The Armstrong Whitworth Argosy is a British post-war transport/cargo aircraft. It was the final aircraft to be designed and produced by the aviation company Armstrong Whitworth Aircraft. Although given different internal design numbers, the AW.650 civil and AW.660 military models were, for most practical purposes, the same design and shared the "Argosy" name.

Development of the Argosy originates in the AW.66, a proposed twin-engined military transport that was designed with British Air Ministry's Operational Requirement 323 (OR323) in mind. While Armstrong Whitworth terminated work on the AW.66, it decided to go forward with a civilian-oriented derivative of the design, designated AW.65, as it was judged to be commercially viable. The AW.65 was redesigned to use four Rolls-Royce Dart turboprop engines, and thus was re-designated as the AW.650. On 8 January 1959, the first Argosy conducted the type's maiden flight. In December 1960, the type received Federal Aviation Administration (FAA) type certification, enabling the initial civil version, referred to as the Series 100, to enter civil service across most parts of the world.

In Britain, military planners took interest in the Argosy and released a new specification for a militarised variant, designated AW.660. First flown on 4 March 1961, this model featured double the range of the Series 100 and otherwise differed by an alternative door arrangement, which was largely to facilitate paratroop operations. Furthermore, an improved civil variant, the Series 200, was introduced at the behest of airline British European Airways (BEA). First flown on 11 March 1964, this model featured a new wing incorporating a fail safe structure, being stronger and lighter than its original counterpart. The Argosy was operated by both the Royal Air Force (RAF) and various civil operators across the globe for numerous years. The type was withdrawn from RAF service during 1978, while the last Argosy was retired from civil operations during 1991.

Development Background The development of the Argosy can be traced back to the development of Operational Requirement 323 (OR323) by the British Air Ministry. During 1955, a specification was issued based upon OR323, which sought a medium-range freight aircraft that would be capable of lifting a maximum payload of 25,000 lb (11,340 kg), while also possessing a range of when carrying up to . British aviation manufacturer Armstrong Whitworth Aircraft took interest in this specification and decided to allocate members of its design team to the task of developing a suitable aircraft to meet its demands. Initially, design efforts were focused upon a twin-engine design intended for military use, which was internally designated as the AW.66.

As it was recognised that the aircraft held sales potential within the civil market, a civilian-oriented variant, designated AW.65, was also designed alongside the military design; the AW.65 principally differed from the AW.66 via the installation of full-section doors at each end of the fuselage to enable rapid loading and unloading operations. However, a lack of available finance contributed to the company's decision to abandon all work towards meeting the military requirement; despite this setback, Armstrong Whitworth had already decided to proceed with developing the civil variant as a private venture. The company believed that the type would have significant appeal to the growing short-haul air freight sector of both the European and American markets. At that time, no other aircraft had been purpose-designed for such a purpose. As work continued, the AW.65 was extensively redesigned, including the adoption of four Rolls-Royce Dart turboprop engines; the resulting aircraft being designated as the AW.650.

On 8 January 1959, the first Argosy performed its maiden flight. It appeared during that year's Farnborough Airshow, by which point five aircraft were flying, having cumulatively amassed about 400 flight hours between them."AW.6S0 Argosy." Flight International, 4 September 1959. p. 112. Certification-related testing of the type was reportedly completed during September 1960. In December 1960, the Argosy received type certification from the American Federal Aviation Administration (FAA), authorising the aircraft's entry to commercial service.Taylor 1965, p. 151. 10 of the initial civil version, the Series 100, were built; construction of these aircraft had commenced months prior to receiving certification so that deliveries could commence as soon as possible.

Further development

While the RAF had lost interest in any acquisition of the original AW.66 design, the service still needed to procure a replacement for its obsolete piston engined transport fleet, including the Vickers Valetta and Handley Page Hastings. During 1959, the British Air Ministry released a new specification that called for a military derivative of the AW.650, the envisioned aircraft was intended to serve in multiple roles, including as a medium-range transport, paratroop and supply aircraft. The resultant design, which was designated AW.660, was significantly different from the AW.650. Changes included the sealing of the nose door, its location being instead occupied by the radome of a weather radar unit, while the rear doors were substituted for by an alternative clamshell style which incorporated an integral loading ramp, while a stronger cargo floor was also installed. A pair of additional doors were fitted, one each on the starboard and port sides, which enabled paratroopers to exit. The military Argosy was powered by an arrangement of four Rolls-Royce Dart 101 turboprops and possessed twice the range of the civil Series 100.Willing Air Enthusiast July–August 2003, p. 57.Gunston Flight 10 February 1961, p. 181. From July 1960, the second Argosy Series 100 was used to flight-test the new clamshell door design. On 4 March 1961, the first of the 56 Argosies destined for RAF service performed its first flight.Taylor 1965, p. 152.

Early on, civil operator British European Airways (BEA) had shown open interest in the Argosy, the company viewed the aircraft as a potential replacement for its existing piston engined freighters; however, evaluations of the Series 100 soon found that its payload capacity would not allow for the type to operate profitably. Early on, as a measure taken to reduce design costs, the wing of the Argosy had been based on that of the Avro Shackleton, a maritime patrol aircraft that was developed and built by another entity within the Hawker Siddeley Group; in order to satisfy BEA's requirements, a new wing was designed which shared the same aerodynamic design, but benefitted from a more modern fail-safe structure rather than the safe-life design used on the earlier wing. This change resulted in a wing that was both stronger and lighter, but was also no longer limited in terms of its fatigue life. The revised version, designated as the Series 200, also featured several other improvements, including the adoption of enlarged cargo doors, integral wing fuel tanks and a modified landing gear arrangement.Willing Air Enthusiast May–June 2003, pp. 42–43. The Series 200 reportedly had better handling than the older Series 100, although some aerodynamic refinements were required during testing.Flight International 28 January 1965, p. 143.

On 11 March 1964, the first Series 200 aircraft conducted its first flight; it was soon followed by six more Series 220s, which were outfitted with more powerful engines.Flight International 28 January 1965, p. 144. While work had commenced upon another Series 220, this airframe was never completed and was ultimately scrapped.Willing Air Enthusiast May–June 2003, p. 42. According to the aviation periodical Flight International, the Argosy had been negatively impacted by the emergence of the long-haul passenger jet, as many surplus propeller-driven aircraft had been converted to freighters during this era, thus driving down both demand and prices for new-build cargo aircraft.Flight International 28 January 1965, p. 141.

Design

The Armstrong Whitworth Argosy was a general-purpose transport aircraft largely used for freight operations by both military and civil operators. At the time of its introduction, the type was considered to be unique in its class. Principally designed as a freighter, the aircraft could also be used for other tasks. The Argosy was offered in a convertible configuration for carrying both freight and passengers; the civil variant could accommodate a maximum of 80 passengers while providing comfort and speed conditions comparable to the contemporary Vickers Viscount airliners. In the cargo role, the Argosy was designed for rapid turnaround times of only 20 minutes without the use of lifting trucks or cranes, utilising pallets and rollers to eliminate packaging."Door to Door freighting with the Argosy." Flight International, 23 December 1960.

In terms of its basic configuration, the Argosy's tailplane was mounted on twin booms that ran rearwards from the inner engine nacelles, leaving the cargo doors at the rear of the fuselage clear for straight-in loading. Sideways-opening doors were fitted at both ends of the fuselage and the flight deck was set above the freight hold. This configuration allowed for an unobstructed cargo space measuring with a sill height corresponding to that of a normal flatbed truck. It had a maximum weight of 88,000 lb (39,915 kg) and a payload of 28,000 lb (12,700 kg). When cruising at 276 mph (444 km/h), it had a range of 1,780 mi (2,865 km) and could seat a maximum of 89 passengers.

The Argosy was powered by four Rolls-Royce Dart turboprop engines with Rotol-built four-blade propellers. The power rating of the engines depended on the aircraft variant. The sound produced by the Dart engines combined with its relatively unusual "pod and boom" basic configuration, which was similar to the earlier C-82 Packet and C-119 Flying Boxcar transport aircraft, has been attributed as the source of the type's nickname "The Whistling Wheelbarrow".

Operational history Civil use

United States Argosies operated within the United States on and off over a 30 year period, with the focus being flying on behalf of US government entities.

The Argosy Series 100 (aka AW.650) first entered service with the American cargo airline Riddle Airlines (later known as Airlift International). In the late 1950s, Riddle wanted to replace its large fleet of Curtiss C-46s and saw potential in the Argosy. In 1960, Riddle was awarded a US domestic Logair freight contract by the US Air Force on the basis of a five aircraft AW.650 fleet. See External links for a picture of a Riddle Argosy with Logair titles. A contemporary article noted the modestly-sized Argosy was well suited to Logair, being well adapted to a short-range system due to its ability to load and unload within 15 minutes. The Argosy's roller-floor system was modified to work with the US military's 463L pallet, of which the Argosy could accommodate 10.

But Riddle was financially distressed and unable to profitably fly the Argosies. In 1962 it returned its fleet of seven Argosies to Armstrong Whitworth in return for being let off the financial hook. By July 1962, Capitol Airways bought five of the ex-Riddle machines to work for Logair. But Capitol made a decision to exit domestic military flying, and the Argosies were out of its fleet by year end 1965.