C-81 Reliant

The Stinson Reliant is a popular single-engine four- to five-seat high-wing monoplane manufactured by the Stinson Aircraft Division of the Aviation Manufacturing Corporation of Wayne, Michigan.

Design and development

The Reliant is a high-wing, fixed-tailwheel land monoplane powered with a variety of radial engines.

1,327 Reliants of all types were made from 1933 to 1941, in different models, from SR-1 to SR-10. The final commercial model, the Stinson Reliant SR-10, was introduced in 1938. A militarized version was first flown in February 1942 and remained in production through several additional versions (all externally identical) until late 1943 for the US and British armed forces.

Reliant production can be broken into two distinct types – the straight-wing Reliants (all models up to SR-6) and the gull-wing Reliants (all models from SR-7 and after, including the militarized V-77/AT-19), with there being little in common between the two groups of types. The straight-wing Reliant has a wing of constant chord and thickness which is supported by two struts each side with additional bracing struts. In contrast the taper-wing Reliant has the broadest chord and thickness of the wing at mid-span, with the outer wing trailing edge heavily angled forward and a rounded cutout on the leading edge root, all supported by a single strut. The taper wing has a significant step up between the fuselage and the wing, and the changes in wing thickness gave it a distinct gull appearance from the front.

Operational history

The Reliant was used by the United States Army Air Forces in World War II as a utility aircraft, designated UC-81, and as trainer designated AT-19. The Royal Navy and Royal Air Force also used Reliants, for light transport and communication duties. After the war they were sold on the civilian market as the Vultee V-77.

The V-77 is a spartan version of the SR-10 with the 300 hp Lycoming R680-E3B, a single door on the left side and the traditional "bump" cowl was replaced with a simpler smooth cowl. Internal structure was beefed up significantly over the commercial models, and a distinctive triangle-shaped counterbalance was added to the rudder.

Variants

All versions of the Reliant were powered with radial piston engines, and could be operated on wheels, floats and skis, and in the following configurations:
* Cargo
* Ambulance (two stretchers)
* Firefighting
* Photographic mapping

Civilian variants

*SR Reliant: Powered by a Lycoming R-680.Wegg 1990, pp. 131, 133.
*SR-1: Powered by a Lycoming R-680-2. Two built.Wegg 1990, p. 132.
*SR-2: Powered by a Lycoming R-680-7.
*SR-3: Similar to the SR-1, but with retractable undercarriage.
*SR-4: Powered by a Wright R-760-E.
*SR-5: Powered by a Lycoming R-680-4.
*SR-5A: Powered by a Lycoming R-680-6.
*SR-5B: Powered by a Lycoming R-680-2.
*SR-5C: Powered by a Lycoming R-680-5.
*SR-5E: Powered by a Lycoming R-680-4.
*SR-5F: Powered by a Wright R-760-E.
*SR-6: Four-seat cabin aircraft, powered by a Lycoming R-680-6.
*SR-6A: Four-seat cabin aircraft, powered by a Lycoming R-680-4.
*SR-6B: Four-seat cabin aircraft, powered by a Lycoming R-680-5.

*SR-7: First gull wing series.
*SR-7B: Four-seat cabin aircraft, powered by a Lycoming R-680-B6. 47 built.Wegg 1990, p. 135.
*SR-7C: Four-seat cabin aircraft, powered by a Lycoming R-680-B5. Three built.
*SR-8A: Five-seat cabin aircraft.
*SR-8B: Five-seat cabin aircraft, powered by a Lycoming R-680-B6.
*SR-8C: Five-seat cabin aircraft, powered by a Lycoming R-680-B5.
*SR-8D: Five-seat cabin aircraft, powered by a Wright R-760-E2.
*SR-8DM: Utility transport version of the SR-8D.
*SR-8E: Five-seat cabin aircraft, powered by a Wright R-760-E23.
*SR-8DE: Utility transport version of the SR-8E.
*SR-9: 1937 series. Fitted with a curved windshield, unique to this series.
*SR-9A: Proposed version with Lycoming R-680-B4 engine. Unbuilt.
*SR-9B: Powered by a Lycoming R-680-B6 engine. 35 built.''Aviation'' February 1937, p. 36.
*SR-9C: Powered by a Lycoming R-680-B5 engine. 65 built.
*SR-9D: Powered by a Wright R-760-E1 engine. 22 built.
*SR-9E: Powered by a Wright R-760-E2 engine. 43 built.
*SR-9F: Powered by a Pratt & Whitney Wasp Junior. 34 built.
*SR-10

*SR-10B: Powered by a Lycoming R-680-D6. One built.Wegg 1990, p. 136.
*SR-10C: Powered by a Lycoming R-680-D5 engine. 46 built.
*SR-10D: Wright R-760E-1 engine. 3 built.Wegg 1990, pp. 136–137.
*SR-10E: Powered by a Wright R-760E-2. 21 built.
*SR-10F: Powered by a Pratt & Whitney R-985 Wasp Junior SB. 18 built.
*SR-10G: Powered by a Lycoming R-680-E1. 12 built.
*SR-10J: Lycoming R-680-E3 engine. 11 built.
*SR-10K: Powered by a Wright R-975E-3. 2 built for New York City Police Department; one with conventional landing gear, one seaplane with Edo floats.

Military variants

;AT-19
:USAAF designation for a training variant of the UC-81 for the Royal Navy under Lend-Lease as the Reliant I, 500 built.
;AT-19A
:Original designation of the L-9A which was a Voyager not a Reliant.

;AT-19B
:Original designation of the L-9B which was a Voyager not a Reliant.
;AT-19C
:Conversions of AT-19s for photo-survey aircraft for the USAAF, 51 conversions.
;UC-81:
:Four impressed SR.8Bs.
;UC-81A
:Two impressed SR.10Gs.
;UC-81B
:One impressed SR.8E.
;UC-81C
:Three impressed SR.9Cs.
;XC-81D
:One civil SR.10F operated by the military for the development of glider pick-up techniques.
;UC-81E
:Four impressed SR.9Fs.
;UC-81F
:Seven impressed SR.10Fs.
;UC-81G
:Three impressed SR.9Ds.
;UC-81H
:One impressed SR.10E.
;UC-81J
:Nine impressed SR.9Es.
;UC-81K
:Five impressed SR.10Cs.
;UC-81L
:Two impressed SR.8Cs.
;UC-81M
:One impressed SR.9EM.
;UC-81N
:Two impressed SR.9Bs.
;L-12
:Two SR.5As impressed into service with the USAAF during World War II.
;L-12A
:Two SR.7Bs impressed into service during World War II.
;RQ-1
:One SR-5 Reliant was acquired by the US Coast Guard in 1935, later redesignated XR3Q-1 and decommissioned in 1941.Pearcy 1991, p. 317.
;XR3Q-1
:One SR-5 Reliant was acquired by the US Navy in 1935.Swanborough and Bowers 1976, p. 469.
;Reliant I
:500 Reliants were supplied to the Royal Navy under Lend-Lease. The Reliants were used for light transport and communications, navigation and radio training duties.

Operators

Military operators

;
*Argentine Navy
;
*Royal Australian Air Force – 1
;:
* Royal Air Force
** No. 510 Squadron RAFHalley 1980, p. 306.
* Fleet Air Arm
** 730 Naval Air Squadron
** 748 Naval Air Squadron
;:
* United States Army Air Forces – A total of 47 Reliants impressed during World War 2Swanborough and Bowers 1963, p. 532.
* United States Coast Guard
* United States Navy
;
* Uruguayan Air Force

Civil operators

;
* Aerolloyd Iguassu
* Aerovias Minas Gerais
* NAB – Navegação Aérea Brasileira
;:
*Grupo TACA
;:
* Aeronaves de México – the Reliant was the first aircraft used by Aeronaves, later to become Mexico's largest airline, Aeromexico, on their initial service between Mexico and Acapulco on 14 September 1934Aeromexico – The Story of a Great Company
last accessed on 2012 November 30
;
*Widerøe
;:
* Líneas Aéreas de Transporte Nacional (LATN)
;:
* New York City Police Department Aviation Unit
* Northwest Airways

Specifications (SR-10F)

See also

References

Bibliography

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External links

Stinson SR-10F Reliant National Air and Space Museum, Smithsonian Institution
*
Stinson SR-9 Alberta Aviation Museum

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1930s United States civil utility aircraft
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