Fighter-bomber

A fighter-bomber is a fighter aircraft that has been modified, or used primarily, as a light bomber or attack aircraft. It differs from bomber and attack aircraft primarily in its origins, as a fighter that has been adapted into other roles, whereas bombers and attack aircraft are developed specifically for bombing and attack roles.

Although still used, the term fighter-bomber has less significance since the introduction of rockets and guided missiles into aerial warfare. Modern aircraft with similar duties are now typically called multirole combat aircraft or strike fighters.

Prior to World War II, general limitations in available engine and aeronautical technology required that each proposed military aircraft have its design tailored to a specific prescribed role. Engine power grew dramatically during the early period of the war, roughly doubling between 1939 and 1943. The Bristol Blenheim, a typical light bomber of the opening stages of the war, was originally designed in 1934 as a fast civil transport to meet a challenge by Lord Rothermere, owner of the Daily Mail. It had two Bristol Mercury XV radial engines of 920 hp each, a crew of three, and its payload was just 1,200 lbs of bombs. The Blenheim suffered disastrous losses over France in 1939 when it encountered Messerschmitt Bf 109s, and light bombers were quickly withdrawn.

In contrast, the Vought F4U Corsair fighter — which entered service in December 1942 — had in common with its eventual U.S. Navy stablemate, the Grumman F6F Hellcat and the massive, seven-ton USAAF Republic P-47 Thunderbolt — a single Pratt & Whitney R-2800 Double Wasp radial engine of 2,000 hp in a much smaller, simpler and less expensive single-seat aircraft, and was the first aircraft design to ever fly with the Double Wasp engine in May 1940. With less airframe and crew to lift, the Corsair's ordnance load was either four High Velocity Aircraft Rockets or 2,000 lbs of bombs; a later version could carry eight rockets or 4,000 lbs of bombs. The massive, powerful 18-cylinder Double Wasp engine weighed almost a ton—half as much again as the V12 Rolls-Royce Merlin and twice as much as the 9-cylinder Bristol Mercury that powered some heavy fighters.

...
Wikipedia