9 Nov
2007
9 Nov
'07
3:04 p.m.
Proof Reading is important...
For eg, for 80lbs of wheels on an 8 foot span with 4 inches of drop: X = 80/(2*4) = 10, F ~= 10, Tension = 10 * 80/2 = 400 lbs
8 feet = 96", so X= 96/(2*4)=12, F =~ 12, Tension = 480lbs...
Also, this online calculator will work, although is uses an equation that assumes the weight is distributed along the cable evenly, whereas mine assumes it's all at the center (providing some built-in margin of error). I should note that I actually ended up buying much stronger cables (a few tons breaking strength) than we technically needed, such that I am able to stand on them with about 1-2 inches of sag.
http://www.spaceagecontrol.com/calccabl.htm
Stuart