# Slingshot Ballista!



## JoergS (Dec 17, 2009)

As announced, I made a handheld inswinger "ballista" slingshot, to find out if it brings additional power.

I made a really wide fork and attached little "plattforms" to the fork ends. Then I added a lever on each side, which can swing inside of the fork. I also installed a stopper that I covered with some black tube, so that the returining lever will be cushioned some.

I attached short pieces of Thera Gold to the shorter end of the lever, and a normal hunter band set to the longer tip ends. I used 8 mm aluminum tube as "axis" for low friction.





































It works! It was dark, so no chrony, but the shots are faaaast. Will test tomorrow, and make a video.

Jörg


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## ARB (Dec 31, 2009)

Very good, I'm looking forward to the video









I should know this but do the short rubbers that move the arms increase the draw weight?

It would be interesting to see the effect of the arms on velocity. Can you lock them in place for a comparison?


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## Bill Hays (Aug 9, 2010)

Interesting.
To test whether it increases speed you don't have to lock the arms in place, just take the short rubber piece off.


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## Gwilym (Dec 9, 2010)

Looks really interesting.It won't change the draw weight in any way assuming you draw the main bands to the same length it will just give you a longer draw at the same weight due to the movement of the arms.


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## bazil (Dec 3, 2010)

That looks fantastic! Can't wait for the video!

Baz


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## roadie (Jan 23, 2011)

wow ! Nice !!


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## Felicko (Jan 23, 2011)

ARB said:


> Very good, I'm looking forward to the video
> 
> 
> 
> ...










I was wondering that too. Does it make a large difference or a small difference in draw weight?


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## John-Boy (Oct 15, 2010)

That looks cool, i always wondered would this method increase the velocity of a projectile. I find flipping a slingshot on release increases velocity a little, this would automatically give the same affect, maybe more so!!

Check your inbox joerg, i sent you a PM a few days ago.


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## JoergS (Dec 17, 2009)

It works, and actually I get about 20% more speed than from a conventional frame!






It's fun.

Jörg


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## John-Boy (Oct 15, 2010)

That slow motion footage from behind was awesome!! More of that in future joerg









Could you see this working in OTT form??


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## jamoni (Jan 21, 2011)

Fancy!
In OTT, it would be almost like a small trebuchet. I'm waiting for Jorg's shoulder launched Onager, I know it's coming.
I saw this, and I immediately thought "SLINGBOW".


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## Tobse (Nov 4, 2010)

i like this Slingshot!!! nice Video!
This system has even more potential if you do the arm length more and the short rubber stronger
nice Slow motion!


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## TastelikeSnozberries (Jul 16, 2010)

The slow motion over the shoulder was awesome! I would like to see that become standard too, that looked amazingly cool


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## bazil (Dec 3, 2010)

Awsome! have to build me one of these!


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## Rayshot (Feb 1, 2010)

I agree, the over the shoulder is a terrific angle for slo mo.

Good job Joerg on the catty design and the photography.


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## e~shot (Jun 3, 2010)

Another good job Joerg, I noticed wider view of slow motion video ball traveling to the target, I like it .....


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## Dan the Slingshot Man (Nov 21, 2010)

really interesting idea. I is kind of similar to the mythbusters episode shooting arows of a horse. The arows went fast on a horse. I guess it works the same on a slingshot


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## ZDP-189 (Mar 14, 2010)

I'm not sure I buy into the logic.


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## JoergS (Dec 17, 2009)

Maybe there is another explanation, but the chrony clearly proves the speed increase. I shot the 15 mm steel balls at 70 m/s, a conventional frame with comparable draw did 58 m/s. That is a big difference.

BTW it was a bit warmer yesterday (about 8 centigrade), and shooting was a lot more fun. Still the speed results were lower than in the summer, but not as lousy as lately in the cold.


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## Bill Hays (Aug 9, 2010)

Hmmm, just a thought... Since the lever creates an extra 4 inches or so of draw length added to your bands... you might be simply making an extended fork slingshot... try tying the arms to the post, so that they are fully forward extended... so that the draw length would be comparably the same with or without the lever.
With the extra draw length and not using the heavy rubber on the lever action.
What's the difference in the two now?
If it is still much faster... the there's a simple compound pulley setup that can be done to create the same effect but is actually fairly easy to hold at full draw.


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## JoergS (Dec 17, 2009)

It really only creates two inches of a draw extension. This really doesn't make a huge difference, as I did not even shoot in butterfly.

I have shot so many different slingshots these last few years that I have a sound "gut feeling" for the band strength and resulting power. The levers DO make a difference, I am quite sure.


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## Devoman (Oct 15, 2010)

I am thinking this has sling bow written all over it!!! Nice Job


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## JoergS (Dec 17, 2009)

A slingbow version is certainly possible. For a slingbow, I could make the arms much longer as there has to be virtually no clearance between the fork arms.

But right now I enjoy shooting steel and lead balls, I kind of go through phases.


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## bazil (Dec 3, 2010)

Could make a lead ball shooting sling crossbow, like this sort of Kostka attachment thing... 




Baz


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## Devoman (Oct 15, 2010)

Joerg, any more work on this idea? I am interested in this concept.


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## JoergS (Dec 17, 2009)

Not at this time. My mind is currently set on a semi/full auto multi shot slingshot crossbow. Not easy, but I have several ideas.

Jörg


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## Warhammer1 (Dec 27, 2009)

my vid: http://app.talkfusion.com/fusion2/viewTemplate.asp?mailId=MTc5OTkxMA%3D%3D&glb=0#.T1kjtrcCYls.facebook

If I had enough strength to stretch 400%, I could do some real damage. Maybe smash two blocks doubled up. not as pretty as yours JoergS, but still works after over 12 years. The heavier slingshot model is now used to power a crossbow. If I could borrow them big arms of yours I could have some real fun. I had to work up to stretching these tubes 250%. There is still power and speed left I cant access because of my emphysema.


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