SpudFiles

I'm in the process of getting my engineering/metalworking friend to make me one of these to test.

Made of 2mm (.07in) thick steel (maybe carbon steel), about 15cm long, tapered and pointed at the end... hopefully I'm making something here that will pierce the side of a shed and possibly continue traveling.

It's not all the obvious from the picture, but the projectile is like a plus shape, but pointed at one end. I'd have to use some form of wadding obviously.

What i don't understand is... WHY? You would have to think about more than just the piercing dynamics. It will prolly flip around a bit!

To see how much damage I can do =) Why does anyone have a cannon?

I could possibly get him to make the main plus bit out of say, aluminium, and the pointy bit out of steel, that would weight it to the front.

You can make it spirail if you bend just a tiny bit of a rear tip on 1 of the fins. That will make it fly way straighter, found that out by building model rockets, didn't get the one fin on exactly straight, it flew better then the rest, so i build them on perpus that way.

Bend all of the fins slightly - in the same clockwise (or anti-clockwise) direction.

If it spins, then you have a very stable projectile. I did some work on the fins on a homemade crossbow bolt, and that was very very stable in flight. It always hit things exactly with the steel point of the bolt, and was travelling straight enough that it would actually penetrate quite well.

uh, isnt the whole point of fins to make it stable?

yes, it is, that's why you use the fins to give the projectile a spin. Without the spin it will fly everywhere, exept the place you are aiming at. Surtainly if you make the arrow like the pic way up here. That design will not work. It will fly, true, but how. It will twist around and the flight will be bended away from your aim.

You need to get relatively heavy weight in front, and a much lighter fin in the back. Twist the fins like said up here by jrrdw, and you have a fine projectile. You can also use a fin like my 5 cm pvc rocket This type of fin is used on bombs to. You can't make this one twist though, or you need to build a cross-shaped fin in the fin itself.

Without the spin it will fly everywhere, exept the place you are aiming at~POS

That is not true, it will fly perfectly straight without the spin, if its perfectly balanced that is. If it isn't, which is likely to happen......Then no, it won't go as straight without spin.

Edit: It will not fly everywhere, just not exactly where you are aiming.

useless edit

Perfect balance is impossible. Why do you think people go though all the trouble in the past to make a bullet spin ?

Spinning projectiles are much more effective, and even fligh further.

Also, make sure to put the center of gravity to the front, you don't want it tumbling. If you shave it down on the rear end (yes, I know that sounds dirty) it will take off some mass, but give you in turn a better projectile.

Unless COG doesn't matter with spinning projectiles. BLB, care to elaborate?

Anti-clockwise = Widdershins

If you want to see a useful design on how to make this work go to any hunting store or even the hunting goods section of Wal-Mart (if you have one) and look at an arrow. Notice how the fletching (feathers) has a slight tremble (the slight down turn inwards) to it? That's what you want.