Next the Handley Page HP.55. The HP.55 was Handley Page's submission for the B.1/35 requirement for a twin-engined heavy bomber able to reach speeds to 230mph while carrying a heavier bombload than the B.3/34. The competition was won by the Vickers 284, an enlarged Wellington derivative which ultimately became the Warwick, but the Handley Page design was regarded favourably and was one of three prototypes commissioned on 7th October 1935 (alongside the Armstrong Whitworth AW.39 development of the Whitley and the Vickers Warwick). The HP.55 could be powered by either the Hercules or the Merlin, had a wingspan of 95 feet, and was expected to have a top speed of 251mph. However the contracts for both AW.39 and HP.55 were cancelled in June 1937. Armstrong Whitworth felt they had taken on too much work to be able to tender to the new B.12/36 heavy bomber requirement, while Handley Page's attention had drifted to the P.13/36 medium bomber and they wished to redesign the HP.55 to meet the new requirement (which they ultimately did as first the twin-engined HP.56, and then the four engined HP.57 Halifax).
By contrast with the manufacturers, the Air Ministry did not want to cancel the B.1/35 contracts and turned down the initial request. Although they finally gave in to their contractors, the HP.55 could easily have flown. If it had been adopted, then the near certainty is that it would have taken the name of a town starting with H, I've chose Huntingdon, but other names are possible. The development history of the Warwick gives us a likely pattern for the HP.55. The prototypes were originally due to fly in 1937, but in 1936 the Air Ministry increased the required fuel and bombload, then in 1937 started to move away from the Hercules and towards the Vulture and the Sabre which promised higher performance, finally settling on the Vulture in late 1938. The first prototype Warwick eventually flew with Vultures in August 1939, the second with Bristol Centaurus, following in April 1940. At one point in 1939 it was proposed to abandon any plan for production, but eventually orders were placed for 250 in December 1940, though the failure of the Vulture and scarcity of the Centaurus meant that they would have to use the inferior Double Wasp. An HP.55 that followed the Warwick's development path would likely have failed for identical reasons, but if it had been delivered as originally intended in 1937, then there might have been a brief opening for it as a partial replacement for the Wellington before the later four-engined heavies came on line. It makes a suitable replacement for squadrons equipped with the Wellington or Blenheim.
The aircraft is shown in the colours of Halifax Q-Queenie of No. 446 Squadron, RAAF, with Bomber Command's No. 4 Group at Driffield in 1944-5, based on the HP.55 illustration in British Secret Projects:3.
. The only significant frontal area is actually the magazine, and that's no worse than any of the bombs carried externally by either the Lysander or other aircraft, and significantly smaller than the spats. If we want to start modelling things like changes in performance with external load, then we really should be measuring larger effects such as changes in performance with altitude.