AW 660 Argosy – Twin-Boom Transport
The Armstrong Whitworth AW 660 Argosy was developed in response to a British government military specification issued in the 1950s. The AW 660 project was intended to be a military aircraft but successive developments led to its design and service being altered towards the civilian commercial market when the Royal Air Force lost interest in the idea.
With a unique pod fuselage design and impressive payload capacity, the Argosy quickly became a favourite among airlines and air freight carriers. Its unique design helped to renew RAF interest in the project and this enabled the Argosy to progress from a would-be prototype to see extensive service in both civilian and RAF roles.
In 1955, the British Air Ministry issued an aircraft specification known as Operational Requirement 323. The specification called for the design of a new, medium to long-range large transport aircraft to replace the Royal Air Force’s (RAF) fleet of ageing piston-driven Handley Page Hastings and Vickers Valetta transporters.
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The specification asked that the new design be an improvement on the Hastings’ capabilities and be capable of carrying a payload of up to 25,000 lb worth of cargo with a range of 2,000 miles. It also called for increased speed and flexibility.
British manufacturer Armstrong Whitworth Aircraft responded to the specification call and assembled their design team to begin work on drafting ideas. The first design blueprint envisaged a twin-engine military aircraft which the company designated as the AW 65 and AW 66.
As the design process continued, Armstrong Whitworth saw potential value in marketing the aircraft to civilian operators as a mixed freight and passenger plane.
However, financial constraints and concerns about lack of funds in meeting the specification almost consigned the AW 65 AND 66 ideas to nothing more than drawings and the project faced shelving.
By the 1950s, Armstrong Whitworth had also become a division of the larger Hawker Siddeley Aircraft Company (now BAE Systems). Both companies saw potential in the idea and continued the AW 65 project as an aircraft for the civilian market and with Hawker Siddeley’s financial backing, Armstrong Whitworth resumed the concept.
The AW 65 design team continued working on the civilian model from the initial base work for the military variant, but the design was altered to feature full section doors at each end of the fuselage (beneath the nose and tail) to allow for more flexible loading and unloading of large objects or vehicles.
The final result was a unique high-wing, four-engine aircraft with a distinctive “double-bubble” fuselage design to allow for generous cargo and passenger space.
Four Rolls-Royce Dart turboprop engines were added to the design to power four bladed propellers on each side. The aircraft was renamed the AW 65 Argosy by Armstrong Whitworth.
The total wingspan of the Argosy was 115 feet.
Perhaps one of the most notable features of the Argosy was its “kneeling” landing gear. The main landing gear of the aircraft was designed to safely lower the aircraft’s cargo deck to the ground, making it easier to load and unload cargo. The lowering feature was controlled by the flight engineer who could raise or lower the gear in accordance with the size and weight of the cargo placed on board.
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In January 1959, the AW 65 completed its maiden flight. It was showcased to audiences and potential clients at the Paris Airshow and the Farnborough Airshow where it was marketed as the AW 65 Argosy Series 100.
Five more units were subsequently manufactured. Certification testing was completed in September 1960 enabling it to perform commercial duties in the United Kingdom. In December of the same year, it also received its certification from the US Federal Air Administration to allow use of the AW 65 in American airspace.
Ten completed airframes of the Series 100 were completed by Armstrong Whitworth, most of which had been manufactured before the certifications were granted enabling a quick delivery to new customers.
The AW 65 saw commercial service with Riddel Airlines in the United States who planned to use the aircraft to perform contracted freight duties on behalf of the US Air Force. When Riddel lost the military contract in 1961, Armstrong Whitworth purchased back the Argosy airframes and sold them to airlines that had taken over Riddel’s contracts.
Two of the AW 65 units were fitted with a pressurized cabin capsule to provide more comfort for passengers and these served with SAFE Air of New Zealand.
In the UK, the Series 100 unit was used by British European Airways (BEA) until 1964 when Armstrong Whitworth introduced the updated Series 220 variant of the Argosy. These served with BEA on different routes to continental Europe until 1970 when they were withdrawn to due lack of profit.
The final civil operator of the AW 65 was the American cargo airline Duncan Aviation who withdrew their final Argosy from service in 1991.
Military Development & Service
Although the RAF had lost interest in the initial Argosy project, it still needed to replace its aging piston engine fleet of transport planes.
The Air Ministry drew up a second specification for Armstrong Whitworth to produce a military variant of their AW 65 civil designs in 1959. The Air Ministry called for the military variant to serve as a duel purpose transport and troop carrying plane, with the ability of either ferrying a cargo load of up to 29,000 lb or being able to transport 69 troops plus 48 stretcher cases and medical provisions.
The specification for the cargo load was intended to allow the Argosy to carry armoured cars such as the Alvis Saracen and the Daimler Ferret to overseas British bases and combat zones.
Armstrong Whitworth decided to create the new military version in tandem with their civilian design and it was designated as the AW 660. They wanted the new design to feature a quick loading time that would save having to use cranes, pallets and wide loading containers to load and contain the cargo.
Although the structure followed the same format as the civilian AW 65, significant changes were made to prepare it for military use.
For example, the front loading cargo door in the nose was removed to make way for a radome unit to contain a weather radar and navigation equipment. At the rear, the single hinge loading door was replaced by a “clam shell” design which opened from the top and bottom. Armstrong Whitworth also increased the engine power and fuel capacity of the aircraft to ensure maximum efficiency when flying long distances.
After initial proving and tests, the AW 660 Argosy entered service with the RAF in 1961. The first production aircraft was delivered to the RAF’s No. 105 Squadron.
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Despite its shaky start over the first RAF specification, the AW 660 proved to be the most successful model of the Argosy with a total of 74 of the AW 660 units being built and delivered the RAF. As intended, the Argosy saw service in a variety of roles, including troop transport and air-to-air refueling.
The AW 660 first saw overseas deployment in 1962 when the 105 Squadron units were transferred to the Middle East. In 1963, a further fleet of Argosy’s were given to RAF 215 Squadron based at Changi Airport in Singapore. The Argosy fleet remained in Singapore until 215 Squadron’s disbandment in December 1967.
In 1963, Hawker Siddeley retired the names of their component businesses meaning the Armstrong Whitworth name disappeared. Instead, the Argosy was now manufactured and sold as the Hawker Siddeley Argosy Mark 1.
The Argosy fleet was then moved to Cyprus where they were based at RAF RAF Akrotiri and reallocated to No. 70 Squadron.
Although the Argosy proved itself to be a reliable and flexible transporter, the RAF began to phase it out of service by 1970 to make way for the newer Lockheed Hercules from America as the RAF’s main transport aircraft.
The final Argosy units remained in service with No. 115 Squadron within the UK and were assigned to RAF Cottesmore in 1964. These remained in service as the last RAF Argosy’s until 1978 when the last unit was retired and was replaced by the Hawker Siddeley Andover transport plane.
After its retirement as an RAF air freighter, there was talk of using the Argosy as an instructing aircraft to train RAF crews on navigation. RAF Trainer Command held discussions with Hawker Siddeley on modifying airframes to fit this role. Hawker Siddeley purchased back two Argosy units to begin work on modified prototypes
Hawker Siddeley presented the updated designs to the RAF as the Argosy T2 trainer with the proposal it would serve with No. 6 Flying Training School Squadron. However, the new project was terminated due to defense budget cuts in the late 1970s and early 80s and the Argosy was completely withdraw from military service.
The Armstrong Whitworth AW 660 Argosy was a unique and impressive aircraft design that left a lasting mark on the aviation industry. Its distinctive features, versatile capabilities, and impressive performance made it popular among air freight carriers, both military and commercial.
It also showed that perseverance at Armstrong Whitworth helped the AW 660 Argosy to see both air force and civilian service rather than just been consigned to history as a one off prototype or a drawing.
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The AW 660 Argosy may no longer be in service, but it will always be remembered as a true icon of the aviation industry, and a testament to the ingenuity and skill of the designers and engineers at Armstrong Whitworth.
- Crew: Four
- Capacity: up to 69 troops, 54 paratroops, 48 stretcher cases or 29,000 lb (13,000 kg) of cargo
- Length: 86 ft 9 in (26.44 m) (overall length)
- Fuselage length: 64 ft 7 in (19.69 m)
- Wingspan: 115 ft 0 in (35.05 m)
- Height: 29 ft 3 in (8.92 m)
- Empty weight: 56,000 lb (25,401 kg)
- Max takeoff weight: 105,000 lb (47,627 kg)
- Powerplant: 4 × Rolls-Royce Dart RDa.8 Mk 101 turboprops, 2,470 shp (1,840 kW) each
- Cruise speed: 253 mph (407 km/h, 220 kn)
- Range: 3,450 mi (5,550 km, 3,000 nmi)
- Service ceiling: 23,000 ft (7,000 m)