1942 experiments The first ten missions of the
Eighth Air Force from England in August 1942 were shallow penetrations of France strongly supported by
Royal Air Force Spitfire fighter escorts.
B-17 Flying Fortresses flew in six-plane squadrons with between squadrons, to avoid mid-air collisions between the inexperienced crews. Although unable to support each other, the six-plane squadrons had the virtues of simplicity and ease of control. The bombers within a squadron were stacked at three altitudes with approximately between the highest and lowest, and except for the lead pair, were not in mutually supporting elements. As missions grew larger in size, deeper in penetration, and faced increasingly effective defenders, the AAF recognized that more compact formations were needed and returned to the three-aircraft vee formation that had been standard before the war. Squadrons consisted of three such vees, all flying at the same altitude, with two such squadrons in a group formation, the second higher, trailing, and staggered to the right. The entire formation was high, deep, and nearly across. It proved cumbersome to maneuver, as did a 36-plane alternative, and left many bomber gunners with restricted fields of fire. The original two heavy bomb groups of the Eighth Air Force transferred to North Africa and were replaced in October and November by four new groups of B-17s (the
306th,
91st,
303rd, and 305th groups), and two of
B-24 Liberators (
44th and
93rd BGs), each of which experimented with its own formations. Their early missions included numerous mechanical turnbacks ("aborts") which hampered development of effective schemes. Between November 1942 and the end of the war various configurations of the combat box were adopted to meet changing conditions, particularly changed German tactics that stressed head-on attacks against the weak forward firepower of the bombers. 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. This aided gunners on the higher aircraft in seeing lower aircraft without being blinded by glare. In the front elevation the formation resembled a set of stairs, but in profile and plan resembled a spear point. Unlike earlier group formations in which the lead bomber had flown in the lowest position, it now was placed in the center of the formation vertically. The 305th successfully tested the formation on a December 6, 1942, mission to
Lille, and it was immediately adopted by the other three B-17 groups. In 1943, the use of
assembly ships, modified older bombers with unique paint schemes, to organize combat boxes was devised. These planes continued to be used throughout the war, even with the invention of other technological advances.
Wing boxes Although the combat box was initially designed around a
group of airplanes, it was expanded to include a formation of three groups flying together as a "combat
wing", all of which were based on the same triangular design of a leading bomber (or grouping of bombers) in the center, and two bombers (or groupings) immediately behind in a vee shape, with one at an altitude above and one below the center in close proximity for mutual defense. 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. This resulted in the rear formations lagging behind which impacted both defensive tactics and bombing performance. The wing box, a 54-plane formation (basically three 18-plane boxes stacked in a similar fashion to the group box), evolved from a need to provide defensive fire against head-on attacks. The formations were stacked so that while squadrons were stacked away from the sun on missions, groups were stacked in the opposite direction, making for a more compact wing box. Because the Eighth AF had only four B-17 units until May 1943, composite groups were formed by combining squadrons from different groups, or a fourth group was added to the wing box to form a diamond-shaped box. The latter was flown in a trailing position behind the wing and proved susceptible to Luftwaffe tactics of attacking the extremities of formations. The wing box was often spread vertically, deep, and across and was difficult to maintain.) in the path of our falling bombs was a B-17 out of position. Later pictures show a B-17 having his left stablizer shorn off by a five hundred-pound bomb dropped from above. That plane went into a steep dive, out of control, and was lost. As mentioned before, the bombs had to fall about five hundred feet or more before the protective vane spun off to leave the bomb armed." —303rd BG pilot Richard Riley Johnson In the summer of 1943 the Eighth expanded in size to 16 groups of B-17s and 4 of B-24s, and by the following June would grow to 39 groups. The
table of organization and equipment for heavy bombardment groups was increased from 35 to 62 planes with a huge influx of new bombers beginning in the autumn of 1943, and the use of composite groups was discontinued as many groups flew two group boxes on a single mission. The 54-plane wing combat box used by the Eighth's B-17s required both practice and discipline to maintain formation.
Turbulence from leading bombers added to the difficulty of maintaining formation. The 54-plane box is capable of fielding upwards of 700 heavy calibre defensive machine guns in total to serve as a formidable defense against fighters, however. 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.
Group combat box revisions In October 1943 the first
radar-guided
Pathfinder group began operations, bringing about a need for a compact 36-plane group formation to optimize bombing performance in adverse weather conditions. This was done initially by doubling the number of three-plane elements in a squadron formation from two to four, and placing all three planes within an element at the same altitude to avoid collisions. A variation of the formation using four 9-plane squadrons in a diamond formation was developed to compress the bombing pattern further. During the winter of 1944–45, minimizing losses to flak became a priority. 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. At the same time wingmen flew more forward on element leaders, creating a box that was stacked vertically, from front to back, and laterally. This final variation presented flak gunners with a small target, produced excellent bomb patterns, and was both easy to fly and control.
B-24 combat boxes 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. One element of each squadron (normally the uppermost in the middle/lead and high/right squadrons, and lowermost in the low/left squadron) was moved to the outside of the formation so that it was abreast of the trailing element. This produced a line formation that was wide and vertically, but only deep, reducing the time over target significantly. The 96th Combat Bomb Wing further refined the formation during its bomb runs by shifting the lead squadron into the highest position, the second squadron overlapping it in trail and lower, and the third squadron in file behind the second and another 150 feet lower. This produced devastatingly accurate bombing results in the last months of the war. == Fifteenth Air Force formations ==