Talk:Magnetic Accelerator Cannon

I think the three metal plates under the Pillar Of Autumn could be its MAC canon, as described in Halo: The Fall of Reach --Climax Viod 10:56, 23 October 2006 (UTC)



What do you think ?


 * Yeah i think that looks right --Xeon 800--


 * I think you could be right.--Ryanngreenday 20:34, 23 October 2006 (UTC)


 * I agree, it most likley is. If it's not... what else could it be? - Knuxchao


 * Yeah I agree with it too, its the closest we've gotten to knowing where the MAC Gun is on the Pillar of Autumn, and it looks big enough for it to be a MAC gun too. User:Joshua 029

I Think those plates are just protection to the bridge. in halo combat evolved wasnt there like a big glass plate to see out of?-Mitch

Should i add this to the MAC article ? --Climax Viod 15:27, 3 November 2006 (UTC)

Are you sure?
http://img130.imageshack.us/img130/3950/poaob1.png Are we really sure this is the right place for the MAc? This image seems like a good place too....--User:JohnSpartan117 23:27, 28 December 2006 (UTC)

Thats what ive been saying --Climax Viod 14:46, 4 January 2007 (UTC)

Actualy after rethinking this i believe this to be wrong --Climax Viod 21:08, 14 January 2007 (UTC)

For anyone who still thinks the muzzle is at the three metal plates, check out the picture of the Marathon class: http://img134.imageshack.us/img134/8809/marathonclasscruiserae9.jpg

At first, you may say "The Marathon class has 3 MACs, and there are three distinct metal plated thingies. They must be the muzzles!" But look again. The third plating thingy near the stern would clearly have to shoot right through the second one, making it impossible that the metal plates represent the MAC muzzles. 74.113.238.25 05:56, 14 April 2007 (UTC)

i believe that either of the se woul be the place of the MAC b/c if you look how large the barrel is on the Super MACs, then this would have to be the location b/c the barrel would have to run almost the full length of the ship, b/c if it was at the bottom then it would be like firing a pistol at a blast door considering the amount of power that it would build up when in comparison to a MAC and a covvie cruiser, so it would need a much larger barrel e.g the 2 that are designated i would think it is the bottom of th e2 b/c it looks more barrel like and dark.(i suspect it is the same place on the marathons single MAC as there is no bottom part like the HAlcyons kk cheers,....... J!MMY8806 22:04, 14 January 2007 (UTC)

Page 272 of Halo: The Fall of Reach says "Captain Keyes drifted toward the stern and noticed concealed and recessed 50mm autocannons for defense against single ships. Underneath were bumps-part of the linear accelerator system for the ships lone MAC gun." This implies the MAC to be somewhere around the underbelly. Also, the Super MAC is much longer that a regular MAC, being that a regular MAC is an underpowered Super MAC. A shipboard MAC does not single-shot a Covenant ship.
 * --RotBrandon 00:54, 15 January 2007 (UTC)


 * Actually, that quote means nothing at all. It doesn't imply that the MAC launch tube is in the underbelly of the PoA, all it says is that part of the acceleration system is located there. I have a lingering suspicion that the only reason ships are designed for a specific length is for the MAC launch tube. After all, why else would the UNSC make all its vessels bilaterally symmetrical and have a straight line from stern bow for placing a MAC tube in? 74.113.238.25 03:19, 12 April 2007 (UTC)

i know that, but it would still have to be of considerable size and if it were at the bottom the barrel would run through the centre of the ship in between the lifepods, yes. so it would have to have some sort of damage of them + with the engines bieng as big as they are i suspect a massive drive system for them located behind them so the actual length of the MAC if it was at the bottom would be around 150-400m which doesnt seam like enough room to fit a weapon that is suppose to be able to nuetralize a ships shealds or destroy a UNSC ship in 1, kk just a though thanks mate, J!MMY8806 14:42, 15 January 2007 (UTC)

The Pillar of Autumn uses Magentic Feild Recyclers and Booster Capacitors to fire 3 succive shots with one charge. It does not have 3 guns. Fall of Reach page 275. --UNSC AI 02:02, 15 January 2007 (UTC)

Question here
Super Macs are the best defense we have against the covenant... Instead of building all these non-essential weapons like the frigate... Why dont we make ships bigger than Marathon Cruisers that have the capabilities of having enough size to feature something like a Super-Mac Cannon. It's wierd... A fanfiction must be written on this! xD Later. CaptainAdamGraves 02:07, 15 January 2007 (UTC)

or even better. Put slipspace and regular engines on MAC platforms! :P --UNSC AI 02:09, 15 January 2007 (UTC)


 * This is exactly why I dont see this the way Halo is as being how realistically we would be in a balls to walls fight for humanity. Wouldn't we strive for the biggest and best shit possible? Like in world war II, because we became a militaristic based nation, we made the best things. If we become a militaristic race, wouldn't we be into crazy big things? And yes, I dont understand why the MAC-Stations are stationary, its stupid... Grrrr.... CaptainAdamGraves 03:11, 15 January 2007 (UTC)


 * Thing of it. putting a Super MAC on one huge ship may seem like a good idea, in theory. but what's the Covenant's first target going to be? they'd blow it out of space before it could even charge the MAC! which i would imagine would take a while! Frigates are smaller, faster, and cheaper to make, which is why they're still used at all.


 * I agree. Also, it would take years (and dont forget the money) to make just 1 of them as a ship. This would be due to the testing of a Slipspace drive powerfull to push an item, atleast over a mile in diamatre. If my calculations are correct, any slipspace engine able to push a super MAC to FTL, would instantly, or almst instantly be blown into subatomic particles. -- 21:45 19/01/07

i have an idea why dont the humans get a super mac platform add alot of battleplate, archer missles, a couple of nukes,a reactor,and engines and call it a capital ship? think about it it could destroy any covenant ship while still being able to dodge the plasma torpedos, pulse lasers, and energy projectors the covenant ship could throw at it. After all marathon class cruisers are about the same length as a super MAC platform.
 * Actually, you are wrong, and I daresay, talking out of your ass. How can you make "calculations" about technology which we have no theoretical concept about? Predict what happens through objects travelling through IMAGINARY dimensions using IMAGINARY technology that nobody really understands?. You can't. Besides, large objects are provably able to enter and travel through slipspace successfully: High Charity manages to do without "instantly be blown into subatomic particles." We have been shown no upper size limit on what can travel through slipspace. 74.113.238.25 03:23, 12 April 2007 (UTC)


 * That point is true. It is stated in the novels that ships are only capable of moving through slipspace BECAUSE of their high mass; in First Strike, the Covenant Spirit dropship is almost shaken to pieces due to its low mass. From various points like this, I believe that the idea is in slipspace, the massier the object is, the more it "stabilizes" the imaginary dimensions, to allow things to exist there. DRS Airwolf

The thing is MAC Stations use broadcast power to charge thier capacitors--UNSC AI 21:37, 19 January 2007 (UTC)

Well it seems the Super-MAC is superior to Covenant weapons so why not make the Super-MAC mobile like Slipspace engines so defending Super-Macs when all is lost can jump to another system like Earth if Reachs Macs woulkd have jumped would have had 320 Super-Macs


 * Frigates and Destroyers are essential to the UNSC fleet because they are fast an maneuverable. The MAC station could not avoid being a primary target. The smaller ships have MAC guns. -ED 19:13, 10 March 2007 (UTC)


 * Super-MAC's need ground-based generators, ferrying the energy needed to power the massively powerful MAC's, to operate. how would they carry them around with them? if they were made smaller, they'd take ages to recharge, and by then the enemy's plasma volley will have wiped them out. by far the best method is to stick to smaller, more manoeuvrable, cheaper ships rather than big, unwieldy things that would be obliterated. -- SpecOps306 07:12, 8 April 2007 (UTC)

Not railguns
The MAC isn't a railgun. It's actually a coilgun. There's a difference. I could explain it, but you could also look it up on Wikipedia.

The Name
Many people call this the MAC cannon. When MAC stands for Magnetic Accelerator Cannon, why do people add a "cannon" after it? They are technically calling it "the Magnetic Accelerator Cannon cannon". I could rant on about how they call it the MAC gun also, but I seem to have reached my point. -Blemo 02:50, 5 April 2007 (UTC)


 * It's like the La Brea Tar Pits, literally meaning "The The Tar Tar Pits." It's weird English stuff that doesn't make sense. -- Dragonc laws ( talk ) 05:09, 12 April 2007 (UTC)


 * Or an ATM Machine. (Automatic Teller Machine Machine.) Just go with it.

Numbers
I was looking at the page, and it says that the Super Magnetic Accelerator Cannon is "capable of accelerating a 3000 ton ferric-tungsten round to 40% the speed of light, or 179 875 474.8 kilometers/s (74,512.9 miles/s)." Since this is neither the correct number nor the correct magnitude, I thought that I should point it out. The speed of light is 299 792 458 meters/s or approximately 300 000 000 m/s. 40% of this number would be 120 000 000 m/s or 120 000 kilometers/s.

Odd. I was going through the Halo: Fall or Reach paperback, and on page 283, the Super MACs accelerated "three-thousand ton projectiles" to "point four-tenths the speed of light". I see that not as 0.4C, but as (0.4/10)C, or 0.04C. --Some Sci-Fi guy 6-27-2007


 * It could be useful if someone with the books or whatever could find the reference where it gives the muzzle speed of the 'standard' MAC (currently 0.1 c in the article). If the SMAC is 0.04 c then some very interesting things start happening once one plugs in the numbers.  Namely: the SMAC produces slightly less KE than the MAC, but about 2 times the momentum.  (That would imply something about Covenant shielding too, no?)  On the other hand, if it turns out the MAC is only, say, 0.01 c then everything works out to the original expectation (i.e. that the SMAC is heads and shoulders above the MAC in all ways.) 74.99.140.28 20:04, 27 June 2007 (UTC)

I would tend to think that it's actuall 0.01C, not 0.1C, since while a shipboard MAC is linked to the power systems that drive the ship (it has to share juice with sensors, propulsion, life support, etcetera) a Super MAC just sits there and blows the crap out of things. Of course, there's always the possibility that Nylund meant either "four tenths" or "point four", but seeing that he's a good writer and the books are pretty much error-free, I'm sticking with Nylund actually meaning .04C 75.61.142.8 00:23, 28 June 2007 (UTC)

Were did the shipboard MAC numbers come from? What page, of which book? The only thing that I remember from reading the books was that in “The Fall of Reach” page 107 “The MAC - Magnetic Acceleration Cannon - was the (ship’s) main weapon. It fired a super-dense ferric tungsten shell. The tremendous Mass and velocity of the projectile obliterated most ships on impact.” The exact weight and speed was never stated as far as I can remember.

AIMING !!!!
How the hell would you aim a MAC? you must have to turn the whole starship because the round travels the lengh of it, like an Bull-pub assault rifle -- Climax-Void   Chat  or  My Contributions

I was also wondering this, maybe it has small thursters kinda like the shuttles or the ISS use to keep in the proper orbit? I remember in Fall of Reach a part where the orbitals re-oriented themselves and blasted covie dropships heading for one of Reaches poles but it didnt say how they maneuvered. Oh and btw its bull-pup not bull-pub;)

In Fall of Reach, the ship that Keyes used before the Pillar had some king of emergency thursters, or something among those lines. So, I agree that the platforms may have some kind of thrusters to allow it to aim at enemy ships. About the ships... Well, basically, yes, you would have to manuever it to aim at the covenant ships. The lenght of the barrel has its problems, and the lack of a alternative in the aiming system reduces the tactical capabilities of the ships. Felix-157 17:51, 4 June 2007 (UTC)


 * The "emergency thrusters" were nothing but tanks of high explosives strapped to the side; designed to ram the ship out of the way of incoming projectiles, as it was used for in Fall of Reach. But it is true that the ships have to maneuvre their entire length to aim, unless some of them have a limited ability to shift their MAC cannon inside.
 * But aiming this way is not much of a problem; due to inaccuracies with slipspace exits, UNSC craft will have their exit target at least 1 astronomical unit (look it up on wikipedia) from all known large objects in the system, as they can sometimes exit 1 AU away from their target, and they do not want to exit inside a planet or a star. Due to this, ships may leave slipspace 2 AU or more away from their destination (due to other planets pushing them even further away), yet no-one ever complains about the long journey to their destination. As such, it can be safely assumed that the UNSC has developed extremely fast engines by Halo's time, and these engines can be used for maneuvres as well as going forward. --DRS Airwolf 09:24, 29 May 2008 (UTC)

3000 ton shell?
In Halo: the fall of Reach, the 20 orbital MAC guns that defended Reach fired 3000 ton uranium shells but Cairo station is an obital MAC gun and in the big room where the anti-matter bomb is, you see the uranium shells being loaded into the cannon but the shells are about as big as the Chief so how can they be 3000 tons? HДĿΘFáṆ 18:03, 4 July 2007 (UTC)

I was thinking that a few weeks back, perhaps there are differnt types e.g. armour piercing? -- Climax-Void   Chat  or  My Contributions

Depleted uranium is ~19,000 kg per cubic meter. That means one cubic meter of depleted uranium could supply over six MAC shells. Forgive me, but I believe the proper argument is the shells were made too big, not too small. P03 James 06:36, 3 November 2007 (UTC)

It's 3000 tons, not pounds though. Since I'm not sure which ton it's referring to I'll provide all three. 3000 U.S. tons is 2,721,554.22 kilograms, which would require 1.4323 cubic kilometers. 3000 UK tons is 3,048,140.7264 kilograms, coming to 1.60428 cubic kilometers. 3000 metric tons is 3,000,000 kilograms, comes to 1.5789 cubic Kilometers

Some massive scale errors there - the size is actually 157.89 cubic meters, or a 5.4m * 5.4m* 5.4m cube. The shell seems to be about the right size.Mutoid Chief 11:46, 1 April 2008 (UTC)

Recoil
Would it be possible to find out how guns deal with the recoil? I mean, because of Newton's third law of motion (for every action there is an equal and opposite reaction), the firing of a MAC cannon would cause the ship to accelerate backward at 0.1c, and an orbital defense platform would shoot toward the planet's surface at 0.4c, thereby rendering the guns more hazard than help. PLEASE respond!

Coil-guns, and therefore MACs, suspend and propel their projectiles magnetically. There is no recoil at all. ~Greenroom

Exactly. No propellant is burned, the MAC is for all intents and purposes a giant tube with electromagnets running down the side of it. Once powered up, these magnets draw the projectile towards itself, and when the magnet is powered down, inertia carries the projectile to the next magnet. In the microgravity conditions of Earth orbit, slow-down would not be a factor to hinder speed. -Atlas503


 * All guns produce recoil. This is the whole Conservation of Momentum thing.  (On a tangent, reaction engines can be regarded as very powerful guns.  The principles that make them work are exactly the same.  This is why really powerful mass drivers can theoretically be used as engines.  Not very efficient though.  As a corollary, really powerful engines can be used as weapons.  See the Kzinti Lesson.)  With things like projectile mass, acceleration, and speed being equal, coilguns and railguns do produce less recoil than your normal deflagration gun simply because they don't have to worry about additional recoil being generated by the exhausting propellent gasses.  But make no mistake: MACs will produce recoil.  So why don't UNSC ships and stations go barrelling 'the other way' when they fire the big one?  Chalk it up to fancy magical devices like 'inertial dampeners' or somesuch. Meco 03:20, 27 September 2007 (UTC)

It is not a gun, in the traditional sense. Consider it as a bunch of ring magnets drawing a huge metal slug. How would it cause recoil? -Atlas503


 * Again: conservation of momentum. The method used to accelerate the mass is irrelevant.  Meco 19:45, 7 October 2007 (UTC)

Meco is right, throwing a 3000 ton slug out of a barrel is going to cause recoil. The only way I can see to get past this is either by having the station use the orbital tether as a backstop, having powerful engines on the bottom of the station, or having a floating barrel. Personally I think that the engines or floating barrel are most likely. --Bravo Kilo 18:53, 25 October 2007 (UTC)

Pardon me for interjecting, but I believe I have something useful to add to the conversation. I believe the reason why ships and orbital stations don't go backwards at 0.1c when they fire their MAC rounds is because of the differing weights. Using an example of a destroyer, consider this: A ship-scale MAC fires a 600 ton shell at 30 km/sec. This works out to be 1.8 billion newtons of force to fire the shell. 3rd law of motion, the shell pushes back at 1.8 billion newtons, however, because destroyers are ~4,000 tons, this only works out to be 450 meters/sec on the destroyer, which can be countered using chemical rockets or by accelerating the ship to a greater speed before firing. The bigger problem that I can see, is how the ships handle the instantaneous backwards acceleration of 450 meters per second, without crushing the crew against high G forces. Any thoughts? P03 James 03:04, 2 November 2007 (UTC)


 * Forgive me, I was in error. I was off by an order of magnitude, I should have typed 18 billion newtons of force. Also, the destroyer is 8,000 tons, not 4,000, meaning the 3rd law of motion recoil from a MAC shell must be 2,250 meters per second backwards acceleration (Assuming they do fire at one-tenth the speed of light, which could be in error). So that is a serious problem, in terms of both still having forward acceleration (particularly when destroyers are mentioned as having two MAC guns firing simultaneously), and how the ship's crew survives the instantaneous acceleration. P03 James 06:42, 3 November 2007 (UTC)

I know next to nothing about all of this... However, I think the point that some of the others were making was that conventional weapons use some sort of explosive to push a projectile forward at high speeds, when the force hits the projectile, that third law causes the force to reflect backwards a bit, causing the recoil. The MAC, from what I can gather uses extremely powerful magnets to pull the projectile, which... wouldn't really produce any recoil in a standard sense. Honestly, have no idea how that would work with the whole action/reaction, thing and my description could be wrong, but that's how I saw it.

In GoO the Spartans had their jet packs fire bursts to compensate for weapons fire while on zero gravity missions, the same thing could work for a ship. They could fire a huge burst from the engine as the MAC fires. -- Smothmoth 05:32, 30 January 2008 (UTC)

You can observe a MAC firing on Cairo station. Whenever it fires, the massive metal block drops down from the top of the gun. I suppose its movement compensates for the recoil. Mutoid Chief 11:55, 1 April 2008 (UTC)

Logically speaking
If we use .5 * m * v^2 = energy (which works well for projectiles traveling less than half the speed of light. It gets progressively worse as one approaches c), then the energy of a Marathon Class's cannon is 115.4 gigatons. Logically, you'd expect the orbital defense stations to have more powerful guns, considering the fact that they need support from power plants on the planet, and are much larger, with longer barrels.

If we use v = .04c, we get the result that the orbital defense station is just as powerful as the Marathon's cannon! Does this really make sense?

If we use v = .4c, we however get the yield of 10,000+ gigatons. Too powerful? Perhaps. Perhaps not. The orbital defense platforms can take out a Covenant battlecruiser in a single hit, yet Marathon class cruisers (with a vast array of missiles and atomic arms) must works in groups of 3+ to take out a Covenant battlecruiser.

The .4c velocity seems to work well with other canon information, and it can be explained in the context of the dialogue by saying that the "tenths" and "point" were added for redundancy. Why else would you try to mesh two systems together? Consider this analogy. You're driving a car, and I say "Go slower. Slower". Taken literally, this means to reduce the rate at which you are going slower. But the use of slower twice is clearly just redundancy.

He was probably just saying "point 4 tenths" because he wanted to make the placement of the decimal clearer, and harder to misinterpret.

As for the issue of action-reaction (the basis of recoil), let's remember why these laws work. When two cars collide, the electrons on the outside of their atoms are repelling, pushing both of them backwards. It is an "equal and opposite reaction" because a magnetic field exerts an equal force on both electrons.

The coilgun doesn't cause an action-reaction in the way that a gun does. The bullet and the gun don't literally touch when they push off of each other. But let's remember that when the coilgun propels its projectile, there are magnets pulling on the projectile. When the magnets pull the projectile forward, the projectile pulls the magnets backward. So yes, there is recoil.

How does station deal with recoil? That's hard to say. Its possible that they're extremely massive, and the recoil only pushes them off slightly. But I find this hard to believe. There's quite a bit of force required to push a projectile to nearly half the speed of light.

It could be said that the orbital defense station has a little "towboat" that pulls it back out every so often using slip space (where apparently its easy to travel fast).

Now of course this violates conservation of energy, since one could just take a rock at the surface of the Earth and keep slip spacing it to orbit, then let it fall. The rock would keep gaining velocity as it travels towards the Earth, but where would that energy come from?

I have an idea that perhaps a ship must put some energy out to travel into slip space, which would solve the conservation of energy issue. Perhaps that's why Regret's ship made such a mess of Mombassa when it tried to slip space away. Perhaps it had to put in energy to go into slip space. Perhaps that's why Mombassa looked like it had been wrecked after the ship went into slip space. The matter in the city was converted into gravitational potential energy by E = mc^2

But this last part is just my speculation...

MAC Yields
I took the liberty of erasing the garbage relating to MAC yields. Apart from being horrendously sourced, the sections removed also featured blatantly incorrect numbers.

1. Stated that FoR puts Shipboard MAC speeds at 30,000 km/s. This is false. FoR states 30,000 METERS per seconds, a full order of magnitude lower.

2. Calced the yield of the SHipboard MACs using the above figures to be around 50 gigatons (50,000,000 kilotons). The actually figure would be closer to 70 kilotons.

3. Stated that Super MACs accelerate projectiles to 0.4 percent of lightspeed (0.4 c). This is false. THe exact quote is "point four-tenths the speed of light", which is erroneous grammar, but taken literally translates to (0.1 * 4/10), or 0.04 c.

4. Calced the yield of the Super MACs to be 5 or so TERATONS (Extinction event in extremis). Actual figure would be closer to 50 Gigatons.

Please, don't delete that stuff. Change it, instead, or we lose a lot of work, regardless of whether it's right or wrong, that someone put effort into.  Specops306 ,  Kora 'Morhek  07:27, 21 March 2008 (UTC)

I understand your concern, and note that I DID take the effort to simply edit the correct numbers in. However, the calculations as to the yield in tons of TNT that were included previously seemed somewhat tangential, and I'm almost certain I've seen similar or identical quotes on message boards such as stardestroyer.net (one of the sources for those passages, conveniently enough) and spacebattles.com. Fan calculations just don't strike me as entirely reliable, hence why I just kept the corrected numbers from The Fall of Reach instead.

dino crater
in case anyone is wondering about my math, here it is:

.5(3048140.7264)(11991698.32)^2*

this equals about 2.2 x 10^20 (22000000000000000000) kJ. the astroid was about 5x10^23kJ and the largest bomb detonated was the Tzar bomb at 2.1x10^17 kJ


 * 3000 tons = 3048140.7264kg and .4/10 the speed of light = 11991698.32