Bomber Battle: B-17 Flying Fortress vs. B-24 Liberator (Who Wins?)

An air-to-air left front view of a B-24 Liberator
June 26, 2020 Topic: History Blog Brand: The Reboot Tags: World War IIB-17B-24BomberEuropean Theater

Bomber Battle: B-17 Flying Fortress vs. B-24 Liberator (Who Wins?)

The argument began in bars and service clubs, where crew members from the two types met while off duty during the war, and has continued ever since.

In January 1945, Eighth Air Force Commander Lt. Gen. James H. Doolittle wrote a letter to Army Air Forces chief of procurement General Barney Giles in which he expressed his preferences for the B-17 over the B-24 for his command. However, the circumstances of Doolittle’s letter are somewhat suspect. He wrote it at a time when the War Department was in the process of cutting back on aircraft production and was making the decision as to which types to continue in production. As the only combat commander at the numbered air-force level who favored B-17s, Doolittle may very well have been concerned about replacements. Within four months after the letter was sent to Washington, the last B-17 to be built by Boeing rolled off the assembly line. Liberator production continued for several weeks after B-17 production ceased, and was only suspended when it became apparent that the war would soon be over.

Doolittle’s letter is interesting because he wrote it at a time when losses in his command had been declining for some time while his sister unit in the U.S. Strategic Air Forces in Europe, the Fifteenth Air Force, was continuing to sustain fairly heavy losses among its force of B-17s and B-24s. Yet no preference was shown for B-17s in the Fifteenth Air Force, where the proportion of Liberators to Forts was reversed from that of the Eighth in England. The heavier losses among Fifteenth Air Force groups were due in part to the longer missions over enemy territory, while two of the most heavily defended targets in Europe—the oil fields at Ploesti and aircraft factories at Wiener-Nuestad, Austria—lay within the Fifteenth’s area of responsibility. On an ironic note, losses among Fifteenth Air Force groups increased even while they decreased in the Eighth as Allied ground forces closed in on Germany.

Which was the better airplane? In reality, it is probably accurate to say that for the kind of war fought by the Eighth and Fifteenth Air Forces in Europe, there was really very little difference. Advocates of the superiority of the B-17 are surprised to learn that their per-sortie overall loss rate was nearly half a percent higher among Eighth Air Force groups than that of their peers who flew B-24s. When comparing the number of sorties flown and losses sustained by the two types, the difference is even greater. Groups flying B-17s flew 60.38 percent of sorties flown by the Eighth Air Force and sustained 69.75 percent of the losses, while B-24 groups flew 29.77 percent of the sorties yet sustained only 26.1 percent of the heavy bombers lost. Groups that operated both types flew 9.85 percent of the sorties and took 4.14 percent of the losses.

Most who look at these statistics quickly jump to the conclusion that the B-17 losses were heavier because of the period in 1943 when they were going it alone on deep-penetration missions over Germany. This theory is contradicted by the fact that Eighth Air Force B-24 groups suffered losses that were even higher on a per-group basis than those of most B-17 groups during the same time frame. Furthermore, the overall losses were lower for the three B-24 groups that were in combat in the summer of 1943 than those for most B-17 groups.

Was the B-17 Safer?

Even more astounding, the last seven Eighth Air Force B-17 groups to enter combat, all of which began their missions during a time when more and more B-24 groups were entering combat, flew 16.93 percent of all sorties and took 22.28 percent of the losses. Yet seven B-24 groups that entered combat during the same time frame flew almost the same percentage of sorties—16.85 percent—but sustained only 14.99 percent of the losses, a difference of more than 5 percent. In the Eighth Air Force, 1.43 percent of all heavy-bomber sorties resulted in an aircraft missing in action. In B-17 groups, 1.66 percent of the sorties resulted in a loss, while in B-24 groups the loss rate was 1.26 percent, a difference of 0.4 percent. These figures relegate to myth the belief that the B-17 was the “safer” airplane. It is also worth noting that the Eighth Air Force B-24s were often used on tactical missions at lower altitudes where ground fire was more effective after the invasion, while in the strategic role their formations operated below the B-17s, where the flak was thicker.

In the Pacific Theater, there was no doubt as to which type was “best” because it became an all-B-24 region by the end of 1943. General George Churchill Kenney chose the B-24 as the heavy bomber for his theater because, unlike the daylight-bombing crowd that had gone to Europe, he had no particular preference for the B-17. Since the European Theater of Operations had been given precedence in the conduct of the war, the Eighth Air Force had priority in equipment and was receiving the new B-17 groups that had already been formed before the outbreak of the war. Before he went to Australia to command the Allied air forces in the Southwest Pacific Area of Operations, Kenney was told he would have to function with only the two B-17 groups that were already in the theater, but that he could have one group of B-24s that was then in the training pipeline.

General Kenney began his World War II combat career in the Pacific with two heavy-bomber groups under his command, the 19th and 43rd, both of which were equipped with B-17s and had been in combat since early in the war. The 19th had been in continuous combat since December 8, 1941, and was already worn out. In late 1942, the 90th Bomb Group arrived in Australia with four squadrons of B-24Ds. Shortly after the 90th arrived, Kenney sent the 19th back to the United States. The 90th got off to a shaky start due to cracks in the nose struts of its airplanes, but once its B-24s began combat operations, they quickly proved superior to the B-17 for the kind of war being fought in the Southwest Pacific. Missions were long and required considerable distances over water, conditions for which the Liberator had been created.

The B-24 in the Pacific Theater

Beginning in the spring of 1943, the 43rd Bomb Group replaced its B-17s with B-24s, ending the combat career of the Flying Fortress in the Pacific. Not a single B-17 bomber ever appeared in the skies over Japan while hostilities were under way. Just as the 43rd began converting to the Liberator, the 380th Bomb Group arrived in Australia and began combat operations with B-24s. The 22nd Bomb Group, which had entered combat with B-26s, then was equipped with B-25s, would also convert to the B-24. Operating from Darwin, the men of the 380th utilized the long-range capabilities of their Liberators by flying a mission to attack the oil-refining complex at Balikpapan, Borneo, a flight that kept the crews in the air for as long as 17 hours.

On the Asian mainland, Liberators assigned to the 7th Bomb Group of the Tenth Air Force were flying 14-hour missions from bases in India to attack targets as far away as Bangkok, Thailand. Other long-range missions were being flown by B-24s assigned to the 28th Composite Group in the Alaska Command. By the end of the war, 28th B-24s were flying missions from the Aleutians against targets in the northern home islands of Japan. The extremely long-range missions flown in the Pacific would have been impossible with the shorter legged B-17s.

The B-24 became a key factor in the plans of Generals Douglas MacArthur and Kenney as they sought to push the Japanese farther and farther north away from Australia and back toward Japan. The MacArthur/Kenney strategy was to isolate major Japanese installations with air power, while capturing terrain on which to construct airfields from which to launch B-24s on long-range missions that eventually were reaching all the way to the Philippines.

As the war moved northward, Far East Air Forces Liberators began attacking the Japanese homeland. Kenney and his bomber commanders worked to extend the range of the four-engine bombers until 2,400-mile round-trip missions were being flown routinely by B-24s. In comparison, the average mission flown by B-17s in Europe was less than 1,600 miles.

Missions by B-24 crews in the Pacific were considerably different from those of their peers in Europe. Much of the flying was over water, which reduced the exposure of the bomber crews to flak to a small percentage of mission time in comparison to the constant exposure faced by Eighth Air Force crews prior to the Normandy invasion. Kenney had no point to prove in regard to daylight bombing, and often his crews struck the most heavily defended targets at night, thus further reducing the exposure of the aircraft and crews. Consequently, B-24s in the Pacific flew missions at much lower altitudes than heavy bombers in Europe, and thus achieved much greater accuracy with their bombs. Shortly after General Kenney arrived in Australia, he introduced the concept of low-altitude “skip-bombing” by heavy and medium bombers. Although the skip-bombing role was assumed by the twin-engine A-20 and B-25 gunships that became important weapons in the Southwest Pacific, some B-24s were modified with radar equipment to become “snoopers,” which flew at night on daring low-level attacks against Japanese shipping.