Armstrong Whitworth Ensign

The Armstrong Whitworth A. W.27 Ensign was a British four engine monoplane airliner and the largest airliner built in Britain during the Interwar period. The British airline Imperial Airways requested tenders for a large monoplane airliner with four Armstrong Siddeley Tiger engines in 1934. Armstrong Whitworth designed the Ensign to seat up to 40 passengers for the airline's European and Asian routes while also carrying airmail. It connected Britain with seaplane flights that continued on to Australia and South Africa. Early operations were hindered by mechanical problems and modifications only ever marginally improved performance and reliability. During the Second World War, the Ensigns were operated by the British Overseas Airways Corporation (BOAC), which had been formed out of the merger of Imperial Airways and British Airways. The type would be flown between Britain and various locations in the Middle East, Africa and India, often in support of military operations. During 1940, three Ensigns were destroyed by enemy action, while one would be captured in 1942 and subsequently operated by the French. The Ensigns were retired following a final passenger flight in June 1946 and the remaining aircraft were scrapped the following year.

The Ensign's origins can be traced to 1934 when Imperial Airways expressed a need for a large monoplane airliner powered by four Armstrong Siddeley Tiger radial engines. Imperial Airways paid £27,000 for the design work, and a further £43,300 for the construction of the first example on 22 September 1934, with delivery anticipated in 1936. and in December 1936, a final order for an additional two aircraft, priced at £39,766 13 shillings 4 pence each, brought the number of aircraft ordered to 14. Performance guarantees required a cruise speed of at 1524.00 m, and a take off distance of under
During the late 1930s, the Royal Air Force's Whitley heavy bomber had priority, which slowed work on the Ensign, and due to a lack of production capacity, assembly was not undertaken at Armstrong Whitworth's main factory in Coventry, but at another member of the Hawker Siddeley group, Air Service Training in Hamble. The two Mark. IIs saw their service entry being further delayed by Imperial Airways and Armstrong Whitworth studying their use as piggyback motherships in the same manner as the Short Mayo Composite's Maia, carrying a smaller long range parasite aircraft. However this idea was abandoned before being any changes were completed. Due to this delay, Everest only flew on 20 June 1940 and Enterprise didn't make its first flight until 28 October.

The Ensign's first flight revealed heavy ailerons, and an excessively heavy rudder which was resolved with an adjustment to its servo. During testing, the elevators intermittently jammed while at altitude, which was resolved by modifying the connecting wire runs, to account for the fuselage contracting due to the cold. A disaster was narrowly averted on 8 March 1938, when all four engines cut out due to an incorrect fuel cock settings, and the aircraft glided to RAF Bicester, making a dead stick landing. Flight testing of the prototype found its handling characteristics to be generally acceptable, although Royal Air Force pilots criticised its slow climb rate, which was attributable to the Tiger XI engines that left it underpowered. Once completed, the aircraft made its first airline service flight between Croydon Airport and Paris, France on 24 October 1938.

The Ensign was a high wing cantilever monoplane of light alloy construction and an oval fuselage with a conventional tailplane. with Dunlop wheels and tyres 1.83 m tall. While most components were designed and manufactured by Armstrong Whitworth, the 16 hydraulic jacks used for the flaps, undercarriage legs, locks and doors were Lockheed units sourced locally. and constant speed propellers This improved performance finally allowed the Ensign to be used in hot climates, however production of the engine ended early in the war, and not only did finding spares become difficult, but the rate of climb still generated complaints by the pilots. A boiler to produce steam was fitted to the engine exhaust, which was channelled through the aircraft to provide heat. It was intended for the Ensign to be operated by a crew of five with two pilots, a radio operator, a steward, and a flight clerk. On the Eastern route a second steward replaced the flight clerk. Eight aircraft aircraft were fitted for Empire routes and four for European routes. The former carried 27 passengers in three cabins or 20 sleeping in bunks, while the latter spread 40 passengers across four main cabins. The modified aircraft were evaluated at Martlesham Heath, during which the type's rate of climb was improved while the use of automatic mixture controls, modifications to the priming system, the installation of constant speed propellers and the replacement of bolts with studs in the engine rocker arm brackets greatly improved reliability. By September 1939, eleven had been delivered. Following the start of the Second World War, the entire fleet was stored in October 1939, It was at this time, in 1940, that several were operated by No.24 Squadron RAF crews, although no serials numbers were assigned. With the Germans invading the Low Countries, supplies were ferried to France, followed by evacuation flights ahead of the German occupation of France in June. Three Ensigns were destroyed by enemy action in 1940. G ADSX Ettrick and G ADSZ Elysian were lost in France, and G ADTC Endymion at Bristol Whitchurch in November 1940. Ettrick had been abandoned at Le Bourget after being damaged by bombs on 1 June 1940, and was rumoured to have been used by Germany, and even given Daimler Benz engines. All eight surviving aircraft were re engined during 1941–43 with and as they were completed they were transferred to the Middle East on BOAC's Africa to India routes. Following engine trouble in which three engines lost power and began leaking oil during a 3 February 1942 flight that had been following the Takoradi route between Egypt and the British colony in Ghana, Enterprise made a forced belly landing in the Vichy controlled French West Africa desert about short of its destination, near Nouakchott, now the capital of Mauritania but at the time a small fishing village. Incriminating paperwork was destroyed, and the crew were taken on to Bathurst in Gambia by an RAF Short Sunderland flying boat. Enterprise was found by a Vichy French patrol on 12 Feb 1942 and repaired at Dakar where it was briefly used by the Armée de l'Air de Vichy before being handed over to Air France in July 1942, when it was named Nouakchott, and the first letter of its registration was temporarily altered from a G for Great Britain to an F for France. After serving for several months in Mauritania, it was flown to France in October 1942, and the French authorities issued a certificate of airworthiness in November 1942, however before it could return to revenue service, the Germans invaded Vichy France in December 1942, and despite being hastily relocated, it was captured by the Germans along with 1876 other French aircraft. Deutsche Luft Hansa was invited to evaluate the captured aircraft in early 1943, but they saw it as an obsolete model that had been restored by the French, and its older Cyclone engines were more useful to them in the Douglas DC 3s they were still operating. The engines were removed from the airframe, which was scrapped by the Germans in Montaudran, near Toulouse in December 1943 without it being flown again. From 1944, the Ensigns were used between Cairo and Calcutta and the final Ensign passenger flight was in June 1946 when G ADSW Eddystone flew from Cairo to Hurn via Marseille, after being delayed in the Middle East by repairs. Conversion of the Ensigns was considered and they were offered for sale, but operating costs were too much for those who showed interest. The aircraft were broken up at Hamble in March and April 1947 and reduced to scrap.

A. W.27 Ensign Mk. I
Powered by four Armstrong Siddeley Tiger IX or Armstrong Siddeley Tiger IXC radial piston engines. A. W.27A Ensign Mk. II
Powered by four Wright GR 1820 G102A Cyclone radial piston engines.