The W.8 (also known as the H.P.18) was the company's first purpose-built civil airliner although it was a development of the wartime Handley Page Type O/400 bomber via the O/7, O/10 and O/11 transports. It had an enclosed cabin for (in most versions) 12 passengers, along with two crew in an open cockpit, and has the distinction of being the world's first airliner to be designed with an on-board lavatory. The prototype first flew on 4 December 1919, shortly after it was displayed at the 1919 Paris Air Show at Le Bourget. The W.8 was subsequently revised to give the W.8b, W.8e (H.P.26), W.9 (H.P.27) and W.10 (H.P.30). It was also the basis for the W.8d (H.P.24), the Handley Page Hyderabad bomber. W.8 Prototype, holding 15 passengers, powered by two 450 hp (336 kW) Napier Lion engines. The original company designation was to have been Handley Page W/400. W.8b To meet an Air Ministry ruling, the capacity was reduced to 12 passengers and the fuel tanks were moved from the engine nacelles to above the top wing. The engines were changed from the Napier Lion to the less powerful but more economical Rolls-Royce Eagle IX. In 1921 the Air Ministry ordered three aircraft, built as the W.8b, for use by Handley Page Transport, and later by Imperial Airways, on services to Paris and Brussels. Another aircraft was delivered to SABENA in 1924 and three more were license built by SABCA in Belgium. W.8c Planned alteration of W.8b for 1923, seating 16 passengers in longer passenger cabin, with radio compartment eliminated and freight capacity reduced. Fuel tanks would be moved to the underside of the top wing, and slotted ailerons would be fitted. Engines would be unchanged. Never built. W.8d The W.8d was the initial designation for the Handley Page Hyderabad heavy bomber. W.8e To reduce the risks involved with engine failure, the W.8e was developed with one 360 hp (270 kW) Rolls-Royce Eagle IX in the nose and two 240 hp (180 kW) Siddeley Pumas in the normal position. The first W.8e was sold to Sabena, which had ten more built in Belgium by SABCA.[4] Three-engined W.8f. W.8f and W.8g Hamilton One three-engine W.8f was built with cabin heating (derived from air circulated around the hot engine exhausts). The W.8f was modified in 1929 as the W.8g with an improved tail and rudder design from the W.10 and the third engine was removed and the other two replaced with 480 hp (360 kW) Rolls-Royce type F.XIIA engines. W.9a Hampstead (As depicted in these photos.) Was a three-engined version with more powerful 385 hp (290 kW) Armstrong Siddeley Jaguar IV radial engines. It was operated by Imperial Airways and created a record on the London-Paris route of 86 minutes. In 1926, the engines were replaced by three 420 hp (310 kW) Bristol Jupiters. The aircraft was moved to Australia but was destroyed by an accident after nine months. W.10 A twin-engined variant with the 450 hp (340 kW) Napier Lion for Imperial Airways (four built).
