unguided bomb

Bomb casings for unguided bombs are typically aerodynamic in shape, often with fins at the tail section, which reduce drag and increase stability after release, both of which serve to improve accuracy and consistency of trajectory. Unguided bombs typically use a contact fuze for detonation upon impact, or some milliseconds after if a penetration effect is required. Alternatives include a fuze with an altimeter to cause an air burst at the desired altitude, and a proximity fuze to cause an air burst at a specific distance from the ground or other target.

• Illustration — An F-111 dropping Mark 82 bombs with ballute-type retardation systems (Mk82AIR / BSU49B) • Illustration — Mk. 82 bomb with a Snake Eye tail retarding device – this photograph shows an unfuzed, museum display Mk 82 with its usual combat paint scheme. For display purposes, the optional high-drag Snake Eye tailfin set used for low-altitude release is shown. The retarded bomb uses a mechanical method of creating increased aerodynamic drag, such as a parachute, ballute, or drag-inducing petals. These deploy after the ordnance is released, slowing its fall and abbreviating its forward trajectory, giving the aircraft time to get clear of the blast zone when bombing from low altitudes or with nuclear ordnance. However, these bombs are less accurate than conventional free-fall bombs. Generally the high-drag tail replaces the low-drag so that the same bomb can be configured for either mode of attack during weapons preparation. High-drag bombs can also be dropped in low-drag mode if the pilot selects this option in the aircraft's weapon system, and will function exactly like a low-drag weapon.