O/100 - H.P.11
Handley Page had been constructing small aircraft, until the Admiralty requested a very large seaplane design in 1914. In light of the stalemate in Flanders, HP instead offered a similar sized landplane patrol bomber. Championed by Churchill himself, the aircraft was to have 2x 150HP engines and winspan eventually reduced from 114ft to 100ft. Originally to be titled the O/300 from the horsepower, security concerned led to the design become a more non-descript O/100 named for the wingspan. An indication of what a significant leap forward this design was, is that the first flight was 12 years to the day from the Wright brothers first flight, and the aircraft's wingspan was only slightly shorter than the length of that first flight.
The initial prototype had an enclosed cockpit, which at test-pilot request was removed.
The first production aircraft were ready for deployment at the end of 1916, but in a bizarre twist one of the aircraft initially deploying to Europe inadvertently landed at a German controlled airfield and was captured before the type had even entered combat. This aircraft was test flown in Germany by many pilots, including the Red Baron himself.
In 1917 a trial installation was made of an anti-submarine recoilless rifle. The tests were unsuccessful, but the raised front cockpit section became the standard on all subsequent aircraft.
The O/100 was original delivered in the standard P.C.10 khaki-drab, but camouflage trials were conducted at Oxfordness with a dappled colour scheme, eventually leading to the inter-war standard NIVO finish.
Several engine modifications were trialled; including the Cossack-engine "intermediate" series of aircraft, and a single four-engine O/100, before the configuration for the revised O/400 was developed.