# Design concept for a very fast and powerful slingshot



## boyntonstu (Jul 16, 2010)

An in-swing crossbow slingshot having very powerful triggered arms that will pull them at 100 fps or more.

Attached to the arms are bands for the slingshot pouch.

The challange is to co-ordinate the two triggers.

One concept is to gang the two triggers so that the in-swinging arms and the pouch are simultaneously released.

Another concept, is the have the arms begin to accelerate and after they travel a very short distance hit a cog that triggers the pouch mechanism.

The force on the arms will be greater than the bands.

Can you visualize it?


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## whipcrackdeadbunny (May 22, 2010)

Phew! I can see it Stu, but that's some serious timing/pressure issues. I think it might be a way to increase pressure ie. you cock the arms, pull tension to the bands and cock them, then release the arms, so you have even more pressure on the bands .. then you can release the shot whenever you wish. Otherwise, I think it might be beyond me. Nice idea though.


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## John-Boy (Oct 15, 2010)

Something like this crossbow design by hoe Click only alot smaller and with vertical pivot arms?


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## boyntonstu (Jul 16, 2010)

John-Boy said:


> Something like this crossbow design by hoe Click only alot smaller and with vertical pivot arms?


That is a nice out-swing design.

An in-swing design would use 2 sets of rubber, one for each arm.

The arm mechanism could be below the barrel and the slingshot located above the barrel.

Each arm could be separately cocked for ease of cocking.

The narrower the fork, the smaller the rubber angle and therefore less power is lost due to vectoring.


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## ZDP-189 (Mar 14, 2010)

Yes, but I have a (I believe) better solution that I was planning to work on before I signed up here.

The crossbow (in my design a swinging lever) has only one arm and that has a single trigger and release. The single line splits to become two and that goes to each side of the pouch.


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## PandaMan (Oct 14, 2010)

For those of us who aren't quite as mechanically imaginative as you people, would any diagrams be possible? If I knew what we were talking about I could help. I'm more of a visual learner


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## whipcrackdeadbunny (May 22, 2010)

Just occured to me, why not remove the elastic, and develop a x-bow to shoot ball bearings? Don't mean to deviate, just an idea.


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## boyntonstu (Jul 16, 2010)

ZDP-189 said:


> Yes, but I have a (I believe) better solution that I was planning to work on before I signed up here.
> 
> The crossbow (in my design a swinging lever) has only one arm and that has a single trigger and release. The single line splits to become two and that goes to each side of the pouch.


If I understand your concept, all elastic is simultaneously drawn.

If that is correct, it would be the same as tapered bands.

With separate in-swing arms, the force on each arm could be much greater than the 2 pouch bands.

Do you have a sketch of your idea?


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## dragonmaster (Dec 24, 2009)

ZDP-189 said:


> Yes, but I have a (I believe) better solution that I was planning to work on before I signed up here.
> 
> The crossbow (in my design a swinging lever) has only one arm and that has a single trigger and release. The single line splits to become two and that goes to each side of the pouch.


I had the same idea only with two levers. Got the idea from the slingcat.


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## boyntonstu (Jul 16, 2010)

Sketches, guys, sketches.


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## ZDP-189 (Mar 14, 2010)

The velocity may be higher, because of the TAN function; there is much acceleration towards the end of the travel.


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## ZDP-189 (Mar 14, 2010)

boyntonstu said:


> Sketches, guys, sketches.


A sketch isn't necessary. The concept is dead simple. One arm (or band) attached to one release, pulling two strings.


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## boyntonstu (Jul 16, 2010)

ZDP-189 said:


> Sketches, guys, sketches.


A sketch isn't necessary. The concept is dead simple. One arm (or band) attached to one release, pulling two strings.
[/quote]

Is the fork affixed to the end of the single arm?

What do the strings do?

In my concept there are 2 sources of potential energy.


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## HOE (Nov 13, 2010)

boyntonstu said:


> An in-swing crossbow slingshot having very powerful triggered arms that will pull them at 100 fps or more.
> 
> Attached to the arms are bands for the slingshot pouch.
> 
> ...


I've problem visualizing from words, I need a sketch of the design! One picture is worth thousand words.


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## boyntonstu (Jul 16, 2010)

HOE said:


> An in-swing crossbow slingshot having very powerful triggered arms that will pull them at 100 fps or more.
> 
> Attached to the arms are bands for the slingshot pouch.
> 
> ...


I've problem visualizing from words, I need a sketch of the design! One picture is worth thousand words.
[/quote]

I did this with Paint online in about 1 minute.

The concept is to have 2 moving arms and having their speed added to the pouch rubber speed.


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## ZDP-189 (Mar 14, 2010)

Here is my original concept, which I didn't fully develop and didn't pursue. I lost the original drawing so sketched this up again:










Here is the generalised concept of one motive force (be it an elastomer or a lever arm) pulling one line attached to two lines. The release catch may be on the end of the elastomer/ lever arm, or at the point where the the line splits, as shown here.


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## boyntonstu (Jul 16, 2010)

ZDP-189 said:


> Here is my original concept, which I didn't fully develop and didn't pursue. I lost the original drawing so sketched this up again:
> 
> 
> 
> ...


O.K. I understand it now.

As I look at your sketch, something jumps into my mind: A Stamp-On slingshot!

Just like a bass drum pedal.

No elastomer needed.

Hit the lever with all your weight and that pouch should fly!


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## boyntonstu (Jul 16, 2010)

Got another idea.

The strong elastomer bands to the in-swinging arms are triggered, and the extra pull on the pouch pulls it free.


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## jamoni (Jan 21, 2011)

If I understand the physics right, with elastic bands you get a HIGH initial acceleration, which quickly tapers off. I would think you could use multiple bandsets like rocket stages, on a sliding track, to prolong that high initial acceleration. 
For example, if you have three separate bandsets, the first one would accelerate the entire mechanism containing the second two. At the appropriate moment, bandset two would trigger, accelerating the mechanism containing the last bandset, which would then fire the ball. 
This might not work, but it would be amazing to watch!


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