Fun with numbers, Gundam style

[4Tran]

This is intended to be a thread to discuss the different mechanics found in Gundam. It can also be used to highlight any unusual implications of the technologies or any pure technology versus comparisons.

To start things off, I present the ever popular Zaku II.

Originally Posted by MAHQ

Model number: MS-06F
Code name: Zaku II
Unit type: mass production general purpose mobile suit
Manufacturer: Zeonic Company
Operator(s): Principality of Zeon; Neo Zeon
First deployment: March UC 0079
Accommodation: pilot only, in standard cockpit in torso (later refitted and replica units equipped with panoramic monitor/linear seat cockpit)
Dimensions: head height 17.5 meters
Weight: empty 58.1 metric tons; max gross 73.3 metric tons
Construction: super-high tensile steel on monocoque frame (A)
Powerplant: Minovsky type ultracompact fusion reactor, output rated at 951 kW (B)
Propulsion: rocket thrusters: 2 x 20500 kg, 2 x 1000 kg (C)
Performance: maximum thruster acceleration 0.59 G; 180-degree turn time 1.7 seconds; (D) maximum ground running speed 88 km/h
Equipment and design features: sensors, range 3200 meters (E)
Fixed armaments: none
Optional fixed armaments: 2 x 3-tube missile pod, mounted on legs
Optional hand armaments: ZMP-50D/120mm machine gun, drum-fed, 100 rounds per drum, spare drums can be stored on waist armor racks; (F)
H&L-SB25K/280mmA-P Zaku bazooka, 4 round magazine, can be stored on rack on rear waist armor; heat hawk Type5, battery powered, can be stored on waist armor racks; MIP-B6 cracker grenade, can be stored on optional storage rack on waist armor racks

Oddities
There seem to be a few strange things with regards to the Zaku II's specifications:

(A) Steel is a rather unusual choice for constructing a warmachine. Normally, one would either go with a light material like aluminum to conserve weight, or a composite to increase armor protection.

(B) A 951kW reactor works out to be 1280 horsepower. This is less engine power than found in some monster cars. It's curious that the Zeon engineers would choose to employ a volatile and expensive Minovsky engine when an internal combustion engine would produce similar results.

(C) Thrust and propulsion are not measure in kilograms. Based on the acceleration stated, it looks like the proper unit they were looking for was the newton.

(D) The 1.7s 180-degree turn specification looks a lot like a turning-radius figure. The only problem here, is that it's really only applicable to aircraft. Ground vehicles obvious don't work like that, and neither do spacecraft. So what the heck is that statistic for?

(E) Since Minovsky Particles block radar and other lower-wavelength electromagnetic radiation, what does the sensor range mean? Does it mean that the Zaku II's radar can see things within 3200 despite Minovsky physics, or is it some other sort of sensor technology. The possibilities are infared, optical , or LIDAR. It could also be the extreme range of its fire control system. Any affirmative answer to this would point towards some interesting implications, but also bring up further questions.

(F) Given that the Zaku II's 120mm "machine gun's" lack of recoil (even in fully-automatic fire mode!), we can safely assume that it has a very low muzzle-velocity. So the question is, what kind of armor-piercing ammunition does it use? Does it fire a solid penetrator or would it be a HE derivatire like HEAT or HESH? Regardless, a low muzzle-velocity will put a cap on its range and accuracy.


Based on the above information, it doesn't look like the Zaku II is not a particularly good combat platform for operations on earth. Interestingly, Zeon forces initially deployed conventional Magella tanks, but later adopted mobile suits for earth. We don't know too much about the Magella, but we know that it is much cheaper than any mobile suit, and that its 175mm main gun is probably greatly superior to a Zaku II's main weapon. So the question is why did Zeon decide to replace the seemingly superior unit with an inferior one? What advantage does the Zaku II have that I'm missing?

[Knightmare213]

Originally Posted by 4Tran

(F) Given that the Zaku II's 120mm "machine gun's" lack of recoil (even in fully-automatic fire mode!), we can safely assume that it has a very low muzzle-velocity. So the question is, what kind of armor-piercing ammunition does it use? Does it fire a solid penetrator or would it be a HE derivatire like HEAT or HESH? Regardless, a low muzzle-velocity will put a cap on its range and accuracy.

First of all, a 18-meter tall mobile suit having a 120mm machine gun and having a very small recoil seems just unreal, even though the Basic Laws of All Anime says that real physics can be bent and ignored.

120mm equals to 4.7 inches, and WWII battleships' secondary gun calibers are five inches. And don't those things have a reasonable recoil for a friggin' battleship? And we're talking about a 73.3 ton mobile suit firing that machine gun at an automatic rate. The Zaku II should be pushing falling on its metallic ass every time it fires a round, IMO, regardless of the muzzle velocity.

An understandable caliber for a mobile suit should be at least be half as big as the current caliber, about 1.50 caliber. That way, it can fire without the recoil affecting the accuracy of the weapon, depending how strong the arm of the Zaku is.

Also, about the steel plates being used as the armor of the mobile suit, I was wondering if you want to make a stealth mobile suit, would it be a good idea to use a carbon composite on the top layer of the mobile suit then a reinforced steel or some other alloy like Kevlar? Just wondering.

[viper]

5 inch guns are relatively small and pathetic mind you. WWII destroyers were carrying 5" guns. The 5" guns on battleships where there primarily for firing AAA, Anti Aircraft Artillery. An Iowa class battleship carried 16" guns if I recall. I'm not too sure, but I think that the fact that all the afformentioned weapons incorporates recoiling barrels which should minimize recoil.

@4Tran
As for thrust, many people and websites often states thrust in pounds. Like for example, the General Electric (GE) website states that a GE F110-400 turbofan engine for an F-14D is stated to have something around 27,000 to 28,000 pounds of thrust at full military (no afterburner) power. This is not just for jet engines. A space shuttle's main engines (SSME) produces roughly 410,000 pounds of thrust each, according to some sources. Those figures too are stated in pounds.

[fizzmaister]

Originally Posted by viper

5 inch guns are relatively small and pathetic mind you. WWII destroyers were carrying 5" guns. The 5" guns on battleships where there primarily for firing AAA, Anti Aircraft Artillery. An Iowa class battleship carried 16" guns if I recall. I'm not too sure, but I think that the fact that all the afformentioned weapons incorporates recoiling barrels which should minimize recoil.

@4Tran
As for thrust, many people and websites often states thrust in pounds. Like for example, the General Electric (GE) website states that a GE F110-400 turbofan engine for an F-14D is stated to have something around 27,000 to 28,000 pounds of thrust at full military (no afterburner) power. This is not just for jet engines. A space shuttle's main engines (SSME) produces roughly 410,000 pounds of thrust each, according to some sources. Those figures too are stated in pounds.

yes and pounds are the equivelant of Newtons (not Kilograms) the US equivelant of the kilo is a slug (actual unit of measurement of mass). Newtons and pounds measure force. Also a recoiling barrel will spread the force over a larger period of time so it wont have such a great impact on the ZAKU. About the ICE, one of those would run out of fuel too fast for practical purposes. Therefore a small nuclear reaction is used.

[Soluzar]

Originally Posted by 4Tran

(A) Steel is a rather unusual choice for constructing a warmachine. Normally, one would either go with a light material like aluminum to conserve weight, or a composite to increase armor protection.

I seem to recall that the ratio of tensile strenght to weight is roughly the same for both steel and aluminium, but the ratio of mass to weight is of course better for Aluminum, which also scores better in compressive strength. There is the fatigue factor to bear in mind, as well. There is a level of load below which steel has an infinite fatigue-life. That number is much lower for aluminium. There is also more than one kind of steel, of course. Check out this page about HSLA Steel. Seems likely that the steel founding industry would continue to advance further into the future as well.

I don't deny it seems odd on the face of it, though. It certainly doesn't seem surprising that the Gundam was so successful.

(B) A 951kW reactor works out to be 1280 horsepower. This is less engine power than found in some monster cars. It's curious that the Zeon engineers would choose to employ a volatile and expensive Minovsky engine when an internal combustion engine would produce similar results.

I'm not convinced that an archaic and already outdated unit of measurement such as horsepower should be applied to anything other than a purely mechanical engine. When you're talking about a reactor that functions based upon an unknown principle, you may be looking at a much greater degree of efficience of power transfer. Some of that power is utilised directly as energy, without the need to convert it to motive force. If your mechanism is more efficient, it requires less power. That's always been the principle. High-output automobile engines are not at all efficient, and nor are they necessary.

(E) Since Minovsky Particles block radar and other lower-wavelength electromagnetic radiation, what does the sensor range mean? Does it mean that the Zaku II's radar can see things within 3200 despite Minovsky physics, or is it some other sort of sensor technology. The possibilities are infared, optical , or LIDAR. It could also be the extreme range of its fire control system. Any affirmative answer to this would point towards some interesting implications, but also bring up further questions.

I'd guess it's talking about the camera the presents the field of view to the pilot, rather than what you or I would normally refer to as a sensor package. It is made eminently clear that those kind of sensors just don't work in the UC universe.

Based on the above information, it doesn't look like the Zaku II is not a particularly good combat platform for operations on earth.

I don't see how the grounds exist to state that. To me it seems like you're comparing mobile suits to cars, and expecting the figures to make sense. I'm not convinced that you can do that. I would say that the vast deficiencies the Zeon mobile suits have when compared to the Gundam are simply because they were constructed without full access the the natural resources of a planet. It's amazing the Zeon were able to get enough metal to build all that they did, really. I know they did their best to secure resources on Earth later, but at the start of the war, where did their stockpiles come from?

Interestingly, Zeon forces initially deployed conventional Magella tanks, but later adopted mobile suits for earth. We don't know too much about the Magella, but we know that it is much cheaper than any mobile suit, and that its 175mm main gun is probably greatly superior to a Zaku II's main weapon. So the question is why did Zeon decide to replace the seemingly superior unit with an inferior one? What advantage does the Zaku II have that I'm missing?

The name is the first clue. Whatever the stats lead you to believe, the Zaku II is a Mobile Suit. The design gives it greater mobility than any other weapons platform deployed on Earth at that time. This much should be clear from the narrative, if not from those stats.

[4Tran]

Originally Posted by fizzmaster

yes and pounds are the equivelant of Newtons (not Kilograms) the US equivelant of the kilo is a slug (actual unit of measurement of mass). Newtons and pounds measure force.

While this is partially true, they aren't talking about regular pounds. They're actually talking about pound-force (pound * gravity), a non-SI unit equivalent to 4.45 newtons, or pound-mass, equal to 0.453 newtons. A kilogram-force does exist, but it would not work for the figures given, and it should be abbreviated as either kgf or kp, instead of the kg for kilograms.

Originally Posted by fizzmaster

Also a recoiling barrel will spread the force over a larger period of time so it wont have such a great impact on the ZAKU.

If you have ever seen videos of M1 tanks (or equivalent) firing their main guns, you would be sure to notice the effect of the recoil. A Zaku II firing its machine gun is effected much less even if it fires in full-automatic mode for a 1s burst. Now if we assume that each Zaku 120mm round is as massive as a M1 round, and that the machine gun has a RoF of 10 rounds per second, it would be obvious the machine gun has 1/10 (or less) the muzzle velocity of the M1 gun. This greatly impacts the machine gun's penetration, accuracy and range.

Originally Posted by fizzmaster

About the ICE, one of those would run out of fuel too fast for practical purposes. Therefore a small nuclear reaction is used.

The Zaku II is not a long-range commando unit by any stretch of the imagination. To compare, a modern tank will have a ~400km operational range. This is quite suitable for every single Zaku II on the ground we see in UC. Note that this would avoid the issue of inherently volatile Minovsky engines. When one of these engines is damaged, the whole machine explodes in a violent explosion - a sure sign of poor engineering.

Originally Posted by Soluzar

I seem to recall that the ratio of tensile strenght to weight is roughly the same for both steel and aluminium, but the ratio of mass to weight is of course better for Aluminum, which also scores better in compressive strength. There is the fatigue factor to bear in mind, as well. There is a level of load below which steel has an infinite fatigue-life. That number is much lower for aluminium. There is also more than one kind of steel, of course. Check out this page about HSLA Steel. Seems likely that the steel founding industry would continue to advance further into the future as well.

When we speak about the strength of armor, we generally are not talking about its load-bearing properties. Normally, we are concerned with its ability to withstand attacks. Homogenous steel of all varieties is rather pathetic at stopping even light anti-tank weapons. This is sort reflected in the fragility of mass-produced mobile suits in MSG, but Zaku IIs should have been easy meat for tanks.

Originally Posted by Soluzar

I'm not convinced that an archaic and already outdated unit of measurement such as horsepower should be applied to anything other than a purely mechanical engine. When you're talking about a reactor that functions based upon an unknown principle, you may be looking at a much greater degree of efficience of power transfer. Some of that power is utilised directly as energy, without the need to convert it to motive force. If your mechanism is more efficient, it requires less power. That's always been the principle. High-output automobile engines are not at all efficient, and nor are they necessary.

Complaining about the horsepower unit is irrelevant. Horsepower is simply a non-SI unit used to measure force. It's hardly archaic since all modern automobiles are rated with it. I just used the unit so that most people can readily identify with it. I could just as easily have stated that many monster cars have >1000kW engines compared to the Zaku II's 951kW.

There is no indication that any UC technology has more efficient power utilization than modern technology. Besides, any greater efficiency is an effect of the rest of the transmission, and has nothing to do with the engine itself. Thus it could be equally applied to an internal combustion engine.

Originally Posted by Soluzar

I'd guess it's talking about the camera the presents the field of view to the pilot, rather than what you or I would normally refer to as a sensor package. It is made eminently clear that those kind of sensors just don't work in the UC universe.

I think that that's a safe assumption. I was just wondering if anybody had further information.

Still, Minovsky Particles don't block visible light, which will make optical and LIDAR systems viable, and they have not demonstrated the ability to interfere with the infared spectrum (When's the last time people couldn't feel heat due to Minovsky interference?), so those systems would be effective as well.

Originally Posted by Soluzar

I don't see how the grounds exist to state that. To me it seems like you're comparing mobile suits to cars, and expecting the figures to make sense. I'm not convinced that you can do that. I would say that the vast deficiencies the Zeon mobile suits have when compared to the Gundam are simply because they were constructed without full access the the natural resources of a planet. It's amazing the Zeon were able to get enough metal to build all that they did, really. I know they did their best to secure resources on Earth later, but at the start of the war, where did their stockpiles come from?

I'm specifically comparing Zaku IIs to Magella tanks. I only used car analogies because that's what other people can identify with. Quite obviously, Zeon forces were perfectly capable of fielding tanks, and their tanks seemed superior to their mobile suits. A Zaku II seems to have both weaker weapons and armor to their tank counterparts, so what advantage did they bring to the battlefield? And why were they used to pretty much replace the Magellas altogether?

Originally Posted by Soluzar

The name is the first clue. Whatever the stats lead you to believe, the Zaku II is a Mobile Suit. The design gives it greater mobility than any other weapons platform deployed on Earth at that time. This much should be clear from the narrative, if not from those stats.

Unfortunately, a slower tank has absolutely no problem hitting and destroying faster enemies. Tanks have been known to shoot down low-flying helicopters with their main guns (some armies even issues special anti-helicopter ammunition to their tankers).

Mobility can confer some advantages, but not enough to compensate for a Zaku II's other failings. This is especially true given that Zeon forces could probably field 5+ Magella tanks for every mobile suit.

[flamingtroll]

Originally Posted by 4Tran

Oddities
There seem to be a few strange things with regards to the Zaku II's specifications:

(A) Steel is a rather unusual choice for constructing a warmachine. Normally, one would either go with a light material like aluminum to conserve weight, or a composite to increase armor protection.

Zaku's are designed ot be used in space in the beginning, so weight is not a major issue. Zakus doesn't have to fly in the air or be launched into space. They probably op for steel over aluminum for durability and strength. And it isnt even specific enough to tell us what kind of high tensile steel it is or where it is used. I don't see a problem.

(B) A 951kW reactor works out to be 1280 horsepower. This is less engine power than found in some monster cars. It's curious that the Zeon engineers would choose to employ a volatile and expensive Minovsky engine when an internal combustion engine would produce similar results.

It would be quite difficult to have an internal combustion engine in the vaccum of space isnt it. Imagine the tanks of air you have to carry with you just to make the engine run. I am not sure what you mean by "volatile" beucase Fusion is probably the most stable type of energy source you can have. Note that the premise of UC is that fusion technology has become so mature that it can be produced cheaply and used almost everywhere.

(C) Thrust and propulsion are not measure in kilograms. Based on the acceleration stated, it looks like the proper unit they were looking for was the newton.

I asked this question personally in another forum and Mark Simmons says that it issupposed to mean the abilty to lift a kilogram under 1G. And he points out that this is one of the oddities UC specs in that non of the 0079 era suit can fly or hover under gravity, since they can't produce enough thrust to do so. I think he mentioned where he thinks the error originated from when the bandai ppl whipped them up, but I forgot the detail.

(D) The 1.7s 180-degree turn specification looks a lot like a turning-radius figure. The only problem here, is that it's really only applicable to aircraft. Ground vehicles obvious don't work like that, and neither do spacecraft. So what the heck is that statistic for?

It means the ability for a suit to rotate itself and face the other direction, not sure if it includes flipping vertically. In space you don't need to turn like an air-craft, so there is no "turn-radius". And for a MS it will be meaningless on earth as well.

(E) Since Minovsky Particles block radar and other lower-wavelength electromagnetic radiation, what does the sensor range mean? Does it mean that the Zaku II's radar can see things within 3200 despite Minovsky physics, or is it some other sort of sensor technology. The possibilities are infared, optical , or LIDAR. It could also be the extreme range of its fire control system. Any affirmative answer to this would point towards some interesting implications, but also bring up further questions.

Probably a combination of what you said, but I believe optical sensing capabilty is hte most relevant. You would have to ask someone like Mark for the details.

(F) Given that the Zaku II's 120mm "machine gun's" lack of recoil (even in fully-automatic fire mode!), we can safely assume that it has a very low muzzle-velocity. So the question is, what kind of armor-piercing ammunition does it use? Does it fire a solid penetrator or would it be a HE derivatire like HEAT or HESH? Regardless, a low muzzle-velocity will put a cap on its range and accuracy.

I personally am not aware of much info on the machineguns in general in UC, so it could be anything. As for lack of recoil, it doesnt necessary mean low muzzle-velocity if the gun has build-in dampers. We shouldn't really assume that these projectile weapons work exactly like real life guns.

Based on the above information, it doesn't look like the Zaku II is not a particularly good combat platform for operations on earth. Interestingly, Zeon forces initially deployed conventional Magella tanks, but later adopted mobile suits for earth. We don't know too much about the Magella, but we know that it is much cheaper than any mobile suit, and that its 175mm main gun is probably greatly superior to a Zaku II's main weapon. So the question is why did Zeon decide to replace the seemingly superior unit with an inferior one? What advantage does the Zaku II have that I'm missing?

I would think is the mobility and versitility of a MS is the main reason. A Zaku can also carry a Magella Top cannon, so the role of a tank is pretty much filled.

[Commander 598]

If you have ever seen videos of M1 tanks (or equivalent) firing their main guns, you would be sure to notice the effect of the recoil. A Zaku II firing its machine gun is effected much less even if it fires in full-automatic mode for a 1s burst. Now if we assume that each Zaku 120mm round is as massive as a M1 round, and that the machine gun has a RoF of 10 rounds per second, it would be obvious the machine gun has 1/10 (or less) the muzzle velocity of the M1 gun. This greatly impacts the machine gun's penetration, accuracy and range.

The Abrams has a 120mm smoothbore gun. It wears out after some thousand or so rounds. The MMP-78 is a rifled automatic weapon. As with most automatic weapons, the size of the round is considerably smaller(Lengthwise) than if it was semi-automatic(7.62x54mm for SVT/SVD/Nagant Rifles vs 7.62x39mm for AK varients). This is also supported by scenes from 08th Team where we see the 100mm MG of the RX-79[G] is rifled and the rounds laying around it(Assuming they are 100mm) are a far cry from a full sized tank round.

All MS MG rounds appear to be standard AP rounds, not explosive(HE/HEAT) nor Sabot(APFSDS). This is likely due to "issues" which could result such as an HE round cooking off in the barrel or a Sabot not liking automatic partially stabilized recoil.

There is also my theory that a Sabot round wouldn't do squat to a mobile suit, mostly because it probably wouldn't hit anything important. Like in 0083 when a 90mm round found it's way into the torso of South Burning's GM Custom which almost wasn't critical. Now imagine something 10 times smaller...

Also note, they are usually shown with recoil. Just not alot. There was also a scene in 0083 when a Zaku was shown firing flak AA rounds.

[viper]

Thrust is often used to measure something's ability to accelerate straight up. Say I have an airplane that weighs 40,000 pounds. If the plane has an engine mounted that can provide 50,000 pounds of thrust, it means it has a thrust to weight ratio greater than 1 to 1 meaning it can accelerate straight up in a 1g enviorment.

[4Tran]

Originally Posted by flamingtroll

Zaku's are designed ot be used in space in the beginning, so weight is not a major issue. Zakus doesn't have to fly in the air or be launched into space. They probably op for steel over aluminum for durability and strength. And it isnt even specific enough to tell us what kind of high tensile steel it is or where it is used. I don't see a problem.

Actually, mass is as important for spacecraft as weight is for aircraft. A more massive vehicle is going to be harder to accelerate than a less massive one.

Originally Posted by flamingtroll

It would be quite difficult to have an internal combustion engine in the vaccum of space isnt it. Imagine the tanks of air you have to carry with you just to make the engine run. I am not sure what you mean by "volatile" beucase Fusion is probably the most stable type of energy source you can have. Note that the premise of UC is that fusion technology has become so mature that it can be produced cheaply and used almost everywhere

True enough, that was why I was mostly speaking of the vehicles operating on the ground. By "volatile", I mean that any hit to the engine would cause the whole thing to go off like a firecracker. Obviously, a real fusion engine would never do that, but then again, the Minovsky-fusion engine bears little resemblance to a real one. Finally, Minovsky-fusion technology doesn't seem to be particularly useful if it doesn't produce much more power than a similar-sized combustion engine.

Originally Posted by flamingtroll

I asked this question personally in another forum and Mark Simmons says that it issupposed to mean the abilty to lift a kilogram under 1G. And he points out that this is one of the oddities UC specs in that non of the 0079 era suit can fly or hover under gravity, since they can't produce enough thrust to do so. I think he mentioned where he thinks the error originated from when the bandai ppl whipped them up, but I forgot the detail.

If the unit represents "a kilogram under 1G" - actually a kilogram-force (kgf), then 43 kgf (total) thrust will accelerate a 73ton Zaku II at 5.8g! It would make more sense if the unit were a newton.

A hovercraft does not create enough thrust to hover either. What it does, is use its skirts to trap circulating air underneath it, thus allowing it to float on a cushion of air. This is likely how a Dom moves. Of course, flight is generally a question of the airfoil lift mechanism, and does not require >1g of acceleration (or anything even close to that).

The writers may have made errors in other places, but I think that the acceleration specs are fairly accurate and consistent. I also tend to have no problems with the mobile suits' dimensions and masses either.

Originally Posted by flamingtroll

It means the ability for a suit to rotate itself and face the other direction, not sure if it includes flipping vertically. In space you don't need to turn like an air-craft, so there is no "turn-radius". And for a MS it will be meaningless on earth as well.

If it indicates time it takes for a Zaku II to completely turn around or flip from a rest position in space, then I find that very hard to believe. This would mean that it would take it about two full seconds to rotate to face a threat from behind. This kind of performance may be expected from atmospheric fighters, but not of spacecraft.

Originally Posted by flamingtroll

Probably a combination of what you said, but I believe optical sensing capabilty is hte most relevant. You would have to ask someone like Mark for the details.

Actually, we already know that larger warships detect spacecraft using infared (heat sources), so it's not too unlikely for mobile suits to have it as well. UC scientists don't seem to have the conception of what LIDAR is, so I don't think that they would employ it.

As an aside, what forum does Mark Simmons hang out in?

Originally Posted by flamingtroll

I personally am not aware of much info on the machineguns in general in UC, so it could be anything. As for lack of recoil, it doesnt necessary mean low muzzle-velocity if the gun has build-in dampers. We shouldn't really assume that these projectile weapons work exactly like real life guns.

There may not be too much info about the machine guns, but we can derive the statistics from its demonstrated attributes. Modern tank guns are already recoil-stabilized. However, it doesn't really mean what you may think it means. Recoil compensating will lessen the effect of recoil on accuracy, vehicle stability and so forth. However, it will not lessen the amount of recoil produced by a gun. To do so would be to violate the conservation of momentum.

Originally Posted by flamingtroll

I would think is the mobility and versitility of a MS is the main reason. A Zaku can also carry a Magella Top cannon, so the role of a tank is pretty much filled.

I can't buy that. If this were a really successful combination as implied, then we would see it much more as opposed to the widely fielded 120mm machine gun. Also, it does nothing to address the Zaku II's relatively weak armor and relative expense.


Thanks, Commander 598, it looks like I'll have to adjust the Zaku II's relative firepower downward. I've always noticed that few anime weapons produce a sonic boom, and I attributed that effect to a generally understood convention. However, the evidence suggests that the 120mm machine gun actually fires subsonic ammunition!

Originally Posted by Commander 598

There is also my theory that a Sabot round wouldn't do squat to a mobile suit, mostly because it probably wouldn't hit anything important. Like in 0083 when a 90mm round found it's way into the torso of South Burning's GM Custom which almost wasn't critical. Now imagine something 10 times smaller...

That's not quite how sabot penetration works, at least at high velocities. When a round hits its target, the impact generates a vast amount of heat and pressure. On penetration, this heat and pressure combines to basically form a cone of superheated metal which produces an explosive effect inside the target. Read on.

If Burning's GM was hit by an APFSDS round, the entire side of his mobile suit's torso probably would have suffered catastrophic damage, and he would have died immediately. Likewise, HEAT and HESH ammunition would also be far more devastating than regular AP.

Originally Posted by viper

Thrust is often used to measure something's ability to accelerate straight up. Say I have an airplane that weighs 40,000 pounds. If the plane has an engine mounted that can provide 50,000 pounds of thrust, it means it has a thrust to weight ratio greater than 1 to 1 meaning it can accelerate straight up in a 1g enviorment.

As an addendum, given sufficient fuel, this airplane can theoretically reach orbit.

[Soluzar]

Originally Posted by 4Tran

When we speak about the strength of armor, we generally are not talking about its load-bearing properties. Normally, we are concerned with its ability to withstand attacks. Homogenous steel of all varieties is rather pathetic at stopping even light anti-tank weapons. This is sort reflected in the fragility of mass-produced mobile suits in MSG, but Zaku IIs should have been easy meat for tanks.

It is stated in MAHQ that the primary use of Zaku II mobile suits was in space. There are very few tanks that can operate in space, short of the one developed by the federation as part of the Gundam project. In short, the Zaku is the tank of space.

Complaining about the horsepower unit is irrelevant. Horsepower is simply a non-SI unit used to measure force. It's hardly archaic since all modern automobiles are rated with it. I just used the unit so that most people can readily identify with it. I could just as easily have stated that many monster cars have >1000kW engines compared to the Zaku II's 951kW.

You seem to have missed the point I was trying to make. When a car engine is rated at a given horsepower value, that's not the raw output of the engine. It's the effective output after drivetrain losses. Now the figure you're quoting for the Zaku is the total output of the reactor, all of which can be utilised.

There is no indication that any UC technology has more efficient power utilization than modern technology. Besides, any greater efficiency is an effect of the rest of the transmission, and has nothing to do with the engine itself. Thus it could be equally applied to an internal combustion engine.

See my point above. When you're firing weapons, or powering electrical systems, it's a given that this direct utilisation of reactor output will be more efficient than the drivetrain of a car. There's just less links in the chain. That's almost certain to give rise to greater efficiency.

I'm specifically comparing Zaku IIs to Magella tanks. I only used car analogies because that's what other people can identify with.

When you go off on your wild tirade about reactor output vs horsepower, you're directly comparing Zaku IIs to cars. It's not an applicable comparison, because of the difference in the way the power is utilised. The reactor output of a Magella tank is not known, or at least MAHQ don't seem aware of it. Therefore, no real comparison is possible.

Quite obviously, Zeon forces were perfectly capable of fielding tanks, and their tanks seemed superior to their mobile suits. A Zaku II seems to have both weaker weapons and armor to their tank counterparts, so what advantage did they bring to the battlefield? And why were they used to pretty much replace the Magellas altogether?

It's already been stated that the Zaku II can carry the same cannon as the tank is issued with as standard. The issue of recoil has already been cast into doubt. That casts some serious doubts on your assertion that the Zaku II is actually inferior the the Magella tank.

[4Tran]

Originally Posted by Soluzar

It is stated in MAHQ that the primary use of Zaku II mobile suits was in space. There are very few tanks that can operate in space, short of the one developed by the federation as part of the Gundam project. In short, the Zaku is the tank of space.

I thought that I was talking about how the Zaku II doesn't make any sense on Earth. Soluzar, do you know where I was saying that about its performance in space?

Originally Posted by Soluzar

You seem to have missed the point I was trying to make. When a car engine is rated at a given horsepower value, that's not the raw output of the engine. It's the effective output after drivetrain losses. Now the figure you're quoting for the Zaku is the total output of the reactor, all of which can be utilised.

See my point above. When you're firing weapons, or powering electrical systems, it's a given that this direct utilisation of reactor output will be more efficient than the drivetrain of a car. There's just less links in the chain. That's almost certain to give rise to greater efficiency.

So are you trying to say that [monster car engine - inefficiencies] == ~1000kW and [Zaku II engine - no inefficiencies] == 951kW?

Can you back up the assertion that the Minovsky-fusion engine has no inefficiencies?

Originally Posted by Soluzar

When you go off on your wild tirade about reactor output vs horsepower, you're directly comparing Zaku IIs to cars. It's not an applicable comparison, because of the difference in the way the power is utilised. The reactor output of a Magella tank is not known, or at least MAHQ don't seem aware of it. Therefore, no real comparison is possible.

If we assume that the Magella has a powerplant equal to the M1A1 as a comparison, then it will generate 1119kW. However, this isn't particularly relevant. Even if we imagine that it is just capable of 40km/h cross-country, then it is quite sufficient for performing its role. Remember that engine output is only important insofar as it pertains to other statistics.

Originally Posted by Soluzar

It's already been stated that the Zaku II can carry the same cannon as the tank is issued with as standard. The issue of recoil has already been cast into doubt. That casts some serious doubts on your assertion that the Zaku II is actually inferior the the Magella tank.

Again:
I can't buy that. If this was a really successful combination as implied, then we would see it much more as opposed to the widely fielded 120mm machine gun. Also, it does nothing to address the Zaku II's relatively weak armor and relative expense.

If you want to prove that the Zaku II is superior on Earth, then please use some numbers to back up your assertion. After all, this thread is about "fun with numbers".

[Blaat]

You guys are realising that these numbers were created without much thought behind it: it was created to please some bunch of otaku. Furthermore as someone pointed out you can't compare it with modern vehicles because there is nothing in today's world you can compare it to.

Originally Posted by 4Tran

Can you back up the assertion that the Minovsky-fusion engine has no inefficiencies?

Can you back up it that it is inefficient? Because neither is stated and neither can be proven right or wrong.

[4Tran]

Originally Posted by Blaat

Furthermore as someone pointed out you can't compare it with modern vehicles because there is nothing in today's world you can compare it to.

Does gravity work the same way in UC Gundam as it does in real-life? How about momentum? Or light? Or heat? If they do, then there's no problem with making comparisons. If they don't, then let's discuss how these fundamental laws differ.

Originally Posted by Blaat

Can you back up it that it is inefficient? Because neither is stated and neither can be proven right or wrong.

Unnecessary. All engines (hell, all mechanical systems) are automatically assumed to have inefficiencies - these are perhaps better known as "friction" and "waste heat". It is therefore an extraordinary claim that a engine type does not suffer from this problem. And extraordianry claims require extraordinary evidence.

[ctrl-z]

Originally Posted by Soluzar

I seem to recall that the ratio of tensile strenght to weight is roughly the same for both steel and aluminium, but the ratio of mass to weight is of course better for Aluminum, which also scores better in compressive strength. There is the fatigue factor to bear in mind, as well. There is a level of load below which steel has an infinite fatigue-life. That number is much lower for aluminium. There is also more than one kind of steel, of course. Check out this page about HSLA Steel. Seems likely that the steel founding industry would continue to advance further into the future as well.

A better ratio would be tensile yield strength to density, which for steel and aluminium works out typically in favour of aluminium, especially for higher strength alloys. As for the ratio of mass to weight... that doesn't make much sense... As mentioned, the concern would be impact resistance (toughness/strain energy), the value of which is conducted through tests such as the Charpy method. Keeping the ratio of toughness to density in mind, a composite would indeed be better.

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With respect to the power output of the reactor, isn't that almost purely for electrical systems and electrical-related systems? So comparing the output to a car (which converts energy to mechanical motion) in the context of speed is irrelevant.

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Originally Posted by 4Tran

If the unit represents "a kilogram under 1G" - actually a kilogram-force (kgf), then 43 kgf (total) thrust will accelerate a 73ton Zaku II at 5.8g! It would make more sense if the unit were a newton.

Edit: It all seems to work out.

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The 1.7 second 180-deg turning time might be realistic if the vernier system (number, deployment, thrust) isn't well-developed.

[Soluzar]

Originally Posted by ctrl-z

A better ratio would be tensile yield strength to density, which for steel and aluminium works out typically in favour of aluminium, especially for higher strength alloys. As for the ratio of mass to weight... that doesn't make much sense... As mentioned, the concern would be impact resistance (toughness/strain energy), the value of which is conducted through tests such as the Charpy method. Keeping the ratio of toughness to density in mind, a composite would indeed be better.

Yeah, it's true. I never really disputed that point, right from the outset, but I just wanted to make the point that the term "steel" applies to more than one variety of iron alloy.

Originally Posted by ctrl-z

With respect to the power output of the reactor, isn't that almost purely for electrical systems and electrical-related systems? So comparing the output to a car (which converts energy to mechanical motion) in the context of speed is irrelevant.

That would be what I have been arguing, yes. It seems likely that the reactor doesn't actually power the thrusters of the mobile suit, but I can't prove that.

[Blaat]

Originally Posted by 4Tran

Does gravity work the same way in UC Gundam as it does in real-life? How about momentum? Or light? Or heat? If they do, then there's no problem with making comparisons. If they don't, then let's discuss how these fundamental laws differ.

We both know I'm not talking about the laws of physics but comparing a car with a mobile suit. What's next you're going to compare the USS Enterprise with a bike? (apple and oranges)
And as I said these numbers were created out of their 'behinds' to please some bunch of otaku. So comparing them with the modern day machines like modern day cars is pointless (its even worse considering we don't know how a mobile suit works).

Originally Posted by 4Tran

Unnecessary. All engines (hell, all mechanical systems) are automatically assumed to have inefficiencies - these are perhaps better known as "friction" and "waste heat". It is therefore an extraordinary claim that a engine type does not suffer from this problem. And extraordianry claims require extraordinary evidence.

Yet we're talking about a SF show where and in SF everything is scientifically possible by some odd compensator (perfect example is the Heisenberg compensator seen in Star Trek) or some material found in space.
As I said, I think its pointless if you compare it with modern day machines is pointless.

[flamingtroll]

Originally Posted by 4Tran

Actually, mass is as important for spacecraft as weight is for aircraft. A more massive vehicle is going to be harder to accelerate than a less massive one.

Mass is import, but we can't actally engineering cost benefit analysis on the choice between aluminum or steel since after all this is merely ficitional data. I am just suggesting a possible rationalization. If you can accept giant robots flying in space, why not this little point.

If the unit represents "a kilogram under 1G" - actually a kilogram-force (kgf), then 43 kgf (total) thrust will accelerate a 73ton Zaku II at 5.8g! It would make more sense if the unit were a newton.

A hovercraft does not create enough thrust to hover either. What it does, is use its skirts to trap circulating air underneath it, thus allowing it to float on a cushion of air. This is likely how a Dom moves. Of course, flight is generally a question of the airfoil lift mechanism, and does not require >1g of acceleration (or anything even close to that).

The writers may have made errors in other places, but I think that the acceleration specs are fairly accurate and consistent. I also tend to have no problems with the mobile suits' dimensions and masses either.

You probably have mistaken what i mean. From MAHQ Zaku spec:

Propulsion: rocket thrusters: 2 x 20500 kg, 2 x 1000 kg

pretty much measn that it can accelerate 41000 + 2000 kg = 43 metric ton at 1 G. Which means it would be at around 43 metric tons * 9.8m/s^2 ~ 430000 Newton. Simple as that

at fulll 73 metirc ton the acceleration would be at around 5.8 m/s^2 which is around 0.59G which matches with the spec for acceleration.

What you said about Dom was debated on Gundamwatch quite a while ago, and it wasn't reall conclusive since offical spec are itself not completely convincing and the fact that the Dom doesnt look like it can generate any air cushion to hover.

It won't make sense for Zaku not to produce higher than 1 G accleration since we do see very often that Zaku's rocket jumps. Attaching a < 1G thruster as a glorified parachute doesn't make much sense either.

If it indicates time it takes for a Zaku II to completely turn around or flip from a rest position in space, then I find that very hard to believe. This would mean that it would take it about two full seconds to rotate to face a threat from behind. This kind of performance may be expected from atmospheric fighters, but not of spacecraft.

Are there fighter today that can change its heading 180 degrees in under 2 second, unless you count sprials that they can do when stalling, which as I recall still takes a bit of time? The G force would be too great for the pilot to endure. You would have to show me if there really is such a thing.

In the case of spacecrafts I think the RCS on the shuttlecraft takes quite a long time to make a 180 degree turn. So i don't see what is so bad about this performance.

As an aside, what forum does Mark Simmons hang out in?

I think he shows up at MAHQ's forum now and then. Probably also at Denburium Stamen's "replacement" forum for Gundamwatch.

There may not be too much info about the machine guns, but we can derive the statistics from its demonstrated attributes. Modern tank guns are already recoil-stabilized. However, it doesn't really mean what you may think it means. Recoil compensating will lessen the effect of recoil on accuracy, vehicle stability and so forth. However, it will not lessen the amount of recoil produced by a gun. To do so would be to violate the conservation of momentum.

If you have internal dampinging mechanision to disspate the momentum, your gun can recoil less superfacially. It doesnt violate the conservation of momentun. You also have to take note on what era of gundam animation you are basing your observation on. If you look at MS IGLOO, the zaku's MG does show some recoling effect.

I can't buy that. If this were a really successful combination as implied, then we would see it much more as opposed to the widely fielded 120mm machine gun. Also, it does nothing to address the Zaku II's relatively weak armor and relative expense.

And you can buy the existence of giant bipedal robot carrying beam sabers and rifles to fight as a premiste to begin with? MS are shown to be more effective in the animation and so it is.

[4Tran]

Originally Posted by ctrl-z

With respect to the power output of the reactor, isn't that almost purely for electrical systems and electrical-related systems? So comparing the output to a car (which converts energy to mechanical motion) in the context of speed is irrelevant.

Actually, I would imagine that the Zaku II's engine output would be used to power its drivetrain as opposed to its thrusters.

Originally Posted by Blaat

We both know I'm not talking about the laws of physics but comparing a car with a mobile suit.

I was merely putting the Zaku II's output in context of modern engines. If you can find a substantial difference between one kW and the other kW, please share it.

Originally Posted by Blaat

Yet we're talking about a SF show where and in SF everything is scientifically possible by some odd compensator (perfect example is the Heisenberg compensator seen in Star Trek) or some material found in space.

And where is this "compensator" in Gundam?

Originally Posted by flamingtroll

pretty much measn that it can accelerate 41000 + 2000 kg = 43 metric ton at 1 G. Which means it would be at around 43 metric tons * 9.8m/s^2 ~ 430000 Newton. Simple as that
at fulll 73 metirc ton the acceleration would be at around 5.8 m/s^2 which is around 0.59G which matches with the spec for acceleration.

Mea culpa. I forgot to calculate gs from m/s^2 at the end. You're quite right.

[QUOTE=flamingtroll]What you said about Dom was debated on Gundamwatch quite a while ago, and it wasn't reall conclusive since offical spec are itself not completely convincing and the fact that the Dom doesnt look like it can generate any air cushion to hover.[/QUOTE
I don't have a problem with the air cushion idea, because it looks like what they were aiming for. It would also be consistent with what is shown of the Dom's performance as well (although it should also be more unstable). The creators didn't quite get the look right, but I feel that it's at least a good attempt.

Originally Posted by flamingtroll

It won't make sense for Zaku not to produce higher than 1 G accleration since we do see very often that Zaku's rocket jumps. Attaching a < 1G thruster as a glorified parachute doesn't make much sense either.

I think that the rationalization here is that the Zaku cannot produce sustained acceleration of 1g, but it can generate bursts in excess of that. It's not the prettiest of solutions, but it'll have to do.

More (much) later.

[Commander 598]

Originally Posted by 4Tran

That's not quite how sabot penetration works, at least at high velocities. When a round hits its target, the impact generates a vast amount of heat and pressure. On penetration, this heat and pressure combines to basically form a cone of superheated metal which produces an explosive effect inside the target. Read on.

If Burning's GM was hit by an APFSDS round, the entire side of his mobile suit's torso probably would have suffered catastrophic damage, and he would have died immediately.

I believe what your referring to is generally what happens with any liquified metal, it tends to explode and spray around but it tends to cool rather rapidly(Finally putting my metalworking knowledge to work). It's been my understanding that it wasn't this that tends to kill [semi]modern armor as much as the rod hitting the ammuntion stores, fuel, and anything inbetween. This is also supported by the number of burned out Iraqi hulks still in one piece after two different US blitzkriegs.

Sabot are also not very useful in the vacuum of space. They can't really stabilize without air...

AP rounds are likely to still be effective when used out of an automatic weapon. Picture a five round burst from a Zaku MG impacting an Abrams. I see a missing barrel and shredded tracks, thats not counting it probably penetrating the top armor(Universal Weak Spot Since 1939!).