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Watch the US Navy Test Its Electromagnetic Jet Fighter Catapult
An anonymous reader sends word via Engadget that the U.S. Navy has tested its Electromagnetic Aircraft Launch System for the first time with a "dead-load" (a wheeled steel sled that weighs as much as a jet) aboard the Gerald R. Ford carrier. The article goes on to say: "Its advantages over traditional catapults that use steam instead of electromagnetic energy include smoother acceleration and its ability to place less stress on the aircraft — plus, it was designed to work even with more advanced carriers that the military will surely use in the future." You can watch a video of the "dead-load" testing here.
Steam seems like an ideal solution to me. Steam expands so well the dynamic range of it's force curve seems apropos to the task. How much of the EM energy goes into force? surge currents and magneto striction are usually things people find shorten the lifetime of electo devices yet here they are at the extreme in these. Presumably there's no shortage of steam available and it's a great way to store energy.
Some drink at the fountain of knowledge. Others just gargle.
http://en.wikipedia.org/wiki/E...
Advantages
Compared to steam catapults, EMALS weighs less, occupies less space, requires less maintenance and manpower, is more reliable, recharges more quickly, and uses less energy. Steam catapults, which use about 1350 pounds of steam per launch, have extensive mechanical, pneumatic, and hydraulic subsystems.[4] EMALS uses no steam, which makes it suitable for the Navy's planned all-electric ships.[14] The EMALS could be more easily incorporated into a ramp.[4]
Compared to steam catapults, EMALS can control the launch performance with greater precision, allowing it to launch more kinds of aircraft, from heavy fighter jets to light unmanned aircraft.[14] EMALS can also deliver 29 percent more energy than steam's approximately 95 megajoules, increasing the output to 122 megajoules.[4] The EMALS will also be more efficient than the 5-percent efficiency of steam catapults.[2]
Mit der Dummheit kämpfen Götter selbst vergebens
WHOOSH!
And it's on topic.
One of the reasons for this is to allow it to adjust the force used to lighter weight drones. Also, it is a lot less complex then the steam driven system, so easier to maintain.
My first thought was, "Since when are aircraft magnetic?" Yeah, really, that was my first thought. Then, I wondered why they didn't just fire the damned things from a rail gun. Oh - wait - in essence, that's what this is. The EM force is acting on the launcher mechanism itself, rather than the payload. Hmmm - wonder why I never thought of that before? It isn't necessary to launch your ferrous accelerator thingamabob. Next up - space launches? Yeah, I realize it would require a bigger launcher, bigger by a few orders of magnitude. It sure would save a lot of rocket fuel though!
"Windows is like the faint smell of piss in a subway: it's there, and there's nothing you can do about it." - Charlie Br
They totally missed that white boat! Looks like about 30 degrees to starboard and they'd have nailed it. Bad aiming there.
Are the generators (that power these things) driven by combustion? I would've thought the massive power req's of an aircraft-sized EM catapult would necessitate a nuclear reactor...
The carriers are all nuclear which means they boil sea water to turn steam turbines.
That means they have lots of steam. Stupid amounts of steam. Always.
The EM system means you have high voltage lines running under the decks and I generally think the system is going to be more complicated and harder to repair/maintain than the steam version.
Smoother acceleration? That also makes no sense. You can make a steam piston VERY smooth. As smooth as an electromagnetic whatever?... probably not but who cares... you won't be able to tell the difference. A machine measuring it might be able to tell. But a difference small enough that the dude getting thrown by the thing wouldn't notice is unlikely to be relevant to the airframe.
I am all for using superior technology. I just think there is a bias sometimes to go with electronics on the assumption that they're always superior. Sometimes they're not. Pneumatics or hydraulics or steam in this case are contextually superior in given circumstances.
We were hearing about them testing robots to go into a nuclear reactor in Japan. The robots all have complicated electronics and micro controllers. That's been shown repeatedly to not work. They radiation destroys the micro controllers.
When it comes to big machines that push heavy things around, you find that such big industrial machines are hydraulic in most cases. They rely on pressure. There is a centralized compressor somewhere that drives pressure through tubes and pipes... and that pressure is controlled to move heavy stuff around.
So here you have this big carrier with I believe two nuclear reactors in it... generating fuck tons of steam... and you're going to draw on the electrical grid of the ship instead of just drawing on the boiler directly?
Why? I'm just not seeing it especially in a battle platform.
What you want in a battle platform is something as robust and reliable as possible. A steam piston is more reliable than some electro magnetic whatever. That catapult goes down and the carrier is useless. Think about that. That is easily one of the most critical components of the entire carrier. Right up there with the flat deck on top in so far as utility. No catapult and most of the planes can't take off at all.
Saying that you can't do this with finesse ignores that the most advanced robots these days actually make use of pneumatic actuators.
I've decided to stop wasting my time responding to AC trolls/sockpuppets... so if you want a response from me... login.
You need a lot more power to push something the mass of an aircraft carrier through water at over 30 knots than what one or two catapults would require. Seriously, not on the same scale at all.
Seven puppies were harmed during the making of this post.
The UK carriers don't have a catapult. They were designed for jump jets like the Harrier (which they used to have) and a variant of the F-35 which they are getting.
Of course while the UK is building two carriers only the first one is being put into service. The second one is being built and basically mothballed right away because the contract was set up so that it was cheaper to do this than to cancel building it. And to make matters even worse while they have the first carrier now (it could be undergoing sea trials and may not be in service but it is built) they won't have the F-35s for it until around 2020. Plus they've already sold their Harriers so they're going to have an aircraft carrier for about five years without any aircraft.
Getting and keeping enough pure water on board ship is NOT easy! If the water is NOT pure; you get more rust. The coolant on the nuke power plant is NOT likely to be water and it is likely to be radioactive. Steam leaks are more likely to cause major injuries than blown electric breakers on a ship. Tim S.
That old news was overcome by events over half a year ago. Prince of Wales is not going to be mothballed at infancy after all. 2014 September 5: "The Royal Navy's second new aircraft carrier, the Prince of Wales, is to be brought into service rather than sold off or mothballed, Prime Minister David Cameron has announced. ... Both carriers will not be fully operational until 2023, the Ministry of Defence said."
Jeeze, struggling to no more than the third and fourth sentences of Wikipedia would have told you that.
The Queen Elizabeth class aircraft carrier program has been beset with enough heavy weather without having to cite obsolete information.
when nations or even non-state groups can put up swarms of, say, 1000 drones for $1M. or 10,000 drones for $10M.
aside from the economics (using $1M+ missiles to shoot down $1000 drones) can a jet fighter even cope with swarms of cheap drones ramming its jet intakes, with or without small explosive charges?
can jet fighters even shoot other targets if there's a huge swarm of drones in the way, programmed to intercept missiles and blow them up before they hit?
and as they get smaller, can a jet and/or its pilot even detect a single drone reliably if its disguised as a bird? a bird with a payload of quarter to half a kilo of C4 to be delivered to the jet engine?
Steam catapults are on the top of the ship, and the reactors are near the bottom. You need an extensive network of pipes to fill the reservoir tanks at each catapult. The steam needs to maintain temperature the entire way. There is a reason we run power lines across the country, and not steam lines.
That same assertion applies to electric, so it is a moot point.
Still easier to design electric than steam systems though.
That is a strangely satisfying thing to see, launching a car off the deck like that. A bus loaded with politicians would have been better, but they probably can't do that.
The 13-year-old me in my brain says there is a lot of play potential in this. "Gee, I wonder if it can launch $THIS off the deck? Let's do it!". Something like the Red Bull Flugtag
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By 2023 they might be able to run them on fuel cells or unicorn farts or whatever the future of alternative energy is supposed to be.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Scotland might wish to take notice... :p
That's all well and good but surely the power you speak of is allocated for propulsion?
No doubt this thought has not eluded them but it sounds to me like people on a project overselling their good features and ignoring possible showstoppers early in the development process. After all maybe they won't show up down the road as being important.
Yes, it's the defense budget. That's how the procurement process works. To hell with accuracy, every project is someone's darling and must be sold. There was a great comedy about the Bradley fighting vehicle procurement, IIRC, with... maybe Kelsey Grammer and Cary Elwes? It would blow up with soldiers inside and we kept building the damn thing, even when Israel made us redesign the ones they bought because ours weren't safe.
Damn; i bet one of these bad boys could accelerate a drone the size of a quarter to a not-insignificant fraction of the speed of light...
And boy will Kenny be pissed...
At first I thought they meant the Navy developed a catapult for their new electromagnetic jet fighter!
The sled looks like it could sink a ship, made a hell of a splash, too bad they cut the video short.
“He’s not deformed, he’s just drunk!”
No chance. That's only eight years from now. Those two carriers have been in the works for over fifteen years - there's no way you're going to see large changes without a correspondingly large war to propel them. It's more likely they'll go into service for a handful of years and then get mothballed for lack of operating funds.
That's all well and good but surely the power you speak of is allocated for propulsion?
Some numbers: the Nimitz-class carrier generates at least 190MW, a steam catapult on that carrier requires up to 72MJ of energy per launch (at maximum). So a Nimitz-class carrier could launch one airplane per second without using a great deal of its power. In practice, it's rare for a steam catapult to launch more than one aircraft per minute, which means that even with 4 steam catapults going at their maximum rate and hauling a maximum load, the average energy use would be about 18MW, or less than one tenth of the steam power available.
Hint for you: not all of the steam power is allocated for propulsion; much is for "other uses". The Nimitz-class carriers can use only up to 140MW for propulsion.
something like the QE has: two gas turbines, 4 diesel, and 4 induction motors to the screws. 77,000 tons to 25+kt.
Political debates have me rolling my eyes so much I think I got optical whiplash. I should sue. - Foamy The Squirrel
I would assume the system involves some sort of captive bolt on a rail. This would make the scenario you're describing highly unlikely. For that you would need a pair of parallel copper rails, a source of ridiculous DC current and a small metal (aluminium?) slug (the bit that completes the circuit and your payload). As for the pipedream of approaching relativistic velocities: with a current of over one million amps, the US Navy have managed to propel a seven pound projectile at just over 1.6 miles a second. This is about a hundred sixteen thousandth the speed of light. To hit one thousandth the speed of light we'd need to channel the entire plasma output of Jupiter-Io through the busbar (that's about thirty trillion amps).
Political debates have me rolling my eyes so much I think I got optical whiplash. I should sue. - Foamy The Squirrel
No chance. That's only eight years from now. Those two carriers have been in the works for over fifteen years - there's no way you're going to see large changes without a correspondingly large war to propel them.
To be fair, a retrofit to fuel cells would be relatively simple, since everything on the boat runs on electricity anyway. And you might be able to run the diesels directly on unicorn farts, it's possible to run them on propane anyhow... or at least a mix of diesel and propane. It's a not-uncommon way to add fuel to an old-ass diesel when increasing turbo pressure, because it's actually cheaper (all told!) than retrofitting most mechanical injection pumps and injectors for higher flow.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Oh, I have no doubt they could retrofit with new technologies if sufficiently motivated. But in the real world you're not going to get a peacetime first world military procurement bureaucracy to do anything significant in less than a decade.
Particularly anything involving these kind of expensive flagship vessels. They spent a lot of time considering things like noise signatures and surviveablilty when they designed it, and all that stuff would have to be gone through again.
Yes, but the steam is long gone as a side effect of running the ship or even supplying heating while electricity is in ample supply.
Yes some carriers have reactors, but some don't, and even if they do you do not want to throw away the incredibly clean treated water in the turbine loop. That means extra heating for catapult steam, even if it's part of the cooling for the turbine loop that's still an extra complication and a pile of extra pipework even if there's no extra energy being consumed.
The last time they had a plan like that Argentina took advantage of it - however they acted on the announcement and not the actual sale (Invincible) or scrapping (Hermes, Ark Royal) of all the carriers and were caught out.
To be fair, a retrofit to fuel cells would be relatively simple, since everything on the boat runs on electricity anyway.
Well yeah, that one's simple, but what about the unicorn farts mentioned by a previous poster? Just the torque converters for that alone would be enormous, not to mention the extra whangle drums and sliding paff gongbudgers.
This is how you test a catapult: Goodbye!
Watch this Heartland Institute video
it's not an 'Electromagnetic Jet Fighter Catapult' - it's a rail gun
What's its typical complement of notoriously clumsy dead former presidents?
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
Why would electronic aircraft even need a catapult? A sudden surge of plasma ought to suffice to a vertical takeoff.
More worryingly, what supplies the motive power, nuclear generators, or JP5?
Steam driven turbines. my boat had 6 of them, and we usually only had 4 running. they make more than enough power. source - former machinist mate (engine room monkey), served on the JFK for 3 years
Stop while you launch aircraft?
I was in the Navy from 1980 to 1991 and served in two different squadrons aboard USS America (CV-66) and USS Eisenhower (CV-69). For much of that time I worked on the flight deck. I'm glad the EM catapults are more reliable and require less maintenance. I am sure sailors and aviators alike will not miss cold cat shots and fires in the cat tracks. Nevertheless, the rising vapor from the steam catapults added a kind of surrealism to the job. I'll miss the "theatrics".
Proverbs 21:19
The problem with propane or any other LNG is they don't want some "Luke Skywalker" to get off one lucky shot and blow the whole thing up, which is what flammable highly compressed gasses tend to do. Most ships run on bunker fuel, and that's more like thick fuel oil rather than traditional diesel, they even have to heat it to get it to burn in the engines.
Apocalypse Cancelled, Sorry, No Ticket Refunds
A brief promo video about a dead weight going off the bow. /. would discuss a little more about the technical details or comparison between it and the steam alternative.
Personally, I'd have hoped a sciency-site like
Anyway, more substance at http://www.defenseindustrydail...
-Styopa
Is the EM system easier, or more difficult to maintain? Which system is less vulnerable to battle damage? The engineer in me is just as interested in the answers to these questions as he is to performance specs.
The USA is only 4X older than me...perspective
:|
If you run even some basic back of the envelope math, you'll see that you're off by quite a few orders of magnitude. You'd need a launch system several miles long and quite a bit more current delivered along the way to even have a shot at making something close to those numbers.
"The UK carriers don't have a catapult."
Because when the builders (BAE) were asked to quote for converting, they gave a figure slightly higher than building an entire new ship.
Common sense on their part. BAE will provide support services for the F35s and if the UK chose something else they'd lose a lot of income.
Of course that assumes the F35-B will actually make it to service, otherwise HMS Sitting Duck(*) and HMS White Elephant will be remain oversized helicoptor carriers plying the waves for a long time past their intended date.
(*) The UK can't field enough ships to form a carrier escort group, so building the things was mostly pointless. Ballistic antiship missiles are likely to render Aircraft Carriers mostly useless in the next 20 years anyway.
Most means of energy 'production' aren't capable of what this system (or any similar one) needs. It's massive, almost instantaneous draw of loads of power followed by zero. Any nuclear reactor capable of that much instant power isn't going to ramp down between shots...so what do you do with that power in the mean time?
All of these systems are going to be using some sort of energy storage and quick delivery...that's entirely different than the production of the energy. Capacitors or supersized batteries are likely what will actually be used to supply the energy to the catapult.
People in cars cause accidents....accidents in cars cause people
nicely played!