WACO OPEN COCKPIT BIPLANES

1931’42

Plane & Pilot

Tuesday, November 30, 1999 at 12:00 AM ET

Verified

Edited By: Omar Filipović

Key Takeaways:

Waco open-cockpit biplanes, first produced in 1923, are predominantly represented today by the F series (introduced in 1930), with the UPF-7 being the most common survivor due to its extensive production as a primary trainer.
Waco aircraft utilized a detailed alphanumeric designation pattern to indicate specific features, with the first letter denoting engine type, the second for the wing, the third for the model style (including year of introduction and seating), and a number for the series.
Construction of Waco biplanes typically involved a wooden wing structure with a metal leading edge and a steel-tube fuselage, all covered in fabric.

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Waco open-cockpit biplanes were first produced in 1923. The most popular and common survivor is the UPF-7 (PT-14) because it was produced in the largest numbers as a primary trainer from 1937 to 1942. The Waco F series was the replacement for the older 1928 0 series and was put into production in 1930. The F series airplanes represent the majority of Wacos still seen flying. The first to be assembled were the INF and the KNF, which housed 125-hp and 100-hp Kinners respectively. In subsequent years, numerous models were added, each differing for the most part by the powerplant: in 1931, the PCF (170-hp Jacobs) and QCF (165-hp Continental); in 1932, the PBF (170-hp Jacobs) and UBF (210-hp Jacobs); in 1934, the UMF (210-hp Continental) and YMF (225-hp Jacobs); and in 1935, the CPF (250-hp Wright) and YPF (225-hp Jacobs).

An explanation is necessary for an understanding of the Waco designation pattern. In the case of the UPF-7, the U stands for the 220-hp Continental engine, the P stands for the Waco wing that was used, the F indicates the model with twin open cockpits and seating for three, and the 7 means it is the seventh in the series of this basic type. After 1930, the third letter designations indicating year of introduction and style were as follows: F, 1930 with seating for three in two open cockpits; G, 1930 single-seat; C, 1931 standard cabin model until 1935 when it became the custom model (20 mph faster); M, 1931 mail plane version; A, 1932 single open cockpit with side-by-side seats; D, 1934 military export open or closed tandem cockpits; C-2, 1935 Standard model; S, 1935 Standard cabin model with four seats; F, 1939 cabin model with five seats; and N, 1939 tricycle version of the C.

The first letter engine designations are as follows: A, 330-hp Jacobs; 13, 165-hp Wright; C, 250-hp Wright; D, 285-hp Wright; F, 350-hp Wright; H, 300-hp Lycoming; 1,125-hp Kinner; J, 365-hp Wright; K, 100-hp Kinner; M, 125-hp Menasco; O, 210-hp Kinner; P, 170-hp Jacobs; Q, 165-hp Continental; R, 110-125-hp Warner Scarab; S, 420-450-hp Pratt & Whitney Wasp Junior; U, 220-hp Continental; V, 240-hp Continental; W, 450-hp Wright; Y, 225-hp Jacobs; and Z, 285-hp Jacobs.

Waco construction generally consisted of a wooden wing structure with metal leading edge covered in fabric and a steel-tube fuselage also covered with fabric.