Stearman 4
| Stearman 4 | |
|---|---|
 | |
| 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 |
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
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
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]
In Canada, Trans-Canada Air Lines (later Air Canada) bought three Stearman for pilot training and surveying new routes in 1937 to 1938. The Stearmans were used from 1937 to 1939. One of them was known to be sold in March 1939.[5]
The aircraft's rugged construction helped it survive heavy handling and loads, and thirteen remained on the U.S. Civil Register in 1965.[6] The aircraft later passed to private owners of veteran planes and a few still survive airworthy and in museums in 2007.[7]
Variants
Reference: Simpson[8]
- 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.
- 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[9]
- 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
- American Airlines[10]
- Richfield Oil Company[2]
- Varney Air Lines[11]
- Western Air Express[12]
Aircraft on display
- Stearman 4EM Senior Speedmail - Canada Aviation and Space Museum, Ottawa, Ontario, Canada[10]
Survivors
- 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.[13]
Specifications (4-E)
Data from Green, 1965, p.298
General characteristics
- Crew: one
- Capacity: two passengers
- Payload: 600 lbs (272 kg)
- Length: 26 ft 4 in (8.0 m)
- Wingspan: 38 ft 0 in (11.6 m)
- Height: 10 ft 2 in (3.2 m)
- Empty weight: 2,426 lb (1100 kg)
- Loaded weight: 3,936 lb (1785 kg)
- Powerplant: 1 × Pratt & Whitney Wasp, 450 hp (336 kW)
Performance
- Maximum speed: 158 mph (256 km/h)
- Cruise speed: 128 mph
- Stall speed: 53 mph ()
- Range: 645 miles (1045 km)
- Service ceiling: 18,000 ft (5490 m)
- Rate of climb: 1,400 ft/minute (7.1 m/s)
References
- Notes
- ↑ Thomas E Lowe, Kennith D Wilson (Summer 1982). "Saga of a Square Tail Stearman". AAHS Journal.
- ↑ 2.0 2.1 2.2 "Vintage Time Machine; The Resurrection of the Jimmie Allen Junior Speedmail". Retrieved 2013-12-15.
- ↑ Skyways: 42. January 1999. Missing or empty
|title=(help) - ↑ Thomas E Lowe and Kennith D Wilson. "Saga of a square tail stearman". Journal of AAHS.
- ↑ "Historical Fleet - Stearman". Air Canada.
- ↑ Green, 1965, p. 298
- ↑ Ogden, 2007, p. 604
- ↑ Simpson, 2001, p. 521
- ↑ Thomas E Lowe, Kennith D Wilson (Summer 1982). "Saga of a Square Tail Stearman". AAHS Journal.
- ↑ 10.0 10.1 10.2 Canada Aviation Museum (n.d.). "Stearman 4EM Senior Speedmail". Retrieved 2009-03-25.
- ↑ Davies, 1998, p=78-79
- ↑ Davies, 1998, p=143
- ↑ "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
Media related to Stearman 4 at Wikimedia Commons
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