Boeing Fortress Mk.I

Boeing Fortress Mk. I AN526, RAF.

With the passage of the Lend-lease Act in 1941, the Royal Air Force requested B-17s. At that time, the US Army Air Corps was suffering from shortages, but supplied 20 to the RAF. Though the Air Corps hadn't cleared the B-17 for combat, they were desperately needed in Britain. The 20 ferried bombers were production B-17Cs (company designation Model 299T), designated Fortress Mk I by the RAF. The aircraft's single .30 caliber nose-mounted machine guns were replaced with 0.5 in (13 mm) Brownings.

Following delivery, the 20 Fortress Mk.Is went almost immediately into frontline service, however they performed poorly. By September 1941, 39 sorties had only resulted in 22 missions, with nearly half of the sorties aborted due to mechanical and electrical problems. Eight of the 20 aircraft had been destroyed by September, half to accidents. Their guns froze-up at altitude and were unable to protect the Fortresses from attack and their effectiveness as bombers was also limited, largely because of problems with achieving an adequate level of bombing accuracy.

Boeing got the serial letters wrong on the batch of Fortress Is for the RAF; they should be AN, not AM. On the left is Air Chief Marshal Sir Hugh Dowding, the former head of RAF Fighter Command during the Battle of Britain.

Bearing British markings, the B-17C (Fortress I in RAF service; serial number AM528) was the first American bomber to be used in stratosphere bombing over Occupied Europe.

Boeing (B-17C) Fortress I, serial number AM528, in RAF colors; circa 1941.

Boeing Fortress Mk I AM521, RAF.

Fortress Mk I AN529 (USAAF B-17C 40-2065) on the ground at Ayr/Heathfield, Ayrshire, shortly after arrival from the United States. AN529 joined No. 90 Squadron RAF as WP-C and was written off after a forced landing near Fort Maddalena, Libya, on 8 November 1941.

Ground crew performing pre-flight check on a Fortress Mark I of No. 90 Squadron RAF. (Imperial War Museum CH3130)

Cleaning the Plexiglas on the nose of a Fortress Mark I of No. 90 Squadron RAF. (IMperial War Museum CH3133)

Ground crew performing pre-flight check on a Fortress Mark I of No. 90 Sqadron RAF. (Imperial War Museum CH3107)

Crews of the Fortress Mark I bombers of No. 90 Squadron RAF arrive by lorry and check up details with ground crews. (Imperial War Museum CH3101)

Waist gunner in a Fortress Mark I of No. 90 Squadron RAF checking his gun before takeoff. (Imperial War Museum CH3109)

A cup of tea before the take-off in a Fortress Mark I of No. 90 Squadron RAF. Refreshments are served to crews by mobile canteens. (Imperial War Museum CH3104)

Crew members of a Fortress Mark I complete with oxygen masks, heated suits and parachutes ready for a flight. (Imperial War Museum CH 3115)

Before getting into their Fortress Mark I of No. 90 Squadron RAF. Activity on the tarmac. (Imperial War Museum CH3098)

Crew entering a Fortress Mark I No. 90 Squadron RAF. (Imperial War Museum CH3119)

Fortress Mark I WP-C piloted by the CCO of the unit of No. 90 Squadron RAF landing after a mission to attack the German battlecruiser Gneisenau at Brest, 30 July 1941. (Imperial War Museum FRE11245)

Crew exiting a Fortress Mark I WP-G No. 90 Squadron RAF after a flight. (Imperial War Museum CH3121)

Crew in discussion after returning from a flight in Fortress Mark I WP-G No. 90 Squadron RAF. (Imperial War Museum CH3120)

Crew of Fortress Mark I WP-C of No. 90 Squadron RAF after a flight. (Imperial War Museum CH3110)

Fortress Mark I AN521/WP-K of No. 90 Squadron RAF based at West Raynham, Norfolk, preparing for takeoff at Hatfield, Hertfordshire, during an inspection of newly-arrived American aircraft by the Chief of the Air Staff and the US Air Attaché.

Fortress Mark I AN521/WP-K of No. 90 Squadron RAF based at West Raynham, Norfolk, preparing for takeoff at Hatfield, Hertfordshire.

Boeing Fortress Mk I AN521/WP-K, No. 90 Squadron,, RAF, June 1941.

Fortress Mark I of No. 90 Squadron RAF checked by ground crew and ready for takeoff. (Imperial War Museum CH3111)

Fortress Mark I RAF, possibly the same aircraft as in the previous photo, and most likely from the same unit. (Imperial War Museum CH3108)

The same Fortress Mark I as seen in the previous photo ready for takeoff. (Imperial War Museum CH3112)

The same Fortress Mark I as in the previous photo. (Imperial War Museum CH3106)

Fortress crew at RAF Polebrook July 19, 1941. (Imperial War Museum CH 3090)

Fortress Mk. I/AN530/WP-F (USAAF B-17C 40-2066) of No. 90 Squadron RAF based at RAF Polebrook. Being flown by the RAF on a raid over Germany; 9 August 1941.

Boeing Fortress I WP-F of No 90 Squadron, RAF Bomber Command, in flight, 3 November 1941. (Imperial War Museum HU83472)

Boeing Fortress I WP-F of No 90 Squadron, RAF Bomber Command, in flight, 3 November 1941. (Imperial War Museum)

Winston Churchill watches a Boeing Fortress Mk I giving a flying display during his visit to an RAF bomber station, 6 June 1941.

The B-17C eliminated the teardrop waist gun fairings but the fuselage cutout shape was unchanged. Twenty B-17Cs were supplied to the Royal Air Force as the Fortress I. Here is a view of the Fortress I interior as an RAF gunner poses at the starboard waist gun. Note that the fuselage of the “shark fin” Forts is considerably smaller than the re-designed “E” model.

Fortress Mk. I AN527/NR-L of No. 220 Squadron (formerly of No. 90 Squadron), seen here guarding a convoy, was the last of its sub-type delivered and one of the few used on maritime 'ops'.

Boeing Fortress Mk. I/AN528 (B-17C/40-2064) prior to being camouflaged.

Boeing Fortress Mk. I/AN529 (USAAF B-17C/40-2065) at Heathfield, Scotland, after arrival from United States, May 1941. (Imperial War Museum E(MOS) 276)

Boeing Fortress Mk. I/AN531 (USAAC B-17C/40-2068), Royal Air Force. Struck off charge on January 17, 1945.

Boeing Fortress Mk I AN519/WP-H, No. 90 Squadron, RAF

Boeing Fortress Mk I.

Boeing Fortress Mk. I cockpit.

Boeing Fortress Mk I AN532/WP-J, No. 90 Squadron, RAF, Egypt.

Boeing Fortress Mk I AN531.

Boeing Fortress Mk I AN530/WP-F, No. 90 Squadron, RAF Bomber Command, the specially formed unit which pioneered very high altitude bombing, and with which the Flying Fortress made its combat debut. 

Boeing Fortress Mk I AN530/WP-F, No. 90 Squadron, RAF. This aircraft, AN530, “F for Freddie,” had an eventful career. It arrived in England on 10 July 1941; just too late to take part in the initial raid on Wilhelmshaven but, as one of the more reliable aircraft, it was selected for the abortive Berlin raid on 23 July. On 2 August it fought off attacks by three Bf 109s of 3./JG 52, shooting down Feldwebel Wilhelm Summerer and damaging the other two. It was later transferred to No. 220 Squadron of Coastal Command and struck off charge in September 1943.

Boeing Fortress Mk I AN523/WP-D, No. 90 Squadron, RAF.

Boeing Fortress Mk I AN519/WP-H, No. 90 Squadron, RAF.

Boeing Fortress Mk I AN519, RAF.

Boeing Fortress Mk I AM528, RAF.

Boeing Fortress Mk I, No. 90 Squadron, RAF.

Boeing Fortress Mk I, No. 90 Squadron, RAF.

Boeing Fortress Mk I, No. 90 Squadron, RAF.

Boeing Fortress Mk I, No. 90 Squadron, RAF. Curtiss (P-40) Tomahawk in center and Douglas (A-20) Havoc at right.

Boeing Fortress Mk I AN529/WP-C, No. 90 Squadron, RAF, Libya.

Boeing Fortress Mk I AN530, No. 90 Squadron, RAF, 1941.

Boeing Fortress Mk I, No. 90 Squadron, RAF.

Boeing Fortress Mk I AN523/WP-D, No. 90 Squadron, RAF.

Boeing B-17C Flying Fortress

Boeing B-17C Flying Fortress (105/MD), assigned to Wright Field in pre-war natural metal finish, USAAF, circa 1941.

The B-17C was a B-17B with a number of improvements, including more powerful R-1820-65 engines. To boost crew safety, the waist-mounted machine gun blisters were replaced with teardrop-shaped, slide-out Perspex window panels flush with the fuselage, and the ventral blister was replaced by a lower metal housing dubbed a "bathtub turret", similar in appearance and general location on the lower fuselage, to the Bola ventral gondola being used on Nazi Germany's He 111P medium bomber. The most important additions made to the "C" series were self-sealing fuel tanks and defensive armor plate added to vital areas.

With the passage of the Lend-lease Act in 1941, the Royal Air Force requested B-17s. At that time, the US Army Air Corps was suffering from shortages of the B-17, but hesitantly agreed to provide 20 examples to the RAF. Though the Air Corps did not consider the B-17 ready for offensive combat, the aircraft was still desperately needed in Britain. The 20 ferried bombers were Boeing production B-17Cs (company designation Model 299T). The aircraft's single .30 caliber nose-mounted machine guns were replaced with 0.5 inch Brownings.

Following their delivery, the 20 B-17C bombers were placed immediately into frontline service and designated RAF Fortress Mk I. They performed unremarkably while in British service. By September 1941, three months after the Army Air Corps became the Army Air Forces, 39 sorties had made up 22 missions. Nearly half of those were aborted due to mechanical and electrical problems. Eight of the 20 aircraft were destroyed by September, half to various accidents. Their machine guns tended to freeze-up at high altitudes and were generally unable to effectively protect the Fortresses from German fighter attack. Their success as bombers were also limited, largely because they were unable to strike targets from the high altitudes at which the RAF flew its daylight bombing missions.

The first of the B-17C series flew in July 1940, with a total of 38 being built. The 18 remaining in Army Air Forces service, following the 20 transferred to the RAF, were upgraded to Boeing's new B-17D configuration. However, one of these bombers, B-17C 40-2047, crashed while being ferried from Salt Lake City, Utah, to Mather Army Air Base, California, on November 2, 1941.

Boeing B-17C Flying Fortress (105/MD), assigned to Wright Field in pre-war natural metal finish, USAAF, circa 1941.

Boeing B-17C Flying Fortress (105/MD), assigned to Wright Field in pre-war natural metal finish, USAAF, circa 1941.

Boeing B-17C Flying Fortress (105/MD), assigned to Wright Field in pre-war natural metal finish, USAAF, circa 1941.

B-17C, Oakland, California; circa 1941.

Boeing B-17C.

Boeing B-17C, serial number 40-2049, at Wright Field; circa 1940.

Boeing B-17C; circa 1940.

Boeing B-17C; circa 1940.

B-17C, Boeing Field, Seattle, Washington, August 28, 1940.

On the B-17C the fuselage blisters were replaced by flush panels; a “bath tub” gun position was installed under the fuselage.

A burned B-17C aircraft rests near Hangar Number Five, Hickam Field, following the attack by Japanese aircraft. Pearl Harbor, Hawaii; 7 December 1941.

A crashed U.S. Army Air Forces Boeing B-17C Flying Fortress (s/n 40-2049) at Bellows Field, Territory of Hawaii. It was flown by 1st Lt. Robert H. Richards, 38th Reconnaissance Squadron, from California and arrived over Oahu during the Japanese attack on 7 December 1941. Richards made a forced landing while being attacked. Although repairable, the aircraft was later used for spare parts and not repaired. 7 December 1941.

Boeing B-17C.

Boeing B-17C.

Boeing B-17C cockpit. This is a really interesting find, this is the cockpit of a B-17C. There are several differences from later variants visible here, including the lack of armor behind the seats, different oxygen bottles behind the pilot, raised flight deck flooring, and early style control wheels. A more subtle change is the position of the photographer himself – in the B-17E and later versions he would be standing where the Sperry dorsal turret structure would be installed.

A Boeing B-17C assigned to the 19th Bombardment Group at Iba Airfield, approximately 100 miles (160 kilometers) northwest of Manila on the island of Luzon, Commonwealth of the Philippine Islands, October 1941. (U.S. Air Force Historical Research Agency)

B-17C at Iba Airfield. Contrary to the belief of some that it was only Clark and Del Monte airfields that could accommodate heavy bombers. This photo dispels the myth. In the background is an A-27.

A Boeing B-17C Flying Fortress, similar to Colin Kelly’s B-17C (40-2045). The Air Corps began camouflaging its B-17s in olive drab and neutral gray during Spring 1941.