Stinson Model A

File:Stinson Model A Tri-motor airliner NC15165.JPG

1936 model Stinson Model A at Sun 'n Fun 2006.

The Stinson Model A was a moderately successful airliner of the mid-1930s. It was one of the last commercial airliners designed in the United States of America with a fabric-covered steel tube fuselage before the introduction of stressed skin aluminum construction.

Design History

The Stinson Aircraft Company’s last trimotor was a low wing monoplane, designed in 1933 as an eight-seat feeder-liner for American Airlines. Featuring an unusual double-tapered wing that, combined with its tubby fuselage and forward-raked windscreen, gave it a markedly sinister appearance, it also boasted retractable undercarriage that left the lower part of the wheels exposed below the engine nacelles while in the raised position, as many pilots forgot to lower the undercarriage on landing. Passengers were seated in two rows of three and a paired seat behind the enclosed cockpit, while fitted aft were a hold for 500 pounds of luggage and freight, and that ultimate luxury for the time, an on-board lavatory.

A total of 30 Stinson Model As were built until production ceased in 1936. It was one of many promising designs whose commercial success was cut short by the introduction of the stressed-skin Boeing 247 and Douglas DC-2.

The Stinson Model A in Australia

Airlines of Australia (AOA) ordered three Stinson Model As in January 1936 – because the waiting lists for either the new Boeing or Douglas were already too long. These aircraft were VH-UGG Lismore (arrived per s.s. City of Winchester on 27 March), VH-UHH Brisbane (arrived per s.s. Wichita on 22 June) and VH-UKK Townsville (arrived 22 July in the s.s. City of Manilla).

All three were quickly reassembled and entered the Sydney - Brisbane service, proving so successful that in August AOA ordered a fourth example VH-UYY Grafton – the very last Stinson Model A to be built – which arrived at Sydney on board s.s. Port Alma on 14 December.

Legendary air disasters and their consequences

With posturing from both AOA and Australian National Airways (ANA) to cut into each other’s turf by late 1936, early efforts by ANA to gain a controlling interest in AOA failed, until the tragic losses of VH-UHH Brisbane in the McPherson Ranges on 19 February 1937 and VH-UGG Lismore on 28 March halved AOA’s main-line fleet. A merger took effect in March 1937, although the two companies retained separate identities until AOA was formally absorbed into ANA on 1 July 1942. The two surviving Stinsons were then renamed VH-UKK Binana and VH-UYY Tokana, in conformity with ANA nomenclature.

Australian conversion from Trimotor to Twin Engine

During the Second World War spare parts for the Stinsons' aging Lycoming radial engines were impossible to obtain, and it was decided to rebuild both aircraft with twin Pratt & Whitney Wasps. The additional power allowed both aircraft to fly faster and carry higher loads, although fuel dumps had to be fitted to allow them to remain under their maximum landing weight of 10,750lb, in case of an aborted take-off.

On completion at Essendon, Victoria in May 1943, Binana returned to the Brisbane-Cairns, Queensland run, while Tokana was similarly converted and re-entered service in October on the run between Melbourne (Essendon), Kerang, Victoria, Mildura, Victoria and Broken Hill, New South Wales. Binana was later transferred to the Melbourne-Tasmania service.

A final Australian disaster

On the morning of 31 January 1945 Tokana was on the Essendon to Kerang leg of its regular service when the port wing separated in flight between Redesdale and Heathcote, fifty miles north of Melbourne. The aircraft then plunged to the ground, killing both crew and the full load of eight passengers. An investigation revealed that metal fatigue had developed in the wing’s lower main spar boom attachment socket, the actual failure possibly being instigated by the aircraft encountering a particularly heavy gust of wind. It was the first known occurrence of this type of accident in an aircraft anywhere in the world, but it was to become a problem all too common in later years where progressively larger aircraft would be built from light-weight alloys that were more susceptible to the underlying metallurgical phenomenon.

It being assumed that the same problems could occur in Binana, its certificate of airworthiness was cancelled, and the old aircraft was subsequently broken up.

Final years of the Stinson Model A

Outside of Australia, examples of the Stinson Model A soldiered on in such far-flung corners of the globe as Korea and Alaska for some years. One example still survives, having crashed in Alaska in 1947, being recovered and rebuilt in 1979, and finally passing to the Aviation Heritage Museum at Anchorage, Alaska in 1988.

A non-flying scale replica was built for a television movie account of the 1937 McPherson Ranges disaster, The Riddle of the Stinson.

Operators

Template:AUS

• Airlines of Australia
• Australian National Airways

Template:USA

• American Airlines

Specifications

General characteristics

• Crew: Two (pilot and co-pilot)
• Capacity: 8 passengers
• Length: 36 ft 10 in (11.22 m)
• Wingspan: 60 ft (18.29 m)
• Height: 11 ft 6 in (3.51 m)
• Empty weight: 7,200 lb (3,370 kg)
• Loaded weight: 10,500 lb (4,760 kg)
• Max takeoff weight: 11,200 lb (from 1944, as twin engine) (5,080 kg)
• Powerplant: 3× Lycoming R-680-5 nine-cylinder Radial, 260 hp (194 kW) each

Performance

• Maximum speed: 128 mph (206 km/h)
• Cruise speed: 116 mph (187 km/h)
• Range: 490 miles (790 km)

References

• John Wegg. General Dynamics Aircraft and their Predecessors, 1990, London: Putnam Aeronautical Books. 
• Macarthur Job. Air Crash, Volumes One and Two, 1991-92, Canberra: Aerospace Publications. 

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Stinson Model A".