“The Model 4 was the best airplane I ever designed!” declared Lloyd Stearman proudly. Forty of these aircraft were manufactured during the period 1929-1931 and perhaps a dozen or so remain. Juptner has this to say about the Model 4: “… the handsomest plane that Stearman ever built…with the N.A.C.A. low-drag engine cowling as an integral part of the configuration, the Stearman 4 was the first production biplane to utilize this deep engine fairing with any measure of the resulting performance caused other heretofore skeptical manufacturers to take a new look at the advantages to be gained with this type of air-cooled engine streamlining.” A few are still flying and by all accounts this is a fabulous airplane. Although it is smaller than the M-2 the Model 4 is larger than the Stearman trainer and therefore has occasionally been erroneously referred to as a “Bull Stearman.”
The Model 4 was designed to be either a single-seat mail plane or could be ordered with a two-passenger front cockpit. This utility was meant to appeal not only to air mail carriers, but also to corporations, which were beginning to use aircraft as promotional platforms, sales aids and executive transports. In spite of the fact that this aircraft had the misfortune to appear during the Depression, several were sold to wealthy private owners as well as corporations (particularly oil companies). Some mail plane versions went to Canada. American Airways bought the final ten examples produced. The Model 4, known as the “Junior Speedmail,” was offered with a choice of three engines:
*4C Wright J-6-9 “Whirlwind” 300 hp
*4D Pratt & Whitney R-985 “Wasp Jr.” 300 hp
*4E Pratt & Whitney R-1340 “Wasp Sr.” 420-450 hp
The mail plane carried the “M” suffix and was known as the “Senior Speedmail.” Three 4EMs were built for Canadian National Airways. There are several of these legendary aircraft still flying. Stearman 4E NC785H is the only one remaining of three built for Standard Oil of California in 1930. With speed fairings and wheel pants, this aircraft represents the pinnacle of biplane design and performance from that era.