CBU-55

The CBU-55 (Cluster Bomb Unit-55) is an air-delivered cluster bomb developed by the United States. It is designed as a fuel-air explosive (FAE) weapon. Its primary intended use was to clear landing zones in jungle or forested areas by creating a large, instantaneous overpressure.

The CBU-55 consists of three BLU-73/B FAE submunitions contained within an SUU-49/B dispenser. Upon release from the aircraft, the dispenser opens at a predetermined altitude. Each BLU-73/B submunition then releases its liquid propellant, which rapidly vaporizes and mixes with atmospheric oxygen. A subsequent detonator ignites the fuel-air mixture, creating a large explosion characterized by a powerful overpressure wave and a relatively long burn time.

The resulting explosion creates a vacuum effect as the oxygen is rapidly consumed. This can cause significant structural damage and be particularly devastating to personnel in enclosed spaces or trenches.

The CBU-55 saw limited use during the Vietnam War. Concerns about its indiscriminate effects and the potential for collateral damage, coupled with evolving operational requirements, contributed to its eventual removal from active service. It is no longer in the active inventory of the U.S. military. The weapon is considered controversial due to its area effect and the potential for unintended harm to civilians.