page_title: Spaced armour
section_title: Composite spaced armours
hierarchical_section_title: Spaced armour / Composite spaced armours
caption_attribution_description: Русский: Т-55-АМ в Музее бронетехники в Кубинке. English: T-55AM in the Kubinka Museum. This file was uploaded with Commonist.
context_page_description: Armor with two or more plates spaced a distance apart falls under the category of spaced armour. Spaced armour can be sloped or unsloped. When sloped, it reduces the penetrating power of bullets and solid shot, as after penetrating each plate projectiles tend to tumble, deflect, deform, or disintegrate; spaced armor that is not sloped is generally designed to provide protection from explosive projectiles, which detonate before reaching the primary armor. Spaced armour is used on armoured military vehicles such as tanks and combat bulldozers. In a less common application, it is used in some spacecraft that use Whipple shields.
context_section_description: Multilayer spaced armors, which also uses special materials, are transition to composite armor, most of the latter are also partially spaced armor.
  In case of Leopard1A3 and later variants the outer layer of spaced armor was hardened steel and the space was filled by elastomer, thus the effectiveness of shattering effect of the outer layer against APFSDS were outstanding, and the protection against early HEAT warheads were increased too. The BDD add-on armor of T-55 and T-62 series based on the same effect, but it had multiple layers within elastomer, therefore it roughly doubled the frontal protection of these tanks against APDS and HEAT weapons, and make the areas of add-on immune against HESH rounds. In T-64 and early T-72 (up to T-72M1) and T-80 (to mid T-80A) used stakloplastika (a special military-grade dense glass-fiber reinforced pressured plastic) as filling in the frontal upper glacis spaced armor. This plastic was effective in lowering the concentration of the jet of shaped charges and in destabilizing kinetic penetrators.
  Hardened steel plates has become commonplace for outer part of spaced armors from '80s not only on tanks but also on APCs and IFVs. With these add-on armors even the APC's thin armor is sufficient against kinetic bullets of 12.7 (Stryker and BTR-80 upgrades) and 14.5 calibers (Bradley, BMP-3) and also provides some protection against IEDs.
  The increase of the number of layers in spaced armor increases the physical damage and destabilization of jets and kinetic penetrators, so it is common in more modern armor to use successive layers alternating between softer (air, aluminum or plastic) and harder (RHA, SHS) layers. With multiple layers the likelihood of bounce in case of kinetic projectiles is also increasing, and SC jets loss from their material when come through between layers with different density and their performance lowered due to the effects pressure and velocity changes (foreshortening) on their concentration. Thus later T-72B and T-90 armors used 7 layered spaced armor (with hardened steel plates) in order to achieve much stronger protection in cost of minimum weight increase.
  The more advanced late cold war tanks were given multi-layer skirts (Leopard 2), in which passive (or reactive) effects significantly reduced the effectiveness of HEAT ammunition. At the same time, these elements are already heavy and have considerable thickness, which increase the size and weight of the vehicle and make maintenance difficult. Russian and some western tanks carries explosive-reactive armor blocks in order to increase effectiveness of spaced armors (particularly in case of side skirts, e.g. TUSK, T-90), and main frontal armor.
  Almost all of modern western and Japanese and most of soviet tanks use some kind of spaced armors on fronts and sides. Side panels of superstructure usually contain fuel, batteries (Leopard 2, Type 10) and other less vital elements or munition of secondary weapons (Merkava), because they also reduce the effectiveness of penetrating projectiles. In most important areas (frontal armor and sides of turret)  the cavity of spaced armor contain composite panels. From 80's most of western tanks has composite armor blocks on the frontal part of skirts made of hardened steel or NERA armor (non-explosive-reactive armor, known as Burlinghton armor). Most of modern MBTs (e.g. T-72B, Leopard 2, M1, Type 10, K2, T-90, Type96) have NERA armor in their spaced armors which supplemented with inner ceramic armor and spall liners in some cases. In contrast, Soviet tanks were initially made with ceramic (corundum or silicate) inserts (T-64A, T-72A, T-72M1, T-80) and NERA-style inserts have spread in the upgraded versions of their vehicles later (T-72B, T-80A, T-72BU). More detail in composite armour.
  Nowadays composite spaced armors with hardened steel outer layer (often filled with NERA or ceramic inserts) are becoming more common on most advanced light battle tanks (ZTQ-15) and IFVs (Namer, Puma).
caption: BDD armor on T-55
exif: {"Image ImageWidth": "5472", "Image ImageLength": "3648", "Image BitsPerSample": "[8, 8, 8]", "Image PhotometricInterpretation": "2", "Image Make": "Canon", "Image Model": "Canon EOS 70D", "Image Orientation": "Horizontal (normal)", "Image SamplesPerPixel": "3", "Image XResolution": "300", "Image YResolution": "300", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop CS6 (Windows)", "Image DateTime": "2014:10:24 22:05:47", "Image ExifOffset": "276", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "966", "Thumbnail JPEGInterchangeFormatLength": "5647", "EXIF ExposureTime": "1/40", "EXIF FNumber": "4", "EXIF ExposureProgram": "Program Normal", "EXIF ISOSpeedRatings": "100", "EXIF SensitivityType": "Recommended Exposure Index", "EXIF RecommendedExposureIndex": "100", "EXIF ExifVersion": "0230", "EXIF DateTimeOriginal": "2014:04:12 14:03:42", "EXIF DateTimeDigitized": "2014:04:12 14:03:42", "EXIF ShutterSpeedValue": "665241/125000", "EXIF ApertureValue": "4", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "4", "EXIF MeteringMode": "Pattern", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "24", "EXIF SubSecTime": "83", "EXIF SubSecTimeOriginal": "83", "EXIF SubSecTimeDigitized": "83", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "5472", "EXIF ExifImageLength": "3648", "EXIF FocalPlaneXResolution": "5021939/2048", "EXIF FocalPlaneYResolution": "5021939/2048", "EXIF FocalPlaneResolutionUnit": "3", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF SceneCaptureType": "Standard", "EXIF BodySerialNumber": "078024005888", "EXIF LensSpecification": "[24, 105, 0/0, 0/0]", "EXIF LensModel": "EF24-105mm f/4L IS USM", "EXIF LensSerialNumber": "00001e29d3"}