# Why tapered bands are faster but do not last as long.



## Charles (Aug 26, 2010)

This is a little intellectual exercise. I have been thinking lately about why tapered bands are faster, but why they do not last as long. I believe I have come to an understanding of why that is the case. Don't worry ... this is not a full scale scientific analysis, although it is based on sound physical principles; anyone should be able to understand it. First, let us get a couple of simple principles out of the way.

Principle 1: The further you stretch a band (up to its breaking limit), the faster it recoils. That is, the closer to its breaking limit you stretch a band, the faster it will snap back. We are speaking generally here; obviously if you stretch a band beyond its limit, it will break, so I am assuming we will not stretch it that far. As a little experimental test of this principle, try snapping yourself with a rubber band. To begin with, just stretch the band a short distance and snap yourself ... not a big deal. Now, stretch it to about half its limit and snap yourself ... a little bit of pain. Finally, stretch it to its limit and snap yourself ... ouch!

Principle 2: The closer to its breaking limit you repeatedly stretch a band, the more quickly it will fail. I suspect we have all experienced this one. If you doubt it, just mount two identical slingshots with the same length bands and start firing ... use one slingshot always stretched to its limit, but use the other stretched to only half its limit. See which one fails first.

Principle 3: On a stretched tapered band, the thinner part is stretched closer to its limit than is the thicker part. To see this in action, look at the following photos. First is my perforated band at rest. I have it clamped so that the unperforated part is 3 inches, and the perforated part is 3 inches.










　
　
In the next photo, I have stretched the band so that the unperforated part has doubled in length to 6 inches ... but in order to do that, the perforated part had to stretch 8 inches.










　
　
So, when we taper bands, the increase in speed is due to a number of factors.

(i) There may be a bit less air resistance due to the smaller profile of the tapered part.

(ii) There is less mass toward the pouch, and less mass means higher acceleration. Higher acceleration over the same distance translates into greater terminal speed.

(iii) The tapered part of the band will be stretched closer to is maximum, and so will retract faster.

O.K. ... so much for speed. What about band life? While the wider part of the band is stretching only moderately, the thinner part of the band will be stretching much closer to its maximum. But repeated stretching close to maximum means the band will fail more quickly. In brief, the short band life is because the thinner part of the band is being repeatedly stretched close to its maximum.

So there you have it ... if you taper your bands, you will get greater speed, but almost certainly you will get shorter band life. A nasty trade-off indeed.

Cheers ....... Charles


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## Tex-Shooter (Dec 17, 2009)

Yes true, but with tapered, you get more bands per sheet, so it is not as much of a trade off as one might think. Also I want my bands to break at the pouch because that way you don't take as much of a chance of getting slapped in the face. Also if you slow down the tapered band sets to shoot the same speed as the non-tapered ones the life goes up some. There is also other ways to get more life out of tapered band sets. In test that I did for Saunders, I got over 2000 shots with thin flat bands, Fork tips, pouch connections, and several other factors lengthen band life. There is no simple formula and no one set fits all solution. -- Tex


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## NaturalFork (Jan 21, 2010)

I find my tapered bands last just as long as the straight ones. With much better performance.


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## Charles (Aug 26, 2010)

As with all things, it depends a great deal on the details.

I agree that cutting tapered bands gives you more bands per sheet ... simple area considerations. My concern is how long the bands last between changes, not with how many bands I can cut from a sheet.

I agree totally that it is better to have a band break at or near the pouch than break at the fork, because of the reduced risk of eye injury.

I also have no doubt that thin flat bands can last a very long time. I have nothing to say on that matter.

My ruminations had to do with comparing the life of a tapered band with one not tapered. Basically what I suggest is that if you start with two straight cut bands of the same dimensions ... then taper one ... the tapered band will give you higher velocity but will break sooner, assuming all other factors are held constant.

NaturalFork, your experience that your tapered bands last as long as your straight cut bands is at odds with the majority of reports on this forum. To understand your experience, one would have to know more about the bands being compared and the extremity of their elongation. For example, if one is not drawing the bands far enough that anything close to maximum is being reached along the length of the band, then the risk of failure is greatly reduced. Of course I am always interested in experimental reports. I would love it if you could provide more details of bands, dimensions, chrony comparisons of speed, and shot counts between failures.

Thanks for your comments, guys ... keeps me thinking.

Cheers ... Charles


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## Dayhiker (Mar 13, 2010)

Thanks for thinking. I can't stand the pain of doing it for myself.


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## rockslinger (Nov 16, 2010)

Dayhiker said:


> Thanks for thinking. I can't stand the pain of doing it for myself.


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## lobodog2 (Nov 10, 2010)

Charles, ****...


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