Boeing B-17 Flying Fortress Overview

In service from beginning to end of the U.S. participation in World War Two, the Boeing B-17 Flying Fortress was evolved in 1934 for a USAAC design competition for an offshore anti-shipping bomber. In 1935 the prototype was completed, as the Boeing 299, and flew for the first time on 28 July 1935, powered by four 750 hp Pratt & Whitney Hornet engines. A change of powerplant to 1,000 hp Wright Cyclones was specified for the thirteen Y1B-17s and one Y1B-17A that were then ordered for evaluation; after trials, these were placed in service as the B-17 and B-17A, respectively.

Boeing B-17 Flying Fortress
Boeing B-17 Flying Fortress
Boeing B-17 Flying Fortress Technical Drawings & Scale Model Plans
Boeing B-17 Flying-Fortress Cutaway
Boeing B-17 Flying Fortress Scale Model Plans
Boeing B-17B/C/D Flying Fortress Scale Model Plans

The initial Boeing B-17 Flying Fortress production batch comprised thirty-nine B-17Bs with modified noses, larger rudders, and internal improvements. They were followed by thirty-eight B-17Cs (higher-powered Cyclones and revised armament), twenty of which were supplied to the Royal Air Force (RAF) in 1941 as the Fortress Mk I. The B-17D, forty-two of which were ordered for the USAAF, was generally similar, and most American B-17Cs were later converted to D standard. It was the B-17E that first introduced the huge, sail-like fin and rudder that characterized all subsequent Fortresses, and the much-improved defensive armament on this model included, for the first time, a tail gun turret to cover the blind spot to the rear of the bomber. Five hundred and twelve B-17Es were built by Boeing, including forty-five which became the Fortress IIA of the RAF.

American B-17Es, serving in the United Kingdom, made the first raids on European targets by the U.S. Eighth Air Force in August 1942, and this Boeing B-17 Flying Fortress version also served extensively in the Pacific theatre. The next model, the B-17F, was subcontracted to Douglas and Lockheed-Vega factories, which, with Boeing, built three thousand four hundred and five. Nineteen of these were converted to F-9 series photographic reconnaissance aircraft.

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The same three companies combined to build eight thousand six hundred and eighty examples of the last production model, the B-17G; eighty-five of these became Fortress IIIs with RAF Coastal Command, and ten others were converted to F-9Cs. The B-17G was characterized chiefly by its β€˜chin’ turret with two additional 0.50 in machine guns, a feature later added to many B-17s in service.

The Fortress’s principal sphere of activity during World War Two was in Europe, where the E, F, and G B-17 models were the mainstay of the U.S. heavy day bomber attacks on enemy targets.

After the war came other photo, training, drone-director, search/rescue and research Boeing B-17 Flying Fortress versions, including many used as engine and equipment testbeds. In 1970, 25 years after first flight, one of many civil Forts used for agricultural or forest-fire protection was re-engined with Dart turboprops!

Boeing B-17 Flying Fortress Specifications
Aircraft Type:
bomber airplane
Dimensions:
wingspan: 103 ft, 9 in
length: 74 ft, 4 in
height: 19 ft, 1 in
Weights:
empty: 36,135 lb
gross: 65,500 lb
Power plant:
4 Γ— 1,200 hp Wright Cyclone R-1820 supercharged radial engines
Performance:
maximum speed: 287 mph
ceiling: 35,600 ft
maximum range: 3,400 mi
Armament:
13 Γ— 0.50 in calibre machine guns
4,000 lb of bombs
Service dates:
1937–1945

B-17 Flying Fortress and the Pacific Campaign

The coming of war to the USA in December 1941 found the USAAF in the Pacific in no position to counter the well-planned Japanese attack throughout Southeast Asia. Given the weakness of the US Asiatic Fleet (a paper or prestige force rather than a properly balanced fighting force) and the inferiority of the US Pacific Fleet to the Combined Fleet of the Imperial Japanese Navy, the Americans, in the absence of large ground forces, had to rely on air power as their only means of countering Japanese movements once the policy of deterrence had failed to prevent the Japanese from going to war. The problem for the Americans, however, was that even in the air, their forces were totally inadequate to meet the Japanese challenge. In December 1941, the USAAF had only 150 B-17s, of which only fifty were the combat-worthy B-17Es. Only one-third of all the Fortresses were in the vast expanses of the Pacific. The USAAF had but a motley collection of 131 aircraft on Hawaii. Of this total there were only twelve B-17Cs and Ds, part of the 5th BG. In the Philippines, the Army deployed 176 aircraft and two Bombardment Groups, the 7th and the 19th. But the 7th was effectively in cadre form, awaiting reinforcement from the USA, while the 19th was drastically understrength. Between them, the two groups mustered just 35 Flying Fortresses, none of them B-17Es.

The opening of the war immediately reduced the already low strength of the Fortresses. Five were lost during the opening attack on Pearl Harbor, and fourteen were destroyed on the ground when the Japanese launched their first strikes on the Philippines. The brunt of the effort to hold the Japanese fell on the depleted forces in the Philippines because the aircraft on Hawaii were too far away either to be of assistance or to carry the fight to the Japanese elsewhere. Though on 10 December 1941, the B-17s in the Philippines carried out the first American bombing raid of the war – an unsuccessful series of attacks on the Japanese invasion fleet bound for Luzon – a steady attrition forced the Americans to pull all their surviving aircraft out from the Philippines by the end of the month.

The surviving B-17s were withdrawn to Australia, where only ten were found fit to resume combat duties. These were rapidly redeployed to Java since they were the only Allied aircraft capable of offering serious resistance to the Japanese invasion of the Netherlands East Indies. Until the capitulation of the Indies in March 1942, these aircraft, plus reinforcements rapidly sent out from the USA, tried in vain to stem the Japanese advance. By the end of the campaign, some eighty B-17s had been concentrated and fought in the theater, 49 in Java itself. The results achieved by these aircraft were singularly unimpressive. Of the 49 on Java, thirty were lost. Nineteen had been destroyed on the ground, but only six had been lost in combat with Japanese aircraft. Of the eighty in the theater, 52 were lost, and a further six had to be written off as a result of accidents in Australia. Postwar analysis was to show that in the 350 missions flown by the B-17s in the opening phase of the war, only two Japanese ships were sunk, a meager return for much bravery. Not unnaturally, the paucity of success was not appreciated at the time, reports of successes being greatly exaggerated and far in excess of actual achievements.

In large part, the poor showing of the B-17 in this phase of the war stemmed from factors beyond its control. The Flying Fortress was really in an impossible situation. It was an offensive, strategic weapon, but in 1942 it had to try to be a defensive, tactical weapon. Understrength at the start of the war and suffering unacceptably high losses in the opening phase of hostilities, the reinforcements sent out from the USA – in the form of the 43rd BG – could be used only to bolster the depleted 7th and 19th. Reinforcements were too few in number and too widely spread in area and time to permit their being in a position to exercise some direct influence in the battle area. Some 53 aircraft were dispatched from the eastern seaboard of the USA, where the 43rd was based. These aircraft were forced to fly via the Caribbean, Africa, and India to reach their operational areas, and perhaps it is remarkable that of the total, only nine never made it. Many of the aircraft sent had come directly from the factories and desperately needed servicing and maintenance, which were not available when they arrived in Java and Australia. The crews, too, were raw, and it was many months after its arrival in the theater that it can be said that the 43rd was properly constituted. By that time, however, the 7th had been redeployed to India in an effort to try to hold the Japanese advance in Burma while the 19th, taking crews and aircraft from the 7th, reconcentrated in Australia. By the time the rearrangement of the B-17s had been completed, however, the flood tide of Japanese conquest had been largely brought to a halt, though it continued to edge its way forward in certain areas for some time afterward. In May 1942, at Coral Sea, American carrier forces had checked the Japanese advance in the Southwest Pacific, forcing the enemy to recast plans for the reduction of Port Moresby and eastern New Guinea. In June, the cream of Japanese naval aviation, the carrier forces, was annihilated at the Battle of Midway. Only in the latter battle did B-17s participate, but their intervention was negligible. In both battles it was American carrier-based aircraft, particularly the dive bombers, that five aircraft was normal; for a group to attack with anything wreaked havoc, not the land-based aircraft.

After the Coral Sea and Midway, the Japanese attempted to consolidate their initial gains by a series of movements through the Bismarck Archipelago into the Solomons, their aim being to outflank Australia and to achieve its isolation from supplies and reinforcements drawn from the USA. After these two successes, however, the Americans were in a position to counter such moves with their sea and land forces, landing in August 1942 on the Japanese-held island of Guadalcanal. In this effort, the B-17s played a significant role, because by Septem- ber the USAAF deployed four Groups in the area. To shore up the defenses there the 5th and 11th Groups from Hawaii were deployed to the New Hebrides, the 35-strong 11th arriving in New Caledonia in July. These forces formed part of the hastily-constituted 13th Air Force. Those forces in Australia were part of the 5th Air Force. Between them, the four groups in September 1942 reached their peak strength of about 155 aircraft. The process of reinforcement had indeed been massive, far higher than these simple figures would suggest. Losses, from all causes, had to be covered, and such was the strain on shipping resources at this critical juncture of the war, and such was the crucial importance of time that many B-17s had to be employed as load-carriers in order to keep their sisters in service. It was paradoxical that the reinforcement of the theater with B-17s came at a time when it had already been decided to phase out the aircraft from the Pacific theater. In the vast area of the Pacific, the Liberator, with its slightly longer range, was preferred to the Fortress, and after October 1942, the process of breaking up units and the re-equipment of new and existing formations with the B-24 began. By the beginning of 1943, the Fortresses no longer carried the weight of the American counteroffensive in the air, but it was not until September 1943 that the 5th and 11th Groups flew their last Fortress mission. Even in the Aleutians the limited numbers of Fortresses were gradually reduced to nothing. By November 1943, apart from command transports, only one B-17 remained in service in the whole of the Pacific area. Nevertheless, for all the time the B-17s were on station, they carried the fight to the Japanese, mainly in the form of attacks on harbors and shipping. Success, as we have seen, was scant, though the 43rd was heavily involved in the devastatingly successful Battle of the Bismarck Sea (March 1943), which resulted in the annihilation of a Japanese military convoy bound for the upper Solomons. This battle, in effect, doomed Japanese efforts to hold the area.

For the most part, however, the record of the B-17 was not convincing, though it must be stated that after the introduction of the B-17E, complete with tail gunners, Japanese aircraft showed a healthy respect for the aircraft. In fact, the new generation B-17s showed that the new Flying Fortresses could look after themselves in fights with Japanese interceptors. The small-caliber guns used by Japanese fighters made it very difficult for them to shoot down the heavy bomber, while their own lack of armor and self-sealing fuel tanks made them very vulnerable to 0.5in gunfire. Had the B-17s remained in the Pacific then, their success may well have been as great as that of those aircraft that replaced them. But the sad fact of the matter for the B-17 was that throughout its period of service in the Pacific it labored under far too many handicaps to be really effective. Probably the most critical weakness lay in the fact that, on all too many occasions, the B-17s were forced to go into action in very small numbers. For most of this period of the Pacific War, for a squadron to be at fifty percent strength in effect, five or more aircraft – was little short of miraculous. For a whole group to attack with more than that number really was an exceptional feat. Against land targets, such numbers were totally inadequate, while to attack shipping in such strength was almost derisory. Even when attacking in formation – an inverted Vee in order to pattern the bombs in a straddle, the chances of hitting a ship were very small. On far too many occasions the B-17s were called upon to commit themselves to actions at the extreme edge of their endurance, thus lessening the amount of bombs that could be carried and, as a result, lessening the chances of a successful operation. Indeed, in many such attacks, it can be quite reasonably argued that had the Japanese been better equipped, particularly with early-warning radar, far heavier losses would have been inflicted on the attacking B-17s than, in fact, were the case. Even allowing for the defensive firepower of the Fortress and the vulnerability and poor performance of the Zero-sen at high altitudes, the smallness of American attacks always ran the risk of defeat in detail, and perhaps the Americans were fortunate to escape without heavier losses.

Allowance has to be made for other factors when assessing the performance of the B-17 in the Pacific. It was the aircraft’s misfortune to be involved in a catastrophic defeat. The B-17 was the major weapon in the aerial armory at a time of chaos and disorganization. It lived a hand-to-mouth existence on rough-hewn jungle strips without proper maintenance, often having to stage through equally or even more primitive airstrips in order to reach objectives. It had to contend with appalling climatic conditions. The alternating heat and rain, bringing dust and mud in turn, made servicing a nightmare. In the air, the bombers could encounter clouds and storms of ferocious violence that stretched the width of the horizon and over which they could not climb. It is not without significance that in seven months of operations, the 11th BG lost six Fortresses to enemy action and twelve to the weather. One raid by three B-17s actually resulted in 100 percent losses when the aircraft could not find their way through a weather front and had to ditch in the sea as the fuel tanks spluttered dry. Overall the Pacific experience was an unfortunate one for the B-17, though the odds were heavily stacked against it from the start. As a result, it left the area not properly or fairly tested because at no time in its operations had it been able to act en masse strategically. That test for the B-17 was to be in Europe.

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