The bomb bay or weapons bay on some military aircraft

Military aircraft

A military aircraft is any fixed-wing or rotary-wing aircraft that is operated by a legal or insurrectionary armed service of any type. Military aircraft can be either combat or non-combat:...

 is a compartment to carry bomb

Bomb

A bomb is any of a range of explosive weapons that only rely on the exothermic reaction of an explosive material to provide an extremely sudden and violent release of energy...

s, usually in the aircraft's fuselage

Fuselage

The fuselage is an aircraft's main body section that holds crew and passengers or cargo. In single-engine aircraft it will usually contain an engine, although in some amphibious aircraft the single engine is mounted on a pylon attached to the fuselage which in turn is used as a floating hull...

, with "bomb bay doors" which open at the bottom. The bomb bay doors are opened and the bombs are dropped when over the target or at a specified launching point.

Large-sized bombs, which may be nuclear

Nuclear weapon

A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission bomb test released the same amount...

, are dropped from hook-type releases or bomb cradles. When a bomber carries many smaller bombs (e.g. iron bombs, JDAMs), the bombs are typically loaded onto mechano-electrical devices known as ejector racks, which allow for larger bomb loads to be dropped with greater accuracy.

Guided missile

Guided Missile

Guided Missile is a London based independent record label set up by Paul Kearney in 1994.Guided Missile has always focused on 'the underground', preferring to put out a steady flow of releases and developing the numerous GM events around London and beyond....

s (frequently standoff missiles) are often carried in the bomb bays of modern aircraft; the missiles are dropped from the aircraft and then accelerate into autonomous flight while the bomber aircraft "stands off" at a safe distance from the target.

Bomb bays were born of necessity. Early military aircraft suffered severe aerodynamic drag (which would further slow down the already lumbering bomb-laden aircraft) with bombs hanging from the wings or below the fuselage, so military aviation designers moved the bombs inside the aircraft.

Before the introduction of stealth technology bomb bays were mostly used by dedicated bomber aircraft; in fighters and attack airplanes bombs and rocket

Rocket

A rocket is a missile, spacecraft, aircraft or other vehicle which obtains thrust from a rocket engine. In all rockets, the exhaust is formed entirely from propellants carried within the rocket before use. Rocket engines work by action and reaction...

s were hung from the wings or fuselage. Notable exceptions are the F-101, F-102 and F-106 interceptor aircraft

Interceptor aircraft

An interceptor aircraft is a type of fighter aircraft designed specifically to prevent missions of enemy aircraft, particularly bombers and reconnaissance aircraft. Interceptors generally rely on high speed and powerful armament in order to complete their mission as quickly as possible and set up...

, all of which had bays used to store missiles, or other weapons stores. Today many designers have moved previously "external" stores into internal multifunction "weapons bays" capable of carrying air-to-air missile

Air-to-air missile

An air-to-air missile is a missile fired from an aircraft for the purpose of destroying another aircraft. AAMs are typically powered by one or more rocket motors, usually solid fuelled but sometimes liquid fuelled...

s, air-to-ground missiles, drop tank

Drop tank

In aeronautics, a drop tank is used to describe auxiliary fuel tanks externally carried by aircraft. A drop tank is expendable and often jettisonable...

s, and other military "stores" and deploying them rapidly in a battle. The principal reason for the change is to use stealth technology

Stealth technology

Stealth technology also termed LO technology is a sub-discipline of military tactics and passive electronic countermeasures, which cover a range of techniques used with personnel, aircraft, ships, submarines, and missiles, to make them less visible to radar, infrared, sonar and other detection...

 to make aircraft more difficult to detect. Military fighters are now designed to have the smallest possible radar cross-section, which has decreased very substantially since attention was paid to this feature. Large racks of missiles and bombs hanging below the wings return very distinct radar signatures which can be eliminated by bringing the weapons inside the fuselage. This also improves aerodynamic performance and increases the payload which can be carried. Examples of modern U.S. fighters with weapons bays are the F-117 Nighthawk

F-117 Nighthawk

The Lockheed F-117 Nighthawk was a single-seat, twin-engine stealth ground-attack aircraft formerly operated by the United States Air Force . The F-117A's first flight was in 1981, and it achieved initial operating capability status in October 1983...

, F-22 Raptor

F-22 Raptor

The Lockheed Martin/Boeing F-22 Raptor is a single-seat, twin-engine fifth-generation supermaneuverable fighter aircraft that uses stealth technology. It was designed primarily as an air superiority fighter, but has additional capabilities that include ground attack, electronic warfare, and signals...

, and F-35 Lightning II

F-35 Lightning II

The Lockheed Martin F-35 Lightning II is a family of single-seat, single-engine, fifth generation multirole fighters under development to perform ground attack, reconnaissance, and air defense missions with stealth capability...

.