# Going all myth-buster on my butterfly bands



## KawKan (May 11, 2013)

The great thing about having a chronograph is that you can test your ideas about slingshot band performance. I have long “felt” that there was a myth about performance of the butterfly draw versus shorter draws. In particular that increased speed was due simply to having more latex in the longer bands.
I spent one of our recent cold and rainy days testing that idea.
Speed is in Feet per Second.








*Big difference:* Draw weight. Bands for the face draw pulled 11.61 pounds and butterfly bands pulled 5.33. I notice that is close to twice the pull for the bands that are twice as wide.
*Speed differences:* Meh. About 3 percent overall performance difference. That could easily be attributed to testing error. The butterfly performance did have a consistent, small advantage across all ammo weights. I suspect my butterfly draw pulling against bands is a bit longer than my butterfly draw holding a steel tape.
*Efficiency:* Output velocity per pound of input draw weight - the butterfly bands win in a cake walk. The butterfly input is about 46 percent of the face draw input for a 3 percent difference in output.









*Method* (details may make your head hurt!)
I cut two sets of bands (GZK .62 orange/yellow), one for a 28-inch draw, and one for a 56-inch draw. So one set is twice as long. The math for getting ⅕ the draw length resulted in latex rectangles 1.5 inches wide by 5.6 inches long (8.4 square inches) and .75 inches by 11.2 inches (8.4 square inches).
The rectangles were each split for band sets with a 1 by .5 inch taper or .5 by .25 inch taper (both 2:1). The lengths were marked on the latex and the tapers were cut at the lines. Identical pouches were mounted on the narrow ink lines and the wide ink lines were mounted into clamps on slingshots with identical fork widths.








Any surprises?


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## JASling (Feb 4, 2019)

Great information!!!

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## spewing (Mar 13, 2016)

thanks for that post. 
Very interesting to see that your measured results confirm my gut feeling.


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## skarrd (Jul 20, 2011)

good info,thank you,yes the math was a bit confusing but the woman was here to help me understand it "more better"
lol


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## Valery (Jan 2, 2020)

Very interesting information. Thank you! I don't shoot butterfly style, but it seems to me that we should compare ribbons of different length but equal taper. For example, 15x20x160 mm for classic style and 15x20x320 mm for butterfly style. In this case there should be a significant increase in speed with equal traction.


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## High Desert Flipper (Aug 29, 2020)

Awesome stuff, I love it! I hadn't thought about looking at butterfly vs short in terms of total volume of latex. Really cool! Also very cool to see that overall speed is tightly linked to latex volume but that draw weight of that volume can be hugely altered by changing the shape that the volume is in, so long as you can draw it to the same elongation. Really cool stuff, thanks for sharing this!


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## Pedroito (Aug 22, 2021)

"*Efficiency:* Output velocity per pound of input draw weight - the butterfly bands win in a cake walk. The butterfly input is about 46 percent of the face draw input for a 3 percent difference in output."

not a single word was understood by me

What is output velocity blabla? is it same speed or faster? totally lost

also the result implies that butterfly is easier to pull?


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## Peter Recuas (Mar 6, 2014)

Thank you very much Ray


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## Tag (Jun 11, 2014)

Thanks for sharing


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## bottlecap (Jan 16, 2021)

Way to dig into it, Ray, gotta love that passion of yours, thanks for sharing!


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## StringSlap (Mar 2, 2019)

Good stuff, Ray! That confirms what I found in my short testing sessions. Velocity pretty much the same, but at a much reduced draw weight for butterfly. Easier draw equals longer, less stressful shooting sessions and longer band life (for the most part). Good news for my preference of shooting pfs, because shooting pfs with short draw feels awkward and unnatural.


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## KawKan (May 11, 2013)

Pedroito said:


> "*Efficiency:* Output velocity per pound of input draw weight - the butterfly bands win in a cake walk. The butterfly input is about 46 percent of the face draw input for a 3 percent difference in output."
> 
> not a single word was understood by me
> 
> ...


There are several ways to measure efficiency, but I chose to compare the draw weight (the energy a shooter puts in - or input) to the ammo speed (velocity) that the bands produce - or output. In this test, the speeds were only slightly different (3 percent) and the draw weight was very different. Butterfly bands were much easier to pull. So, easier pull for the same speed is more efficient.
Additionally, @Pedroito, this test supported others that I've done and read about regarding latex and draw weight. If you make the latex twice a wide it will double the draw weight. But making the latex twice as long does not change the draw weight, although you still have twice the power!


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## High Desert Flipper (Aug 29, 2020)

It just occurred to me you could interpret this forward or backward. The reverse could be for short draw shooters to take heart. They can get the same velocity as butterfly shooters using the same volume of latex. The short draw crowd just needs to get to the gym and bulk up so they can pull 3x the draw weight!

Someday I will need to dedicate some time to getting consistently accurate with butterfly, the speed per unit of draw weight is really impressive.


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## Ibojoe (Mar 13, 2016)

That’s a head full Ray. I think both have certain advantages. I’ve shot butter for years now. The only thing I miss about a face anchor is the speed which I could load and shoot. Just can’t pull that weight anymore but still can’t stop shootn big ammo. 
thanks for the comparison info. That was a big undertaking.


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## Hoss (Jun 3, 2014)

Great information, thanks for sharing. 

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## KawKan (May 11, 2013)

Ibojoe said:


> That’s a head full Ray. I think both have certain advantages. I’ve shot butter for years now. The only thing I miss about a face anchor is the speed which I could load and shoot. Just can’t pull that weight anymore but still can’t stop shootn big ammo.
> thanks for the comparison info. That was a big undertaking.


Glad you liked it, Joe!
The hardest part of this project was figuring out how to eliminate as many variables as possible so the test would be focused on the change in band length, not the change in the quantity of latex.


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## Biker_Bob (Mar 26, 2020)

I've done similar tests myself.
So if I interpret correctly you used the same amount of latex, but cut to different shapes for face and butterfly.
When I did the tests that didn't occur to me, my butterfly bands were the same taper as the face anchor bands but just longer.
For a 40mm to 30mm taper and 170mm length for face anchor I got 11.01 ftlbs with 12mm lead.
The same 40 to 30mm taper and 270mm length for butterfly gave 14.05 ftlbs with the same 12mm lead.
As you found the butterfly is more efficient given the same draw weight, the energy in the projectile is the result of how hard it's pushed and how long it's pushed for.


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## altusflute3 (9 mo ago)

Thanks for posting this .I love butterfly shooting .
I usually use a floating anchor depending on what I am shooting at. Watch out when learning though. I assure I am not the only one with scar on my cheek obtained from learning how to shoot at full draw.


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## Flatband (Dec 18, 2009)

Man Ray, you did some serious work there Bud! Reading through it I felt I was in a College Physics class!  Excellent job and some surprising results too. Thanks for the effort!


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## Reed Lukens (Aug 16, 2020)

That's a significant difference in speed to me for the same amount of latex. 
Very Cool Ray 😀


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## Pedroito (Aug 22, 2021)

thanks, I note this down though I had already heard that advice from Nathan Masters and Joerg Sprave
but here it's crystal clear

it applies to tubes as well ofc


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## Rb1984 (Sep 25, 2020)

Good info! I love these experimentation threads, although I have to read them carefully to understand them well😂. I have more desire to shoot butterfly. And to buy me a chronograph.


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