US Bomb, 250 lb Target Identification, M89, M90, M91, M98, M100

 

1410-f191

Description

The body ls a modified 250 pound GP Bomb AN-M57 body with a metal closing cup riveted to the base. An integral booster of four ounces of black powder is placed immediately behind the fuze seat liner and serves as an expelling charge. A wooden nose piece fits around this booster. and a steel piston, in turn, is seated in the base of the nose piece. A steel tube or piston stem is welded through a hole in the piston and extends from the black powder booster to the plywood ignition disc in the center of the bomb. Six wooden thrust members reach from the piston plate to the tail closing cup and serve to transmit stress to this cup without imposing any of the force on the candles. Felt 1/2 inch in thickness lines the entire interior cylindrical surface of the bomb. The 61 candles are in two banks of 30 and 31, and have their ignition ends facing toward the quick match strands stapled on the ignition disc which separates the two banks.

The tail, in appearance, is a standard box-type tail. It is attached to the bomb by means of four spring latches fitting into cut-outs in the tail closing cup .and can be locked in place by stamped steel strips pivoting over the ends of the springs.

Horizontal suspension is provided by standard lugs, 14 inches apart.

The bombs are used to form a pattern of red. green, or yellow colored light approximately 100 yards in diameter around or on a target; the light should be visible from altitudes of 25,000 to 35,000 feet day or night. They are used to spot individual targets, once the general target area has been marked by flares dropped by pathfinder planes. The explosive charge in the Candles M105 is ignited by the flare composition at the end of burning. These charges serve to prevent any removal of the candles by the enemy, once the candles are on the ground.

The M89 contains 61 Non-Delay Candles M103.

The M90 contains 57 Non-Delay Candles M103 also; two Exploding Candles M105, burning for one minute, and two exploding candles burning for two minutes.

The M91 has 16 Non-Delay Candles M103, 15 red 2 3/4-minute Delay Candles M104, 15 4-minute Delay Candles M104, and 15 5 1/4-minute Delay Candles M104.

The M98 contains 31 Non-Delay Candles M103, 10 Exploding Candles M105, burning for one minute, 10 Exploding Candles M105, burning for 1.5 minutes, and 10 Exploding Candles M105, burning for two minutes.

The M100 contains Two-Color Combination Candles M104.

See Also

Nothing else to see.

Source(s)

Collaborative Ordnance Data Repository

OP 1664, Volume 1 - US Explosive Ordnance (1947)

USNBD - Bombs and Fuzes, Pyrotechnics (1945)