Mmmmm…railguns

A missile punch at bullet prices

Railgun


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A demonstration of the futuristic and comparatively inexpensive weapon yesterday at the Naval Surface Warfare Center at Dahlgren had Navy brass smiling.

The weapon, which was successfully tested in October at the King George County base, fires nonexplosive projectiles at incredible speeds, using electricity rather than gun powder.

The technology could increase the striking range of U.S. Navy ships more than tenfold by the year 2020.

“It’s pretty amazing capability, and it went off without a hitch,” said Capt. Joseph McGettigan, commander of NSWC Dahlgren Division.

“The biggest thing is it’s real–not just something on the drawing board,” he said. “It could go to the field right now. We just want to improve it, to make it better.”

The prototype is an 8-megajoule device, and a 32 megajoule prototype is to be delivered this summer. The proposed 150mm production gun will have a barrel energy of 64 megajoules and a range of 200 to 250 miles. It will be cover that distance in about six minutes, and the warheads will not be explosive. The kinetic energy delivered to the target will be plenty.

Recoil on these weapons will be less than that of current 5″ naval rifles, which means that the rail guns could conceivably be mounted on a very large variety of platforms. As long as the juice is available.

The article says that specifications call for the weapon to be able to fire four to six times per day but that the developer expects to be able to reach ten shots per day. I thought that everything I’ve read previously indicated a rather high firing rate, along the lines of ten shots per minute of sustained fire. (This DoD .pdf from 2003 seems to claim 6-12 shots per minute.) I have trouble buying this “ten shots per day” claim, as the use of such a weapon would be fairly limited. Is it possible that the writer mixed up “per day” and “per minute”?

I can see it now: Marines ashore are under fire and they call in for support. The first round is off by 50 meters, and they radio in a correction. “No problem,” the DD(X) responds. “Next shot in 144 minutes!”

Comments

  1. The concept is not new. It was born in the 1970s then promoted two decades ago when President Ronald Reagan proposed the anti-missile ‘Star Wars’ Strategic Defense Initiative. The SDI rail gun was originally intended to use super high-velocity projectiles to shoot down incoming ballistic missiles. Ya’ gotta’ love the way we stay right on the leading edge of technology all the time. As I recall, the liberals have been referring to this as ‘risky technology’ for decades. Yeah, real risky. Let me see, what else has electromagnets in it that alternate polarity sequentially to cause motion? Oh yes, that would be every electric motor in my house. My electric razor uses a linear electric motor. It is an oscillating rail gun, if you will. I guess that officially puts the Japanese decades ahead of the US Navy. Too bad NASA isn’t interested in this technology as a cheap method of getting to low Earth orbit. They’re still screwing around with their 1940’s, Von Braun rocket. They’re resurrecting a 40 year old design derived from 30 year old parts.

  2. That’s good news. I had heard that they were having trouble with the gun disintegrating from the tremendous propulsive force. Nice to hear that they fixed that problem, or my info was faulty. No doubt the shots/day claim is a typo. In other cool news, did you see Rathyeon’s new laser defense weapon? It was on Breitbart, but I forgot to save the link :(. Anyway, it explodes incoming mortar shells 500 yards away. Pretty cool.

  3. Buckethead: Don’t poke the poor guy with pointed sticks, man…I’ve just been keeping my fingers crossed that this isn’t the same DFENS from the ‘Falling Down’ movie. If he stops by and wants to buy a Coke, I’m outta here.

  4. Good call, Murdoc. I just want to go home. The Osprey is a piece of crap. The down wash from the two laterally opposed rotors impinge below the fuselage and cause all kinds of problems, including the vortex ring state, but a very different vortex ring from what helicopters experience. Theirs is in a vertical rather than a horizontal plane. Bell’s own VTOL research showed this to be a bad approach, which is why they mainly went with 4 rotor designs. They also showed the advantages of the ducted fans in that research which they abandoned with the Osprey. Designs that start out bad never get better. And yes, it is very frustrating to watch this industry that used to set the pace of technology creep along at a snails pace, or even go backwards in many cases. It wasn’t always like this. Add to that the fact I get to watch my friends ship off to war where they fight to protect me and my family from terrorists… How could any reasonable person not get angry about the state of things? I’m not saying I’m reasonable, but even if I was, this is nuts.

  5. IMO the Osprey is not a piece of crap. It’s an expensive piece of crap that is actually less capable then the aircraft it purports to replace. Consider for cost of one Osprey you could have anywhere from 2 Chinook’s with all the bells and whistles or up to 6 Chinooks without the fancy electronics. Anyway, railguns have been around for years. The concept of trying to incorporate inflight GPS guidance into the slug does not pass the laugh test. It does however pass the theoretically possible and therefore capable of producing years of R&D test.

  6. Yeah well, F=ma, right? If ‘a’ is too high for your electronics to stand, increase ‘m’. If you hold ‘F’ constant, ‘a’ has got to decrease. There are other things that can be done too. If you want a given muzzle velocity and the maximum accelleration your electronics can stand is fixed, then increase the path length over which you accellerate your projectile. Didn’t Murdoc recently have an example of that approach? It seems to me he had some sort of rail gun thing that started out like a snail shell. I can’t get to the archives for this site for some reason. I haven’t been able to for a while now using IE or Firefox. Don’t get me wrong, I think its great that they fire these projectiles at such a high speed, but at some point you’ve got to realize that the whole thing is just research for the sake of perpetuating the research.

  7. As for Rate of Fire, I imagine that’s limited by how fast you can charge the capacitors. If it’s 64MJ per shot, assuming 100% efficient capacitors, that would take 64MW for 1 second or 32MW for 2 seconds etc. a little over 10MW for 6 seconds (i.e. 10 rounds per minute). 10MW is something like 13,410 horsepower. Within reason for a turbine engine on a ship. Add a bit for various inefficiencies, you’re looking at needing something like 20,000 horsepower to drive a generator for 10 rounds per minute at the higher energy level of 64MJ per shot. Spruance class destroyers have 80,000 shaft horsepower. So the only trick is having large enough generators to convert 25% or so of that power into electricity. Hence, 10 rounds per minute sounds reasonable, 10 rounds per day does not.

  8. Yeah, but that is only if they divert power from the deflector shields. Sorry, just having a Star Trek flashback.

  9. CDI report questions whether Osprey fit for combat duty Aerospace Daily & Defense Report 01/18/2007 With the U.S. Marine Corps set to put the V-22 Osprey tiltrotor into actual combat, the Center for Defense Information (CDI) is questioning whether the aircraft is ready for the job. CDI, a Washington-based military watchdog group, is scheduled on Jan. 18 to brief a report – ‘V-22 Osprey: Wonder Weapon or Widow Maker?’ – which cites U.S. military and other government reports as reasons why the V-22 is too dangerous to be used in battle. ‘This aircraft should not be used in combat,’ report author Lee Gaillard said in a Jan. 16 interview. For example, Gaillard said that the high twist incorporated in the aircraft’s propellers could make it more susceptible to blade stall and vortex ring state. To make matters worse, he said, the V-22 pilot’s manual calls for auto-rotation – essentially relying on the blades to keep spinning enough to slow the aircraft’s descent even after both engines stall – even though open Pentagon literature states that the Osprey cannot auto-rotate. Gaillard said other combat-necessary equipment has not been installed on the aircraft – such as adequate defensive weapons systems or a personnel hoist – to make it combat-ready. Ready for battle, Marines say In briefings throughout the fall, Marine Corps leaders maintained that the Osprey is ready for battle. They said any previous shortcomings have been dealt with and the V-22 represented a major leap forward for aircraft technology and capability over fixed wing or conventional helicopters. That’s especially true when moving between places quickly and then landing in remote locations, the Marines say. Only the tiltrotor Osprey technology offers the speed of a fixed-wing aircraft with the vertical versatility of a helicopter, they say. Marine leaders also say that their helicopter fleet is aging – both chronologically and technologically. The Marines have bypassed other helicopter buys to make room for and invest money in the Osprey. Some think tanks, like the Lexington Institute, have questioned whether the Marines gambled too heavily on V-22 development and deployment. Gaillard said that’s one of the reasons the Marines still plan to deploy the Osprey, despite the safety issues. He said those safety risks mitigate any benefit the Marines might get from such a speedy aircraft. Gaillard acknowledged that Congress has been made aware of the risk of V-22 deployments. But Osprey contractors and subcontractors exist in 63 percent of all House districts, making it difficult for any lawmaker to kill the program, he said. With this year’s brief, CDI hopes that the thought of putting such a risky aircraft into combat could provoke lawmakers or others to take a harder look at the Osprey, he said. Then, the $2.3 billion earmarked for production of 16 Ospreys in FY 2007 – about $144 million per aircraft – could be used to buy safer helicopters, Gaillard said.

  10. One problem with that is every time you shoot it, your satellite ends up in a higher orbit. I proposed using astronaut waste as reaction mass for a rail gun to keep the space station in its orbit once. It did not go over very well. Something about shooting stars that were really astronaut turds…

  11. D: hypervelocity turd station keeping. I like it. I didn’t mean to partly hijack the thread with the Osprey, that was just the first example of a troubled system that managed to limp into service that popped to mind. The Marines are certainly willing to take the risk for the kind of airplanes they want – look at the crash rates of the Harrier. But back to railguns – I agree that the ten shots a day has to be a typo. Unless they’re talking about ten shots a day for the prototype. I wonder what the final payload size for the projectiles would be? 15cm is pretty big. But the problem of electronics surviving the launch doesn’t seem that great, given that we’ve invented guidance packages for artillery munitions. Granted, the acceleration in a railgun is more – but is it that much more?

  12. In today’s environment anything is a good excuse. I think that may have been James’ point too. I’ve worked on R&D programs like that. Never get an answer, just get an excuse for more funding.

  13. Actually my issue with a GPS guidance has actually little to do with getting the electronics to survive the thousands of G’s. That is going to be a hard slog, but it could be done. (However it will be expensive – an Excalibur runs at 60K and only has to survive a fraction of the G’s a rail gun puts out. Plus the Excalibur is lot bigger thus more run to put stuff.) The real issue is that a slug going at Mach 8-10 is going to generate a nice plasma field that will block the GPS signals. Next, having fins and like for guidance is going to be next to impossible. The external temps are going to be in the 4000F range. You are going to a need ton of exotic tech to get this baby to work and then you are going to have to shrink it all down + protect it from the extreme heat and shock. The last issue is why? Now I’m most likely talking out my ass on this one, because I’ve never seen a study on the effects of wind on the flight path of a hypersonic projectile. I would venture to say, that if you design your slug right, you are not going worry much about wind deviation.

  14. Ok, I’ve got to admit, you’re way ahead of me on this one, James. You’re right, of course. Although, don’t they communicate with the shuttle all the way down now? I was under the impression they don’t lose contact during the hottest part of reentry now days. Still, I suppose packaging that kind of hardware on a chip with enough power to punch through the plasma is no small feat. Especially when you’re trying to get that signal from a GPS satellite. Like you say, just possible enough to make a massive research project out of it. As far as making it accurate enough without guidance, the article said it goes 95 miles up and 200 down range. I’m thinking it’s going to need guidance at those distances. Naturally, if they went with one that shoots a projectile out at Mach 3 or 4 they could have that gun in the field already and it would be an improvement over the guns they use now, but noooo. Where’s the big development program? Where are the decades of leaching off the US taxpayer? I don’t know why you let us get away with this crap.

  15. Yes, there is full communication with the shuttle all the way down. NASA uses 4 S-Band PM antennas to transmit signals to backtrace the shuttles path to several satellites which then relay the signal back to Houston. While this works for the shuttle, its not the magic bullet. Speaking of research projects. http://dodtechmatch.com/DOD/Opportunities/SBIRView.aspx?id=AF071-228 As soon as you see the word ‘innovative’ in a project solicitation, you know, they have no clue how to do it.

  16. Does anyone have any idea of the viability of a smaller, direct fire railgun mounted on a humvee or tank? To my uninitiated mind it seems like the silence of the weapon, the increased amo carrying capability, and the possible larger damage over a .50 caliber gun would make it a powerful alternative.

  17. If they made a ‘hybrid’ Humvee it might be practical because you’d already have the generator on board. Generally the electromagnets and capacitors required make these rail guns pretty heavy. One advantage of actually building things like rail guns instead of only studying them to death is often many evolutionary break throughs result from people tinkering with them. If there were some out there being used, who knows, maybe your .50 cal replacement would be just around the corner. It would be a nice stealth weapon.

  18. Well I say, put the railgun on a giant space ship, and have it fire a 10m diameter titanium sphere at supersonic speeds down towards the planets surface. We’ll call it a ‘mass driver’

  19. Personally I think the Ma Duce is fine weapon and why try to fix a weapon that is not broke? That said, incorporating a linear accelerator dampeners to create a zero recoil gun has a lot going for it. A stealth weapon would need to fire subsonic rounds. So a 40mm EM based launcher has some nice potencial. It must be said though – This program is vaporware – actually worse then vaporware since budgeting decisions are based on this program. (eg. killing the battleships, the DD(X, the Marines not get bombardment support) Signs the program is vaporware The biggest one – The title ‘A missile punch at bullet prices’ This title would only be true if they are going for the unguided slug. Once you add the precision requirement the cost per slug is going to be in the missile cost range. (Remember the most expensive part of a missile is its guidance system.)This precision addition will kill any realistic chance of the weapon being fielded in the next 20 years or so. Note: a JDAM GPS guidance kit runs at 29,000 and does not need to be shocked proofed to thousands of G’s and miniaturized. So how do you get the 1,000 per shot cost? The next one – the 200-250 mile range. There is no requirement for that kind of range. A clear sign of vaporware – filling a nonexistent need. If this weapon actually has a 250 mile range, why would we need the F-18? IMO this range is included to basically insure that the weapon is never fielded or if it is – it will be pushed to way in the future. *** Now if they can put together a nonguided 64mj weapon that can reach 500K feet, would it not be better to park next it to a nuclear power plant and use it too shoot down incoming ballistic warheads?

  20. So basically you’re talking about a rail gun/grenade launcher? I like it. You could spread some serious destruction with one of those, and have the projectile travel at M 0.9. No one would hear it coming or where it came from. We would only build something like that if we had a defense industry that was about something other than sucking down corporate welfare.

  21. It occurs to me that with a rail gun you could adjust the impulse given to the projectile as well as the weight, shape and type of projectile, so if you wanted to fire it supersonically you could, or it could have a stealth mode, or it could function as a mortar, or it could launch small missiles for a variety of uses including anti-aircraft. It is an electromagnetic catapult. The only requirements for the projectile is that it not hit anything on the way out. What fun we could have, if only they’d let us [sigh].

  22. A true variable impulse rail gun like you describe would solve a lot of problems. We could move on from our current custom solution to a common launcher platform where your ammo load is defined by the mission. Moreover by making a common luncher we can get away from the contractors making everything proprietary. For starters we could base the weapon on a Dragon wagon – that way you would have enough room for a 5-10Mw turbine or fuel cell. Yea it would be big, but the idea is build the concept with enough overwhelming capability so it could not be ignored. Plus its a lot easier to scale down once you got the plumming right.

  23. Plus you carry a lot less of the stuff that goes ‘BOOM’ on board your vehicle, yet still carry more offensive power than anything out there.