OVERVIEW: The BLU-27/B is a 750 lb class U.S. Air Force incendiary bomb developed during the Vietnam War era. Designed for use against personnel, infrastructure, and light materiel targets, it disperses thickened fuel (napalm) over a wide area.

DETAIL: The BLU-27/B is part of a family of air-dropped incendiary weapons that succeeded earlier M-series bombs, optimized for improved safety, reliability, and burn coverage. It consists of a cylindrical metal casing filled with a thickened incendiary agent (commonly a gasoline-based gel like Napalm-B). Upon impact, the bomb bursts open, spreading the flammable contents across the target area before ignition. The incendiary fill is designed to adhere to surfaces, causing sustained fires and extreme thermal damage.

The BLU-27/B can be dropped from high or low altitudes and is typically fuzed for instantaneous or short-delay detonation to optimize incendiary dispersion. Compared to earlier variants, the casing design of the BLU-27/B improves spread patterns and reduces dud rates. It was frequently used in large-scale area-denial or deforestation missions, as well as in strikes on enemy positions and fuel storage.

This weapon is primarily deployed in missions requiring mass incendiary effect over open terrain, jungle, or soft targets. Delivery typically involves medium- to low-altitude release from tactical aircraft. While largely retired from frontline USAF service, the BLU-27/B established the standard for subsequent U.S. incendiary bomb design and employment.

NOTE:
IOC: Early 1970s
Operators: United States Air Force
Platform: F-4, F-100, F-105, A-1, A-7, A-37, B-52
Conflicts: Vietnam War, Laos, Cambodia

SOURCE:
U.S. Air Force Historical Studies
U.S. Department of Defense Archives
Federation of American Scientists (FAS): https://fas.org
GlobalSecurity.org: https://www.globalsecurity.org