Boeing B17G 'Flying Fortress', Duxford 2010 ©Nigel Key
28 July 1935.
The prototype B-17, designated Model 299, was designed by E. Gifford Emery and Edward Curtis Wells as a multiengine bomber to replace the Martin B-10.
The design combined features from Boeings experimental XB-15 bomber and their 247 transport aircraft.
The Model 299 was designed to carry a payload of up to 4,800 lb (2,200 kg) of bombs and was powered by 4 x Pratt & Whitney R-1690 Hornet radial engines.
The first flight of the Model 299 was flown by Chief test pilot Leslie Tower and whilst observing the aircraft, a reporter for The Seattle Times called the aircraft a ’15-ton Flying Fortress’ because of all the machine guns protruding from the aircraft, a name which was quickly adopted by Boeing.
On 30 October 1935, during an evaluation flight piloted by Major Ployer Peter Hill and Les Tower, the Model 299 crashed killing both pilots. The cause of the crash was identified as being due to the ‘gust locks’ (they lock the control surfaces in place whilst the aircraft is on the ground) not being disengaged prior to flight.
Despite the crash during evaluation, the USAAC had been impressed by the prototypes performance and on 17 January 1936 the Air Corps ordered 13 aircraft designated YB-17 for service evaluation.
The YB-17 differed from the Model 299, mainly having more powerful Wright R-1820-39 Cyclone engines fitted.
Between 1 March and 4 August 1937, 12 of the 13 aircraft, now designated Y1B-17, were issued to the 2nd Bombardment Group for operational development and testing.
A 14th Y1B-17 was upgraded with General Electric turbochargers and had its first flight on 29 April 1938. Once service testing was completed their designation was changed to B-17 signifying operational status.
Modifications were carried out to the B-17, including larger flaps and rudder and a 10-panel plexiglass nose, and then designated B-17B. In July 1940 an order for 512 B-17s was issued.
The Boeing B-17 Flying Fortress was produced from 1936 to 1945, with 12,731 built.
4 x Wright R-1820-97 Cyclones, producing 4800 hp.
Press play to hear the Flying Fortress
13 x Browning 0.5” machine guns
12,800 lb (5,800 kg) bomb load.
The B-17 became operational in 1941 during World War II with the RAF and the US Army.
The 19th Bombardment Group had been relocated to Clark Field in the Philippines as a planned build up in the Pacific a few weeks before the Pearl Harbour attack. Half of the B-17’s were lost on 8 December 1941 when they were caught refuelling and rearming.
Early in 1942 the 7th Bombardment Group started to arrive in Java, a Squadron of B-17’s were redeployed to the Middle East to join the First Provisional Bombardment Group becoming the first American B-17’s to engage the Germans.
In July 1942 the first USAAF B-17’s arrived in England joining the Eight Air Force.
The B-17’s were mainly utilised in daylight precision bombing against German targets such as airfields, factories, warehouses, docks and U-boat pens.
|Crew - 10|
|Length - 74ft 4in (22.66m)|
|Wingspan - 103ft 9in (31.62m)|
|Height - 19ft 1in (5.82m)|
|Empty Weight - 36,135lb (16,391kg)|
|Max. Weight - 65,500lb (29710kg)|
|Max. Speed - 287 mph (462 km/h)|
|Range - 2,000 miles (3,219 km)|