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)


 * Metal plates indicate something that needs protecting, and as MAC openings would need protecting, (You wouldn't want the muzzle to be damaged, have the shell hit the imperfections in the muzzle and damage the ship with the impact, would you?) muzzles for MAC cannons are something that extra armour can indicate on all ships equipped with such. --DRS Airwolf 14:47, 29 May 2008 (UTC)

The Bridge isn't even near those plates. Watch the intro to Combat Evolved. The bridge is the box on the forward tier, below the dual guns. The MAC is a tunnel that goes through the length of the whole ship. The muzzle is the forward most tier, in the direct center of the ships bow. You need to remember that these ships are massive. The bridge is relatively small and those plates are too large for it to be protecting that. Besides, if you've read the books, Keyes is always complaing his Bridge is unprotected. My educated guess is leaning towards the plates being used for space docking. MAC guns are protected well, by the ENTIRE hull of the ship. The MArathon and Holcyon Classes aren't exactly the same and differ on dozens of counts. Don't use them as interchangable resources for information. You are all partially correct and partially wrong on all parts. --Spartan-150 15:27, 17 April 2009 (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)


 * Actually, the quote could mean something. A coilgun's acceleration system is placed around the barrel, and evenly on opposite sides, so if part of the acceleration system reached that far down but the barrel was much further up, it would mean the entire height of the Autumn would be filled with the coilgun's acceleration system, something I highly doubt. As for damage to the lifepods, magnetic material will stop a magnetic field, so just encase the MAC in iron or steel and you have very good shielding so long as the casing is thick enough. Also, the barrel would not be very far across, (I remember 5 or 6 metres mentioned somewhere, probably in another part of this page, but on the Cairo it looks closer to 1 to 1.5 metres, so that needs clearing up by someone.) so the magnetic field inside the coils would be very powerful due to close proximity to them, however, it would be much weaker outside, due to the fact outside is not surrounded by the coil on all sides. Not sure how clear that explanation was, so if it isn't very then to anyone who understands it, feel free to explain better. --DRS Airwolf 14:47, 29 May 2008 (UTC)
 * And also, the Forward Unto Dawn is only around 300m, by estimations I have made on the last H3 level, yet its MAC is still considered powerful enough to be of use. On the Autumn, if we assume where the rear bulge starts is where all engine mechanisms start, and the MAC's barrel ends at the plating, this gives it 500m, perhaps 600m length, around double what the FuD's is. (estimated from the PoA's length being 1.17 km, which can still be disputed) --DRS Airwolf 14:35, 30 May 2008 (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)


 * or at least strap on some defensive weapons like the standard 50mm point defence guns and archer missiles pods. if they had these then the Athens and Malta would still exist...as would all the brave souls abourde them at the time. Maiar 06:44, 19 April 2009 (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)


 * thats why they put reactors ON BOURD. like someone up there already said numbnuts. and braudcast power is realy inneficiant so a reactor on the actual station would run better. Maiar 06:47, 19 April 2009 (UTC)

To answer the original question, why doesn't America use M1 Abrams and nothing else? Many reasons. The simplest of which is money. Then you have the fact that these MACs take an incredible amount of energy to fire. Then the fact that the slugs they fire are very hard to make. Then you have the fact that the Covenant had found ways around it. If all we had was MACs we'd have to wait to be attacked. We'd be unable to lure the Covenant away from others. Then you have the fact that would make our troops worthless, leaving them to die on the planet when its glassed. Then, all the MACs on orbital stations draw their energy from groundside reactors. As with Reach, once those reactors go out, the planet falls. Your thinking on this isn't logical. I don't beleive that humanity wasn't dependent enough on MACs, I beleive they were too dependent.--Spartan-150 15:31, 20 April 2009 (UTC)

The reasons the larger MACs are not built in bulk are many. For one, these are massive weapons, and as we've seen are very, very tempting targets. Why waste that many resources on something that's going to be out of the battle in the first or second exchange? There is also the time constraints to building so many. Sgt Johnsons said that when he shipped out for basic, some 25 odd years before the events of Halo 2, the platforms had not even begun to be built. This means that it takes a very, very long time to make even 1 of them, let alone sufficient numbers to compete against the numbers the Covenant could throw. Another reason is energy. Each Orbital Defense Platform required such a large reactor to charge it, they had to be built on the ground where the energy was transfered into orbit to charge the cannons. Yet another reason is that such a large cannon would require a massive superstructure around it to not only keep the thing from shaking itself apart just by firing, but also to armor and protect it from enemy fire. On the flip side of such large size, it would require massive engines to even get it moving, and because of its mass it would take a rather long time to even maneuver it. Creating a fleet of Super MAC warships was simply impossible to create at the time of the Covenant war, especially when you had to keep up the fleet to defend against attacks, as well as when shipyard after shipyard was falling to the enemy. Perhaps after the Covenant war, this could be possible, but it would be unwise, as such massive ships are cumbersome, targets for enemy fire, and would be extremely expensive to not only build, but keep supplied, especially on the frontlines.

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.

Rail Guns are a fast firing Magnetic accelerated bullets ain't they. to this MAC would be like magnetic accelerating cannon shell right? just saying makes sense DeadReanimation 11:23, 12 July 2009 (UTC)

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.

When you speak of the Sahara, do you say "Sahara"? Or "Sahara Desert"? Sahara means desert. Its the same logic. People simply add things to the simpler names to reaffer what they're saying. If you know nothing about Halo, would you know the MAC is a Cannon? Or would I have to tell you?--Spartan-150 15:24, 20 April 2009 (UTC)

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.

I was re-reading "The Fall of Reach," on page 108, after the first description of how a MAC works, the velocity of the projectile is given as 30,000 m/s which is 0.01% the speed of light. However, I have not been able to find a reference to the mass of a MAC slug in FoR. "Contact Harvest" page 119 gives the mass as 160 metric tons. Given that the ship in "Fall of Reach" was a frigate and Contact Harvest is set in 2525, its possible that larger, more powerful MACs like the one mounted on the Pillar of Autumn could fire a 600 ton slug, but I just can't find the actual reference and it's bugging me. So if anyone remembers could you help me out by posting here or adding a citation to the main page? Thanks

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)

The MAC gun's aiming is quite simple, in reality. Every human ship before the reverse engineering of Covenant technology would have microthrusters mounted everywhere along the hull, very similar to what current spacecraft use in that they use compressed air to push on that area of the ship. Mostly, these would be called maneuvering thrusters, and nowhere near the power of the emergency thrusters, or the main thrusters which power the ship. The size of the MAC basically makes the entire ship into one massive gun, which means the entire ship will have to turn on a direct line toward the target area. I say 'target area', because in most instances both the human ship and its intended target will be moving, and at the ranges these weapons are mostly used, this would mean you would have to lead the target enough to place each round on target. As for the round travelling the length of the ship, this is unknown, as the actual length of the MAC's barrel has never been defined for any ship. You would need a long barrel to propel the round at the speeds it reaches, but until actual figures are given, there is no real information about barrel length.

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)

Wow...this is getting confusing. allow me to summurise. Depleted Uranium has a density of about 19,100 kg per cubic meter. It is probobly safe to assume that the writers used american tons (~907 kg) so 3,000x907kg = 2,721,000kg, 2,721 metric tonnes devided by 19.1 t/m3 = ~142.5 m3...hang on...i may have made a mistake, someone please identify. Gunnery-sergeant Maiar 08:33, 17 April 2009 (UTC)

I agree with Mutoid Chief. Logically.--Spartan-150 15:21, 20 April 2009 (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 believe that the figure for standard MAC shells has been accepted at .01 c, rather than .1 c, so I believe your original figure of 1.8E9 N is correct. As for how the crew survive, consider the fact that in original Halo, first level, there is gravity. Halo 2, first level, there is gravity. And both of those maps are in space, aboard UNSC vessels. I believe from this that the UNSC must have developed some form of gravity generator, which could counteract it. Another solution would be having an equivalent mass fire in the other direction at the same moment, counteracting the push, though stopping this mass without having it slam into something and create the same backwards push is another story. Perhaps have several masses at a lower speed, and slow them down at an even rate along the ship's length, spreading out the backwards force over time to allow the engines to counteract it? --DRS Airwolf 14:05, 29 May 2008 (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)

Can somebody please explain why there is a muzzle blast when a MAC fires. The reason that appears around guns is because the gunpowder is exploding, but with a MAC gun, there is no gunpowder, or anything else explosive in the barrel, so there should be no blast. Is this just some liberty that Bungie takes, or are we missing something here? D1134 00:42, 24 October 2008 (UTC)


 * Maybe its some kind of epic sonic-boom. Maiar 06:34, 19 April 2009 (UTC)

He is correct, it would be a sonic boom, even though the Pellet passes the speed of sound before it even leaves the barrel, the opening into space (space is a vacuum) would suck out all particles from inside the barrel, which keeps the sonic boom from happening internally and blowing apart the barrel.--Spartan-150 15:18, 20 April 2009 (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).


 * Slight correction; it isn't easy to travel fast in slipspace, however, travelling a certain distance in slipspace equivalates to a much greater distance in normal space. --DRS Airwolf 14:29, 30 May 2008 (UTC)

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...


 * Not directly relevant to this bit of discussion, but I'm mentioning it because it's a point that needs clearing up; Regret's ship made a mess of New Mombasa because slipspace entry is not entirely stable. In fact, far from it. Putting it in words from somewhere in the novels; (but I do not remember where) entering slipspace is tearing a rip in space-time. You expect that to leave the area around nice and clean? Cortana does mention in Fall of Reach that the Covenant slipspace technology is far more advanced than the humans, and is more like easing out of normal space, but we must remember Cortana is an AI far more intelligent and capable than any of the Covenant AIs or navigators, and as such the Covenant might not be able to use their slipspace drives so neatly. --DRS Airwolf 14:29, 30 May 2008 (UTC)

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

Speeds are wrong
MACs don't fire rounds at 40% the speed of light - if they did then hitting a target at 100,000 kilometers wouldn't be a problem, the round would hit in less then a second. The standard MAC fires slugs at 30,000m/s and the Super 12,000km/s. Also, PoA's MAC isn't stated to fire slugs any faster then a standard ship, and is also said to fire smaller rounds, so where the .1c and 600 tons comes from I'm not sure. Harvest mentioned 160 ton metric ton rounds, which could be the smaller rounds in question.

MAC Firing
If it uses magnets, then why is there always a large blast coming out of the top of cairo station when it fires. I think the stations may use a shell w/ propelant.

A Gauss Cannon on a M12G1 Warthog generates a muzzle-flash effect, so why wouldn't a Super Mac gun, too? Also, try using this to help with Calculations: .--Phazon Blade 20:31, 27 August 2008 (UTC) When the Mac guns fire, theyy use massive amounts of energy to work. That energy is going in the same direction as the projectile. The energy doesnt just disipate, it comes out of the barrel.

Power
Using the equation Force = Mass x Acceleration I have calculated a rough number for the power behind a Super MAC. Assuming the weight of the shell is 3 000 metric tons and the acceleration is 11991698.32m/s then we get a number of 3.597509496E+13 in Newtons.--L55 03:35, 14 February 2009 (UTC)

Large Hadron Collider
Has anyone else noticed the Large Hadron Collider (L.H.C.) uses the same technology as a MAC cannon? Dreaddraco2


 * Actually, it doesn't. The MAC is a simple railgun, using magnetic strips to accelerate a metal projectile. The LHC is a particle accelerator. --  Administrator  Specops306  -  Qur'a 'Morhek   Honour Light Your Way!  01:10, 11 June 2009 (UTC)

The particles are Magnetically Accelerated, if you turned the L.H.C. into a cannon, it would techniqually be a magnetic acceleration cannon. Dreaddraco2


 * As per Specops. Also, the MAC can only go in a straight line, and cannot fire individual particles. The LHC is curved, and does not have an opening at the begining or end, but keeps going round. It also cannot fire anything larger than several particles.  General ONI   recon   111  -  [[Image:General.svg|30px]] 15:27, 15 June 2009 (UTC)

Ship-mounted MAC recharge time
The page says the main drawback to ship-mounted MAC cannons is the extended recharge time. However, it doesn't specify just what the recharge time is. Can anyone tell me what it is? Tophvision 17:08, 13 August 2009 (UTC)

Also, what's the source for the claim that ship-mounted MAC cannons have a yield of 5 megatons? Someone on the discussion page said the cannons more properly have a yield of 70 kilotons, significantly lower. Tophvision 21:32, 13 August 2009 (UTC)

Interestingy, I calculated the mass and acceleration stated for shipboard MAC cannons to get the yield. It came to 1.56e11 joules, or only 37 kilotons. Do I have my math wrong, or is something seriously wrong with the stated yield of 5 megatons? Tophvision

Correction: 1.56e11 joules is just 38 tons of TNT, not even kilotons. Something's inconsistent here. Tophvision 02:27, 14 August 2009 (UTC)

Okay, I did my math wrong, the yield with the given numbers is correct, BUT I've read that the speed for MAC cannons is 30,000 meters per second, or 30 km/s, not 260 km/s. What's the source for the 960,000 kmph number? Tophvision 16:00, 14 August 2009 (UTC)

General5 7, please don't just revert the edits, but actually PROVE THE NUMBERS. You do know that part of the page beforehand was honest about the MACs being 30 km/s, and the SMACs being 4% lightspeed? One's right, one's wrong. TFoR says 30 km/s is right. What's the source for the higher number? Tophvision 01:59, 17 August 2009 (UTC)

Barrel diamater of a MAC gun?
I have very poor math skills, so could somebody help me out? Judging from the size of a MAC gun for a Frigate, what would somebody skilled in math say is that diameter of the gun? I think it would certainly be bigger then a 16 inch gun on a Iowa-class battleship. Could somebody also give me an estimate for the Super MAC as well? I'm trying to put together a personal project and need help.

Information on the "Super Mac Cannon"
http://halo.wikia.com/wiki/Orbital_Defense_Platform

Before the Covenant invasion of Reach, there were 20 of these super Mac Cannons, if you follow the link I put in you can find sufficient information on the orbital defense platforms.