# Speed & Power, Heavy Draw less Draw Length -V- Lighter Draw Weight, Longer Draw



## Aussie Allan In Thailand (Jan 28, 2013)

*Hi Again All,*

*I bet it has been mentioned before, but I can't find it; but think I know the answers, just not certain.*

*So can someone tell me in general terms: how does very heavy draw strength required, for a shorter anchor point draw; stack up in comparison to a lighter draw strength, but much longer draw to nearly half butterfly ?.......*

*For of course the same weighted ammunition.*

*In anticipation of some assistance.*

*Cheers*
*'*
*Allan*


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## TimR (May 22, 2011)

In theory, assuming a perfect linear spring constant, if you double the length of draw at the same weight (I mean the same 10 pounds of force draws back 30 inches instead of 15 inches) you should increase speed by 40% or so. 41.4% I think.


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## Tex-Shooter (Dec 17, 2009)

As I have shot, the longer draw wins the speed and power factor. -- Tex


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## Winnie (Nov 10, 2010)

Latex is so weird I don't know how linier the power to draw ratio is but there is no doubt that you will get way more power with butterfly, or even half butterfly. Unfortunately you lose your aim point and, instead, must shoot instinctively.

I shoot butterfly exclusively but, fortunately for me, I would rather hear a solid thud than actually hit my target.  (I'm amazed at my ability to remember my good hits and forget my bad hits.)

winnie


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## Chevas (Oct 29, 2012)

The energy in elastics increases expotentially. I think you have to consider the thickness of each band. Tapering is a considerable variable, 3:2 ratio, like 1 1/2 down to 1" is a good taper. Let's compare this to a 3"down 2 inch taper, or in essence doubling the amount of band. Let's say the larger band is pulled back, but it's a struggle, not as accurate, let's say to 28 inch draw. You been heavier pouch, a little more drag, etc, but you got a good shot. This time, 11/2 taper to 1 inch, 1/2 the energy to pull back so the draw length comfortably can extend to a 34 inch draw. Because of the six extra inches on an Expotential curve, I think the lighter bands would be faster on .38 cal stainless. The curve is the same, the thicker bands start at a higher location but the end result would be that pulling the lighter band further would be more accurate, just as fast and you shoot longer. I am not sure of this, I think it is correct. 6 inches is a long way in an Expotential system, Good luck, may need to experiment.


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## bullseyeben! (Apr 24, 2011)

Hey Allen, to give you a quick but fairly accurate exanple... shooting a .33 lead ball ( about 8.4mm) with 1 inch straight cut latex bands, cut at a tied off length of around 9.5" inches, ill get between 240fps and 270fps apron depending on temp, exact release stretch pouch weight etc etc.... tapering them 25mm wide bands down to around 8 - 10mm at the pouch end will get you around 330 fps at a 45" draw (approx) ... Thicker at the fork end of the band will provide torque to accelerate the weight of the shot, while usually the pouch end when tapered down is stressed much harder, providing acceleration whilst already reacting in motion...providing the amo isn't too heavy for the taper.....


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## dgui (Jan 12, 2010)

You will obtain Greater Speeds and Impact by a Faster Draw N Release. Do an experiment and take a half second to draw and release on a can and then on an identical can at the same distance and hold for 5 seconds and see the difference in penetration on the 5 second shot and then see the dent at holding for 5 seconds. Shorter tubes or flat bands wins at least it does for me. The ammo comes out of the pouch at the same place with relationship to the pouch either slowing down with longer tubes and flat bands vs short tubes and flat bands the short ones are still forcing at a higher rate of speed. When the heat generated is at its maximum and released right away then you obtain maximum performance. Of course this is my opinion based on can and not crony evidence.


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## bigron (Nov 29, 2012)

:yeahthat: i would listen to the quick draw master.yoda the kid he is the man on speed and accuracy


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## bullseyeben! (Apr 24, 2011)




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## Aussie Allan In Thailand (Jan 28, 2013)

*Thanks all and i get the point.*

*Currently I am fairly accurate on my 9 meter home range (just shorter than my 10 meter frontage, allowing for target placement, and not standing on the boarder fence to shoot).*

*However, I have 3 slingshot I shoot, with 3 different relaxed band lengths, and taper, and 5 different ammo types.*

*Hence the ballistics are different for all 3.*

*Therefore, I have to for simplicities sake, find a band type, and tapper; to allow me the full 44 to 46 inches, (a bit over half butterfly given at 5'6" my arms are not as long as a taller guy for draw length, regardless of my strength); for all three, and soon to be twice as many slingshots used.*

*While still retaining my aiming point shooting gangster style.*

*This complicated a little, that 1, and soon 2 or maybe 3 of my slingshots are Dankungs, and use tubing.*

*But regardless, from measurements of relaxed length to full draw, I am achieving a bit over 5 times the lengths in stretch, which I think is pretty near the max bands will stretch, from trying to recall what I have read.*

*From the forks to an anchor at my lips is 30 inches, anchor at my ear lobe is about 33/34 inches; the half butterfly I can get with A+ Slingshots PS 1 is 44 to 46 inches, and I can still aim very well with my left/top fork.*

*Therefore comments, and suggestions, on both tubing type, and relaxed length at the forks for the Dankungs: and Latex or TheraBand Gold for the others: would be very much appreciated.*

*Thanks all and I look forward to reading suggestions.*

*Cheers Aussie Al*


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## halbart (Jan 23, 2013)

bullseyeben! said:


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Thanks Bill. This kind of solid evidence is invaluable . You give a real service to shooters.


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## bullseyeben! (Apr 24, 2011)

halbart said:


> bullseyeben! said:
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No worries mate, but I'm Ben.. 
 just joking with ya lol


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## bullseyeben! (Apr 24, 2011)

Aussie.Allan said:


> *Thanks all and i get the point.*
> *Currently I am fairly accurate on my 9 meter home range (just shorter than my 10 meter frontage, allowing for target placement, and not standing on the boarder fence to shoot).*
> 
> *However, I have 3 slingshot I shoot, with 3 different relaxed band lengths, and taper, and 5 different ammo types.*
> ...


It's all about experimentation Allen, my suggestion would be to start making your own band / tube rigs and play around to see what works best for you.. a self healing cutting pad, a good brand rotary blade is about all you need along with the rubber & maybe a tying jig ( a good missus / wife can also work here depending on time of the month) and your about set..  Personally, being a flat band man I have seemed to settled with one measure of cut that is working well for me at present.. 10" long bands once tied ( about 26cm before tying) tapered as I've mentioned before , 25mm to about 10mm.. with this cut I'm not really over stressing the bands for my general Target shooting draw, but if the need arises I can really pull them back for some speed increase. So if your comfy with a 40 - 45 " draw I would recommend starting about there..good band life, speed there if its needed  cheers , Ben


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## Crac (Mar 3, 2013)

:stupidcomp:


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## Aussie Allan In Thailand (Jan 28, 2013)

*Thanks all so far.*

*I saw a vid of Game Keeper John using a 30 mm to 10 mm taper, supposedly around 20% faster than his usual bands sets.*

*So even if slightly less band life.*

*I think I will go with his tapper guidelines from the vid.*

*Now just got to get some TheraBand Gold from ebay I guess.*

*Cheers Aussie Al*


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## Hrawk (Oct 25, 2010)

My most extreme speeds from Thera Band Gold come form 50 to 10mm tapers.

Don't expect your bands to last very long though.

Every think is a compromise : Speed vs band life - power vs draw strength.


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## Aussie Allan In Thailand (Jan 28, 2013)

*Great, thanks for the advice.*


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## Crac (Mar 3, 2013)

The short answer is

For a '14lbf' draw and based on my preferred strain the results are:

30.0 Inch: a single set of 1842, 142mm free length, 11.0mm ball
33.5 Inch: a single set of 1842, 158mm free length, 11.0mm ball
45.0 Inch: a single set of 1842, 212mm free length, 12.5mm ball

The 1842 is a little lower force.

A single set is two pieces of rubber, one on the left fork and one on the right.

If you want more 'bite' 1745

30.0 Inch: a single set of 1842, 142mm free length, 12.0mm ball
33.5 Inch: a single set of 1842, 158mm free length, 12.0mm ball
45.0 Inch: a single set of 1842, 212mm free length, 13.5mm ball

The 1745 is a little higher force.

A single set is two pieces of rubber, one on the left fork and one on the right.

For Theraband gold:

The same lengths: 142mm, 158mm, 212mm.

Same ammo as 1745: 12mm, 12mm, 13.5mm.

4 pieces of ~9.2mm wide straight cut. (9mm to 11mm)

I've aimed for around 70m/s (~220 fps) in all cases.

https://docs.google.com/file/d/0B_1zOFn3YZGTTXlLajZmOUlWMHM/edit?usp=sharing
https://docs.google.com/file/d/0B_1zOFn3YZGTakxMSFRUYUZxRVk/edit?usp=sharing
https://docs.google.com/file/d/0B_1zOFn3YZGTX3JhM09TZmdUNkU/edit?usp=sharing
https://docs.google.com/file/d/0B_1zOFn3YZGTcVpDQVFibjRPMWc/edit?usp=sharing
https://docs.google.com/file/d/0B_1zOFn3YZGTdmIwUGpXemRxZUU/edit?usp=sharing
https://docs.google.com/file/d/0B_1zOFn3YZGTNHB4UFdSRHI4cTg/edit?usp=sharing

It's only a little bit of reasoning...

p.s think about the taper...


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## Aussie Allan In Thailand (Jan 28, 2013)

*Very detailed information in the links, thanks Cracks.*

*Also a lot to consider.*


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## Crac (Mar 3, 2013)

Obviously the native form for A3 landscape its a little easier to read on screen... but exporting it AAAAAAAAARRRRRRRRRGGHHHH :stupidcomp: :stupidcomp: :stupidcomp: :stupidcomp: :stupidcomp: :stupidcomp: :stupidcomp: :stupidcomp: :stupidcomp: :stupidcomp:

might try to fix it later...

6 pages (A4 landscape) and 6 ideas... I've really tried to explain the ideas in the simplest possible terms. While using the correct technical notation. So what looks like a ton of reading is pretty low density. The set are all the same piece, so you don't need to read them all! Plus the summary is above.

The first picture is very important to understanding band design... The 2nd and 3rd tells the reader more about the author and which point, refer back to the first picture.

I'm glad to see you come over to 'dark' side with flatbands. My perfered choice anyhow.

However, it ties to the outline in the PM.... But I think it might be of some interest to a few others?

As ever call for the corrections. It is technically a private work in progress...


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## Crac (Mar 3, 2013)

Updated:

Ammo: 11mm ,12mm ,13mm.

But other options availible....

Gold Set.

https://docs.google.com/file/d/0B_1zOFn3YZGTUFUtVVdBVjF0RFE/edit?usp=sharing
https://docs.google.com/file/d/0B_1zOFn3YZGTd0lyQ0tsYTJZMnM/edit?usp=sharing
https://docs.google.com/file/d/0B_1zOFn3YZGTcHZsVDBYakhYM1k/edit?usp=sharing

The previous files are toast.


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## Aussie Allan In Thailand (Jan 28, 2013)

*I am curious Crac.*

*Why the seeming lowish end of the speed scale; and even your largest ammo sizes, are at the lighter weight side of what I prefer to use.*

*Yes I do fire occasionally 8 mm lead, which weighed on pharmacists scales came in at 1 gram; and glass marbles, weighed at the same time at 1.15 gram.*

*Although most of the time it is half inch steel at 8.5 gram, cylindrical lead from an ebay seller renovation leather, at 20 gram; and yet to be weighed, but noticeably heavier than the 20 gram lead heavier hex nuts (guessing around 25 grams).*

*I use these weights so as to ensure as much as practical, even with not pin point accuracy, but to within 1 to 2 inches of point of aim, a fairly certain instant kill.*

*And even with the video not yet done, due to repeated error readings on the Chrono Connect app.*

*With the marbles, and smaller lead balls; I am regularly achieving speeds of the mid to high 300 fps, and occasionally cracking the 400 fps by a very small amount.*

*So I guess my objective is, even with the heaviest ammo I use, would be a band set obtaining 200 plus fps. *

*Cheers Aussie Al*


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## Aussie Allan In Thailand (Jan 28, 2013)

*Oh, and these speeds, (probably not surprisingly to an experienced shooter); are from my PS 1 A+ Slingshot, which requires the least strain to reach half butterfly at around 42 to 44 inches.*

*The other 2 slingshots with doubled bands each side, or tubes in the Dankung Alien model; with more effort required to reach their, or my max draw, of 30 inches for the Bill Hays Hathcock, and 32 inches for the Dankung. Are both noticeably slower, both in the high 200 fps mark, but neither with max effort by me, cracking the 300 fps barrier.*


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## Crac (Mar 3, 2013)

The slow speed was picked to be constant across the range of draw length. I've not been able to create a general solution which is stable enough for others to use. The ammo is only 10%-30%+ of the slung mass, and then there is how people attach it. It comes down to a balanced approach we can quantify what is happening with the bands statically... Sure I could try and solve it with a fast simulation but I don't want to waste the time trying. (It might take 2 or 3 weeks and use most over night computer time) Or I could shoot over a chrony for 45 mins and take all the data I need...

The speed of the draw, hence the heat generated plus the temperature difference might all effect the tensile model, hence everything else. But I suspect your pulling more draw wieght too.


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## halbart (Jan 23, 2013)

bullseyeben! said:


> halbart said:
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> > bullseyeben! said:
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Oops ! Sorry Ben, mate. What a mistaka to maka !


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