When Britain and France declared war on Germany in September 1939, the RAF had no heavy bomber. The Handley-Page Halifax and Avro Lancaster both originated as twin engine bombers, but were rapidly redesigned for four Rolls-Royce Merlin engines and rushed into service once the technical problems of the larger Rolls-Royce Vulture emerged. The Halifax joined squadrons in November 1940 and flew its first raid against Le Havre on the night of 11–12 March 1941. British heavy bomber designs often had three gun turrets with a total of 8 machine guns. In January 1941, the Short Stirling reached squadrons. It was based on the successful Short Sunderland flying boat and shared its Bristol Hercules radial engines, wing, cockpit and upper fuselage. The hull of the flying boat was replaced by a lower fuselage. It carried up to 14,000 lbs of bombs – almost twice as much as a Boeing B-17 Flying Fortress – but over just a 300 mile radius. Due to its thick, short wing, it was able to out-turn the main German night fighters, the Messerschmitt Bf110 and the Junkers Ju88. Heavy bombers still needed defensive armament, for protection, even at night. British heavy bomber designs often had three gun turrets with a total of 8 machine guns. The Stirling`s low operational ceiling of just 12,000 ft – also caused by the thick wing – meant that it was usually picked on by night fighters. And within five months, 67 of the 84 aircraft in service had been lost.
Due to the absence of British heavy bombers, 20 US Army Air Corps Boeing B-17 Flying Fortresses, were lent to the RAF, which during July, 1941 commenced daylight attacks on warships and docks at Wilhelmshaven and Brest. These were complete failures. After eight were lost, due to combat or breakdown and with many engine failures, the RAF stopped daylight bombing by September. It was clear that the B17C model was not combat ready and that its five machine guns gave inadequate protection.
Combat feedback enabled Boeing engineers to improve the aircraft. When the first model B17E started to operate from English airfields in July 1942, it had many more gun turrets including a vital tail gunner. Eventually U.S. heavy bomber designs, optimized for formation flying, had 10 or more machine guns and/or cannons in both powered turrets and manually operated flexible mounts to deliver the best arcs of fire. These guns were located in tail turrets, side gun ports either just behind the bombardier's clear nose glazing as "cheek" positions, or midway along the rear fuselage sides as "waist" positions. US bombers carried .50 caliber machine gun), and dorsal (spine/top of aircraft) and ventral (belly/bottom of aircraft) guns with powered turrets. All of these machine guns could defend against attack when beyond the range of fighter escort. Eventually 13 machine guns were fitted in the B17G model.
Even this extra firepower, which increased empty weight by 20% and required more powerful versions of the Wright Cyclone engine, was insufficient to prevent serious losses in daylight. Escort fighters were needed but the RAF interceptors such as the Supermarine Spitfire had very limited endurance. An early raid on Rouen-Sotteville rail yards in Brittany on August 17, 1942, required four Spitfire squadrons outbound and five more for the return trip.
Usage in War ThunderEdit
Heavy bombers in War Thunder are usually the biggest bombers in the sky, and usually pack 1000lb or kg bombs or more. They tend to have a large defensive armament, having several turrets and single machine guns positioned around the aircraft. Heavy bombers usually attack area ground targets, as they do not have the pin point accuracy of dive bombers or ground attack aircraft to hit moving targets.