Boeing B-17 Flying Fortress is a four-engine heavy bomber aircraft developed for United States Army Air Corps introduced in 1930s
Although Boeing lost contract because prototype crashed, Air Corps was so impressed with Boeing's design that they ordered 13 B-17s
B-17 was primarily employed by United States Army Air Forces in daylight precision strategic bombing campaign of World War II against Germindustrial, civilian, and military targets
From its pre-war inception, USAAC touted aircraft as a strategic weapon; it was a potent, high-flying, long-ranging bomber capable of unleashing great destruction, able to defend itself, and having ability to return home despite extensive battle damage
aircraft, 640,000 t were dropped from B-17s
Air Corps were looking for a bomber capable of reinforcing air forces in Hawaii, Panama, and Alaska
prototype B-17, designated Model 299, was designed by a team of engineers led by E
B-17 was armed with bombs – up to 4,800 lb , much faster thcompetition
At fly-off, four-engine Boeing design's performance was superior to those of twin-engine DB-1 and Model 146, and then-Major General Frank Maxwell Andrews of GHQ Air Force believed that long-range capabilities of four-engine large aircraft were more efficient thshorter-ranged twin-engined airplanes
His opinions were shared by Air Corps procurement officers, and even before competition was finished they suggested buying 65 B-17s
crew forgot to disengage airplane's "gust lock," a device that held bomber's movable control surfaces in place while plane was parked on ground, and having taken off, aircraft entered a steep climb, stalled, nosed over and crashed, killing Hill and Tower
crashed Model 299 could not finish evaluation, and while Air Corps was still enthusiastic about aircraft's potential, Army officials were daunted by much greater expense per aircraft
"loss was not total, however, since fuselage aft of wing was intact, and Wright Field Armament section was able to use it in subsequent gun mount development work, but Boeing's hopes for a substantial bomber contract were dashed
Boeing Y1B-17 in flight
Regardless, USAAC had been impressed by prototype's performance, and on 17 January 1936 Air Corps ordered, through a legal loophole, 13 YB-17s , term "XB-17" was retroactively applied to airframe and has entered lexicon to describe first Flying Fortress
Between 1 March and 4 August 1937, 12 of 13 Y1B-17s were delivered to 2nd Bombardment Group at Langley Field in Virginia and used for operational development and flight test
One suggestion adopted was use of a checklist to avoid accidents such as Model 299's
In one of their first missions, three B-17s, directed by lead navigator Lieutenant Curtis LeMay, were sent by General Andrews to "intercept" Italioceliner Rex 610 mi off Atlantic coast and take photographs
successful mission was widely publicized
13th Y1B-17 was delivered to Material Division at Wright Field, Ohio, to be used for flight testing
A 14th Y1B-17 , originally constructed for ground testing of airframe's strength, was upgraded and fitted with exhaust-driven turbochargers
Scheduled to fly in 1937, it encountered problems with turbochargers, and its first flight was delayed until 29 April 1938
aircraft was delivered to Army on 31 January 1939 and was redesignated B-17A to signify first operational variant
Improved with larger flaps, rudder and Plexiglas nose, B-17Bs were delivered in five small batches between July 1939 and March 1940
Prior to attack on Pearl Harbor, fewer th200 B-17s were in service with Army, A total of 155 B-17s of all variants had been delivered between 11 January 1937 and 30 November 1941, but production quickly accelerated with B-17 eventually setting record for achieving highest production rate for large aircraft
aircraft went on to serve in every World War II combat zone, and by time production ended in May 1945, 12,731 aircraft had been built by Boeing, Douglas and Vega
B-17 begoperations in World War II with RAF in 1941, USAAF Eighth Air Force and Fifteenth Air Force units in 1942, and was primarily involved in daylight precision strategic bombing campaign against Germindustrial targets
Approximately 4,750, or one third, of B-17s built were lost in combat
Two of three aircraft dispatched attacked target but did not hit their targets and temperatures were so low that machine guns froze up
On 24 July, target was Brest in France, but again they missed completely, damage to one aircraft was so severe that it broke up on landing
remaining aircraft were transferred to different commands for deployment to various duties including coastal defense
experience had showed both RAF and USAAF that B-17C was not ready for combat, and that improved defenses, larger bomb loads and more accurate bombing methods were required, which would be incorporated in later versions
Moreover, even with these improvements, it was USAAF and not RAF that was willing to remain faithful to using B-17 as a "day" bomber
These were later augmented in August 1942 by 19 Fortress Mk II and 45 Fortress Mk IIA
Air Corps , utilizing B-17 and other bombers, bombed from high altitudes using then-secret Norden Bombsight, which was optical electro-mechanical gyro-stabilized analog computer
During daylight bombing missions and sorties, device was able to determine, from variables input by bombardier, point in space at which bomber's ordnance type should be released to hit target
On 17 August 1942, 18 B-17Es of 97th, including Yankee Doodle, flown by Major Paul Tibbets and Brigadier General Ira Eaker, were escorted by RAF Spitfires on first USAAF raid over Europe, against railroad marshalling yards at Rouen-Sotteville in France
operation was a success, with only minor damage to two aircraft
he two different strategies of Americand British Bomber commands were organized at Casablanca Conference in January 1943
Since airfield bombings were not appreciably reducing Germfighter strength, additional B-17 groups were formed
Germans shot down 36 aircraft with loss of 200 men, and coupled with a raid earlier in day against Regensburg, a total of 60 B-17s were lost that day
Of 291 attacking Fortresses, 59 were shot down over Germany, one ditched in English Channel, five crashed in England, and 12 more were scrapped due to battle damage or crash-landings, a total loss of 77 B-17s
122 bombers were damaged to some degree and needed repairs before their next flight
Five were killed and 43 wounded in damaged aircraft that made it home, and 594 were listed as Missing in Action
resulting losses were a result of concentrated attacks by over 300 Germfighters
Eighth Air Force was to suffer similar casualties on 11 January 1944 on missions to Oschersleben, Halberstadt and Brunswick
Most of escorts turned back or missed rendezvous, as a result 60 B-17s were destroyed A third raid on Schweinfurt on 24 February 1944 highlighted what came to be known as "Big Week"
With P-51 Mustang and P-47 Thunderbolt fighters escorting Americheavies all way to and from targets, only 11 of 231 B-17s were lost
Losses to flak continued to take a high toll of heavy bombers through 1944, but by 27 April 1945, rate of aircraft loss was so low that replacement aircraft were no longer arriving and number of bombers per bomb group was reduced
Combined Bomber Offensive was effectively complete
Brereton planned B-17 raids on Japanese air fields in Formosa, in accordance with Rainbow 5 war pldirectives, but this was overruled by General Douglas MacArthur
By time that B-17s and escorting Curtiss P-40 fighters were about to get airborne, they were destroyed by Japanese bombers of 11th Air Fleet
FEAF lost fully half its aircraft during first strike, and was all but destroyed over next few days
Another early World War II Pacific engagement on 10 December 1941 involved Colin Kelly who reportedly crashed his B-17 into Japanese battleship Haruna, which was later acknowledged as a near bomb miss on heavy cruiser Ashigara
Kelly was posthumously awarded Distinguished Service Cross
Noted Japanese ace Saburo Sakai is credited with this kill, and in process, gained respect for ability of Fortress to absorb punishment
B-17s were used in early battles of Pacific with little success, notably Battle of Coral Sea and Battle of Midway
While there, Fifth Air Force B-17s were tasked with disrupting Japanese sea lanes
Air Corps doctrine dictated bombing runs from high altitude, but it was soon discovered that only one percent of their bombs hit targets
However, B-17s were operating at heights too great for most A6M Zero fighters to reach, and B-17's heavy gun armament was easily more tha match for lightly protected Japanese planes
A peak of 168 B-17 bombers were in Pacific theater in September 1942, with all groups converting to other types by mid-1943
As a result, B-17s' loss rate was up to 25% on some early missions resulting in degradation of Luftwaffe as effective interceptor force between February and June 1944, that B-17 became strategically potent
B-17 was noted for its ability to absorb battle damage, still reach its target and bring its crew home safely
airplane was reported as shot down by observers, but it survived and brought its crew home without injury
Stories abound of B-17s returning to base with tails having been destroyed, with only a single engine functioning or even with large portions of wings having been damaged by flak
After examining wrecked B-17s and B-24s, Luftwaffe officers discovered that on average it took around 20 hits with 20 mm MK 108 cannons was made, which could bring a bomber down in just a few hits
During World War II, after crash-landing or being forced down, approximately 40 B-17s were captured and refurbished by Luftwaffe with about a dozen put back into air
Given Germmarkings, captured B-17s were used for clandestine spy and reconnaissance missions by Luftwaffe, most often used by unit known as Kampfgeschwader 200
One of B-17s of KG200, bearing Luftwaffe markings A3+FB, was interned by Spain when it landed at Valencia airport, 27 June 1944, and remained there for rest of war
Some B-17s kept their Allied markings and were used in attempts to infiltrate B-17 formations and report on their position and altitude
practice was initially successful, but Army Air Force combat aircrews quickly developed and established standard procedures to first warn off, and then fire upon any "stranger" trying to join a group's formation
Still other B-17s were used to determine airplane's vulnerabilities and to train Germinterceptor pilots in tactics
Few surviving aircraft were found by Allies following war
did not offer B-17s to Soviet Union, however, at least 73 were used by Soviet Air Force
These were aircraft that landed with mechanical trouble during shuttle bombing raids over Germany, or had been damaged by a Luftwaffe raid in Poltava
They were concentrated in 890th bomber regiment of 45th bomber division
In 1946 regiment was assigned to Kazan' factory in order to aid in Soviet effort to reproduce Boeing B-29 as Tupolev Tu-4
Following World War II, B-17 was declared obsolete and Army Air Forces retired most of its fleet
Flight crews ferried bombers back across Atlantic to United States, where majority were sold for scrap and melted down
By late 1950s, last B-17s in operational USAF service were QB-17 target drones, DB-17P drone controllers at Davis-MonthAir Force Base, Arizona
Perhaps most famous B-17, Memphis Belle, is being fastidiously restored to its wartime appearance by National Museum of United States Air Force
At first, these planes operated under their original USAAF designations, but on July 31, 1945, they were assigned naval aircraft designation PB-1, a designation which had originally been used in 1925 for experimental flying boat
Since most of Fortresses involved were actually built by Douglas or Lockheed and not by Boeing, a more logical designation would have been P4D-1W or P3V-1G respectively
Twenty-four B-17Gs were used by Navy under designation PB-1W
A large radome for AN/APS-20 search radar was fitted underneath fuselage and additional internal fuel tanks were added for longer range
These planes were painted dark blue, a standard Navy paint scheme which had been adopted in late 1944
Most of these planes were Douglas-built aircraft, flown directly from Long Beach factory to Naval Aircraft Modification Unit at NAS Johnsville/NAS Warminster, Pennsylvania, during summer of 1945, where APS-20 search radar was fitted
However, war ended before any PB-1Ws could be deployed and defensive armament was subsequently deleted
VW-1's mission set was similar to that of VW-2
PB-1Ws were retired to Naval Aircraft Storage Center at NAS Litchfield Park, Arizona and were stricken from inventory in mid-1956
Many were sold as surplus and ended up on civil aircraft register and 13 were sold as scrap
Two ex-USAAF B-17s were obtained by Navy under designation XPB-1 for various development programs
first was transferred to Navy in June 1945, and second was transferred in August 1946
second plane was used by Cornell Aeronautical Laboratory in a jet engine test program and was stricken in 1955
In May 1947, six additional B-17Gs of unknown serial numbers were transferred to Navy and assigned BuNos 83993 to 83998
They were stored at NAS Corpus Christi, Texas, until August 31, 1947, when they were stricken after no apparent use
Two additional PB-1s were transferred to Navy in 1950, these planes coming from Air Force, which had modified two EB-17Gs to PB-1W configuration for test programs
After completion of these tests, these planes were transferred to Navy
Seventeen ex-USAAF Vega-built B-17Gs were used by U
In July 1945, 18 B-17s were set aside by USAAF for transfer to Coast Guard via Navy
These aircraft were initially assigned Navy Bureau Numbers and first PB-1Gs were delivered to Coast Guard beginning in July 1946
Only fifteen PB-1Gs were actually transferred to Coast Guard
Coast Guard PB-1Gs were stationed throughout hemisphere, with five at Coast Guard Air Station Elizabeth City, North Carolina, two at CGAS SFrancisco, two at NAS Argentia, Newfoundland, one at CGAS Kodiak, Alaska, and one in Washington state
They were used primarily for air-sea rescue, but were also used for iceberg patrol duties and for photo mapping
Air-sea rescue PB-1Gs usually carried a droppable lifeboat underneath fuselage and were painted in yellow and black air-rescue markings
chin turret was often replaced by a radome
This airplane was sold as surplus, operated as air tanker for many years, and is now on display in Arizona
About a dozen B-17s are still operable of some 50 airframes known to survive
Many of these surviving examples are surplus or training aircraft, which stayed in U
However, there are a few exceptions
Several B-17s, along with other World War II bombers, were converted into airliners or corporate aircraft
Of 13 YB-17s ordered for service testing, 12 were used by 2nd Bomb Group of Langley Field, Virginia, to develop heavy bombing techniques, and 13th was used for flight testing at Material Division at Wright Field, Ohio
A 14th plane, Y1B-17A, originally destined for ground testing only, was upgraded with turbocharger
When this aircraft had finished testing, it was re-designated B-17A, and in April 1938 was first aircraft to enter service under B-17 designation
To enhance performance at slower speeds, B-17B was altered to include larger rudder and flaps
Most significantly, with B-17E version, fuselage was extended by 10 ft , a much larger vertical fin and rudder were incorporated into original design, a gunner's position in tail and improved nose were added
engines were upgraded to more powerful versions several times, and similarly, gun stations were altered on numerous occasions to enhance their effectiveness