turns per inch

[stx44]

Is there a magic number of turns per inch length of motor loop?

This would obviously vary between brands, but it see,s tan II can take more turns that Guillows own brand rubber (I know power delivery is different).

I ask because I found a reference in a magazine article to putting 1800 turns on a 430mm (thats about 17-18") loop, and that seems incredibly high to me.

[Steve Blanchard]

Turns per inch also depends on the cross-section as well as the length. a 17" loop of 1/16" could get up to the numbers you speaking about but not a loop of 1/8". Even if you take 2 loops of 1/16" to make the 1/8", your cross-section doubles thus reducing the turns per inch. There were definitely references as a guide only for Tan II but since Tan II is no longer produced you will need to create a reference for whatever rubber you are purchasing now, whether it is Tan Super Sport, Tan Sport, or Guillows etc (If you have Tan II laying around get rid of it immediately, it's bad for your health. People will knock you out for it. I'd be happy to take it off your hands and assume the risk). The best way to do this is take a loop of each cross-section that you have : 1/16, 1/8, 3/32, 3/16, 1/4, lube it well, stretch it or whatever you normally do for break-in, place it around a hook of some sort and stretch wind being careful to count the winds. Wind until it breaks. Do this a couple more times and get an average of max winds. Do this for each size. This will give you a reference for the batch of rubber you have for each size. I hope this helps.

Steve