece times 2.
So all things being equal-block position compared to notch compared to tie off, the distance of fall will be different with a 10 foot spar than a 20 foot spar.
Of course a close block to notch position enables greater control, but don't forget about the extra inertia factor when dealing with longer spars.
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I think the equation is:
Distance from the block to the center of the length (not necessarily the center of gravity) of the falling piece times two.
(From "All in ALL, It's the Same Distance of Fall", Peter Donzelli, Arborist News, Dec. '99).
But this measures how far the center of the piece will fall. The center of a longer piece will fall farther than the center of a shorter piece and obviously the top of the longer piece will also fall farther. This is important when you are trying to avoid hitting obstacles below with the top of the piece, but it does not follow that the piece will end up farther from the block and the climber.
Given the same block-to-notch position, length of rope, and weight of the piece, the butt (cut) end of a ten foot long piece will end up the same distance from the block as the butt (cut) end of a twenty foot long piece. In both instances, the butt end will begin at a certain distance above the block, rotate around the block, and end up the same distance below the block.
As for distance of fall, I believe it's:
Distance of Fall = Distance from the Block to Center of
Gravity of the Falling Piece times 2.
So all things being equal-block position compared to notch compared to tie off, the distance of fall will be different with a 10 foot spar than a 20 foot spar.
Of course a close block to notch position enables greater control, but don't forget about the extra inertia factor when dealing with longer spars.
[/ QUOTE ]
I think the equation is:
Distance from the block to the center of the length (not necessarily the center of gravity) of the falling piece times two.
(From "All in ALL, It's the Same Distance of Fall", Peter Donzelli, Arborist News, Dec. '99).
But this measures how far the center of the piece will fall. The center of a longer piece will fall farther than the center of a shorter piece and obviously the top of the longer piece will also fall farther. This is important when you are trying to avoid hitting obstacles below with the top of the piece, but it does not follow that the piece will end up farther from the block and the climber.
Given the same block-to-notch position, length of rope, and weight of the piece, the butt (cut) end of a ten foot long piece will end up the same distance from the block as the butt (cut) end of a twenty foot long piece. In both instances, the butt end will begin at a certain distance above the block, rotate around the block, and end up the same distance below the block.
