Armstrong Whitworth Apollo

The Armstrong Whitworth Apollo was a British four‑engine airliner produced by Armstrong Whitworth Aircraft in the mid‑1930s. Conceived as a response to Imperial Airways’ demand for a modern, long‑range passenger machine, the prototype first flew on 24 March 1936 from RAF Barnoldswick. Only three examples were built, two for Imperial Airways and one for the Royal Air Force as a transport and ambulance. The Apollo featured a low‑wing, all‑metal monocoque fuselage, a retractable undercarriage and a fully enclosed cockpit. Its four Armstrong Siddeley Tiger XI radial engines, each delivering 530 hp, drove three‑blade propellers and gave a cruising speed of about 190 mph with a range of 1,000 mi, allowing nonstop flights between London and destinations such as Paris and Brussels. Inside, the cabin accommodated up to 22 passengers in comfortable, heated seats and offered a galley and lavatory, a rarity for the era. Though quickly eclipsed by larger, more efficient aircraft like the Douglas DC‑3, the Apollo demonstrated the feasibility of all‑metal, multi‑engine transport designs in Britain and helped pave the way for post‑war airliners such as the Vickers Viscount. Its brief service highlighted Armstrong Whitworth’s contribution to the transition from biplane mail planes to modern commercial aviation.