Skip to comments.US Navy Tests Supersonic Heavy Gun Firing Magnetically-Propelled Shells @ Mach 7
Posted on 03/02/2012 5:28:46 AM PST by Reaganite Republican
I think we need to take it up a notch from “Rods from God” to “Relativistic Kill Vehicle”
From the wiki:
“ExampleA 1 kg mass traveling at 99% of the speed of light would have a kinetic energy of 5.47×1017 joules. In explosive terms, it would be equal to 132 megatons of TNT or approximately 32 megatons more than the theoretical max yield of the tsar bomba, the most powerful nuclear weapon ever detonated. 1 kg of mass-energy is 8.99×1016 joules or about 21.5 megatons of TNT.”
Imagine if all the money wasted on those solar scams had been applied to this program.
Obamoa wants to cripple our military from being able to spend in the future. Ayers, Soros, Obamao are enemies of our country.
You have to have recoil. The whole, equal and opposite reaction law.
1. the senate armed services committee voted to kill this and a similar program several months ago. i’m not sure of the status or eventual impact of this decision.
2. this testing done here:
Could you imagine a version that would splinter into hundreds of thousands of shards at about a half mile above a group of ships?
For the non-physisist, there are 3.6 million joules of energy in 1 kilowatt-hour of electricity.
Assume a ‘barrel’ 10 meters long, an exit velocity of 2400 meters per second (just over Mach 7 at sea level), and a constant acceleration while in the ‘barrel.’
My cocktail napkin says that it experiences 28,800 G’s during the 1/120 second it is in the ‘barrel’.
Impressive feat, but to be fair Paris wasn't moving...
Great idea. Any idea how much energy you'd have to put into the system to accelerate a 1 kg mass up to .99 C?
Hint: Probably just a tad more than you expect to get back out of it... ;)
‘The USN has already spent seven years and $200M+ on development...’
Wow, thats amazingly inexpensive as far as weapon systems go w/ this much umph. Its hard to understand why it wouldn’t continue to be funded if its meeting engineering/performance goals & expectations.
I wonder if another version couldn’t be made for anti-aircraft and anti-missile. Have a rod that will “shotgun” after coming out of the barrel. Get a Mach 7, 10 or 20ft pattern of BBs coming at an aircraft, missile or a speedboat.
hmmmm, add that to the defensive layer along with our missiles, Phalanx guns, and hopefully some tactical lasers.
“Gee Bears.” Dan Simmons, “Flashback.”
Well - this isn’t exactly rocket science (TM ;-) This is a Magnetic Rail gun - it works on the same exact principal as a MagLev train. Just different scaling. Building a practical one is the big secret - not the physics is using.
Recoil is an interesting issue. For a regular gun, it depends on the mass of both the power charge and the projectile (and sabot, etc, if present).
As a rough estimate, you can assume all that mass, including the gases resulting from the powder charge, acquires a velocity equal to the muzzle velocity of the projectile proper.
Thus, the total momentum can be approximated by the total of the above masses times the projectile velocity. This is the impulse, the ‘kick,’ that is transferred to the gun, the ship, and the ocean (according to the law of conservation of momentum).
I don’t know what the comparison of powder mass to projectile mass is for big guns, but for small ones you often find the same order of magnitude, meaning that somewhere around half the kick of a small weapon is due to the propellant gas.
If this holds true for large naval guns, then the railgun
1. Has no recoil contribution powder gases;
2. Has less recoil due to the smaller projectile (how much smaller I know not)
3. Has more recoil due the the higher ‘muzzle’ velocity.
(By the way, there are large peak forces internal to the power supply, regardless of the technology it is based on.)
I don’t know the numbers for traditional big naval guns, but let’s say the railgun projectile is, say, 100KG, which is much smaller than that of a big gun.
Taking the railgun postulated in my previous post, the peak reaction force on the railgun and the ship would be 28.8 million newtons, or around 3600 tons.
The firing will impart 2.88 million KG-M of recoil impulse, and the projectile will possess a kinetic energy of 288 megajoules.
They’d better have a good energy-absorbing mount, or the recoil from the gun will eventually tear the ship and its contents to pieces! Of course, this issue has been dealt with continually since the days of the rope-restrained cannon on wooden warships.
(Anybody have a clean napkin, check my math.)
While rail gun is amazing and without question a game changer the 16” guns on the Iowa Class battleship have a 24 mile range not a 15.. but of course, sadly the iowa class boats are currently mothballed.
Seems like theres loads of potential. I think (not completely sure) the biggest problem is the power supply. At least in the beginning they were massive. I think they still are. For a ship thats not a problem but anything else makes it a nonstarter. The good news is theyre putting research $ into it so theres a hope for better, smaller in the future.
Well, since its relying on electromagnetism and not gunpowder, I suspect the kick is far less than one should suspect. At least as far as I understand the technology.
You aren’t directing an explosion, that wants to expand in all directions here out a nozzle here, you are progressively moving a projectile with magnetic force faster and faster over a short distance.
Think of it more along the lines of a SUPER roller coaster magnetic launcher, than a standard gun. Just far more powerful, and extreme.
Only if the projectile's mass was really small. The kickback force is exactly equal to the launching force, which is: F = m x a. (Force equals mass times acceleration.)
Such a gun would have a much higher recoil than convensional simply because the acceleration is high.
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