Boeing B-17 Fortress
Type: High-altitude strategic bomber.
In May 1934 the US Army Air Corps issued a specification for a multi-engined anti-shipping bomber to defend the nation against enemy fleets. The answer was expected to be similar to the Martin B-10, but Boeing proposed four engines in order to carry the same bomb load faster and higher. It was a huge financial risk for the Seattle company but the resulting Model 299 was a giant among combat aircraft with four 750hp Pratt & Whitney Hornet engines, a crew of eight and stowage for eight 60 lb (272-kg) bombs internally.
The service-test batch of 13 Y1B-17 adopted the Wright Cyclone engine, later versions all being turbocharged for good high-altitude performance. The production B-17B introduced a new nose and bigger rudder and flaps, though the wing loading was conservative and an enduring characteristic of every Flying Fortress was sedate flying.
With the B-17C came a ventral bathtub, flush side guns, armour and self-sealing tanks. In return for combat data 20 were supplied to the RAF, which used them on a few high-altitude daylight raids with 90 Sqn of Bomber Command. It was found that the Norden sight tended to malfunction, the Browning guns to freeze at the high altitude and German fighters to attack from astern in a defensive blind spot.
While surviving Fortress I’s operated with Coastal and Middle East forces, the improved B-17D joined the US Army and bore the brunt of early fighting in the Pacific.
But extensive combat experience led to the redesigned B-17E, with powered dorsal, ventral (ball) and tail turrets, a huge fin for high-altitude bombing accuracy and much more armour and equipment. This went into mass production by Boeing, Lockheed-Vega and Douglas-Tulsa. It was the first weapon of the US 8th Bomber Command in England and on 17 August 1942 began three gruelling years of day strategic bombing in Europe.
Soon the E gave way to the B-17F, of which 3,405 were built with many detail improvements, including a long Plexiglas nose, paddle-blade propellers and provision for underwing racks.
At the end of 1942 came the final bomber model, the B-17G, with chin turret and flush staggered waist guns. A total of 8,680 G models were made, Boeing’s Seattle plant alone turning out 16 a day and the total B-17 run amounted to 12,731.
A few B-17F’s were converted to XB-40s, carrying extra defensive guns to help protect the main Bomb Groups, while at least 25 were turned into BQ-7 Aphrodite radio-controlled missiles loaded with 12,000 lb of high explosive for use against U-boat shelters. Many F and G models were fitted with H2X radar with the scanner retracting into the nose or rear fuselage, while other versions included the F-9 reconnaissance, XC-108 executive transport, CB-17 utility transport, PB-1W radar early warning, PB-1G lifeboatcarrying air/sea rescue and OB-17 target drone.
Users: British RAF, US (AAC/AAF, Navy).
Animated 3D model of Boeing B-17G Flying Fortress
Data for Boeing B-17 G Fortress
|Boeing B-17 G Flying Fortress||data|
|Type||high-altitude strategic bomber|
|Power plant||four 1,200-hp Wright Cyclone R-1820-97 radial piston engines with exhaust-driven turbochargers|
|Wing span||103 ft 9 in|
|Length overall||74 ft 9 in|
|Height overall||19 ft 1 in|
|Wing area||1,420.0 sqft|
|Weight empty||36,135 lb|
|Weight maximum loaded||72,000 lb|
|Max wing loading||?|
|Max power loading||?|
|Max level speed||287 mph|
|at height||25,000 ft|
|to height of||20,000 ft|
|Service ceiling||35,600 ft|
|Range||2,000 miles (with 6,000 lb normal bomb load)|
|Range with maximum bomb load||1,100 miles|
|Range maximum||3,400 miles|
|Boeing B-17 G Flying Fortress||data|
|Turrets||4 x twin 12,7-mm(0.5-in) MG guns (800 rpm, velocity 2,180 ft.sec, bullet wt. 1.71 Oz., range 7,200 yds) turrets: under nose, aft of cockpit, under central fuselage and in tail|
|Single guns||Five 12,7-mm(0.5-in) MG mountings: in each side of nose, in radio operator's batch and in each waist (beam) positions|
|Bomb load||normal internal bomb load 6,000 lb, but maximum of 12,800 lb possible on short distances|
|Boeing B-17 Flying Fortress||data|
|First flight (B-17 prototype)||28 July 1935|
|Production delivery service test-batch Y1B-17||January 1937|
|Production delivery (B-17B)||June 1939|
|First combat mission Europe (B-17E)||17 August 1942|
|Production delivery (B-17G)||end of 1942|
|Operational delivery (B-17G)||July 1943|
|Service delivery of unpainted B-17G||January 1944|
|Final delivery||April 1945|
|Unit cost||$ 238,329|
|Total production figure (all)||12,731 (8,680 B-17G)|
|Number of US Sorties, Europe 42-45 (all)||291,508|
|Bomb Tonnage US, Europe 42-45 (all)||640,036 t|
|US Lost in Combat, Europe 42-45 (all)||4,688|
|Enemies claimed destroyed by US, Europe 42-45 (all)||6,659|