sad to say, americans haven’t developed their own new tank gun in almost 40 years. it’s still the german 120mm smoothbore up to now. the russians came up with a 135mm gun which was used onlt briefly (they’re back to the 125mm.) the germans experimented with a 140mm. the chinese already have a 155mm gun mounted on one of their MBTs.
Tanks are amazing weapons, but they are vulnerable to air attack.
In the last year of WWII, the allies equipped fighter planes with air-surface rockets. Were these powerful enough to destroy a tank?
Also, armor-piercing shells: today, we have “HEAT” warheat shells-which will melt through any thickness of armor. There are also tungsten tipped shells that will shatter armor. So is the modern tank at the point where further development is impossible?
I can’t see spending upwards of $100 million on a tank, if it can be knocked out by a missile or shell, so easily.
Why do you suppose that bigger has to be better?
Tackling these really quickly:
Sometimes. Hitting the tank was the problem (back then) – The book Hell Hawks on P-47s used largely as ground-attack aircraft quotes a postwar study that found the underwing rockets had a 4% hit rate on vehicles.
HEAT will melt through almost any thickness of steel. Modern armor isn’t just steel, though. As developed by the British and improved by the Americans, modern armors use highly classified composite formulation, believed to include ceramics, to defeat the jet of molten metal a HEAT round creates, and high-density materials (typically depleted uranium) to defeat kinetic penetrators. This is fairly effective – US attempts to destroy their own abandoned M-1 tanks during recent wars have had considerable difficulty. In some cases absolutely point-blank main gun rounds failed to penetrate (and presumably they were aiming at weak spots, given their intention). Eventually, weaponry will catch up, but for now, very high-tech gear has swung the seesawing advantage back to armor (assuming you spend the big bucks).
Uh…you’re right they’re expensive, but you’re off by an order of magnitude.
[QUOTE=Wikipedia]
About 6,000 M1A1 Abrams were produced from 1986–92 and featured the M256 120 mm (4.7 in) smoothbore cannon developed by Rheinmetall AG of Germany for the Leopard 2, improved armor, and a CBRN protection system. Production of M1 and M1A1 tanks totaled some 9,000 tanks at a cost of approximately $4.30 million per unit.
[/QUOTE]
Later/current production cost a bit more:
[QUOTE=Wikipedia]
The government-owned Lima Army Tank Plant in Lima, Ohio, currently manufactures the Abrams,[1] the Detroit Arsenal Tank Plant in Warren, Michigan manufactured it from 1982 to 1996. It costs upwards of US$5 million a tank.
[/QUOTE]
To interested readers: This week on the Military Channel they’re running Tanksgiving, a day of tank-themed programming.
Best username/post combo ever.
Yes, if you scroll down on the link it breaks down production into variants of each chassis.
The Panther’s mechanical problems were never really sorted out. They fixed the problem of the engine spontaneously catching fire and improved its reliability somewhat, but even in its later variants it remained much less reliable mechanically than other tanks; the engine required more maintenance, required more frequent complete overhauls, and suffered more breakdowns on the march than most tanks.
tanks guns are intended to be used against heavy, armored venicles. for this, the century-old formula of heavier projectile weight and higher velocity to produce higher kinetic energy still holds. take this match-up: the t-75 vs the m1 abrams. the russian has a more powerful gun (125mm) compared to the 120mm smoothbore. the american reaction was to improve armor. the next generation of soviet MBTs would have mounted 135 and 155s so installing DU armor to cover future upguns was the smart move.
And why are you so sure that a heavier warhead necessarily delivers more kinetic energy to a target? A smaller caliber using a far heavier charge could have the same effect, and more importantly more of an effect on a smaller area, which is the reasoning behind modern sabot rounds. There are also far more important factors than pure penetration such as accuracy and range.
You’re also forgetting the fact that some types of tank munitions, such as HEAT, are not dependent on kinetic energy for penetration.
No it doesn’t. As kombatminipig noted, modern KE AP rounds use sabots, the penetrator rod on the M829 series 120mm rounds is a 20 or 22mm dart.
Not true. The 120mm on the M1 fires more powerful AP rounds than the former Soviet 125mm. In this case the reason is a better sabot round, but a lot more goes into the AP ability of a gun than bigger is better in barrel diameter. In solid shot AP rounds, a major factor is muzzle velocity, and longer barrels will produce more muzzle velocity with all other things being equal. The 75mm gun of the Panther was more powerful than the 88mm gun of the Tiger I in armored penetration. The reason? The Panther used a 75mm L/70, the Tiger I an 88mm L/56. The “L/##” is the length of the barrel in calibers, meaning the barrel was longer on the Panther relative to the diameter (and also absolutely at 5.25m vs. 4.928m), producing a higher muzzle velocity that more than compensated for a smaller diameter round.
you guys are implying that, with tungsten or DU sabot rounds, there is little or no need for upgunning. sheer logic says this is wrong. a larger gun will of course feature sabot rounds as well and that will likely be more effective than one fired from a smaller caliber gun. and when you start talking about HEAT and HESH rounds, there’s little to credit a smaller gun.
Gentlemen, you can’t fight in here, this is the War Room!
It’s true that larger bore does not, by itself, mean better armor penetration, but if two guns were equal in all respects, the larger-bore gun would be capable of firing a more massive projectile, and mass is one element of f=mv squared.
However, there’s an upper limit to practical gun size. Larger bore (and consequently longer barrel to keep the muzzle velocity high, as posted above) means bigger breech mechanism, fewer rounds carried, heavier turret machinery, more area to cover with weighty armor, and so on. These things have to move around under their own power, and some of the limiting factors are not under control of the tank designer, or even the military. For example, civilian bridge designers inadvertently establish an upper limit on the mobility of super-heavy vehicles.
Whether we’re at or approaching that limit is outside my expertise. But the history of the Tiger tank itself shows that bigger is not always better.
Another factor against mega-bore guns is the sheer weight of the ammunition. Once you get over a certain size (wikipedia suggests about 125mm) human loaders just can’t handle the weight. You could use an autoloader to mitigate this, but that ends another complicated system with its own problems to the mix.
the M1 still has manual loading. jeez, a 70-pound cartridge. upgunning can be facilitated with a turretless design (experimented on by nearly all armies in the 80s.) all you have is the squat tank chassis and a mechanical gun mount on top of it. this will render issues of manual loading and other human inputs moot. sometimes, i regret the fall of the soviet union. the superpower arms race was simply fascinating. the soviets were already experimenting with 50- to 60-tonne tanks mounting a 152mm gun, with enough ceramic and face-hardened armor up front to defeat tungsten rounds, and chock full of reactives on the sides and back…
Where do you get your numbers? The M829A1 comes in about 45 lbs; later variants top out right about 50 lbs. And, since I used to hump the fuckers into the breech of the M256, I’ll let my post be my cite. Don’t believe me? Check the user name.
And the formula, as Sailboat points out, is F=MV^2. So, for any increase in mass of the projectile, you get a 1:1 linear increase in Force. But even small increases in velocity yields an exponential increase in Force.
Since sabot penetrators are sub-caliber munitions (they are a smaller caliber than the bore of the firing system, hence the need for a sabot), upgunning isn’t necessarily the solution to “more power!” Depending upon the metallurgy, a lighter (and probably smaller) projectile may yield a significant increase in velocity, yielding increased terminal Force, and also allowing for more ammunition stowage.
Look, you have kombatminipig, Dissonance, Sailboat, lisiate, and now me telling you that you are wrong.
Stop relying upon your “common sense” that “bigger is better,” and let science and math reign supreme.
Yes, all of that but beyond that, the Tiger Tanks were Porsches.
@ extank,
i’ll accept your 50-lb correction, thanks. regarding the subject of bigger-is-better, it’s a debate, not a battle between fact and ignorance. in another thread, i have five pages of posters all of whom are against me. the five of you hardly matter.
I’m not jumping one mac’s side but won’t the increase in velocity itself require exponential increases in propellant? Unless I’m wrong, which might quite well be the case, doubling the velocity requires 4 times as much propellant and the propellant (and the gases it produces) are itself mass which must be propelled forward which means that doubling the velocity requires more than 4 x the propellant. That isn’t that big a deal when going from 1000fps to 2000fps, but I think the M1 gun’s APFSDS’s round goes at something like 4500 fps, right?
Is it kinetic energy or momentum that matters for armor penetration?
From what I understand, you want as high a ratio between momentum and contact surface. It’s the same principle that makes it so that if someone steps on you with boots, it won’t injure you but if they do in high heels, it likely will.
Also, a projectile doesn’t lose its mass but the faster it goes, the faster it will lose its velocity since air resistance goes up at the square (right?).
So you would want an undercalibered, long and heavy projectile and put more emphasis on the projectile being heavy than fast.
Perhaps there’s something I’m no getting but I’m hoping that as an ex iron geegee crew member, you can tell me more.
a smaller but faster projectile can perform as well as a bigger but slower slug, given roughly equal momentum. the question is how they perform upon hitting the target. ligher projectiles tend to break up, or deflect more, or lose velocity faster. so you want a very durable material (tungsten or uranium) that will retain its integrity and penetrate deep, using the ratio you mentioned.
having a sub-caliber round that weighs almost as much as a full-caliber one basically defeats the purpose. it will travel at the same velocity and will only have the small-area concentration to its advantage.
there’s another forum that discussed the upgunning of the german leopard tank from the present 120mm to 140mm. issues of re-designing the mechanicals, cartridges that weigh almost 100 pounds, and a likely ammo capacity of only 20 rounds in the leopard makes upgunning look unattractive. you really need to build a new tank.
Dr. Porsche argued (to no avail) that the Tiger tank was too much tank (overly complex, over engineered with inefficient manufacturing) and that the Germans should merely copy the more primitive Russian tanks and try to maximise manufacturing output.