Combat box

The combat box was a tactical formation used by heavy (strategic) bombers of the U.S. Army Air Forces during World War II.

[1] Initially formations were created in keeping with the pre-war Air Corps doctrine that massed bombers could attack and destroy targets in daylight without fighter escort, relying on interlocking fire from their defensive machine guns, almost exclusively the "light barrel" Browning AN/M2 .50 calibre (12.7 mm) gun.

The bombers within a squadron were stacked at three altitudes with approximately 150 ft (46 m) between the highest and lowest, and except for the lead pair, were not in mutually supporting elements.

The 305th BG innovated the 18-aircraft "javelin down" formation, which stacked planes within an element and squadrons within a group downwards in the direction of the sun.

[8] In 1943, the use of assembly ships, modified older bombers with unique paint schemes, to organize combat boxes was devised.

The new combat boxes continued to be used, but groups were placed in a horizontal column and stacked at increasing altitude to decrease their vulnerability to attack.

[5] The most serious disadvantage of the wing box was that the lowermost and uppermost elements, trailing at the end of the formation, had the least mutual protection.

As flak became the greater threat in May 1944, the 36-plane box was resurrected in a much looser formation and became the standard through the remainder of the war except on days when significant fighter opposition was anticipated.

However, the close stagger of the four-squadron 36-plane was difficult to maintain, and increased the likelihood of a bomber flying at the bottom of the box being struck by bombs dropped from a higher plane.

[14] Although the 36- and 27-bomber group combat box became standard for most of 1944, a diamond-shaped formation of four 10-plane squadrons was developed for B-24s of both the Eighth and Fifteenth Air Force.

The 27-plane box became standard for B-17s for all of 1945, spread more laterally to avoid catastrophic damage to the formation from a single shell burst.

This final variation presented flak gunners with a small target, produced excellent bomb patterns, and was both easy to fly and control.

[14] B-24s of the 2nd Air Division, more difficult than B-17s to fly in formation at high altitudes and with more restricted cockpit visibility, used a variation of the 27-plane group box.

The other four aircraft of Able Box were from the two squadrons assigned to the unit for that mission, with the six bombers formed in two vee formations in trail and stepped lower in altitude.

[21] As with the six-box formation, the trailing elements were stacked downward from the high leader, and the Tail-end Charlie of the fourth box (Dog Ten) was still often referred to as "the Purple Heart position".

[20] The four-box formation proved easier to assemble and organize, provided a tight bomb pattern, and concentrated defensive firepower against fighter attacks.