Sales success of the Cessna C-34 led to three improved versions of the versatile monoplane before the winds of war forced an end to production.
The year 1936 witnessed a slow return to economic stability for the United States. Times were still tough and unemployment remained high, but Americans were going back to work thanks in part to President Franklin D. Roosevelt’s “New Deal” policies. By the end of that year the Cessna Aircraft Company had delivered 42 of the popular C-34 cabin monoplane and demand remained steady. The competition, in particular the handsome Fairchild 24W and rugged Waco cabin biplanes, was becoming increasingly stiff. Dwane L. Wallace, who had assumed presidency of the company after Clyde Cessna resigned during the autumn of 1936, knew the time had come to reinvent the C-34.
Armed with only a shoestring budget, late that year Wallace and fellow engineer Tom Salter began thinking how best to improve the existing airplane. High on the list was increasing cabin comfort followed by redesigning the flaps and improving the main landing gear. Production No. 32 of the C-34 served as a prototype for what would become the Cessna C-37.
- Width of the forward fuselage increased 4 inches at the front wing fittings
- Adding 2 inches to the fuselage width at the rear corner of the cabin entry door
- Lowering the engine mount 2 inches
- Firewall narrowed by 1 inch
- Electrically operated wing flaps, although the original manual system was optional (the C-37 was the first Cessna airplane to feature wing flaps)
- Modifying the Warner engine’s cowling and baffle arrangement for improved cooling
- Increasing main landing gear tread to 7 feet
- Wheel size increased to 6.50 x 10 inches
First flight of the new ship occurred Dec. 22, 1936, with Wallace at the controls. As a result of these modifications a new Approved Type Certificate (ATC) was required, and ATC 622 was awarded by the Civil Aeronautics Authority (CAA) Feb. 8, 1937. The first production C-37 rolled out of the factory Jan. 22 and was one of 46 airplanes manufactured through December of that year. Price was $5,490 for a standard C-37, $6,000 for a “Deluxe” version with upgraded interior.
In addition to the standard airplane, Cessna offered a special version fitted with large windows in the lower forward fuselage and the cabin floor for aerial photography; seven were built. The C-37 was also approved for operation on Edo 44-2425 floats and the option included installation of a Curtiss-Reed metal propeller featuring a lower pitch and greater diameter than a standard propeller. Maximum gross weight was 2,500 pounds and an empty weight of 1,560 pounds compared to 2,250 pounds and 1,304 pounds, respectively, for a standard C-37.
Although the C-37 was popular and sold well, there was still room for improvement and the next year saw introduction of the C-38. It was the first of the series to be designated Airmaster – an appropriate name for Cessna’s little monoplane that, for its price range, mastered the competition in terms of overall value for the dollar.
The C-38 was very similar to its predecessor but incorporated a new main landing gear using a heat-treated, curved tube that increased tread width by 10.5 inches. The tube was made of 4130 chrome molybdenum steel with an outside diameter of 3 inches and a wall thickness of 5/32-inch. In addition, the oil-spring shock struts were improved by installing a new piston with four metering ports to allow more oil flow to better absorb takeoff and landing loads.
Other minor changes included installation of rubber Lord mounts to reduce engine vibration into the airframe structure, and a new tailwheel lock featuring a spring-mounted pin to secure the eight-inch tire in the trailing position until released for full-swiveling action. One peculiar feature of the C-38 was a large, split flap mounted under the fuselage immediately aft of the landing gear struts. It acted as more of a speed brake than a flap, providing a generous amount of drag so the pilot could carry more power on final approach to landing. The flap reduced landing airspeed to about 49 mph.
The flap was operated by a hydraulic pump under the instrument panel that was accessible from either front seat; a cable-operated indicator on the cockpit floor displayed its position. When fully extended the flap caused only a minor pitch change. The vertical stabilizer and rudder were slightly larger than those of the C-37, and the aileron and elevator were hinged using ball bearings to reduce friction. Changes were also made in the cockpit. The control sticks were relocated 6 inches farther forward, and the seats were more comfortable thanks to molded rubber cushions. Plexiglas replaced obsolete Pyrolin for the windows and windshield, significantly improving visibility for all cabin occupants. The C-37’s wind-driven Hodge generator in the right-wing leading edge was retained as standard equipment.
The C-38’s maximum speed was 162 mph at sea level with a cruise speed of 143 mph at 75% power setting. Price increased slightly to $6,490 for a standard airplane. The float-equipped version sold for $10,000 and featured complete corrosion proofing of the fuselage tubing and float fittings.
The CAA issued Cessna’s new Airmaster ATC 668 June 25, 1938. Only 16 of these airplanes were built before production was terminated in August of that year in favor of developing the next and final version, the Cessna C-145 and C-165.1
It was difficult to improve on the Airmaster because the basic design was sound and only minor refinements were considered. The chief change was the availability of two powerplants – the 145-horsepower Warner Scarab and the 165-horsepower version of the seven-cylinder radial engine. Initially, the airplane’s designation was to be C-39, but was changed to Cessna C-145 or C-165 depending on the engine installed. The prototype C-145 was completed in September 1938 with the C-165 following in April 1939.
The fuselage of both aircraft were lengthened to 25 feet from the C-38’s 24 feet, 8-inches, and empty weight increased to 1,380 pounds for the C-145 and 1,400 pounds for the C-165. Gross weight, however, was the same for both versions at 2,350 pounds. The cable-operated mechanical wheel brakes were replaced by a hydraulically actuated system operated by heel pedals in the cockpit. Only minor changes were made to the wings to accommodate flaps that were mounted immediately aft of the midchord point on the lower surface. The flaps were actuated electrically and were synchronized to extend and retract together. The aft cabin windows were curved to improve appearance and provided a slight increase in viewing area.
To increase the number of paint options, the company offered 27 different colors for the new Airmaster, including the popular “Pee Wee Green,” “Drake Blue” and “Diana Cream.” Standard practice in the dope and paint shops was brush coats of clear dope on the cotton fabric followed by two spray coats of clear dope to ensure proper tautening. Next, two coats of aluminum-pigmented dope were cross-sprayed followed by water sanding to ensure a smooth surface. Finally, three coats of color were cross sprayed that yielded a lustrous finish that reflected the high standard of workmanship found throughout the Airmaster series. To save weight, only two coats were applied to the bottom of the fuselage, horizontal stabilizer and elevator panels.
In terms of performance there was little difference between the C-145 and C-165, with a maximum speed of 162 mph and 169 mph, respectively. Rate of climb for the more powerful Airmaster was about 925 feet per minute (sea level) and service ceiling was 19,300 feet. Prices at the factory increased to $7,875 for a standard C-145, and $8,275 for the C-165. Airplanes built to accommodate Edo floats costed $10,635 and $11,035 (C-165).
One other version designated C-165D powered by a 175-horsepower Warner Super Scarab engine driving a Hamilton-Standard, constant-speed propeller. Only three were built, all in 1941. Production of the Airmaster ended that year after the company had delivered 42 of the C-145 version and 38 of the C-165.
During the seven-year production span covering the C-34, C-37, C-38 and C-145/C-165 airplanes, 186 airplanes were built. Today, the Airmaster is remembered as a pilot’s airplane. In 1941 it represented the current state-of-the-art for light aircraft design and construction and had established itself as one of the best examples of a four-place cabin monoplane found anywhere in the world. Few, if any, single-engine ship in its weight and engine cubic-inch displacement class could equal the Cessna’s overall performance and value for the dollar.
In 1936, Wallace flew a C-34 to victory in the Miami All-American Air Races that featured a series of different competitions similar to those held in 1935 by the Detroit News. A C-34 was declared the overall winner then, and Wallace repeated the feat, earning the C-34 the impressive title as “Worlds’ Most Efficient Airplane.” The C-34 and the Airmaster series was (and still is) a truly classic flying machine.2 The sleek monoplane kept the Cessna Aircraft Company in business when the economic times were tough and won praise and admiration from pilots fortunate enough to own and fly the patriarch of Cessna Aircraft’s product line.
It is important to note that in 1938 Cessna engineers were busy completing design details of Cessna’s Model T-50 – the company’s first twin-engine airplane that first flew in March 1939.
According to the FAA’s Aircraft Registry, as of 2018 there are 49 Airmasters listed in the United States. One Airmaster is flying in Australia (VH-UYG) and at least one airworthy Airmaster is based in England. Worldwide, it is estimated that about 15 airplanes are airworthy. (Information courtesy Dan and Wayne Muxlow, owners of the first C-34, NC12599.)