BY FURROWING the surface of metal plate with angular ridges, a Philadelphia inventor has materially increased the strength of armor designed for use on tanks, warships, and aircraft. In recent ballistic experiments conducted before ordnance experts, high-powered bullets fired from a distance of fifty yards pierced a test section of flat armor plate one half inch thick. When a slightly thinner section of corrugated armor was used, however, bullets fired from the same distance failed to penetrate its surface, but ricocheted off the sides. Armor penetration depends on a bullet’s angle of impact. Corrugated armor plate, the inventor explains, presents a surface inclined at an angle of forty-five degrees; bullets strike it a glancing rather than a direct blow.

  1. Stephen says: August 12, 20115:40 am

    This is one of those cases when something looks as if it should work, but there must have been some reason against it or we would be seeing it everywhere. What is wrong with it, though, I can’t see myself.

  2. Scott B. says: August 12, 20116:02 am

    Stephen – My guess is that it probably adds ungodly amounts of weight without offering enough protection against armor-piercing shells. Still, the concept does seem sound.

    I love the look of that tank, too. Very Art Deco. 🙂

  3. The_WOZ says: August 12, 20118:04 am

    Maybe it was good against antitank rifles, but offered a higher contact surface to explosive cannon shells? (meaning more shrapnel released inside the tank)

  4. Hirudinea says: August 12, 20119:06 am

    Probably this was abandoned when larger rounds were brought in, but the idea of angling armour is a good idea, look at the T-35.

  5. JMyint says: August 12, 20119:19 am

    Angling armor on a larger scale was more practical, worked better against larger rounds, and was easier to implement with thicker armor.

    Angled armor works in many different ways. It increases the cross sectional thickness without increasing weight. It increases the area of contact of a projectile, therefore spreading its energy. It deflects some of the energy of the projectile increasing the chance of ricochet.

  6. Paul says: August 13, 20118:37 am

    My guess is the idea simply became obsolete with the development of modern composite armour, such as Chobham, which is far more effective with a lot less weight.

  7. Jari says: August 13, 20114:18 pm

    Paul: It was obsolete at the birth. Any kind of explosive shell would have penetrated that. Chobham was developed in the sixties and there were no armored vehicles using corrugated armor in WW2 as far as I know.

  8. Sean says: August 15, 20114:56 am

    The concept of sloped armor goes back at least as far as the Civil War when people began really thinking about armor scientifically. The Merrimack/Virginia got its distinctive ‘floating barn roof’ look because its sides were sloped to help cannon balls ricochet off. As an added measure, they covered them with pork fat to make them slippery. (This was quickly found to be unneeded.)

  9. J Paul says: August 15, 20118:21 am

    grandfather of the batmobile/trumbler,B-2 and F-111!

  10. Maunicio says: August 22, 20116:59 am

    Jari: There was the magnificence, that was the Bob Semple Tank.

  11. Jari says: August 23, 20119:18 am

    Maunicio: I’d rather use the word “monstrosity”. What I gathered around the net, it wasn’t exactly successful as a tank….

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