Stearman 4

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Stearman 4
Stearman 4-D Lakeland FL 04.07R.jpg
Stearman 4-D of 1931 wearing markings of Western Air Express at Lakeland Florida in 2007
Role single-engined commercial biplane
National origin United States
Manufacturer Stearman Aircraft
Designer Lloyd Stearman
First flight 1930
Status several currently fly in private ownership
Primary user commercial
Number built 41
Unit cost
$16,000 base for a model 4E in 1929[1]
Developed from Stearman C3
A Stearman 4EM Senior Speedmail in the Canada Aviation Museum.

The Stearman 4 is an American commercial biplane that was manufactured in the 1920s by Stearman Aircraft. They were marketed at the time as fast and luxurious executive transports and mail planes for about US$1600. [2]

Development[edit]

Stearman Aircraft developed the Model 4 from the C3, adding a deeper fuselage and offering a range of more powerful engines. These features enabled the Model 4 to carry heavier cargo loads. Being larger than the C3, but smaller than the M-2 and LT-1 models, it filled a gap in the Stearman product line. Designer Lloyd Stearman said that it was the best airplane he ever designed.[3] Heaters were provided for both cockpits.

Operational history[edit]

Stearman sold the Model 4 to commercial operators in the United States, building 41 before ending production. Users of the type included Varney Air Lines and American Airways (later American Airlines). Standard Oil operated three Junior Speedmails for product promotion. The aircraft was produced in Wichita, Kansas from September 1929 to August 1930.[4]

The aircraft's rugged construction helped it survive heavy handling and loads, and thirteen remained on the U.S. Civil Register in 1965.[5] The aircraft later passed to private owners of veteran planes and a few still survive airworthy and in museums in 2007.[6]

Variants[edit]

Stearman 4C

Reference: Simpson[7]

4-C Junior Speedmail
300 hp (224 kW) Wright J6-9
4-CM Senior Speedmail
Similar to the 4-C, but a single-seat model with the front seat replaced by a dedicated forward cargo compartment.
4-D/4DX Junior Speedmail
300 hp (224 kW) Pratt & Whitney Wasp Junior The single 4DX produced had a canopy over both cockpits.[citation needed]
4-DM Senior Speedmail
Similar to the 4-D, but a single-seat model with the front seat replaced by a dedicated forward cargo compartment.
4-E Junior Speedmail
420 hp (313 kW) Pratt & Whitney C-1 Wasp or 450 hp (336 kW) Pratt & Whitney Wasp[8]
4-EM Senior Speedmail
Similar to the 4-E, but a single-seat model with the front seat replaced by a dedicated forward cargo compartment.
4-RM Special
Four seat model powered by a 450 hp (336 kW) Ranger GV-770
Model 80
A two-seat primary trainer variant from 1933 with dual controls, only one built with a Pratt & Whitney Wasp Junior engine.
Model 81 Sportster
A variant of the Model 80 with a cockit canopy and larger fuel tanks. Fitted with floats for a demonstration tour of South America and subsequently sold to the Mexican government.

Operators[edit]

 Canada

 United States

Aircraft on display[edit]

Survivors[edit]

Stearman NC667K at the 2013 SUN 'n FUN Fly-in and Expo
  • Stearman 4-E Junior Speedmail - Aircraft NC667K is the oldest surviving Model 4 Junior Speedmail still in operation. Originally delivered to the Richfield Oil Company in 1929, it flew exclusively as the flagship for Richfield's sponsorship of the "Jimmie Allen Flying Club" until 1937. Fully restored by Jim Kimball Enterprises in 2007, it is currently owned and operated by pilot Sarah Wilson and is a regular on the North American air show circuit.[2] In 2013, this plane won the Grand Champion - Antique award at Sun n Fun.[12]

Specifications (4-E)[edit]

Data from Green, 1965, p.298

General characteristics

Performance

References[edit]

Notes
  1. ^ Thomas E Lowe, Kennith D Wilson (Summer 1982). "Saga of a Square Tail Stearman". AAHS Journal. 
  2. ^ a b c "Vintage Time Machine; The Resurrection of the Jimmie Allen Junior Speedmail". Retrieved 2013-12-15. 
  3. ^ Skyways: 42. January 1999. 
  4. ^ Thomas E Lowe and Kennith D Wilson. "Saga of a square tail stearman". Journal of AAHS. 
  5. ^ Green, 1965, p. 298
  6. ^ Ogden, 2007, p. 604
  7. ^ Simpson, 2001, p. 521
  8. ^ Thomas E Lowe, Kennith D Wilson (Summer 1982). "Saga of a Square Tail Stearman". AAHS Journal. 
  9. ^ a b c Canada Aviation Museum (n.d.). "Stearman 4EM Senior Speedmail". Retrieved 2009-03-25. 
  10. ^ Davies, 1998, p=78-79
  11. ^ Davies, 1998, p=143
  12. ^ "Sun 'n Fun Fly-In and Expo Facebook Page Award Album". Retrieved 2013-12-15. 
Bibliography
  • Davies, R.E.G. (1998). Airlines of the United States since 1914. Smithsonian Institution Press. ISBN 1-888962-08-9. 
  • Green, William (1965). The Aircraft of the World. Macdonald & Co. (Publishers) Ltd. OCLC 2641875. 
  • Ogden, Bob (2007). Aviation Museums and Collections of North America. Air-Britain (Historians) Ltd. ISBN 0-85130-385-4. 
  • Simpson, Rod (2001). Airlife's World Aircraft. Airlife Publishing Ltd. ISBN 1-84037-115-3. 

External links[edit]

Media related to Stearman 4 at Wikimedia Commons