Why Tanks Shoot Arrows
You might be thinking to yourself after reading this title, “What in the world?” After all, wouldn’t the most advanced fighting machines on this Earth fire massive versions of bullets, bombs, or artillery shells, and not primitive darts that became obsolete 500 years ago? Surprisingly, no! The answer, like any, is much more complex and, unexpectedly, ingenious.
Tanks nowadays commonly shoot massive steel darts with a dense core, usually made of tungsten or even depleted uranium and are so ubiquitous that almost all modern tanks have this type equipped. This ammunition is called APFSDS (Armor-Piercing, Fin-Stabilized Discarding-Sabot). To make sense of such a mouthful of an acronym, let’s break it down:
On the left is a midair snapshot of the sabot throwing itself away from the fin-stabilized dart. On the right is a depiction of the depth such a round can penetrate. Such darts can pierce up to half a meter of armor.
Armor-Piercing: This shell is designed to defeat the armor of other vehicles, so it needs to be able to penetrate incredibly deep.
Fin-Stabilized: Fins are needed to spin the dart and increase accuracy, much like what feathers do for an arrow.
Discarding-Sabot: This is an outer shell that centers the actual dart in the middle of the barrel and peels off once it is fired.
These elements all combine to create, in essence, a massive arrow that is tailor-made to pierce tank armor like how an archer's arrow perforates a knight’s chainmail. When this arrow is fired, the sabot peels away due to its anti-aerodynamic properties, leaving the penetrating dart traveling at over a kilometer a second. This penetrator then penetrates the tank at a very small point and disintegrates into extremely hot metal once through the layers of armor, bouncing around the walls of the tank, turning crew members into red dust, and setting stored ammunition off like fireworks. Not a fun time.
Because this dart is a mainstay in every modern tank in a nation’s inventory, and it can in addition pierce any modern tank, why don’t engineers just add more armor to their own tanks? If you accumulate enough steel plates over a certain area, the kinetic force behind an APFSDS round would eventually be overcome. Although this seems like common sense, engineers are already finding solutions to this, just in the opposite direction.
To illustrate, imagine, of all things, an onion, with all its layers. Each layer must be peeled before the next layer can be arrived at. Now imagine your tank’s survivability as this onion. Before you can even get penetrated, you must first be hit; before you can get hit, you must be identified; before you can be identified, you must be detected; and before you are detected, you must be there in the first place. Engineers realized that it’s much easier to improve a tank’s engine or decrease its armor than to load on more and more steel. This means a vehicle is able to avoid simply “being there” by rapidly relocating between shots with its improved mobility.
In essence, the most primitive and even downright backwards ways can yield the most fruitful results. From bows to ballistae to spears to today, armies never stopped throwing giant darts at each other; we only got more efficient. So whenever you spot the next technological marvel waiting at our doorstep, remember that we need not always reinvent the wheel, as oftentimes, the best solutions are the simplest ones.
Sources:
https://www.britannica.com/technology/armour-piercing-fin-stabilized-discarding-sabot
https://www.ryanmcbeth.com/single-post/the-survivability-onion
