Home Forums Hunting & Shooting Hunter's Campfire New Weapon system??--Looks fishy to me!!

DREAD Weapons System

Mike

interesting.

Well, this part of it is horse puckey anyway.

If the metal balls are supersonic, that means that the edge of the disc that releases them is traveling at supersonic speed as well.

Ever been at a small airport and heard a piston-driven propeller plane take off? Did you have any trouble locating it? The vast majority of what you hear in such a case is not the engine, but the propeller tips spinning up into the transonic region (it's generally a bad idea to let them go supersonic, so the system is designed so that they max out just subsonic).

Supersonic would be even louder.

Does anyone know the mass of a 50 cal steel round ball, and I wonder how much horse power it takes to accelerate 100 of them to 2500 fps in one half of one thousandth of a second.

This weapon would require one hell of a fly wheel to store this much kinetic energy. (in a 28 pound weapon?) Or maybe this guy has managed to repeal this portion of Newtons Laws as well as the part dealing with actions and equal reactions.

Man, if DOD has gotten around "conservation of energy", I want to hear about it.

If this thing works as advertized, we could use the acceleration technology to put a man on Mars next month.

Color me skeptical!

Except at those G-forces I suspect he/she would be more of a gelatin once they reaced terminal velocity! <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />

Not that I think it's a viable weapons system (yet.) I do wonder about the supersonic issue.

Would a solid disk, with no protruding parts or edges, spinning at an rpm fast enough to cause it's outer diameter to exceed the speed of sound cause a sonic boom?

I'm guessing the answer is no.

I believe the idea is to have the weapon turned on prior to firing so that the centrifugal device can get up to speed, then the ammo is released into it when the trigger is activated.

The .30 cal. steel balls at 5000 fps or much higher would carry a LOT of kinetic energy, but then a sphere is one of the worst aerodynamic shapes so it would lose a lot of energy to air friction right away. However, at speeds of 100,000 fps it would be glowing hot by the time it reached the target.

As to noise, no, it would not be silent, but anything that lessens the noise a soldier has to endure nowadays firing a SAW or Ma Deuce would be welcome. Besides, who says that the entire external portion of the device has to be spinning? Why not have the spinning part inside in a virtually airless environment? Then the only noise it would make would be the ammo hitting the air at supersonic speeds. Again, not totally silent but then the inventor is not claiming total silence. The fact that the muzzle velocity can be varied to suit the situation does allow total silence, however. Lots of elk and deer fell to a single .50 caliber lead ball launched between 1200-1800 fps. Can you imagine a hosing stream of .50 caliber steel balls coming at you at 1200 fps on a dark night? I suspect that all you'd hear would be the soft thwocks of your comrades being torn apart.

I can see lots of engineering difficulties to overcome, especially at such a high rate of fire,but it sure seems like a viable concept. Definitely thinking outside the box for a projectile weapon.

Until we get plasma rifles in the 40 watt range it is certainly useful to consider all means of improving projectile weapons.

I don't know either, but I'd guess the answer would be yes, because of the boundary layer. Boundary layers are pernicious things: viscous layers of air that stick to moving surfaces and are pulled along with them. Avoidance of the boundary layer is why you see engine cowlings on jet fighters offset from the fuselage by an inch or two.

It wouldn't be a sonic boom, of course, of the Sound of Freedom! type we remember from when we were youngsters; my guess is that you'd have some sort of oscillation set up where the shock wave would form and break repeatedly, probably producing a BRAAAAAAAK sort of noise.

I am still waiting on a lightsaber to hit the market.
<img src="/ubbthreads/images/graemlins/grin.gif" alt="" />

EG

How much torque does all that spinning produce?

How much torque? The precise answer is "A LOT!".

However, I'm not a trained engineer, I just have the thick glasses, so someone tell me - wouldn't that spinning device act as a gyroscope?

Well, let's see. According to my handy, much-abused Pocket Ref, a cubic inch of steel weighs 4.53oz. The volume of a half-inch sphere is 4/3 * pi * 0.25^3, or 0.0654 cubic inches, which seems a little on the low side to me. Can you make fifteen half-inch balls out of a cubic inch of steel? Maybe so.

Anyway, that means a half-inch steel ball weighs 0.281oz

From the illustration, the radius of that disk looks to be about a foot. They speak of 8000fps. A projectile can be accelerated from 0fps to 8000fps in one foot if a linear acceleration of 16000fpsps is applied. (The acceleration of this device wouldn't be linear, but I don't want to deal with the extra math right now, so I'll assume that it is.)

Force equals mass times acceleration. Force required to apply 16000fps to 0.281oz, then, is 4500oz, or 281lb. That force applied over one foot represents 281 foot-pounds of work.

This work would be done in 1/4000 of a second, which means 1.12 million ft-lb/s. My Pocket Ref says one ft-lb/s is 0.00182 horsepower, which means that accelerating one 50cal steel ball to 8000fps in one foot would require 2040hp to be exerted during the 1/4000 of a second in which it was accelerated.

The website speaks of 120,000 rounds per minute, which is 2000 rounds per second. That's a 50% duty cycle: fire for 1/4000s, rest for 1/4000s, repeat. Therefore, only half of that 2040hp, or 1020hp, would appear at the output during sustained fire. Depending on the efficiency of the device, you'd need to be able to supply significantly more than 1020hp...say four hopped-up small-block Chevy V-8s. And you'd need five hundred pounds of steel balls for each minute of sustained fire you expected.

But of course all of this assumes sustained fire. For short bursts, you could probably devise some sort of energy-storage arrangement so that you could run maybe just one small-block V-8 at full bore for awhile to store up the energy for a burst.

The web page says 32" wide giving it a radius of 16", so you'd have to redo your calculations based on the extra 4" allowed for acceleration.

Hmm, sounds like a V6 might be up to it... <img src="/ubbthreads/images/graemlins/wink.gif" alt="" />

Now that you put numbers to it the idea does sound a bit far fetched, certainly not something a soldier is going to tote around on his back any time soon.

I just like the idea of thinking up new ways to do stuff. I imagine the first propellor jockeys looked at a jet plane and wondered how in the hell it was going to stay in teh air.

There's no sonic boom from a turbine, and it spins faster.

I'll bet it doesn't make a difference, since the same volume of steel has to be accelerated to the same speed in the same time.

But let's see.

To accelerate to 8000f/s in 16", you need 12000f/s/s. Applying that to 0.281oz requires 211lb of force. That over 16" is our old familiar 281ft-lb of work again.

However, now you have longer to accomplish that work--a whole 1/3000s rather than a mere 1/4000s. That works out to only 843000ft-lb/s of power, down from our 1.12M, which is just 1530 instantaneous horsepower.

But--here's the rub--we no longer have a 50% duty cycle. We still have to fire every 1/2000s to achieve a 120,000rpm rate of fire, but now two-thirds of that period is spent firing and we can only rest for 1/6000s. So the continuous horsepower we need is two thirds of 1530 instead of one half of 2040, which works out to the same thing: 1020hp.

On the other hand, the radius of the rotor is a third again as great, which means we'll have 1.78 times as much area to generate aerodynamic drag. I don't know the formula, but I'll bet with greater radius, even with slower speed, you get increased gyroscopic effects, which might make maneuvering and aiming a bit more interesting.

But you would get more range: while the ball would still be launched from a point even with the axis of the disc on one side, the axis would be three inches further away from you, if you were standing behind it. So...you'd get three inches more range with a 32" disk than with a 24" disk.

Now my head hurts! <img src="/ubbthreads/images/graemlins/tongue.gif" alt="" /> <img src="/ubbthreads/images/graemlins/tongue.gif" alt="" />
7mm

My call would be that "ma duece",that grand old girl,will be around for quite a while yet. It's about the KISS principle.Can you even begin to imagine the freindly fire/op. error potential of this particular infernal machine?
Work safe, GTC

Good point. There'd be a constant recoil pressure of just over 140 pounds (what they say about zero recoil is hogwash, unless they're firing simultaneously in opposite directions), and since the point at which it was exerted would be 16" out from the axis, it would be expressed as a torque of 187ft-lb. If it ever got loose from its mountings, it'd spin around and spew steel all over the place.

Another question: since they're using aerodynamically-inefficient balls, rather than streamlined bullets, why do they compound the inefficiency by making them out of a light, expensive, hard-to-work material like steel, instead of a heavy, cheap, easy-to-work material like lead?

I don't believe that's correct. With the exception of SCRAM Jet technology all jet engines operate with subsonic airflow internally, even when operation at high supersonic speeds.

I think the system under discussion is a pipe dream. High volumes of fire require large quantities of ammo, high velocities infer high energy to provide the impulse. Don't see that here at all. Round Ball ballistics are such that even if the system works it is a short range weapon and fraught with the potential of friendly fratricide. If you gotta buy stock make sure it's a short position. <img src="/ubbthreads/images/graemlins/wink.gif" alt="" />

That thing has got to be an elaborate hoax. Look at it. It looks just like the Starship Enterprise on Startrek. If it is a weapons system, the potential for friendly fire and collateral damage is mind-boggling. Also, each gun will need an attached 18 wheeler to carry the ammo because you can bet, that if it will shoot at 120,000 rounds per minute, that is what that PFC manning the HUMVEE swivel mount will be shooting it on. <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />