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The Slingshot Channel Thread

All non-spudgun related discussion goes here such as projects, theories, serious questions, etc. All "off-topic" posts (aka useless posting, determined by moderators) will be removed.
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Unread postAuthor: JoergS » Mon Nov 09, 2009 2:38 pm

Have attached my Walther tactical flashlight (quick and dirty method for now). I have to say that this works better than a laser. The distance to the tree is 18 meters, and still the light is pretty focused. The light is bright enough even in broad daylight!

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Unread postAuthor: psycix » Mon Nov 09, 2009 2:43 pm

With a strong scope, I think you learn that you need to pull the trigger at the right moment. Right when you shake through the bullseye!

Just shaking over your target and then jerking the trigger is not the correct way of shooting. It may work, but in the end you will shoot better if you learn to stabilize your aim and gently increase pressure on the trigger until the gun fires.

Giving a pull right at the moment of the shot may give a better result, but just for that shot. Over time, doing this will only cause you not to learn how to aim. When training your accuracy, you should never do it. When you are not training for accuracy, but just want to hit something, you could.

Of course, the above is for firing an (air)gun. For slingshots and bows, this may not apply. Under tension you will always wobble.
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Unread postAuthor: Brian the brain » Mon Nov 09, 2009 5:03 pm

At close range I too have found that a flashlight works very effectively for sighting.

Overall good job!
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Slingshots: Are thinner bands more powerful?

Unread postAuthor: JoergS » Sat Nov 14, 2009 5:36 am

As you may know. my slingshots are much, much more powerful than the ones (most of us) used as a kid.

The main reason is the far better rubber we can use today, no longer are we limited to inner tubes and surgical tubing.

I have used the Thera Band Gold flat bands so far, which is the thickest (but still thin) stuff you can get.

Recently, a fellow slingshooter in a German forum posted that multiple layers of thin flat bands are faster than the same amount of rubber in thicker material.

The eternal hunt for power goes on! A great new frontier.

I have bought Thera Band Black, which is a lot thinner than Thera Band Gold. The manufacturer says the draw force is 0.43 in comparison with Thera Band Gold.

So I converted my favorite Gold setup (9cm * 6 cm * 20 cm) to 21 cm * 7 cm * 20 cm of Black. Have to use two layers as the roll is only 14 cm wide. It is true, same resistance.

Compared to the Thera Tube Black, the flat band has the same draw force in 14 cm width, so compared to Thera Tube Black my band set is 1.25 times harder to draw out. That works.

OK here is the result.

.75 l = 19 mm lead ball, 36 gramms, 576 grains
.60 s = 15 mm steel ball, 12 gramms, 192 grains
.38 s = 9.5 mm steel ball, 4 gramms, 64 grains

TBG = Thera Band gold, 9 x 6 x 20 cm
TBS = Thera Band black, 21 x 7 x 20 cm


TBG .38 s 78 m/s, 255 fps
TBG .60 s 73 m/s, 239 fps
TBG .75 l 54 m/s, 177 fps

TBS .38 s 90 m/s, 295 fps
TBS .60 s 79 m/s, 259 fps
TBS .75 l 63 m/s, 206 fps

Max. Energy TBG = 52 Joule = 38 fpe
Max. Energy TBS = 71 Joule = 52 fpe

The black bands did not tear throughout the tests.

Temperature was 14 degrees celsius, 57 degrees Fahrenheit.

The theory works! Now let's see what will happen if my thiiiiin Thera Band Tan band arrives. This is the thinnest material you can get. I guess to get to the same force, I will have to use ten layers per side.


Jörg

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Unread postAuthor: POLAND_SPUD » Sat Nov 14, 2009 5:53 am

ohh that seems like a quite substantial gain.... good job

Max. Energy TBS = 71 Joule = 52 fpe

TBS stands for Terra Band Schwartz, right ?? you might want to correct that :D

EDIT
ohh dammit you mentioned that earlier in the post... my bad
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Last edited by POLAND_SPUD on Sat Nov 14, 2009 5:57 am, edited 1 time in total.
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Unread postAuthor: qwerty » Sat Nov 14, 2009 5:56 am

Interesting. Can you pull back the multi-layered ones further than just the plain single TBG?
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Unread postAuthor: JoergS » Sat Nov 14, 2009 5:57 am

Same draw force, the two band sets feel exactly the same. That was to be expected, I used the conversion table provided by the manufacturer of the rubber.
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Unread postAuthor: john bunsenburner » Sat Nov 14, 2009 6:25 am

Hmm, this calls for a layer calculator and a simulator...If you get more data perhpas a pattern can be found...
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Unread postAuthor: Pookydarts » Sat Nov 14, 2009 8:54 am

Sie sind zweifellos an der vordersten Reihe der Schleuder-Entwicklungstechnologie. Das einzige Ding, das ich denken kann, um zu schreiben, besteht darin, dass ich pflegte, zwei Schichten von dünnen Bändern zu verwenden, um meine Schleudern anzutreiben. Ich spreche Deutsch übrigens nicht, ich verwendete einen On-Line-Übersetzer. Das einzige Ding, das ich habe, der deutsch ist, ist mein Nachname. Jesus Christus, schauen Sie auf alles, dass gobyldygook ich die Sprache an dieser Rate nie lernen werde!!! :lol: :lol: :lol:
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Unread postAuthor: CpTn_lAw » Sat Nov 14, 2009 9:09 am

Ich habe während sieben jähre Deustch gelernt, und ich bin stolz, weil ich deine meldung verstanden habe, es prüft, dass ich es alles nicht verloren habe XD

I have learned during seven annual Deustch, and I'm proud because I have understood your message, it verifies that I have not lost everything XD
Translated by google.

To get back on topic, I would've not thought of that!! Will you make a nice video about it?

Edited by jrrdw.
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Unread postAuthor: Pookydarts » Sat Nov 14, 2009 9:15 am

Ich lache, weil ich eine komplette Flasche des Hafens verbraucht habe!
(Edit) I laugh, because I have just seen the translation! :lol:
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Unread postAuthor: POLAND_SPUD » Sat Nov 14, 2009 9:31 am

eine komplette Flasche des Hafens verbraucht habe
I laugh, because I have just seen the translation
these two doesn't mean the same :)
if it had been a traditional polish drink you couldn't write at all


Recently, a fellow slingshooter in a German forum posted that multiple layers of thin flat bands are faster than the same amount of rubber in thicker material
do you have any idea theory why it works like this ??
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Unread postAuthor: Ragnarok » Sat Nov 14, 2009 9:46 am

Interesting. That's a big difference in energy.
I've got some vague ideas about why, but I'll need to look into them more fully first.

Pookydarts wrote:Ich lache, weil ich eine komplette Flasche des Hafens verbraucht habe!

I don't speak German either, but even I know the word "bottle" probably has no part in that sentence.
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Unread postAuthor: Pookydarts » Sat Nov 14, 2009 9:48 am

I laugh, because: "I have just consumed an entire bottle of port" and "I have just consumed the entire harbour" are significantly different... I give respect for the fact that a new level of understanding for the acceleration of projectiles has been reached. 8) Word.
Cheers! JoergS!
)Edit(
these two doesn't mean the same
if it had been a traditional polish drink you couldn't write at all

You Polish need to meet some more Austrarians! :lol:
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Unread postAuthor: JoergS » Sat Nov 14, 2009 10:48 pm

Translators are really funny! Especially the "user manuals" you can sometimes find whenyou get a product made in China. Those are jokes in themselves.

I have now cut a band set of Thera Band Blue, which is even thinner. The sheets are now two layers of 13.5 x 9 x 20 cm = one layer of 27 x 18 x 20 cm. Same draw resistance!

Will test it in a few hours, when it is light enough for the chrony.

The theory is: Inner resistance. The thicker the rubber, the more friction between the latex molecules occurs. So solid rubber tubes or squares are the slowest, thin hollow tubes are faster, flat rubber is the fastest, and the fastest is the thinnest of the flat rubber.

Unfortunately the "life expentancy" works the other way round.

So for a record shot it is clear:

Use the thinnest rubber you can possibly find, and shoot on a hot, hot day. Stretch to the max. Use very heavy ammo to max out the energy.

If you want the most shots out of a band set, go for the thickest material you can find. and only draw it out like 70% of the max.

So you have to find your own compromise.

Personally, I love strong slingshots and will probably stick with the fastest rubber set that gives me about 100 shots. I much rather change the bands more often, the stuff is fairly cheap.

Jörg
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