DREAD

[daftandbarmy]

Wot, no bayonet?

The US Army must have whole buildings full of people working hard to come up with cool acronyms for weapons like this...


DREAD is an innovative new weapon system that has “no recoil, no sound, no heat, no gunpowder, no visible firing signature (muzzle flash), and no stoppages or jams of any kind.” Video after the jump.

So, instead of using self-contained cartridges containing powdered propellant (gunpowder), the DREAD’s ammunition will be .308 and .50 caliber round metal balls (steel, tungsten, tungsten carbide, ceramic-coated tungsten, etc…) that will be literally spun out of the weapon at speeds as high as 8000 fps (give or take a few hundred feet-per-second) at rather extreme rpm’s, striking their targets with overwhelming and devastating firepower

http://www.techeblog.com/index.php/tech-gadget/video-dread-the-silent-weapon-system

 

[a_majoor]

There must be something in Australian beer, I have seen this device before (in fact it might be buried here several pages back) and like the Metalstorm (another innovative, if somewhat bizzare weapon) it comes from an Australian inventor.

The downside to this device lies in physics. As a rapidly rotating flywheel, it acts as a gyroscope, which means it is very stable where it is, and will violently resist changes in orientation. I belive a gyroscope will attempt to turn it axis 900to the direction you are trying to turn it, so elevation and depression will be rather fun, to say the least.

In addition to ripping the arms off the unfortunate gunner on a ground mount, it will also induce undesirable effects on any vehicle it is mounted on once the vehicle starts moving. This effect will be most pronounced on smaller lighter vehicles, and helicopter pilots will not want to fly with this attached.

 

[Synthos]

I would assume that this weapon spits out the pellets from a curved exit. You might be able to tilt the exit instead of the whole fly wheel to account for elevation/depression...

As for heli's and vehicles wouldn't it depend on the mass that's spinning?

 

[GO!!!]

Now I'm no rocket surgeon, but gyroscopic effects can be countered, right?

If you were to mount two dreads, one rotating opposite to the other, and placed 90 degrees to each other, this gyroscopic effect would in effect cancel itself out - right?

Also, unless the dread rotates continuously, you could just reposition it once it's rotation stopped - right? Some sort of braking mechanism to stop the spinning, reposition and fire again.

Of more concern, I believe, would be the electrical requirement of this weapon.

 

[George Wallace]

I'm at a little loss for words, in wondering what you're going on about with your reference to gyros.  There are three gyros in the Leopard keeping the gun stabilized.  Why would this be any different than a Tank turret in motion? 

I am sure any forces being generated are countered by opposing forces or absorbed in opposing directions. 

Guess this is why I'm not a Mechanical Engineer making the big bucks.

 

[Good2Golf]

There would be minimal effects in changing azimuth of the weapon or associated platform as there is no gyroscopic effect for coaxial motion.  Tilting away from the vertical axis that the DREAD is oriented to would have significant induced forces, however.  Basically, you'd be good to go if you wanted to traverse the weapon, but altering elevation would be...interesting.

G2G

 

[cplcaldwell]

More info at Defense Review.

Jeez, I'm glad we got the G wagen, the Iltis would've only carried about a 2-second burst for this thing. On second thought, even with the 'G' it'll be light packing and a two man crew.... ;D

 

[aesop081]

, but altering elevation would be...interesting.

I'm no mechanical engineer so i have to ask..........WHY ?

Our INS systems use mechanical  gyros and the way we toss the airplane around in all 3 axis they dont topple.  if this flywheel behaves like a gyro, why would changing the elevation be a problem ?

 

[Synthos]

To simplify the idea behind these 'induced forces' think of a bicycle. Part of the reason you can balance so easily on a bicycle is because when the wheels are spinning they resist forces that want to change their orientation. Thus if the bike starts to tip a bit to one side, the wheel resists that tipping, thus making it easier to balance.

With the DREAD if there is a fair bit of mass spinning in this thing it will resist being tipped up or tipped down, just like a bike wheel. Once you have it tipped though it will be steady. The more mass spinning the harder it is to tip it.

 

[aesop081]

To simplify the idea behind these 'induced forces' think of a bicycle. Part of the reason you can balance so easily on a bicycle is because when the wheels are spinning they resist forces that want to change their orientation. Thus if the bike starts to tip a bit to one side, the wheel resists that tipping, thus making it easier to balance.

With the DREAD if there is a fair bit of mass spinning in this thing it will resist being tipped up or tipped down, just like a bike wheel. Once you have it tipped though it will be steady. The more mass spinning the harder it is to tip it.

Well...again i'm not engineer, but......

The guys who designed this thing most likely are. I would think its fair to say they must have thought of that.

?

 

[George Wallace]

To simplify the idea behind these 'induced forces' think of a bicycle. Part of the reason you can balance so easily on a bicycle is because when the wheels are spinning they resist forces that want to change their orientation. Thus if the bike starts to tip a bit to one side, the wheel resists that tipping, thus making it easier to balance.

With the DREAD if there is a fair bit of mass spinning in this thing it will resist being tipped up or tipped down, just like a bike wheel. Once you have it tipped though it will be steady. The more mass spinning the harder it is to tip it.

OK

Now take that wheel off the bike and hold it with your outstretched arms, while it is spinning, and change it's attitude.

Do you notice the forces being applied now?

If you were standing on a 'turn table/lazy susan', the centrifical forces would actually turn you.

 

[Good2Golf]

I'm no mechanical engineer so i have to ask..........WHY ?

Our INS systems use mechanical  gyros and the way we toss the airplane around in all 3 axis they dont topple.  if this flywheel behaves like a gyro, why would changing the elevation be a problem ?

cdnaviator, internally, the gyros in the INS stay rotationally fixed in space, only the aircraft and gyro housings around them move. 

Any time a gyro is moved "rotationally" in one of the other two axes other than the principal rotating axis, there are gyroscopic forces induced (reacting in the direction of rotation, 90* past the point on the rotational axis where the force was applied.)  In the case of an INS or AHRS gyro, the drag of the gimbal mounts holding the gyro are the only induced forces, and they are relatively minor.  For the DREAD weapon, we're talking a rather large spinning mass...this is like the "spinning bike wheel" experiment.  With a spinning bike wheel off the bike, turn the axel threads in your hands while the tire spins...not much effect there (that's the no co-axial force thing)...now try to tilt the wheel...it rocks 90* away from where you intended to tilt it...the same would happen with DREAD, try to raise or lower elevation, and there would be an induced gyroscopic force to try and tilt the weapon left or right (depending on the direction of rotation)

G2G

 

[cplcaldwell]

OK

Now take that wheel off the bike and hold it with your outstretched arms, while it is spinning, and change it's attitude.

Do you notice the forces being applied now?

If you were standing on a 'turn table/lazy susan', the centrifical forces would actually turn you.

If not, go finish that bottle of rum, perch yourself on top of that moving dolly in the garage, and try it again1....

>


1- Please , please have someone take out a cell phone and record it,  this one will rule on youtube

 

[old man neri]

I'm at a little loss for words, in wondering what you're going on about with your reference to gyros.  There are three gyros in the Leopard keeping the gun stabilized.  Why would this be any different than a Tank turret in motion? 

I am sure any forces being generated are countered by opposing forces or absorbed in opposing directions. 

The gyros in a tank are on gimbals(I think). The whole point of them is that when the vehicles rotates and bounces around they gyros will remain fixed in reference to space (or ground). Throw in some computers and sensors and you stabilize the gun. The exact same thing is used in aircraft instruments to simulate the horizon when the aircraft spins and rolls in the air. It is called the artificial horizon. A gyro does not want to rotate it's axis. So if you fix a big gyro (like a giant spinning dish) on a vehicle and it is up high it can have some very interesting effects. You can simulate this effect at home by playing with a spinning bicycle wheel and trying to move it around, you will see some unusual effects, even more fun if you do it on a spinning chair.

I found some you tube videos that simulate what a gyro can do.
Bicycle wheel
CD players in space, really good demo, watch it all

The artillery now uses gyros. By having one spin up with some fancy computers and sensors it can determine which way is north. The gyro senses the spinning of the earth. Accurate to about +/- 0.1mil.


And to answer your question, yes I am a geek.

Guess this is why I'm not a Mechanical Engineer making the big bucks.

Trust me, you make more.

 

[George Wallace]

......... A gyro does not want to rotate it's axis. So if you fix a big gyro (like a giant spinning dish) on a vehicle and it is up high it can have some very interesting effects. You can simulate this effect at home by playing with a spinning bicycle wheel and trying to move it around, you will see some unusual effects, even more fun if you do it on a spinning chair.

Isn't that what I was saying in Reply # 10 ?

 

[Yrys]

To long ago  !

 

[old man neri]

Isn't that what I was saying in Reply # 10 ?

Yes, my apologies, I took a while to type my response that I didn't see the other replies.

 

[George Wallace]

You're going to have to improve those typing skills, or you'll get lost in the back pages.  ;D

 

[a_majoor]

2 pages now. And I thought the problem was with Australian beer........ ;D ;D ;D :cheers:

BTW, clever fixes like counter rotating disks=twice the mass and power consumption. Starting and stopping the rotor means waiting a considerable time to get your weapon into action and would require a honking electrical system to do so in any reasonable time.

Frankly, I would expect the real "next" generation of weapons to use directed pulses of energy (lasers and microwaves), electromagnetic propulsion of projectiles for KE weapons (railguns and coil guns), and use some sort of smart projectile capability (XM-25; BLAM projectile). What we are really waiting for is a very compact, high energy generator or storage system to power the weapon. I would expect such a device would make electrical propulsion of the firing platform a trivial problem (electric tanks, ships and even "jets" using electrical fields for propulsion).