# All POWER shooters pls read



## Powerseeker707 (7 mo ago)

So I've got an idea. I've got the 148 joule shot "Thors Hammer" 3D .STP file.
I already spoke to a 3D print guy in Sacramento whos cool with this for about $60-$80 bucks. 
Possible changes:
Make the grip a little more balanced.
I really like the grip on the SS Hammer.
Make the forks lower.
Maybe make the forks 35-40mm
I'm going to be shooting halfbutterfly
and PFS twisting so no fork hits.
Instead of TBG, use Great White 1mm
or Snipersling .8mm bands
20-30mm Lead or Tungstein.
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Plausable or do I need a straight jacket?


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## karaolos (Jan 12, 2014)

I'm not a power shooter, but have done some 3D printing... What material are you printing with? How heavy of a draw are you expecting to pull? Any chance you can run a stress simulation on the model before printing?

Definitely vice test well above the pull you're expecting, before using.


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## Powerseeker707 (7 mo ago)

karaolos said:


> I'm not a power shooter, but have done some 3D printing... What material are you printing with? How heavy of a draw are you expecting to pull? Any chance you can run a stress simulation on the model before printing?
> 
> Definitely vice test well above the pull you're expecting, before using.


I wont actually know 100% until I have it in hand but we are talking 39 inch draw and I can start with single band TBG and work my up. I can easily shoot 60mm folded and even 1.5mm bands stretched out so my hands/wrists are tough enough for it.


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## Powerseeker707 (7 mo ago)

Oh and ASA filament 100% is what they can offer. Just under Polycarbonate in terms of strength. No weather condition can harm it.


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## Konrad (May 2, 2020)

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Power Rangers


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## karaolos (Jan 12, 2014)

Powerseeker707 said:


> I wont actually know 100% until I have it in hand but we are talking 39 inch draw and I can start with single band TBG and work my up. I can easily shoot 60mm folded and even 1.5mm bands stretched out so my hands/wrists are tough enough for it.


I'd definitely test the finished thing properly before use, with a vice and appropriate weight.

Even before printing... I'm sure you can run a test on that model for the exact material and construction method you're going to use. Some information about how it's held and how the bands attach should be enough for an engineer / designer to run a structural simulation. Sometimes the 3D print shops can do it, or they could possibly know someone who can. 

Regardless, test it in a vice before you put it in front of your face.

I shoot small caliber, really I don't have experience with heavy draws... Perhaps some more experiences shooters can offer more insight on the design changes you're thinking about...


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## Biker_Bob (Mar 26, 2020)

The most important factors determining strength are filament type, wall thickness and infill %.
The frame will not be solid, there will be an outer shell and the internal space will be filled with a 3d crosshatch.
What power are you hoping to get?
I've been up to 40ftlbs using a starship with a 60lb draw weight.
I'll be impressed if you can draw that sort of weight to butterfly or 1/2 butterfly.
Use lead ammo.


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## Powerseeker707 (7 mo ago)

1000% agreed. Im going to cement it with the 3D guys that this needs to be reinforced as much as it can be. I could always start with 1 model and then go to someone else to have a stronger copy made.

I'm very careful with any kind of possible hand finger eye ball anything related fast movers. It took me a long time to even pull a clay round up to my right ear with gloves on I'm that detailed on what works or doesn't.

Thank goodness for jawbreaker candy and heavy duty construction gloves.

Power? I'm just curious on what's possible.
How strong can a hand cannon catapult go?


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## Biker_Bob (Mar 26, 2020)

Mr Sprave got 100ftlbs but that was using a slingshot he put his feet on and used both arms to draw back.
You are limiting yourself because you want to hold the frame, that immediately reduces the length of the power stroke you can use. Butterfly or half Butterfly counteracts this by increasing the draw length, but not many poeple have the strength to pull 50 or 60lbs backwards behind their shoulder.
I recently had a setup with a hand held frame that gave 24ftlbs with 1oz lead balls, shooting 1/2 Butterfly, but I had to fix my right arm behind me then swing the frame over in an arc to the shooting position - very bad for the rotator cuff!
So, if you can get 30ftlbs with a hand held frame I think you'll have done very well.
A starship can instantly give you 50% more if you get the geometry right.


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## FORGES&SLINGS (4 mo ago)

Biker_Bob said:


> The most important factors determining strength are filament type, wall thickness and infill %.
> The frame will not be solid, there will be an outer shell and the internal space will be filled with a 3d crosshatch.
> What power are you hoping to get?
> I've been up to 40ftlbs using a starship with a 60lb draw weight.
> ...


holy smokes on the draw weight! Does this use a trigger type device that holds the drawn slingshot until pressed or are you actually pulling that back and holding it until release?


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## Biker_Bob (Mar 26, 2020)

Holding it with my hand, but it's a 1" ball so that isn't difficult. 
The most power I've had is 40ftlbs with my full arm starship fitted with a full strip of TBG each side.
This 140 odd joule business is nonsense IMHO...


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## FORGES&SLINGS (4 mo ago)

Biker_Bob said:


> Holding it with my hand, but it's a 1" ball so that isn't difficult.
> The most power I've had is 40ftlbs with my full arm starship fitted with a full strip of TBG each side.
> This 140 odd joule business is nonsense IMHO...


That’s prety incredible seeing as how a lot of guys on here think that a 20lb draw is too heavy to hold and still be able to aim properly.


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## Biker_Bob (Mar 26, 2020)

FORGES&SLINGS said:


> That’s prety incredible seeing as how a lot of guys on here think that a 20lb draw is too heavy to hold and still be able to aim properly.


20lb? Look, I'm no strongman but 20lb isn't a lot to pull.
I should point out we're not talking butterfly here, that 40lb draw is a face anchor, I couldn't butterfly draw that.


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## FORGES&SLINGS (4 mo ago)

Biker_Bob said:


> 20lb? Look, I'm no strongman but 20lb isn't a lot to pull.
> I should point out we're not talking butterfly here, that 40lb draw is a face anchor, I couldn't butterfly draw that.


I’m not talking about myself but I’ve just seen some people on here who say their frame hand starts to shake if their draw weight is above ~15lb. There are some older folks so I’m guessing it’s probably them saying this type of thing. I’m not sure what the max I could hold steady to aim is but I’m pretty confident I would be fine with 20+. I also shoot with a face anchor. I anchor right in front of my ear. I’m very new though and don’t really even know much about form while shooting and how other people do it, so far I’ve just been trial and error figuring it out.


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## Henry the Hermit (Jun 2, 2010)

Experience suggests that slingshots are only about 50% efficient, so to achieve 148J/110lb/ft, you will need to store about 300J in the bands. Draw weight at full extension should be close to 220 lbs. That is obviously beyond the ability of most of us. Good luck, and be careful. At very high power levels, slingshots can be very dangerous.


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## Biker_Bob (Mar 26, 2020)

Yes, a 50% efficient slingshot is a rare thing, especially given the hysterisis of the thermal cycle in latex, not only would the draw weight x draw length need to be at least double target power output, you would have to loose almost instantly after reaching full draw.


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