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Posted: Sun Aug 30, 2009 4:46 pm
by theBOOM
Wow good job man your making slingshots every day now :lol: :)
How is the gatling going whats your top time score atm?

Posted: Sun Aug 30, 2009 6:31 pm
by boyntonstu
Joerg,

Is there a speed difference between bands?

IOW If you use 2 yellows to equal the pull of a green, is the speed the same?

I am concerned that heavier bands may not snap back as fast as the lighter bands.

Is there a simple way to measure the effect of tube thickness on velocity?


BoyntonStu

Posted: Sun Aug 30, 2009 7:34 pm
by jonnyboy
boyntonstu wrote:Is there a simple way to measure the effect of tube thickness on velocity
I would guess you would pull each back to the same weight say 5 pounds then chrono them.

Posted: Sun Aug 30, 2009 8:53 pm
by theBOOM
I got some questions

What material are you slingshot made of? And how hard is it to get good at welding whatever material they are made of? Where can I get the different rubber bands from? How do you make those awesome custome handles for your slingshots?

Posted: Sun Aug 30, 2009 9:16 pm
by mobile chernobyl
JoergS - take a look at US Patent # 7506642

(Short description excerpt)

"The present invention provides a high-power and high-velocity slingshot that overcomes the deficiencies of the prior art and that falls between a bow and arrow and a slingshot as a hunting weapon, without resorting to mechanical means such as springs, offering several advantages over the prior art."

This slingshot DOES have a wrist band though, and from what I've briefly read from your post's, they are illegal in Germany (on a slingshot)?

Either way, this sling shot uses a spring steel wrist guard assembly, in an arched shape so as to attain as much potential energy from the "pull back" as possible.

Pretty cool and the design piqued my interest for sure... I definitely loved the slingshot as a kid, now with a little more strength in my arms I may be able to step up to a higher performance theraband slingshot deal.

On that note - Joerg - Do you have any recommendations on how to recommend a theraband tubing color to someone? like do you have a chart of the tension force required to pull each band back to a set distance?

Posted: Sun Aug 30, 2009 9:25 pm
by c11man
joerg, how strong are the blue bands? thats what im using and im just curious how it stacks up to others

Posted: Sun Aug 30, 2009 9:35 pm
by mobile chernobyl
Joerg - I found this on theraband's site with appx 1 minute of searching (sorry for being lazy lol)

This shoudl help other's in determining the correct band to choose for a sling shot regarding their own fitness levels. These quantities are in pounds, and they are staged at percentage elongation (stretch) from the static length.

Image

The next most logical questions is what percentage elongation are we looking at for a typical sling shot design, and for a higher performance design like some of Joerg's?

These ratings follow a curve which is not perfectly linear, so at say 500% we would need to plot the known values we have in this chart in an excel sheet, and obtain a formula for the curve with %elongation being the open variable.
Then we could put in the %elongation as a value at 500 and get a value hopefully close to what the actual value would be. From what I can tell, static length of tubing doesn't seem to play a very important roll in the force required to extend it, mainly because these values are given in % of elongation, and not per set distance. So that's a good thing at least.

Posted: Sun Aug 30, 2009 9:39 pm
by c11man
oh i guess i have some decent bands then. i couldnt pull back 4 blue bands an i understand why. i went down to 2 and its still a pretty hard for me. now i just have to get a good pouch....

Posted: Sun Aug 30, 2009 9:44 pm
by THUNDERLORD
I got some questions

What material are you slingshot made of? And how hard is it to get good at welding whatever material they are made of? Where can I get the different rubber bands from? How do you make those awesome custome handles for your slingshots?
Sounds like a cop posing as a 13 year old.......... :roll:

Home depot, if not Lowes has surgical tubing.
For stronger stuff, go to Ross or Marshall's and look at the fitness section,
They usually (sounds funny) have g@ywad exercise bands (same thing) that are $10 or less in different strength levels too.

If you want them for free, there's a way to do that too, but against the rules to tell you how....course any competent spudder can figure that out.
Good luck on the moped mods and yur time machine! :P

Cool design Jeorg!!!
Got a personal website yet??? 8)

Posted: Mon Aug 31, 2009 3:19 am
by Biopyro
Another ace slingshot, like the colour scheme. You say that a wrist brace is illegal, but what's to stop you making one anyway? It's not like you're using this in public, and I think it will save you a lot of greif later down the line from arthiritis etc.
I understand if you're in a very built up area, but it seems to me you have a decent bit of land, where the police won't come snooping?

Spudguns are pretty much illegal by UK law, (no specific clause, but certainly without them registered on your firearms licence they are) but we still build them because we keep to ourselves and don't cause trouble. I like to think if the police came around they could either be fooled by a decoy (low pressure shots etc), or would see it's just a "toy" and use their discretion.

If I was shooting in the local park I'd expect to be arrested, but I'm not.

Posted: Mon Aug 31, 2009 3:22 am
by spudamine
How do you make those awesome custome handles for your slingshots?
It's all here in his video:
http://www.spudfiles.com/forums/video-h ... 19071.html

I don't have any fimo so I'm going to try using polymorph which I do have in abundance, I don't think it will be quite as neat though.

Joerg, I'm having problems with finding some leather for a pouch, my best idea so far is a belt I am currently too fat for, is 2.6mm thick leather ok for a pouch?

Posted: Mon Aug 31, 2009 3:27 am
by inonickname
If you want a brace, but would like to be able to remove it for use in public why not thread the brace so it can be removed when required? If you don't have suitable taps and dies a nut could be welded to the main part and a bolt welded to the brace. I was originally going to do that, but decided if the police came looking for stuff here a slingshot probably isn't the most interesting thing they would find.

Naise.

Posted: Mon Aug 31, 2009 3:32 am
by JoergS
Biopyro wrote:You say that a wrist brace is illegal, but what's to stop you making one anyway?
Can't. I legally own 34 modern firearms, probably a record in my home town.

One illegal action and they will take all my guns away from me, and I won't risk that for a slingshot wrist brace.

I like my slingshots as I can legally build them myself, and shoot them in my garden. That is totally illegal even for air rifles (except, if your patch of land is about as big as Texas, so even if you shoot up into the sky at a 45 degree angle the pellet can not leave your fenced property).

Posted: Mon Aug 31, 2009 3:36 am
by JoergS
inonickname wrote:If you want a brace, but would like to be able to remove it for use in public why not thread the brace so it can be removed when required?
The law is water tight. If the slingshot is prepared for a brace attachment, it is illegal.

But I really don't need braces. My arm is very strong (my wrist has a 24 cm circumference, my biceps are 50 cm). Plus, my slingshots have very flat forks.

Posted: Mon Aug 31, 2009 3:39 am
by JoergS
theBOOM wrote:I got some questions

What material are you slingshot made of? And how hard is it to get good at welding whatever material they are made of? Where can I get the different rubber bands from? How do you make those awesome custome handles for your slingshots?
Here is my video about sources for material.

[youtube][/youtube]

I find welding very easy, but I have a good welding set. It works like a pistol, you press the trigger button and the wire spools out, melting together with your steel objects.