The Boeing B-17 Flying Fortress was a four-engine heavy bomber aircraft developed in the 1930s for the United States Army Air Corps (USAAC). The B-17 was primarily employed by the United States Army Air Forces (USAAF) Eighth Air Force, and the Fifteenthth Air Force, in the daylight precision strategic bombing campaign of World War II against German industrial and military targets. The United States Eighth Air Force, based at many airfields in southern England, and the Fifteenth Air Force, which was based in Sicily then Italy.

Development

On August 8th, 1934, the US Army Air Corps put out a tender called Proposal 32-26 for a 250 mph bomber with a range of 2000 miles and an operating ceiling of 10,000 feet. An ailing Boeing Company, headed by Edward C Wells, took up the challenge. Wells used near enough all the spare capital Boeing had - and the manpower - to complete the task. The name of the project was Model 2-99. In response for the Army's request, the B-17 (Model 299) prototype, financed entirely by Boeing, went from design board to flight test in less than 12 months. It was designed was of a low-wing monoplane that combined aerodynamic features of the XB-15 giant bomber, still in the design stage, and the Model 247 transport. In July 1935, Boeing Model 2-99 was rolled out. It was an all-metal four-engine bomber, weighing in at 15 tons. Its specifications were well above those laid down by the US Army Air Corps. The B-17 was the first Boeing military aircraft with a flight deck instead of an open cockpit and was armed with bombs and five .30-caliber machine guns mounted in clear 'blisters'. The plane first flew in Seattle and one watching journalist is said to have commented that the plane, when in the air, was a 'flying fortress' due to the number of machine guns it carried and the nickname stuck. As war approached in Europe, the United States Army Air Corps only had 30 B-17's.

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Into Service

The first B-17s saw combat in 1941, when the British Royal Air Force took delivery of several B-17s for high-altitude missions. The first full B-17 mission against Germany took place in August 1942. The B17's flew in a wedge formation that should have given them massive fire power against any attackers. However, German fighter pilots quickly learned that a frontal attack effectively neutralised the huge armaments of the B17's that were primarily carried on the sides of the bombers. As World War II intensified, the bombers needed additional armament and armor. The B-17E, the first mass-produced model Flying Fortress, carried nine machine guns and a 4,000-pound bomb load. It was several tons heavier than the prototypes and bristled with armament. It was the first Boeing airplane with the distinctively enormous tail for improved control and stability during high-altitude bombing.

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Fighting the Luftwaffe

On August 17th 1943, B-17's attacked the ball-bearing factory at Schweinfurt. This was a very important target as 52% of all of Germany's ball-bearings were produced there. It was also a massively defended factory. 211 B-17's took part in the raid, some 60 planes were lost, a loss rate of just under 30%. In 1943, it was estimated that 1/3rd of all B17 crews would not survive the war and the huge losses sustained in daylight raids nearly caused an end to such raids. However, a study done by the 8th Air Force in 1943, also showed that over 50% of plane losses were as a result of B-17's leaving the protection of their formation. In 1944, a revised pattern of flying was introduced. B-17's had traditionally flown in wedges of 18. Now they were to fly in a pack of 36. There would be three flights of 12 B-17's tightly packed together, one on top of the other. This gave the flight of 36 huge firepower especially as the new Model G had been given more fire power including more machine guns at the front of the plane to fight off frontal assaults. The Model G now carried thirteen .50 calibre machine guns giving each plane a massively increased firing capacity. However, flying so tightly also led to collisions.
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By 1944, the B17's also had fighter protection in the shape of the P-51 'Mustang' long range fighter that could accompany the B-17's deep into Germany. With their increased fire power and their new bodyguards, the B-17 could now concentrate on two primary targets which was left of the Luftwaffe's factories and Berlin itself. In February 1944, Operation Big Week took place and the B-17's went all out to destroy the factories that kept the Luftwaffe flying. In all, 3,500 B17s were involved in bombing raids on factories in Germany. 244 planes were lost (about 7% of the planes taking part) in just a week but the back of the factories producing for the Luftwaffe had been fatally broken. While the Lutwaffe had planes, many were forced to stay on the ground as they had limited supplies to keep them airborne. Berlin was the next target. This was probably the most defended city in the world at this time. The Luftwaffe had kept what reserves it had for planes to defend the city. On March 6th, 1944, in a massive raid on Berlin, 69 B17's were lost, but the Luftwaffe lost 160 planes. Whereas the 8th Air Force could recover from these losses, the Luftwaffe could not. By the end of the war, The 8th Air Force and the RAF had destroyed 70% of Berlin. After Berlin, the 8th Air Force turned its attention to Germany's synthetic oil factories. Attacks on these factories started on May 12th. In just one month, the USAAF dropped 5000 tons of bombs on these factories. In August 1944, 26,000 tons were dropped and in November 1944, the attacks peaked at 35,000 tons. However, the raids on the oil factories took their toll and 922 B17's were lost in total with the loss of nearly 10,000 men killed, wounded or captured.

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In the Pacific

The B-17 was to achieve its first taste of combat in American hands at Pearl Harbor. On December 7, The 38th Reconnaissance Squadron with four B-17Cs and two new B-17Es was inbound from Hamilton Field, California to Pearl Harbor on their way to the Philippines to reinforce the American force there. None were armed. They arrived at Pearl Harbor at the height of the attack (radar operators mistakenly thought that the Japanese attack force was this flight arriving from California). Some of the planes managed to land at a short fighter strip at Haleiwa, one set down on a golf course, and the remainder landed at Hickam under the strafing of Japanese planes. Twelve B-17Ds of the 5th Bombardment Group were parked on the ground at Hickam Field during the attack. Five of these B-17s were destroyed, and eight were damaged. News of the Pearl Harbor attack was received at about 3 AM on Dec 8 in the Philippines. According to the previously-agreed upon plan, if hostilities were to break out, an attack on Japanese bases in Formosa was to be immediately carried out by the 19th Bombardment Group's Fortresses. On Dec 8, there were 35 USAAC B-17s in the Philippines, with two squadrons at Clark Field on Luzon with a total of 19 planes, and two squadrons at Del Monte on Mindanao 500 miles to the south with the other 16 B-17s. A planned raid on Formosa was delayed and in order to prevent them from being destroyed on the ground by a Japanese air attack, all flyable B-17s based at Clark Field had been ordered into the air and to patrol the waters around Luzon. In the meantime, General Lewis H. Brereton, General MacArthur's air commander, finally got approval to carry out the strike against Japanese bases on Formosa, and the B-17s were recalled to Clark. When the Fortresses returned to Clark, three of them were equipped with cameras for reconnaissance and the remainder were loaded up with 100-lb and 300-lb bombs in preparation for the planned mission to Formosa. The three reconnaissance B-17s were taxiing out for the initial photographic mission to Formosa when about 200 Japanese aircraft struck. Unfortunately, all the P-40 fighters had been recalled for refuelling and were on the ground. The attack was devastating. All except one of the B-17s were destroyed or damaged on the ground. The sole survivor had not taken off on the morning alert, and had been taken up in the air while the rest were being prepared for the Formosa raid.
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The Fortresses at Del Monte 500 miles to the south were out of range of the Zeros from Formosa and were left untouched. At Clark Field, three or four of the damaged B-17s were put back into service. They were joined by the B-17s from Del Monte. By December 9, reconnaissance missions were being undertaken by the 19th Bombardment Group in search of the Japanese fleet. On December 10, a Japanese convoy was spotted, and five B-17s were dispatched. This was the first American bombardment mission of World War II. No fighter opposition was encountered, and some hits were recorded on the transports. By December 14, out of the original 35 B-17s in the Philippines, only 14 remained. They were all stationed at Del Monte, hopefully out of range of Japanese aircraft. Beginning on December 17, the surviving B-17s based there began to be evacuated to Batchelor Field near Darwin, Australia. The first mission out of Australia took place on December 22, with 9 B-17s taking part. It was an attack on Japanese shipping at Davao. They landed at Del Monte on Mindanao, which was still in American hands. On that same day, Japanese forces landed on Luzon, and quickly advanced on Manila, driving MacArthur's forces onto Bataan and then to Corregidor. In March of 1942, A B-17E flew General MacArthur out of Del Monte airfield in the Philippines and evacuated him to Australia. The Philippines fell to the Japanese shortly thereafter.
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In Hawaii, the B-17E-equipped 5th and 11th Bombardment Groups were used in the Battle of Midway to attack Japanese surface fleets. High-altitude bombing attacks against moving ships capable of evasive action proved to be completely unsuccessful at Midway. Although several attacks were made by the B-17s, none of their bombs actually hit a single Japanese ship. An attack against naval vessels at sea was found to be a job best done by low-altitude medium bombers or by dive bombers. By August of 1942, the 43rd Bombardment Group in Australia had become the fifth B-17E group to be deployed against Japan. The 5th Bombardment Group carried out air search duties from bases in Hawaii, and was transferred to the South West Pacific in time to participate in the drive from the Solomons back to the Philippines. By mid-1943, most Fortresses had been withdrawn from the Pacific in favor of the longer-ranged B-24 'Liberator'. The B-24 was better suited for operations in the Pacific, having a higher speed and a larger bombload at medium altitudes. In addition, the losses in Europe were reaching such magnitudes that the entire B-17 production was urgently needed for replacements and training in that theatre. Shortly after the Battle of the Bismarck Sea, it was decided that no more B-17s would be sent to the Pacific.

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Production and Aftermath

Boeing plants built a total of 6,981 B-17s in various models, and another 5,745 were built under a nationwide collaborative effort by Douglas and Lockheed (Vega). Only a few B-17s survive today; most were scrapped at the end of the war. Some of the last Flying Fortresses met their end as target drones in the 1960s.

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Specifications(B-17G):
Country of Origin: USA
Crew: 10
Length: 74 ft 4 in (22.66 m)
Wingspan: 103 ft 9 in (31.62 m)
Height: 19 ft 1 in (5.82 m)
Empty weight: 36,135 lb (16,391 kg) Loaded weight: 54,000 lb (24,500 kg)
Max. takeoff weight: 65,500 lb (29,700 kg)
Powerplant: 4 × Wright R-1820-97 radial engines, 1,200 hp (895 kW) each
Performance
Maximum speed: 287 mph (249 kn, 462 km/h)
Cruise speed: 182 mph (158 kn, 293 km/h)
Range: 2,000 mi (1,738 nmi, 3,219 km)with 2,700 kg (6,000 lb) bombload
Service ceiling: 35,600 ft (10,850 m)
Rate of climb: 900 ft/min (4.6 m/s)
Armament
Guns: 13 × .50 in (12.7 mm) M2 Browning machine guns in 8 positions
Bombs:
Short range missions (<400 mi): 8,000 lb (3,600 kg)
Long range missions (800 mi): 4,500 lb (2,000 kg)
Overload: 17,600 lb (7,800 kg)
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