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Revolutionary Knex Gun Competition 1 Results Answered

The winner is a weight powered slingshot made by Hiyadudez.

His explanation of how the gun fires;
It's basically a normal gun rail, with a 'car' on the rail. Attached to the 'car' is string that runs to the front of the gun and over some pulleys. Attached to the other end of the string is a big weight/counterweight. When released, it pulls the car forward (the bullet is in front of the car) and sends it flying out of the barrel, but the car stays in. It shoots a blue rod 10-15 feet.

Thanks to everyone who participated. The next contest can be found here.


All objects fall at the same rate. The speed of the projectile would depend more on how far the weight fell than how much it weighed. You could use pulleys though.

What must happen if you want a feather and a bowling ball to fall at the same rate?

Tape the feather into a solid ball. They must be aerodynamically the same or be dropped in a vacuum to fall at the same rate.

That's only really true on the moon.  Here we have to contend with air resistance on the weight.

He's actually right, all objects fall at nearly the same rate in the presence of air resistance. They fall at exactly the same rate in the absence of air resistance. Read the link that I posted above.

Imagine what happens with 30 pounds.  I will be sitting in a pool of broken knex.

Lol, you would have to make a thicker gun of course. But I don't think that you realize how many pounds of tension elastics create. I'm sure that there are knex guns that use more than 30 pounds of tension for firing elastics already.

Actually, most guns use more than that, but it's almost always applied in effectively a straight line; using that much weight to pull it going in both a horizontal direction and a vertical direction would just break your pieces.

Yes, but it's still nothing a thicker gun couldn't fix.

Cool!  It won out of 2 entries!

Four entries. But I'm not going to quit hosting the competition. The resulting guns are worth it.

Oh, I though only webby and him entered.  Do not stop the competition, who cares about how many entries there are?


8 years ago


Yay! Thanks man :-)