42 replies to this topic

[Sam]

ZDP-189, on 23 July 2010 - 09:16 AM, said:

BTW when you do your 500% charts, you'll need to test the force-contraction curves as well as the force-elongation curves and also measure the velocity of the bands to test the band efficiency you wrote of earlier. I think you'll get some interesting and revealing results past 350%.

I agree, I look forward to seeing the results!

[919h]

Most of us using the “force elongation” 1000mm or 39.37”

The band slingshot is arount 200mm or 8”

Also

For 100% elongation band , we have 200mm + 200mm = 400mm or 16”

For 200% elongation band , we have 200mm + 400mm = 600mm or 24”

For 300% elongation band , we have 200mm + 600mm = 800mm or 31”

For 400% elongation band , we have 200mm + 800mm = 1000mm or 39”

For 500% elongation band , we have 200mm + 1000mm = 1200mm or 47”

So what interest to us is the extension to 400%

I’m on a right or wrong way ?

Excuse me for my bad english

@+

Thomas

[ZDP-189]

Sorry, the relationship is not linear. There are example force elongation and force contraction curves in my blog.

[PandaMan]

i don't know which thera band to use... I remember when I was 9 I tried archery and I could do it ok with an adult's bow, which surely has a strong draw weight... I think maybe black or silver, which do you guys think?

[ZDP-189]

I would start out with a medium weight band and decide whether you need more energy when shooting larger projectiles.

[PandaMan]

that would be good, but I really have very little money to work with. I get £2.50 a week, so if I'm going to buy thera band, I want to make sure it's the right strength first time. I'm maybe thinking blue or black?

[ZDP-189]

Truly, it doesn't matter. You cut the band as wide or narrow as you want to match your draw strength. I would start with Gold bands because they'll be narrower. Thin bands of the same draw are wider and that can be harder to control but somewhat faster.

BTW - I'm talking about flatbands not tubes.

PM me an address to send it to and I'll mail you some free pieces of whatever I have lying about in my workshop. I'll even send you a pair of my Fastbands if you like.

[PandaMan]

ZDP-189, on 24 October 2010 - 03:05 AM, said:

Truly, it doesn't matter. You cut the band as wide or narrow as you want to match your draw strength. I would start with Gold bands because they'll be narrower. Thin bands of the same draw are wider and that can be harder to control but somewhat faster.

BTW - I'm talking about flatbands not tubes.

PM me an address to send it to and I'll mail you some free pieces of whatever I have lying about in my workshop. I'll even send you a pair of my Fastbands if you like.

wow. I'd really appreciate that. Thanks, PM sent.
and if you're willing to send a pair of Fastbands then you can, I don't mind. Free stuff is good.
And also I'd like you even more if you could send 4 inches of tube. It would make it easier to mount the bands onto my slingshot. But you don't have to.
Thanks.

[Botus]

Interesting data. Does anyone know at what percentage elongation the band moves from elastic to plastic deformation, obviously it would change depending on the type of band that was used. Surely there are instances when say a 500% elongation merely damages the band i.e. plastic deformation and therefore a draw of this elongation is pointless. Sadly im bogged down with work at the moment but have plans to undertake some experiments myself in the new year.
By looking at this chart surely for someone like myself with a short, more compact draw the biggest advantage I could gain would be by shortening the length of the band set in the first place, thus increasing the maximum possible elongation I could achieve using the same draw. I understand other factors come into play but this is what the data would lead me to believe!
Would the volume of band utilised also have a significant effect on the possible power returns?
I understand that this are all questions I should probably answer myself through experimentation but if anyone can give a few pointers in the right direction I can refine the proposed experiments I plan to undertake.
Cheers then!

[hickymick]

[Aras]

I wanted to ask what band should I use. I'm only 14 years old, and I'm afraid, that thera band gold is too strong for me. Any suggestions?

[Sleepy]

I went shopping for thera-band at Amazon. There was listed there bands and tubes. In all these colors listed. And they were also in either latex rubber or non-latex rubber. Do the two, i.e., latex vs non-latex pull with the same resistence ?
Thank you very much for these charts by the way.

[Formidonis Noctu]

Ive come to the right forum, this along with so many other posts and articles here have been of tremendous help.
Thank you everyone

[Hugh Neverknow]

Would I be right or wrong to think that the amount of force required to stretch a length of latex is not a measure of the speed it sends a projectile?

For instance, would a set of bands made of green Theraband, that requires the same force to stretch as a set made of gold theraband (the width of the gold cut to match the force of the green) send a projectile of the same weight at the same velocity. I think but have no evidence yet that the red would be more powerful. And for the same reason that flat is better than tube or solid, the thinner the profile the quicker it can dissipate heat and return to its un-stretched form.

The ultimate aim is to have the highest velocity for the lowest stretching force. I realize other factors come into play such as durability, pouch size, %age of stretch and no doubt a lot of others. But all other factors being equal I think the thinner the band the better

I now await to be told I am wrong and why, while I wait for my chrony to arrive so i can settle this for myself. It is almost like science!

[Hit and run]

Hugh Neverknow, on 08 June 2011 - 01:26 PM, said:

Would I be right or wrong to think that the amount of force required to stretch a length of latex is not a measure of the speed it sends a projectile?

For instance, would a set of bands made of green Theraband, that requires the same force to stretch as a set made of gold theraband (the width of the gold cut to match the force of the green) send a projectile of the same weight at the same velocity. I think but have no evidence yet that the red would be more powerful. And for the same reason that flat is better than tube or solid, the thinner the profile the quicker it can dissipate heat and return to its un-stretched form.

The ultimate aim is to have the highest velocity for the lowest stretching force. I realize other factors come into play such as durability, pouch size, %age of stretch and no doubt a lot of others. But all other factors being equal I think the thinner the band the better

I now await to be told I am wrong and why, while I wait for my chrony to arrive so i can settle this for myself. It is almost like science!

Generally, for two bands with the same mass the one with the highest surface area will contract the fastest. (http://www.melchiorm...info_power.html subsection band shape)
The big disadvantage of the thinner bands is that you need a broader band to propel the same mass, (Green vs. Gold around 2.5x the width) and they break faster.

[Hugh Neverknow]

That makes sense - I was trying to think of why the thinner band would be faster but surface area would be the reason for the transfer of heat?

Of course the wear factor, wind resistance, general practicality will be issues but this was bugging me thank you for your clarification

Hit and run, on 11 June 2011 - 02:27 AM, said:

Hugh Neverknow, on 08 June 2011 - 01:26 PM, said:

Would I be right or wrong to think that the amount of force required to stretch a length of latex is not a measure of the speed it sends a projectile?

For instance, would a set of bands made of green Theraband, that requires the same force to stretch as a set made of gold theraband (the width of the gold cut to match the force of the green) send a projectile of the same weight at the same velocity. I think but have no evidence yet that the red would be more powerful. And for the same reason that flat is better than tube or solid, the thinner the profile the quicker it can dissipate heat and return to its un-stretched form.

The ultimate aim is to have the highest velocity for the lowest stretching force. I realize other factors come into play such as durability, pouch size, %age of stretch and no doubt a lot of others. But all other factors being equal I think the thinner the band the better

I now await to be told I am wrong and why, while I wait for my chrony to arrive so i can settle this for myself. It is almost like science!

Generally, for two bands with the same mass the one with the highest surface area will contract the fastest. (http://www.melchiorm...info_power.html subsection band shape)
The big disadvantage of the thinner bands is that you need a broader band to propel the same mass, (Green vs. Gold around 2.5x the width) and they break faster.

[slingshotwizard]

Thanks i was having trouble gauging the strength of my bands

[cheese]

whats the resistance for tubes?

[Hrawk]

cheese, on 06 January 2012 - 03:39 PM, said:

whats the resistance for tubes?

Dude, it's in the first post !!!

NightKnight, on 18 December 2009 - 12:39 AM, said:

Both Thera-Band resistance tubing and bands are calibrated to offer the same resistance levels at the same percent elongation.

[cheese]

Hrawk, on 06 January 2012 - 04:46 PM, said:

cheese, on 06 January 2012 - 03:39 PM, said:

whats the resistance for tubes?

Dude, it's in the first post !!!

NightKnight, on 18 December 2009 - 12:39 AM, said:

Both Thera-Band resistance tubing and bands are calibrated to offer the same resistance levels at the same percent elongation.

oh, i thought that was just for bands.

[cheese]

i hate reading so i tend to just skim over things.

[Hrawk]

[cheese]

Hrawk, on 07 January 2012 - 02:44 PM, said:

ive done that once!