The Insane Engineering of the M1 Abrams

Summary

M1艾布拉姆斯坦克自1980年服役以来，以其高速、重装甲和尖端技术在战场上提供了巨大优势。首次在沙漠风暴行动中亮相，便在沙特阿拉伯和科威特的沙漠中迅速树立了声誉。该坦克采用德国设计的120毫米滑膛炮，射程更远、射击更精准，并且使用了更先进的弹药，轻松击败了伊拉克军队的苏制坦克。预计今年美国将向乌克兰交付一个营的31辆M1艾布拉姆斯坦克，再次面对它设计之初旨在对抗的苏制坦克。乌克兰军队需要接受训练以维护和操作这些新型坦克。尽管这些坦克已有40多年的历史，但由于不断的现代化和前瞻性设计，它们在战场上仍然非常有能力。M1艾布拉姆斯的引擎启动时，声音更像是军用飞机准备起飞，其涡轮发动机为坦克提供了轻量化和高功率重量比的优势，允许在不牺牲加速度或最高速度的情况下增加装甲层。M1艾布拉姆斯还采用了先进的复合装甲，包括陶瓷材料和贫铀衬层，以及反应装甲和烟雾发生系统，以提高生存能力。此外，M1艾布拉姆斯的悬挂系统和弹药处理机制也被设计得尽可能安全和可靠。尽管M1艾布拉姆斯的服役时间很长，但它仍然是现代军队中最有能力的坦克之一，对乌克兰地面部队将是巨大的资产。

Takeaways

• 🚀 M1艾布拉姆斯坦克自1980年起服役，以其高速和重装甲，配备最新技术，在战场上具有优势。
• 🏜️ M1在沙漠风暴行动中首次亮相，在沙特阿拉伯和科威特的荒芜沙漠中迅速树立了声誉。
• 🔥 M1采用的燃气轮机引擎使其能够在困难的地形上快速移动，帮助解放科威特免受伊拉克占领。
• 🤖 M1装备的德国设计的120毫米滑膛炮具有更远的射程、更精确的火力和更先进的弹药。
• 🚀 预计今年美国将向乌克兰交付一个营的31辆M1艾布拉姆斯坦克，再次面对它被设计用来对抗的苏联坦克。
• 🛠️ 乌克兰军队需要接受训练以维护和操作这些新型坦克，因为它们与其他坦克不同。
• 💼 尽管M1坦克已有40多年的历史，但由于持续的现代化和前瞻性设计，它在战场上仍然非常有能力。
• ✈️ M1艾布拉姆斯启动时的声音更像是一架军用飞机准备起飞，随着发动机转速的提高，音调逐渐升高。
• 🛡️ M1艾布拉姆斯使用的柴油燃料可以作为额外的装甲层，液体非常善于吸收爆炸和动能武器的能量。
• 🌡️ M1的燃气轮机还可以使用大多数燃料类型，这在军事后勤上是一个巨大的优势，尤其是在与北约的联合行动中。
• 🔩 M1的燃气轮机工作原理类似于飞机喷气发动机，但有一些重要的区别，例如它使用了一个热交换器（再生器）来降低热信号并提高燃油效率。

Q & A

M1艾布拉姆斯坦克是在什么时候开始服役的？

M1艾布拉姆斯坦克是在1980年开始服役的。

M1艾布拉姆斯坦克在哪个军事行动中首次使用？

M1艾布拉姆斯坦克首次在“沙漠风暴行动”中使用。

M1艾布拉姆斯坦克使用的是什么类型的发动机？

M1艾布拉姆斯坦克使用的是高速度涡轮发动机。

M1艾布拉姆斯坦克的主炮是由哪个国家设计的？

M1艾布拉姆斯坦克的主炮是德国设计的120毫米滑膛炮。

为什么M1艾布拉姆斯坦克的发动机选择使用涡轮机？

涡轮发动机比同等柴油发动机轻，功率大，允许M1在增加装甲的同时不牺牲加速度或最高速度。

M1艾布拉姆斯坦克使用的主要燃料是什么？

M1艾布拉姆斯坦克主要使用柴油燃料，因为柴油可以作为额外的装甲层。

M1艾布拉姆斯坦克的装甲材料有哪些特性？

M1艾布拉姆斯坦克的装甲使用了复合陶瓷材料，如Chobham装甲，它由非常硬且轻的陶瓷层组成，具有很高的硬度和能量吸收能力。

M1艾布拉姆斯坦克的装甲系统是如何防御穿甲弹的？

M1艾布拉姆斯坦克的装甲系统通过使用压缩陶瓷装甲来抵御穿甲弹，陶瓷装甲在受到冲击时会破碎，分散冲击能量，并通过金属背板吸收剩余能量。

M1艾布拉姆斯坦克的烟幕系统是如何工作的？

M1艾布拉姆斯坦克的烟幕系统有两种工作方式：一种是将燃料喷入发动机排气中产生烟幕；另一种是通过安装在炮塔外部的榴弹发射器发射烟幕弹。

M1艾布拉姆斯坦克的乘员配置是怎样的？

M1艾布拉姆斯坦克没有自动装弹机，而是有一名专门的装填手来装填炮弹。它还包括一名驾驶员、一名炮手和一名坦克指挥官。

M1艾布拉姆斯坦克的悬挂系统是如何设计的？

M1艾布拉姆斯坦克使用的是扭杆悬挂系统，它占用空间小，但会显著提高坦克的高度。

M1艾布拉姆斯坦克的最新型号是什么？

M1艾布拉姆斯坦克的最新型号是M1A2 SEP V4。

Outlines

00:00

🚀 M1艾布拉姆斯坦克的战场优势

M1艾布拉姆斯坦克自1980年服役以来，以其快速、重装甲和先进技术在战场上占据优势。它在沙漠风暴行动中首次亮相，并在沙特阿拉伯和科威特的沙漠中迅速获得声誉。该坦克由高速涡轮发动机驱动，能在恶劣地形上快速移动，装备德国设计的120毫米滑膛炮，具有更远射程、更精准的火力和更先进的弹药，能轻易击败伊拉克军队的苏制坦克。预计今年美国将向乌克兰交付31辆M1艾布拉姆斯坦克，以再次对抗其设计初衷的苏制坦克。乌克兰军队需要接受训练以维护和操作这些新型坦克。尽管这些坦克已超过40年，但得益于持续现代化和前瞻性设计，它们在战场上仍具有强大的能力。M1艾布拉姆斯坦克启动时的声音类似于军用飞机准备起飞，其涡轮发动机的选择为其提供了重量轻和高功率的优势。该坦克还能使用多种燃料，包括柴油、汽油甚至煤油，这在军事后勤上是一个巨大优势，尤其是在多变气候的乌克兰。

05:03

🔧 M1艾布拉姆斯坦克的发动机与装甲技术

M1艾布拉姆斯坦克的发动机与飞机喷气发动机类似，但具有重要的区别。它包括两个传动轴，一个由高压涡轮驱动，另一个由专用动力涡轮驱动。该坦克的热交换器（recuperator）是其与典型飞机喷气发动机的最大区别，它降低了排气的热签名并提高了燃油效率。尽管M1艾布拉姆斯坦克的油耗是可比柴油发动机的两倍，美国军方认为为了涡轮发动机提供的能力，这一成本是值得的。坦克的装甲也随着时间演变，早期型号使用了一种名为Chobham的复合陶瓷装甲，它由极其坚硬且轻质的陶瓷层组成，提供了卓越的防弹性能。陶瓷装甲在压缩下表现更好，可以通过添加面板和螺栓固定来实现。此外，坦克还配备了防碎片衬层，以限制由高速撞击产生的碎片。M1艾布拉姆斯坦克还可以装备反应装甲瓦片，以有效对抗成型装药。

10:06

🛡️ M1艾布拉姆斯坦克的防御系统

M1艾布拉姆斯坦克除了装甲和反应装甲外，还具备生成烟雾的能力，以在交战中隐蔽自己。它有两种产生烟雾的系统：一种是将燃料喷入发动机排气中，另一种是通过安装在炮塔外部的榴弹发射器。M1艾布拉姆斯坦克没有自动装弹机，而是有专门的装填手负责装填炮弹。装填手通过炮塔舱口进入，坐在主炮左侧，负责从身后的弹药箱中取出炮弹并装填。为了提高生存能力，M1艾布拉姆斯坦克设计了装甲弹药门，仅在装填时打开，以防止弹药盒被击中时发生致命的爆炸。炮弹发射后，炮管中的推进气体需要排出，M1的120毫米炮配备了炮口排气器，以帮助排出这些气体。M1艾布拉姆斯坦克使用的两种主要弹药是M829贫铀穿甲弹和M830A1高爆反坦克弹。

15:07

🔩 M1艾布拉姆斯坦克的悬挂与履带系统

M1艾布拉姆斯坦克的重量在52到68吨之间，因此需要一个能够承受这种重量的履带和悬挂系统。传统的螺旋弹簧对于重型车辆存在局限性，因此M1采用了扭杆弹簧，虽然它们较重，但提供了更长的行程和更好的乘员舒适性。扭杆弹簧的长度对于行程至关重要，更长的扭杆弹簧在断裂前可以扭转更多。M1的扭杆弹簧沿着船体的宽度延伸，由于它们位于船体内部，因此提高了船体高度。M1的前导轮先遇到颠簸，因此比跟随轮吸收更多的力量，导致前扭杆弹簧磨损更快。现代坦克越来越倾向于使用液气悬挂系统，这种系统更小、更轻、更易于维护，同时降低了坦克的高度，降低了其轮廓，使其更难以被击中。尽管液气悬挂系统在M1开发时被考虑过，但由于当时这是一项相对较新的技术，因此选择了扭杆弹簧。

20:08

🛠️ M1艾布拉姆斯坦克的改进与未来

M1艾布拉姆斯坦克在过去的40年中不断进行增量改进，出现了M1、M1A1和M1A2三个主要变种，以及更多特殊迭代版本。这些改进包括更新的传感器和控制系统，如M1A2 SEP的Crows II系统增强包，增加了额外的热视瞄准器、辅助动力单元以及远程控制瞄准器。目前，M1艾布拉姆斯坦克正处于M1A2 SEP V4变种，美国陆军正在考虑M1计划的未来，可能是M1A2 SEP V5，或者是一个全新的平台。尽管M1是现代军方服役时间最长的坦克之一，已有40多年的历史，但它仍然非常有能力，将成为在乌克兰地面部队中的宝贵资产。

25:09

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Keywords

💡M1 Abrams

M1艾布拉姆斯坦克是美国的一种主战坦克，自1980年服役以来，以其高速、重装甲和先进技术而闻名。视频中提到，M1艾布拉姆斯坦克在沙漠风暴行动中首次投入使用，并在沙特阿拉伯和科威特的沙漠中迅速获得了声誉。M1艾布拉姆斯坦克的设计和持续现代化使其即使在40多年后，仍然能够在战场上保持竞争力。

💡复合装甲

复合装甲是一种由不同材料层压而成的装甲，旨在提高对各种威胁的防护能力。视频中提到，早期的M1变种使用了一种名为Chobham的复合陶瓷装甲，这种装甲因其极硬且轻质的陶瓷层而具有很高的防弹性能。复合装甲通过陶瓷的硬度和金属背板的韧性相结合，能够有效分散和吸收来袭弹药的冲击力。

💡燃气轮机

燃气轮机是一种发动机，通常用于喷气式飞机，但在M1艾布拉姆斯坦克中也被采用。燃气轮机因其高速度、操作简便和重量轻等特性被选用，尽管它比同等的柴油发动机要重。视频中指出，燃气轮机比柴油发动机轻，能够产生1500制动马力，而挑战者2的V12柴油发动机则重达2吨，只能产生1200制动马力。

💡柴油

柴油是一种燃料，M1艾布拉姆斯坦克主要使用它，因为柴油可以作为额外的装甲层。视频中解释说，液体非常擅长吸收爆炸和动能武器产生的能量，尤其是对抗成型装药时非常有效。此外，柴油不易燃，如果将点燃的火柴扔进柴油池中，火柴会被熄灭，这使得柴油可以相对安全地用作装甲。

💡反应装甲

反应装甲是一种特殊的装甲系统，旨在对抗成型装药弹头。视频中提到，反应装甲通过在两块金属板之间放置一个爆炸性装药来工作。当成型装药的射流击中上层板时，会引爆内部的爆炸物，下层板随后向外飞出，干扰来袭的射流，同时爆炸产生的冲击波也会破坏接近坦克的金属流。

💡热成像瞄准镜

热成像瞄准镜是一种夜视设备，它允许坦克乘员在黑暗或视线不佳的条件下探测和瞄准目标。视频中提到，M1艾布拉姆斯坦克的炮手使用日间和热成像夜视瞄准镜，以及激光测距仪来输入目标距离到弹道计算机中，以提高射击精度。

💡烟幕系统

烟幕系统是坦克用来隐蔽自己以避免敌方视线和制导武器的装置。视频中描述了M1艾布拉姆斯坦克有两种生成烟幕的系统：一种是将燃料喷入发动机排气中，另一种是通过安装在炮塔外部的榴弹发射器发射烟幕弹。这些系统可以在坦克周围产生大量不透明的云团，从而隐蔽坦克的行动。

💡扭杆悬挂

扭杆悬挂是一种用于坦克等重型车辆的悬挂系统，它通过扭杆的扭转来吸收冲击力并支撑车辆。视频中指出，M1艾布拉姆斯坦克的扭杆悬挂系统允许较大的轮子行程，提高了车辆的越野性能和乘员的舒适性。扭杆悬挂系统相比螺旋弹簧悬挂，具有更长的行程和更好的耐用性。

💡贫铀装甲

贫铀装甲是一种使用贫铀材料制成的装甲，因其高密度和硬度而提供出色的防护性能。视频中提到，从1988年开始，某些M1A1坦克开始升级为使用贫铀装甲衬层，而所有新型的M1A2坦克都配备了贫铀衬层，以提高对穿甲弹的防护能力。

💡M829 贫铀穿甲弹

M829是一种使用贫铀材料制成的穿甲弹，它是M1艾布拉姆斯坦克的主要弹药之一。视频中提到，M829是一种脱壳穿甲弹，具有极高的穿透力，能够对付敌方坦克的装甲。贫铀材料的使用使得这种弹药在击中目标时更具有破坏力。

💡M1A2 SEP V4

M1A2 SEP V4是M1艾布拉姆斯坦克的一个现代化变种，它包括了多种系统增强包（SEP），以提高坦克的性能。视频中提到，M1A2 SEP V4配备了额外的热成像瞄准镜、辅助动力单元以及远程控制的CROWS II瞄准具，这些升级使得坦克在21世纪的战场上更加有效。

Highlights

M1艾布拉姆斯坦克自1980年起服役，以其快速、重装甲和最新技术在战场上占有优势。

在沙漠风暴行动中首次投入使用，M1坦克在沙特阿拉伯和科威特的沙漠中迅速获得声誉。

M1坦克使用高速度涡轮发动机，能够在困难的地形上快速移动，帮助解放科威特免受伊拉克占领。

德国设计的120毫米滑膛炮具有更远的射程、更精确的火力和更先进的弹药。

M1坦克预计将于今年向乌克兰交付一个营的31辆M1艾布拉姆斯坦克，再次面对它被设计用来对抗的苏联坦克。

乌克兰军队需要接受训练以维护和操作这些新型坦克，因为它们与其他坦克不同。

尽管M1坦克已有40多年的历史，但由于不断的现代化和前瞻性设计，它在战场上仍然非常有能力。

M1艾布拉姆斯坦克在启动时的声音更像是一架准备起飞的军用飞机。

涡轮发动机的选择为M1坦克提供了两个巨大优势：它们比同等的柴油发动机轻，且功率更大。

M1艾布拉姆斯坦克主要以柴油为燃料，因为柴油可以作为额外的装甲层。

涡轮发动机能够运行在大多数燃料类型上，这对军事后勤来说是一个巨大的优势。

M1坦克的涡轮发动机类似于飞机喷气发动机，但有一些重要的区别，包括其维护的便利性和热交换器的使用。

M1艾布拉姆斯坦克的装甲在过去40年中不断演变，使用了Chobham复合陶瓷装甲。

M1坦克的装甲设计利用了陶瓷材料的硬度和金属背板的韧性，以提高对穿甲弹的防护能力。

M1坦克还配备了反应装甲和烟幕系统，以提高生存能力和战场隐蔽性。

M1艾布拉姆斯坦克没有自动装弹机，而是有专门的装填手，这被认为可以提高可靠性并允许第四名乘员执行其他任务。

M1坦克使用120毫米口径的平滑炮管，发射M829贫铀穿甲弹和M830A1高爆反坦克弹。

M1艾布拉姆斯坦克的履带和悬挂系统设计能够承受其重量，使用扭杆弹簧提供良好的行驶性能。

M1艾布拉姆斯坦克经历了数十年的逐步改进，有M1、M1A1和M1A2三种主要变体，以及更多的专门迭代。

Transcripts

The M1 Abrams entered service in 1980.

A fast, heavily armored tank with the very latest technologies to give it every advantage

on the battlefield.

First seeing action in Operation Desert Storm.

The plain arid camouflaged tank gained a reputation quickly in the barren deserts of Saudi Arabia

and Kuwait.

Powered by a high speed turbine engine, the M1 raced across this difficult terrain to

liberate Kuwait from Iraqi occupation.

The german designed 120 mm smoothbore cannon had longer range, more accurate fire and more

advanced ammunition.

It easily dispatched the lower tech soviet supplied tanks of the Iraqi Army

Sometime this year it’s expected that the US will deliver a battalion of 31 M1 Abram

tanks to Ukraine to once again face off against the Soviet tanks it was designed to battle.

The Ukrainian Army will need training to maintain and operate these new tanks, because it’s

unlike any other tank.

And although this tank are over 40 years old it's still more than capable of holding its

own on the battlefield, thanks to continual modernisation and forward thinking design.

This is the insane engineering of the M1 Abrams.

The M1 Abrams, upon engine start up, sounds more like a military aircraft getting ready

to take off.

*minor pause 1-3 seconds to allow sound to be heard*

A terrifying increasing pitch as the engine revs up to speed.

The whirring sound emanating from the rotating turbine blades hidden inside.

The turbine engine, typically used for jet aircraft, is an engine designed for high speed

operation with minimal weight, a counter intuitive choice for a heavy battle tank.

So why was it chosen?

The turbine engine would give the M1 two huge advantages.

They are much lighter than an equivalent diesel engine, weighing just 1.1 tonnes, developing

1500 brake horsepower.

The V12 diesel engine of the Challenger 2 produces just 1200 brake horsepower with 2

tonnes of metal.

This compactness and extreme high power to weight ratio allows the M1 to stack on layers

of armor without sacrificing acceleration or top speed.

We can plot torque vs shaft speed of the HoneyWell AGT1500 turbine engine of the M1 against the

V12 MTU 883 of the Challenger 2E, and we can see the turbine has a massive torque advantage

at lower shaft speeds.

In its lightest configuration M1 weighs 61.8 tonnes.

A typical toyota corolla weighs 1.1 tonne.

That’s equivalent to 56 Toyota Corollas, yet this thing can still accelerate from 0-32

kilometers per hour in just 7 seconds with a top speed of 72 kilometers per hour.

The M1 Abrams primarily uses diesel fuel, as diesel can act as an additional layer of

armor.

Liquids are extremely good at absorbing energy from explosions and kinetic energy weapons,

they are most effective against shaped charges, and tanks carry a lot of liquid in the form

of fuel.

It may seem counterintuitive to use a fuel as protection from an explosion, but diesel

fuel is not very flammable.

In fact if you throw a lit match into a puddle of diesel it will put out the match.

Diesel engines require immense pressure and a sustained flame to ignite.

Because of this diesel can actually be used with relative safety as armor.

However the turbine engine can also operate on most fuel types.

This is a huge advantage in military logistics.

Making joint operations with NATO vastly easier.

In the years following World War 2.

The Soviets favored diesel compression ignition engines.

The western Allies used a mixture of both gasoline spark ignition and diesel compression

ignition.

Transporting fuel is one of the largest logistic challenges in war.

Needing several types of fuel makes it all the more difficult.

The M1 can run on marine diesel, gasoline or even kerosene if needed.

Which not only makes it easier to procure fuel in a warzone, but comes with the added

bonus of helping the M1 Abram operate in hot or cold weather.

Dealing with the wild swings in temperature that Ukraine can expect throughout the year

with ease.

Where diesel fuels can crystallize at low temperatures, kerosene can be used instead.

The turbine engine of the M1 works similarly to aircraft jet engines, with some important

differences.

Air enters the engine here, where it is compressed by the low pressure compressor, and then the

high pressure compressor, each individually driven by separate turbine stages.

These turbine stages are driven by the combustor, which works a little differently to typical

aircraft combustors.

It is mounted perpendicularly to the engine, and protrudes out of the engine.

This makes maintenance access to the combustor easier, with only a simple bolted cover needing

to be removed.

There are two drive shafts in this engine.

A secondary drive shaft, driven by the high pressure turbine, which runs forward to an

accessory gearbox that runs things like compressors, electronics and hydraulics.

The main drive shaft, driven by a dedicated power turbine, which is not connected to the

compressors, runs rearward to the tanks drive sprockets.

This primary driveshaft and its reduction gearbox is surrounded by something called

a recuperator.

This is the biggest difference between this turbine engine and a typical aircraft jet

engine.

We don’t want the hot exhaust of the engine spewing out like a jet engine, the heat signature

this would create would be a giant beacon for heat guided missiles and give the tanks

location to any enemy using thermal vision.

We also don’t want to waste all that heat energy.

The recuperator is essentially a giant heat exchanger.

Air coming from the compressor stage is passed through it, where it is heated by the exhaust

before entering the combustion chamber.

This lowers the heat signature of the exhaust and increases fuel efficiency, transferring

more heat energy back into the engine instead of losing it to the atmosphere.

But the M1 Abrams is still a thirsty machine, even by tank standards.

The turbine engine uses twice the fuel as a comparable diesel engine per kilometer.

Where the M1A1 consumes around while cruising at 40 kilometers per hour, the Leopard 2 consumes

2.2 liters per kilometer.

[REF] [1] But the US military deemed this issue a cost

worth paying for the capabilities the turbine engine provided.

Allowing the M1 to carry an obscene amount of armor, while keeping its acceleration high.

The armor installed on the M1 Abrams has evolved and changed over the last 4 decades.

The exact details of its thickness, location, materials and layering is classified for obvious

reasons, but there is a great deal known about the science and nature of its armor.

It is well publicized that early M1 variants used a type of composite ceramic armor called

Chobham.

Which derives much of its ballistic resistance from an extremely hard and light ceramic layer.

Hardness in material science is a measure of a material's ability to resist localized

deformation, like a scratch.

Diamonds are extremely hard, and because of this industrial diamonds are coated onto cutting

tools to help them cut through materials, without being eroded themselves.

A hard material can scratch and erode a softer material.

Hardness can be measured with a vickers hardness test, which pushes a pyramid shaped diamond

into the material.

The hardness is then calculated by dividing the force applied by the resulting surface

area of the indentation.

The rolled homogeneous armor steel of world war 2, has a Vickers Hardness of 380, a high

carbon hard steel is about 550, while a ceramic like silicone carbide offers a hardness 5

times greater, up to 2500 [2] While being much lighter than steel.

Making it an excellent candidate for armor.

But, anyone that has dropped a dinner plate knows that ceramics are extremely brittle.

They shatter into a million pieces with little force,

but this can be used to the tanks advantage when combined with a tougher metal backing

plating.

In this configuration the ceramic is placed on the outside of the metal plating, acting

like an extremely hard outer shell.

When a round strikes the armor the compressive strength and hardness of the ceramic coating

causes the round to fracture and break apart, at the same time the ceramic coating begins

to fracture and fragment, spreading the energy of impact across a larger area which is then

absorbed by the tougher metal plate backing the ceramic.

Tough in material science meaning it can absorb a lot of energy without fracturing, the opposite

of brittle.

Further research and experimentation found that ceramic armor performed even better when

placed under compression.

This can be achieved by simply adding a face plate and bolting the two pieces together.

This changes the dynamics of an impact significantly, and helps immensely with resisting attack

from long-rod kinetic energy projectiles.

[REF][3]

These are rounds specifically designed as anti-armor weapons.

They are thin, long dart-like projectiles that require a sabot to launch out of tank

barrels.

They are typically manufactured from high density materials like Tungsten.

With a thin aerodynamic shape and high density, these weapons have an extremely high ballistic

coefficient, allowing them to ram into targets at a distance at high velocities.

They can obliterate rows of concrete walls with ease.

Embedded compressed ceramic armor can defeat these kinetic energy weapons.

[REF][4]

When the long rod projectile strikes the face plate it sends a pressure wave through the

ceramic that pulverizes it and increases its volume.

This creates what is essentially an abrasive maze of extremely hard and sharp particles

the penetrator has to push through, gradually grinding it away.

[REF][5]

Computer simulations of this effect show that the harder the material the better.

This is the magic of ceramic composite armor.

[REF] [6]

On top of these metal and ceramic layers there is typically a very dense inner liner called

a spall lining.

Projectiles don’t necessarily need to penetrate every layer of armor to be deadly.

If they hit with enough force the kinetic energy can simply transfer through the material

as a wave and cause material on the inside of the tank to splitter and turn into deadly

shrapnel inside the crew compartment.

This is called spall.

Some munitions are specifically designed to cause this.

High explosive squash heads are made from soft plastic explosives that spread out over

the armor's surface.

With the increased surface area and direct contact with the armor, the explosion transfers

a great deal of energy through the material and blows out the armor's backing.

This works by sending a compressive shock wave through the material and reflects and

rebounds inside the material, creating regions of intense stress that fractures the armor.

The spall liner is a ductile and dense material that limits spalling.

For early M1s this layer was typically composed of lead, but beginning in 1988 certain M1A1s,

began to be upgraded with depleted uranium spall liners, which are even denser than lead.

And all new M1A2s were assembled with depleted uranium liners.

However, modern composite armor makes it difficult for this shock wave to transmit through the

material and a spaced layer with an air gap can defeat this squash head munition completely.

Additional reactive armor tiles can be added to the outside of the M1 too.

Reactive armor is particularly effective at dealing with shaped charges.

Shaped charges consist of a charge shaped with a hollow indentation, lined with a ductile

metal liner.

When the charge is detonated a pressure wave forms behind this metal liner, deforming it

and accelerating the metal into a lance stream of particles.

The shaped charge effectively creates a hypersonic projectile at point black range.

[REF][7] It’s highly effective at cutting through armor.

Reactive armor works by placing an explosive charge between two metal plates.

When a jet from a shaped charge strikes the upper plate it detonates the inner explosive.

You may think this could damage the tank, but tank’s lower armor is more than capable

of dealing with the relatively blunt pressure formed by the reactive armor detonation.

The outer plate then flies outwards to disrupt the incoming jet while the shockwave formed

by the detonation also breaks up the stream of metal approaching the tank.

Ofcourse, the best defense is to not be hit at all, and the M1 can create a smoke screen

for itself when needed.

The M1 has two systems for generating smoke to conceal itself in an engagement.

The first involves simply spraying fuel into the engine exhaust, which vaporises the fuel

and creates a large opaque cloud behind the tank.

However it’s extremely important that the driver remembers which fuel the tank is running

on.

This works for diesel fuel, but if gasoline or kerosene is used it won’t conceal the

M1, it will set it on fire.

The second system uses these grenade launchers mounted on the outside of the turret.

There are two versions that the M1 uses.

The 8 canister M257 typically used with US Marine Corps M1s, and the more widely used

6 can M250.

These launchers are controlled from the tank commander's seat here.

Pressing 1 button launches 6 grenades, 3 from the left and right side.

Pressing both buttons launches all 12 of the grenades.

Launching them about 30 meters from the tank and providing a shrouding curtain of smoke

to hide it’s movements.

The engineers of the M1 Abrams did everything in their power to make the M1 as survivable

as possible, protecting the crew inside.

And the highly trained crew are the most important part of this machine.

The M1 Abrams does not have an automatic loader, like many modern tanks.

It has a dedicated crew member, the loader, to load rounds into the breach.

Autoloaders are a feature of modern Russian tanks, however the USA has shunned them in

their tanks, seeing an autoloader as an unnecessarily complex mechanism that would impact the M1s

reliability.

Seeing a forth crew member, capable of keeping watch, maintaining the vehicle and taking

over responsibilities in an emergency as an advantage, not a disadvantage.

The loader enters the tank through the turret hatch, sitting to the left of the main gun

with access to the ammunition box behind them . The gunner to their right is in charge of

aiming at targets using these day and thermal night vision sights, along with a laser range

finder to input target distances into the ballistics computer.

When instructed by the tank commander, sitting behind the gunner, the loader will press a

switch with their knee to open a hydraulically actuated armored door behind them.

The tank commander will specify the round needed and the loader will take it out and

load it into the breach, close the breach and move the safe handle into the armed position.

This process will be repeated until a ceasefire is called by the tank commander.

The armored ammunition access door is only open when loading, and this is crucial for

the survivability of the M1 Abrams.

If a round penetrates the ammunition box it can result in a lethal detonation of the ammunition

stored inside.

This armored door is capable of withstanding this blast, and panels on top of the tank,

called blow out panels, are designed to break and allow the pressure and heat to be directed

upwards and away from the crew.

[REF][8] These rounds are fired out of the M1s 120

mm cannon.

Early M1s were fitted with a 105 mm cannon.

105 referring to the bore diameter of the gun.

This decision was made primarily to allow a sharing of ammunition and parts between

the 105 mm on the previous generation M60 tank.

With the development of depleted uranium rounds it was viewed that this gun was more than

adequate to deal with any soviet armor.

However US allies like Germany did not want to use depleted uranium round due to ethical

implications, and were moving towards 120 mm cannons with the British Chieftan tank

using the Royal Ordanance L11 and the German Leopard 2 using the Rheinmetall RH-120.

This posed a problem for NATO’s goals of standardizing wherever possible to optimize

logistics.

With ammunition factories across NATO countries producing the same ammunition, this ensured

ammunition could not only be shared, but manufactured as close to the frontline as possible.

The 120 mm guns of the M1A1 and M1A2 are in fact the German Rheinmetall RH-120 manufactured

under license in the US.

A 5.3 metre long, 3.3 tonne smooth bore cannon.

This large bulge in the middle of the cannon is designed to help evacuate the barrel of

propellant gasses after each firing.

Once the round leaves the barrel atmospheric pressure can prevent the gasses from leaving,

and once the breach is opened the potentially harmful and explosive gas can enter the crew

compartment.

The bore evacuator is a pretty simple solution, with holes that allow gasses to enter the

evacuator as the round passes by.

This acts like a pressure reservoir.

When the round leaves the barrel with this attachment, the pressure is released from

forward facing holes at the far end of the evacuator that pushes the remaining gas outwards.

The two primary rounds used by the M1 are the M829 Depleted Uranium round, which is

a saboted kinetic energy round, and the M830A1 HEAT Round, which, despite its name, does

not use heat as part of its offensive.

It uses a kinetic energy shaped charge.

We have been piling on weight in this vehicle.

The armor, cannon, engine and ammunition makes this an extremely heavy vehicle.

Weighing between 52 and 68 tonnes depending on the generation and configuration.

The M1 Abrams needed a track and suspension system capable of bearing that weight.

For a vehicle this heavy typical helical springs have some problems.

First, their maximum travel is limited.

At a particular load the layers of a helical spring will meet and no further travel is

possible, bottoming out and providing an extremely uncomfortable ride for the crew.

To deal with a heavier vehicle we need to increase the spring coil diameter, taking

up an increasing amount of space.

This was an issue for world war 2 era tanks, with the M4 Sherman opting to use a volute

spring, which is a conical spring that is capable of compressing to a much smaller size

as the sheets of spring steel overlap.

However most modern tanks utilize the torsion springs, which take up very little space inside

the tank, though they do raise the tanks height considerably.

The torsion springs of the M1 are located here, and because they are inside the hull

they raise the hull height by 150 millimeters.

The road wheel is attached to a lever that can travel up and down, this lever arm is

attached to the torsion bar so that it twists when the lever arm moves up and down.

The spring force is derived from the bars resistance to torsion.

Older tanks incorporating torsion bars had limited travel.

The M1’s predecessor, the M60, had a wheel travel of just 20 centimeters.

During development of the M1 the two tanks were pitted against each other, with the M1

benefiting from 20 years of material science progress, its max travel was nearly double

that of the M60 at 38 centimeters.

When tested on a track with a series of 30 centimeter bumps at 32 kilometers per hour.

The M60 managed to break its front front wheels, lost control, and broke the drivers arm.

The torsion spring of the M1 runs along the width of the hull.

Making them quite heavy.

We need the torsion spring to be as long as possible because the travel distance is a

function of the torsion bar's length.

Longer torsion bars can twist more before breaking.

An interesting quirk of the torsion spring system is that typical designs, like the M1’s,

mean that the road wheels cannot be aligned.

We cannot simply connect the lever arms of opposite road wheels to the same torsion spring,

as they would frequently travel together, creating no torsion.

The far end of the bar needs to be rigidly mounted to the body of the tank in order to

develop a spring force.

So two torsion bars need to be mounted alongside each other, creating an offset in distance

between the two sides of the tracks.

The two sides of the M1 are not symmetrical.

This comes with some drawbacks.

The leading road wheel will hit bumps first, meaning it will absorb more force than the

trailing road wheel.

Increasing the wear on the leading torsion spring, resulting in more frequent replacement.

Torsion bars are very easy to swap out when they aren’t broken, but if bent or shattered,

or if the body of the tank is bent, it can be difficult to pull the long torsion springs

out.

Modern tanks are increasingly moving towards hydrogas suspensions.

Which look like this.

The road wheel has an attached axle pivot arm, which in turn turns a crank and con-rod

piston.

This piston connects to the hydragas suspension cylinder.

The first chamber is filled with a fluid, typically oil.

The oil is relatively incompressible, and so provides marginal spring force, but this

chamber has a damper valve that serves to restrict the transfer of fluid between this

chamber and the next, which contains a floating piston with a compressed nitrogen gas on the

other side.

This provides resistance to ensure the road wheels stay in contact with the ground, but

also dampens out vibrations.

[REF] [9]

This system is much smaller, lighter and easier to service than a torsion bar, while lowering

the height of the tank, lowering its profile and making it harder to hit.

Not only that, but each individual suspension can be remotely adjusted by changing the gas

pressure inside the cylinder.

Allowing the tank to take a crouched position if needed.

Hydrogas suspensions were considered for the M1 during development, but it was a relatively

new technology at the time, and so the torsion spring was chosen.

[REF][9]

The M1 Abrams has had incremental improvements added over the past 4 decades.

With three primary variants the M1, M1A1 and M1A2, with even more specialized iterations

in between.

With updated sensors and controls to bring the tank into the 21st century.

Like the Crows II on the M1A2 SEP.

SEP standing for systems enhancement package.

Which added additional thermal sights for the tank commander, an auxiliary power unit

to run it’s electronics without running the fuel hungry engine, and the CROWS II controller.

A remote control sight that allows the tank commander to operate the gun from the safety

of the turret.

[REF][10]

We are currently on the M1A2 SEP V4 variant, and the army is considering the future of

the M1 program, whether that’s an M1A2 SEP V5, or a completely new platform, but make

no mistake, despite the M1 being one of longest serving tanks in a modern military, over 4

decades old it’s still highly capable and it will be a massive asset to the troops in

the ground in Ukraine.

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