Armstrong Whitworth Ensign

By Wikipedia,
the free encyclopedia,

http://en.wikipedia.org/wiki/Armstrong_Whitworth_Ensign

A.W.27 Ensign

An Imperial Airways Ensign in flight: note the distinctive nose-down attitude caused by the angle of incidence at which the wing was mounted. The Ensign shared this feature with its stablemate, the Whitley
Role	Airliner
Manufacturer	Armstrong Whitworth Aircraft
First flight	24 January 1938
Introduced	1938
Retired	1946
Primary users	Imperial Airways BOAC
Number built	14

The Armstrong Whitworth Ensign was a British four-engine airliner built during the 1930s for Imperial Airways. It could seat 40 passengers and was designed for European and Asian routes, connecting Britain with further seaplane flights to Australia and South Africa.

Design and development

Armstrong Whitworth Aircraft started on the A.W.27 Ensign in 1934 after receipt of a specification from Imperial Airways. The first aircraft was ordered in September of that year, with delivery expected in 1936; 11 more were ordered in May 1935. An order for a further two aircraft in 1937 brought the total to 14.

The Ensign was a high-wing cantilever monoplane of light alloy construction and an oval, semi-monocoque fuselage with a conventional tailplane. It had retractable landing gear and a castoring tail wheel. The main landing gear was hydraulically operated and retracted into the inner engine nacelles. The cockpit had side-by-side seating for two pilots with dual controls; there was also accommodation for a radio operator. The fuselage was divided into separate cabins, either four cabins with accommodation for 40 passengers or three cabins with room for 27 by day or 20 at night with sleeping accommodation.

Production of their Whitley heavy bomber for the Royal Air Force was a priority, and work on the Ensign proceeded slowly. Construction took place not at the main Coventry factory, but at the workshops of Air Service Training Ltd in Hamble. Constant changes were requested by Imperial, slowing production further. As a result, the Ensign's maiden flight did not take place until 24 January 1938 . Despite being underpowered, the aircraft was certified, and full airline service began between Croydon and Paris, France in October of that year.

Operational history

Three more Ensigns were completed by Christmas, 1938, and were dispatched with the holiday mail to Australia. All three suffered mechanical problems and did not reach their destination; all Ensigns were removed from active airline service and returned to Armstrong for improvements. Reliability was improved, and more powerful Armstrong Siddeley Tiger IXC engines aided performance somewhat.

11 aircraft were in service at the outbreak of World War II, with a 12th following soon after, and all were withdrawn in October 1939; they were to be camouflaged before flying a new route from Heston to Le Bourget Airport, Paris. The aircraft remained in service after formation of BOAC that November. Three Ensigns were destroyed or captured due to enemy action in 1940 , with one ("Ettrick"), which had been abandoned at Le Bourget after being damaged by bombs, eventually being used by the Germans, being re-engined with Daimler-Benz engines.

The final two aircraft that had been ordered by Imperial were equipped with more powerful Wright Cyclone geared radial engines and completed as A.W.27A Ensign Mk. 2s. The new engines significantly improved performance and allowed the Ensign to be used in hot climates and at high altitude. All eight surviving airframes were upgraded with these newer engines in 1941-43 and worked for BOAC on Africa to India routes.

Ensigns flew throughout the war. One ("Enterprise") force-landed in West African Vichy territory and served the Vichy forces and Air France, subsequently ending up with the Luftwaffe after being re-engined like "Ettrick". Several were broken up for spare parts to support the remaining fleet. The final Ensign flight took place in 1946, and the last seven aircraft were scrapped in 1947.

Variants

A.W.27 Ensign I: Four-engine medium-range transport aircraft. Powered by four 850 hp (630 kW) Armstrong Siddeley Tiger IXC radial piston engines.
A.W.27A Ensign II: Four-engine medium-range transport aircraft. Powered by four 950 hp (710 kW) Wright GR-1820-G102A Cyclone radial piston engines.

Operators

Civil operators

France

Air France

United Kingdom

Military Operators

Germany

Luftwaffe

Vichy France

Armée de l'Air de Vichy

United Kingdom

Royal Air Force
- No. 24 Squadron RAF

Specifications (A.W.27A)

Data from Jane's Fighting Aircraft of World War II

General characteristics

Crew: 5 (captain, first officer, radio operator, two cabin stewards)
Capacity:
- European routes: 40 passengers in 4 cabins
- Asian routes: 27 passengers in 3 cabins
Length: 114 ft (34.8 m)
Wingspan: 123 ft (37.5 m)
Height: 23 ft (7.02 m)
Wing area: 2,450 ft² (227.6 m²)
Empty weight: 35,075 lb (15,900 kg)
Loaded weight: 55,500 lb (25,200 kg)
Useful load: 12,000 lb (5,450 kg)
Powerplant: 4× Wright GR-1820-G102A geared radial engines, 1,100 hp (820 kW) each

Performance

Maximum speed: 210 mph (180 kn, 330 km/h)
Cruise speed: 180 mph (160 kn, 290 km/h)
Range: 1,370 mi (1,190 nmi, 2,200 km) at 5,000 ft (1,500 m)
Service ceiling: 24,000 ft (7,300 m) when fully loaded
Rate of climb: 900 ft/min (4.57 m/s)
Wing loading: 22.6 lb/ft² (110 kg/m²)
Power/mass: .079 hp/lb (130 W/kg)

External links

Armstrong Whitworth Ensign web page from Imperial 42 project
Armstrong Whitworth Ensign web page from British Aircraft Directory

Text from Wikipedia is available under the Creative Commons Attribution/Share-Alike License; additional terms may apply.

Published in July 2009.

Click here to read more articles related to aviation and space!