This Halifax RAF British heavy bomber was operational from 1941 to 1952. The Halifax was designed originally to meet the same P.13/36 requirement as the Avro Manchester. A change to four Rolls Royce Merlin engines was made in anticipation of a shortage of Vultures, thereby avoiding the engine troubles that were to beset the Manchester in service. The first prototype flew on 25 October 1939, and the first production Halifax I on 11 October 1940. Powered by four 1280 hp Merlin Xs giving a maximum speed of 265 mph, this version carried a crew of seven and up to 13 000 pounds of bombs. Defensive armament comprised two 0.303 inch machine guns in the nose turret, four in the tail turret and others in beam positions on some aircraft. The first operational sortie was made against Le Havre by six aircraft from Number 35 Squadron, RAF Bomber Command, on the night of 11-12 March 1941. ,,,,,,,,,,,, ,,,,,,,,,,,,The Halifax went on, with the Lancaster, to form a mainstay of the great RAF night offensive in Europe, dropping 227 610 tons of bombs in 75 532 sorties. Altogether 6 176 Halifaxes were built for the RAF, in many versions. Later bombers had more powerful engines, including the 1 615 - 1 800 Bristol Hercules radial on the Marks III, VI, and VII. The design was improved, with a stream lined nose instead of a turret, to improve her performance and so reduce losses. Some Halifax bombers operated against the Afrika Korps, from Egypt, others flew as special duties squadron, dropping agents and arms by parachute to help the Resistance movement in Europe. In other forms, Halifaxes served with distinction with Coastal Command and as paratroop transports and glider tugs.