Centrifugal weapon could deliver stealth firepower

New Scientist ^ | 5/11/05 | Will Knight

[Dinsdale]

"Young man, in this house we obay the laws of physics!" Homer Simpson

It does'nt mater what kind of contraption you use to get something up to speed.

Think of this problem. Put a ball trap in front of your device, run the balls back into the gun.

Do you have a reactionless drive? (i.e does the regular recoil of the balls hitting the trap now pull the whole thing forward?)

If you do you are rich beyond averace and have brought the stars into reach. I don't think you do.

[IronJack]

I don't see the parallel you're trying to draw. How does a sling have any recoil? All that happens when you release it is the centripetal force goes to zero, which unbalances the centrifugal force and allows the projectile to fly away tangentially. There is no recoil because there is no equal and opposite force imparted instantaneously to the projectile. It's energy is kinetic at that point, having been imparted (as a moment of inertia) by the act of twirling it. I envision the same physics applying here.

But, as I've said, I might be misunderstanding the construction of this device.

[Dinsdale]

It's not a parrallel, the point is that a 'recoilless' gun is a reactionless drive once you capture the projectiles. At 120000 rounds per minute you could point it straight up and hover (tuning the lift with muzzle velocity or rate of fire), reusing the captured rounds untill you ran out of energy, never using any reaction mass. This is a silly supposition. If it worked it would make the weapons applications dwindle in importance.

The slingperson imparts the final forward velocity on the projectile during the last quarter turn of the sling. During the previous quarter turn the slingperson had done the same work killing the energy in the opposite direction (in the axis of the throw).

Perhaps a sling designed for bowling balls and a trip to the nearest ice rink would satisfy your intuition.

[IronJack]

I'm not satisfied, but I'll give it a rest. Thanks.

[Boazo]

I'm gonna' need some pliers, and a set of 30 weight ball bearings.Ball bearings? Fellas fellas, it's all ball bearings now with jet engines!

[tricky_k_1972]

I know this is an old article for you, but what if you used the energy from the "recoil" and pumped it into a storage battery although that sounds a lot like perpetual motion, at a guess there would be energy loss due to heat, but maybe you could negate most or all of the recoil, or consider some way of turning the recoil force to force in the direction of the spin.

My physics is very rusty here and I'm way out of my depth with this I know, but there must be some way to use that recoil force and therefore negate it and lose some energy to friction.