1931 Stearman Senior Speedmail 4CM-1

History

The Stearman Model 4

Lloyd Stearman started the Stearman Aircraft Factory in 1926 after having worked as an engineer at the Swallow and Travel Air Airplane Manufacturing companies.  The Model 4 was his fourth design at the new company and the last to be produced in any quantity.    Late in his life he said:  “It was the best airplane I ever designed.”

The Model 4 is a large biplane of classic proportions produced in three models that were virtually identical with the exception of engine and cockpit variations. 4C, 4D and 4E incorporated 2 cockpits with a provision for two passengers in the front cockpit with elegant interiors. The 4CM-1, 4DM-1 and 4EM-1’s were single place mail planes with large mail pits upfront and utilitarian interiors. Models 4C and 4CM-1 were powered with the 300 hp Wright J69 engines.  Models 4D and 4DM-1 were powered with 300 hp Pratt & Whitney R 985 engines. Models 4E and 4EM-1 were powered with 420 hp Pratt & Whitney 1340 engines.

Between 1929 and 1931, 41 Model 4’s were built.  Many were used as private and “corporate” aircraft.  Several large oil companies, including Texaco and Standard Oil used Model 4’s in their fleet. American Airways purchased twelve Model 4’s to be used as mail planes.

By the end of the 1930’s, the Model 4 was obsolete.  Most faded away but some survived as ships that American Airways sold to crop dusters that used them through the 1970’s.   It is estimated that there are seven flyable Stearman Model 4’s in the US.

N489W was flown by American Airways (The predecessor of American Airlines) for eight years – first as a mail plane and then as an instrument trainer with dual controls.  It then worked as a crop duster before being purchased for restoration.   The restoration project began in the 1990s, involving airframe refurbishment, all new wood in fuselage and wings, paint, electrical system, avionics, and a new engine.   The conformity inspection was completed in 1998.    The airplane saw minimal use over the next 18 years.

In 2016, the current owner brought the airplane to his home airport and started a project to update the restoration.   The final steps of the restoration, completed in 2021, included a fresh Covington Pratt and Whitney R-985, a new MT ground-adjustable propeller, new engine mount, new oil cooler, new exhaust and new avionics.   The work was accomplished with a FAA Form 8110-3 issued by a DER.   The engine has logged fewer than 100 operating hours.

N489W is painted in authentic Standard Oil of California colors.  The company operated three of these aircraft in the 1930’s painted in their Red, White and Blue color scheme with large wheel pants.

N489W exemplifies top-tier biplane design and performance.   Fast, smooth and long range with excellent ground handling.   In 2018, N489W participated in the 100 Year anniversary celebration of the US Airmail Service by flying the original CAM 8 airmail route from San Diego to Seattle.   In 2024, the airplane flew a round trip from Spokane to San Diego.   Both flights demonstrated the speed and range of the Speedmail.