Saturday, October 29, 2011

Thera Band Gold calculator: Online!

I wrote the algorythm (in Commodore BASIC, the only programming language I ever learned), my brother Hartmut converted it into a java script, and Thomas Kole implemented it into my web site...

Here it is:

Check it out on my homepage!

It will probably take some for fine tuning, but in the end it should be just perfect.

25 comments:

  1. Oh no! I gotta think in metric? Horrors and woe upon me! :)
    Excellent calculator Joerg. Thank you very much for doing this for us.

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  2. WOAHHH!!! thank you so much for that. it works great. if i was female, i'd ask you to marry me. thanx a lot. :-)

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  3. This is one of the greatest tools a slingshot shooter could have. The will most definitely help me and others around the world with band set-up. THANK YOU Joerg for these calculations, they are greatly appreciated

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  4. Just got a catapult from rkcatapult. Your band calculator suggests that double 20cm bands, tapered from 25mm to 20mm is way overpowered for shooting 10mm steel for targets. I already took it down to single bands.
    For a 90cm draw, and choosing 6 & 6 (middle of the road) your calculator shows getting a ~ 23cm bands, tapered ~1.3cm to 0.7.
    (I can't see the difference between 0.7 and 0.64 mm, so I sure can't cut that accurately ;-)
    I seems that unless I put in 14mm lead, double theraband gold 25mm->20mm is crazy overkill...

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    Replies
    1. I used the calculator my first time, then used the length it gave me which was 27.56cm at a draw of 80cm I think, I forgot the the width and did 3cm tapered down to 2cm it is powerful and I can not pull it out to full draw because I've lost about 5cm on the pouch and forks. I've not found any over kill with 12mm steel ball bearings however it obliterates pigeons.

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  5. Rational Root, yes, those original bands are good for heavy lead ammo, 10 mm steel is pretty light.

    The original bands would also give you a terrible handslap when you shoot 10 mm.

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  6. i test the calculator, there was too little rubber and too little stretching for me, maybe this was made for beginners :-)

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  7. Tobias, yes, the calculator is aimed at the average user, not the world record keeper...

    Seriously, I may have to change the algorythm for the "extreme" settings. Currently, I use a max,. stretch of 5,5 and 600 gramms of draw weight per gramm of bullet weight. So a 30 gramm ball would need 18 kg draw.

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  8. yes, this change is necessary because number 9 = max power.

    i´m use 900g draw weight per gramm of bullet weight
    with 16mm steel
    and 1400g for 12mm steel
    for the big ball are 600gramms OK.

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  9. Nice to see both experts (Tobias and yourself) agree in principle for an 'extreme' setting. Since many of your fans want to follow you in this path of 'more power', a guide or formula to achieve (or at least just try to achieve) this would be very much appreciated. Since you mentioned your calculator would need possible 'tweaking', I submit my request for this 'extreme' setting with an already existing appreciation for what you have already done with the calculator. Thank you again for the calculator.

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  10. Thanks for the reply, I've taken the RK down to Single bands, and ordered some Theraband Gold to make up my own bands. I'm over 190cm tall, so even anchoring at my chin give me a 90cm draw. Right now, until I can hit things smaller than a wall, power does not matter much.

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  11. Your my favorite yoda Jörg!
    Greetz aus deinem Heimatland

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  12. Thanks Joerg, This is really handy. I, also am interested in the extreme setting. All the way to 11.

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  13. WOOOOOOOOOOOOOOOHOOOOOOOOOOOOOOOOOOOOOOOOOOOO!!!!!! I've been waiting for this ever since u mentioned it on the old forum :)

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  14. Hey all I want to buy some Thera band Gold but do not want to buy it from feebay.Where is the best least expensive place to buy it? Already got a nice black HDPE (high-density polyethylene sling/catapult from fee bay.
    eric_botts@yahoo.com

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  16. Just getting ready to test the calculator. However, I don’t have access to Theraband Gold where I live (it’s complicated)! The best I can manage is a blue DOMYOS “Fit Band” rated at 10kg/22lbs (not sure how that’s measured). Here’s the website: http://www.decathlon.co.uk/fit-band-id_8212968.html#avantages
    Anywho, I would like to see another variable added to your calculator where the rubber type/draw-weight/gauge can be taken into account. Too bad it’s limited to ONLY one type of rubber, the Theraband Gold (too limited for real world application).

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  17. Hi Joerg,
    On what do you base your 0,6 kg per gram bullet weight?

    Cheers,

    Adrian.

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  18. does the length in the results include some spare space for tying? or should i just cut what it says?

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