OVERVIEW: A U.S. air-dropped thermonuclear bomb, the B28 was developed during the Cold War for strategic delivery by bomber aircraft. It was designed for high-yield nuclear deterrence and tactical nuclear strike missions.

DETAIL: The B28 was designed by Los Alamos National Laboratory in the 1950s and entered service in 1958. The designation "B" stands for Bomb, and the weapon employed a two-stage thermonuclear design with variable yields. It featured multiple versions suited to free-fall, parachute-retarded, and laydown delivery methods. With a diameter of approximately 20 inches and a weight of about (1,000 kg), the B28 could be deployed from a variety of U.S. strategic and tactical aircraft.

The B28 Mod.0 was a strategic bomb with a yield of approximately 1.45 megatons. It was optimized for high-altitude release from long-range bombers and featured internal arming and safety devices to ensure secure handling and deployment. It was among the highest-yield U.S. bombs to be carried in operational readiness during its era.

It was intended to be used by strategic bombers such as the B-47 and B-52 under high-altitude penetration or stand-off delivery tactics. Delivery parameters could be configured for ballistic or retarded release, depending on the mission and threat environment.

SPECIFICATION:
Weight: ~1,000 kg
Length: ~170 in (4.3 m)
Diameter: ~20 in
Yield: ~1.45 megatons
Guidance: None (unguided)
Fuse: Contact, airburst, or laydown options

PERFORMANCE:
Range: Aircraft-dependent (air-delivered)
Delivery Altitude: High-altitude to low-altitude profiles
Deployment Modes: Free-fall, retarded, or laydown
Accuracy: Ballistic (bomber released)

NOTE:
IOC: 1958
Operators: United States
Platform: B-47, B-52, B-58, F-100, and other nuclear-capable aircraft
Conflicts: Cold War (deployed, not used in combat)

SOURCE:
U.S. Department of Energy: https://www.energy.gov/
Los Alamos National Laboratory: https://www.lanl.gov/
National Museum of the USAF: https://www.nationalmuseum.af.mil/
Federation of American Scientists (FAS): https://fas.org/nuke/guide/usa/bomber/b28.htm