High power 3D printed pop slingshot for target shooting with over 7.5 joules of kinetic energy and serious performance.

Caution

I made this kind of slingshot at elementary school from a curtain ring, tape and a balloon. The slingshots were quite popular at school until someone got a pea in their eye. After that, they were banned at my school. That was several decades ago now.

Therefore: this model is not a toy! Do not shoot at people or animals!
Only for hunting small and large monsters, as well as shooting at targets, bottles, cans and other practice targets. Be responsible.

And protect your eyes! Always!

Assembly

Cut off the neck of a balloon.

Stretch the balloon over the underside of the inner part.

It should lie smooth and nicely below the thread.

Now pull the locking ring over the thread and down to the bottom edge.

Now screw on the top and tighten it firmly. The lock ring presses on the balloon and secures it.

Fully assembled.

Use steel balls for a serious punch, clay balls for exploding fun and TPU bullets for practicing inside.

7.5 joule? How was that measured?

A steel ball weighing 2.18 g was fired from a height of 1.5 m and an angle of 0° (horizontal). The ball flew 50 m until it touched the ground.

The rest is physics. In theory, the ball would fly more than 800 meters, at an angle of 45 ° and disregarding air drag. Briefly summarized:

t=sqrt(2 * 1.5 m / 9.81m/s) ≈ sqrt(0.305 s) ≈ 0.55 s

The ball was 0.55 seconds airborne.

v = 50 m / 0.55 s ≈ 90.91m/s

The ball traveled 50 meters in 0.55 seconds, the ball therefore had a speed of 90.01 m/s.

KE = 0.5 * 0.00218 kg * ( 90.91 m/s )² = 9.01 joule

With a mass of 2.18 g and a speed of 90.91 m/s the ball had 9.01 Joules of kinetic energy.

For reference: Paintball guns are only sold and used by adults in Germany and have a maximum of 7.5 joules. Fortunately, this does not apply to slingshots.