SpudFiles

wouldnt it be awesome! a large catapault could be powered by a piston!
you could still even have the counterweight with a double acting!

a clippard brand cylinder is like 20$ so this could actually do something!

That's not even a half bad idea. I know what pneumatic rams do at thousands of psi and the power could no doubt be adapted.

Speaking in terms of energy transferred to the projectile it's less effective but would have a coolness factor and would no doubt win a school catapult competition.

yeah! you get it! it could be decorated like a medival catapault with air tanks
would it still be as cool if air was used to cock a traditional catapault?
much easier to get it to be high power i suspect.
and air could trigger it too.
stick a gass powered compresser on it and its a air/combustion/catapault hybrid!

You'd need pretty substantial construction to stop it shaking itself to pieces though.

would it still be as cool if air was used to cock a traditional catapault?

That would be more conceivable and certainly take the effort out of doing things the medieval way.

You could also take a captive piston design like a pneumatic nailgun and scale it up.

how about one of those air powered rotary actuators at the pivot? there floting around ebay fo 99-150. i dont think i will be spending that much on one but its interesting
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I don't think that will give you as much power as a ram attached to a lever, or a ram used to propell the projectile directly.

A few years ago i watched a program were these engineers made arrow shooting weapons one of them was a trebuchaut type design were a heavy metal cylinder swung down and hit a bb gun type piston(scaled up) and shot the arrow over 200m down range!

Pretty nice ehh?

qwerty wrote:One of them was a trebuchaut type design were a heavy metal cylinder swung down and hit a bb gun type piston(scaled up)

I had suggested a similar system a while ago that would be a feasible way of creating a gravity powered projectile weapon with ancient technology.

I don't think that will give you as much power as a ram attached to a lever, or a ram used to propell the projectile directly.

Not as much power, no, but velocity....
You could adjust the transmission ratio. Air does not like to flow above its speed of sound, but with a different transmission ratio, the ram does not have to go supersonic while the projectile will.
Of course this is only applicable to pneumatics, hybrids don't need it.

psycix wrote:

I don't think that will give you as much power as a ram attached to a lever, or a ram used to propell the projectile directly.

Not as much power, no, but velocity....
You could adjust the transmission ratio. Air does not like to flow above its speed of sound, but with a different transmission ratio, the ram does not have to go supersonic while the projectile will.
Of course this is only applicable to pneumatics, hybrids don't need it.

That's a very valid point. A small plane at the local airfield has an extremely high revving engine, so high that without gearing the tips of the blades will break the sound barrier and the prop will destroy itself. So of course, it's geared down.

With a strong enough arm and powerful actuation you could force the trebuchet arm to supersonic velocities.

An air powered trebuchet?
sounds interesting
need to think on that one.
I was think outloud that instead of using weight use an air powered piston of sorts?

MrDEB wrote:I was think out loud that instead of using weight use an air powered piston of sorts?

That's the basic idea. With some basic calculations you can work out the forces involved and what sort of piston and pressures you require for your purposes.