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32 Posts
Discussion Starter · #1 ·
I've been thinking about this for a long time "tape thickness", "taper" and "drawweight"

Question 1
Let's say I use GZK's Green .50 and use a "taper" 18-12-295 if I use a GZK's Green .40 instead what should the taper be to get the same drawweight?

Question 2
Your answer to question 1 is it a "gamble" or "what do you think" or "is it something you have calculated" in that case how do you calculate?

Question 3
I "think" that the speed will be higher with uses of a thin band with wider taper than a thick band with narrow taper. Or am I completely wrong?

1,218 Posts
For question 1, I don't know if there is a way to calculate this or not- there probably is and I am just not aware of it. It may well be somewhere on this board.

I think the power / draw weight are related to the total amount of latex there, i.e. the volume of latex in the band. I haven't tried calculating this but would guess that if you adjusted the dimensions of thick vs thin bands so that they had the same amount of latex (volume) they would be similar in draw weight and power.

What is known is that thinner bands are slightly faster than thick bands- this has been tested / demonstrated several times on the forum. I did one where I compared double 0.4 bands to a single 0.8 band of the same dimension and found the double thins were slightly faster. And my test was far from the first, I just did it to confirm what many others had shown and to see it for myself.

I think I have heard this explained as surface area to volume ratio being the key factor, the thinner bands have more surface area per unit volume of latex. To get the same volume of latex you have to use a wider thin band vs a narrower thick band. In this case the thin band would likely be a bit faster. This would be a fun one to test. This is probably why people are using thin sheets of latex vs long solid squares or cylinders.

Lots of fun stuff to think about and think back to what has been tested, thanks for posing the questions!

228 Posts
The same amount of latex (i.e) volume, would be similar in draw weight and power.
Give High Desert Flipper a gold star. ( please forgive my edits to the above. )

Before: 0.5 mm, 18.0 mm to 12 mm, cut at 33.33 cm, tied to 29.5 cm
After: 0.4 mm, 22.5 mm to 15 mm, cut at 33.33 cm, tied to 29.5 cm

Just opinion... nothing to see here. You'll never satisfy everyone.

The theory is right: thinner bands are usually faster. Or more precisely, the higher the surface area to cross sectional area the faster the bands can convert heat into kinetic energy… However the higher the surface area to cross sectional area the faster the bands will cool. So the right thickness is a matter of temperature, wind and long term testing.

Question 4. Where would a difference in thickness show an increase in speed ?

Slingshots have three speeds:

1. Slow, when the ammo is exceeds the optimum weight. Performance would be easy to ballpark guess.
2. Optimum ( fast :D ), when the ammo is about right. This is a little subjective, detailed calculations could be used. Or use a chrony and have a shooting glove ready for the hand slaps! I feel this point is something of a limit, be that weight or speed. It is the limit of what can be calculated. This is maybe the answer you are looking for. Answers here are going to be a reasoned guess.
3. Dry-fired, when the ammo is too light. This is wild guessing territory. It’s also not my style of shooting.

Speed makes things difficult, I would like to correct my answer. ( read EDIT here )

We should be able to know what both band sets can achieve with ‘larger’ sizes. Note: This size would be very specific to each particular setup. Performance should be identical, both in principal and in practice.

I think you find a difference in the optimum speed, oh say 11/32” steel vs 3/8” steel. This would be interesting. So principal vs practice? I think the thickness is too small in this case. I’d really like to see this tested. So this sounds like a good excuse to stock up on a range of ammo and have a day of shooting :)

As for dry firing… I think we are back to general theory: Thin rubber shoots faster. It’s also a really easy thing to test.
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