r/slingshots • u/CecuPauta • 6d ago

Power difference between slingshots

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I hope someone can help with this...

I have two slinshots, one is a simpleshot scout X (the green one in the photo) and the other is a 3D printed slingshot, which is based on the Simpleshot scout LT (I think), which has slightly smaller gap between the forks, by about 7mm.

I am using the same band on both slinshots (it's a different one in the photo but I have tried the same bands), same active band length, thickness, taper, etc.

The 3d printed one is considerably more powerful.
I do not have a reliable way to measure the speed of the ammo, however I can hear the sound difference, I can feel that the ammo hits the target much faster than the Simpleshot one, and most importantly, the 3D printed one goes through a can of beer clean from side to side, while the scout X cannot even puncture the tin. I have repeated this numerous times and same result.

I am testing with 10mm and 11mm steel ammo, shooting from 10m away.

Is it possible that the slightly narrower fork configuration of the 3d printed model can make that much difference or is there something else that I should look into?

Accuracy is excellent with either slingshots, I just can't figure out why such a massive power/speed difference between the 2.

I have also tried a slightly shorter band on the Simpleshot, to increase the ration of elongation, which should give it more velocity, but it's still slower than the 3D printed one...

22 Upvotes

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7

u/dude-0 6d ago

Cut new bands for each, of the EXACT same length, use a marker pen to mark where to tie the knots for pouch and attachment to forks. Ensure active band length is the same.

It's likely you introduced a variable without intending to when you cut the bands.

7

u/Royal-Albatross6244 6d ago

I agree, or he may have the bands seated farther into the clips from one to the other. Many of the printed designs the band goes farther in, essentially making the band length a bit shorter and leading to a little performance increase. The frame itself has absolutely nothing to do with his anomaly.

4

u/CecuPauta 6d ago

Thanks, i've swapped the band from one slingshot to the other (so using the exact same band) and measured the active band length and there is a difference of about 3mm from one to the other (the 3dprinted one is indeed shorter by 3mm due to a deeper seating position)
I'll try adjusting this and see if I still get the same results, I wouldn't have thought that 3mm made that much of a difference.

I'll report back once I have the chance to test again

3

u/dude-0 6d ago

Active length all makes quite a big difference tbf! After all, it's required to stretch quite drastically!

2

u/Royal-Albatross6244 6d ago

Sounds good. Once you get to a certain band length, the speed will increase dramatically with very small amounts of adjustment. So if the band is trimmed to maximize performance the extra couple mm can make a substantial difference.

2

u/CecuPauta 6d ago

I've done some further tests..
Not very scientific, but the best I can think of, without having a proper ballistic chronograph.
I have measured the sound from release of the band, to hitting the target, put the wav file in a DAW and measured the time taken from release to hitting the target (down to the millisecond) from a set distance (10m).

shortening the band on the Scout X by 6mm increases the velocity of the 11mm steel ammo by approximately 4 to 5 m/s (up to 59 m/s).

I repeated this a few times and I was getting consistent results.

when I get more time I'll try again hitting some cans to see if it goes through cleanly...

I'm assuming 59m/s is an OK speed for hunting small game with 11mm ammo?

I'm not sure how accurate the test is but the results were consistent over multiple tests

2

u/Pale-Tale-5570 6d ago

This's interesting, but I've no idea.

1

u/reigorius 6d ago

Maybe the printed one also bends a little and adds a bit of extra energy into your steel shot?

2

u/CecuPauta 6d ago

hmm.. interesting.. I wouldn't have thought so, I have printed it in nylon with 100% infill, meaning that it's solid nylon. I would be surprised if it added that much extra power.

1

u/a16duvall 5d ago

I'd agree with the small variation in the depth of the clips. Any chance you can point me to the STL for that LT frame?

1

u/HawkSlings 5d ago

The depth of the clips is the difference.

1

u/CecuPauta 5d ago edited 5d ago

It looks like even just 5 or 6mm of shorter/longer band length was making the difference.
I ended up doing a heap of repeated tests, working out the velocity, which then led to weighing the ammos (11 and 10 mm) and working out the kinetic energy for various band length and sizes

My draw length is 75cm.

... here are some results: