Waco F series

Development

The Waco 'F' series of biplanes supplanted and then replaced the earlier 'O' series of 1927/33. The 'F' series had an airframe which was smaller and about 450 pounds (200 kg) lighter than the 'O' series, while continuing to provide accommodation for three persons in tandem open cockpits. A similar performance to the earlier model was obtained on the power of smaller and more economical engines.

The initial models were the INF (125 hp (93 kW) Kinner engine), KNF (100 hp (75 kW) Kinner) and the RNF (110 hp (82 kW) Warner Scarab), all of which had externally braced tailwheel undercarriages. Many further sub-models followed with more powerful engines of up to 225 hp (168 kW). The most powerful in the range was the ZPF of 1936/37, intended for executive use.

Operational history

The 'F' series was popular with private owner pilots for sporting and other uses and continued in production through the late 1930s. The tandem cockpit UPF-7 was adopted by the Civilian Pilot Training Program and continued in production until 1942 by which time over 600 had been built.

The 1934 model YMF was substantially redesigned with a longer and wider fuselage, larger rudder and other structural changes, and put into production in March 1986 by WACO Classic Aircraft of Lansing, Michigan as the YMF-5. Over 100 YMF-5s were completed as of 2012 with new examples being built to specific orders.

The WACO Aircraft Company of Ohio Inc had built three replicas by December 2011, which they designated MF.

Considerable numbers of 'F' series biplanes, both original and newly built, remained in service in mid-2009.

Variants

Listed in approximate chronological order (per Simpson, 2001, p. 573)

INF

125 hp (93 kW) Kinner B-5, Certified ATC#345 on 2 August 1930.

KNF

100 hp (75 kW) Kinner K-5, Certified ATC#313 on 12 April 1930.

MF 

275 hp (205 kW) Jacobs R-755, built by WACO Aircraft Company of Ohio Inc by 2011

RNF

110 hp (82 kW) Warner Scarab, Certified ATC#311 on 7 April 1930.

PCF

170 hp (127 kW) Jacobs LA-1 and new cross-braced undercarriage, PCF-2 Certified ATC#473 on 2 October 1931.

PBF

as PCF with modified 'B' wings

QCF

165 hp (123 kW) Continental A70, QCF-2 Certified ATC#416 on 9 April 1931.

UBF

210 hp (157 kW) Continental R-670

UMF

210 hp (157 kW) Continental R-670A and longer wider fuselage and larger vertical fin

YMF

as UMF with 225 hp (168 kW) Jacobs L-4

YPF-6 and YPF-7

225 hp (168 kW) Jacobs L-4

ZPF-6 and ZPF-7

285 hp (213 kW) Jacobs L-5

UPF-7

tandem training version with wider-track undercarriage and 220 hp (164 kW) Continental radial (designated PT-14 by the USAAC)

YMF-5

new design roughly based on the YMF, built by WACO Classic Aircraft from March 1986 onwards.

YMF-5D

further improved variant of YMF unveiled in June 2009.

JW

Two UBF designated XJW-1 were used by the US Navy as hook-up trainers for the Curtiss F9C Sparrowhawk airship-borne fighters.

Note: from 1936 Waco added year suffixes to designations—e.g. YPF-6, YPF-7, with the numeral being the last figure of the model year.

Military operators

 Guatemala

Guatemalan Air Force - At least 1 Waco YMF-7 received in 1934. Was still in airworthy condition in 1998.

 United States

United States Army Air Corps - Adopted the UPF-7 as the PT-14, with one XPT-14 and 13 YPT-14s being purchased, with an additional UPF-7 impressed in 1942 as a PT-14A.

United States Navy

Specifications (UPF-7)

Data from Green, 1965, p. 307

General characteristics

Crew: 1

Capacity: 1 trainee or passenger

Length: 23 ft 1 in (7.04 m)

Wingspan: 30 ft 0 in (9.14 m)

Height: 8 ft 5 in (2.57 m)

Wing area: 244 ft² (22.67 m²)

Empty weight: 1,870 lb (848.22 kg)

Gross weight: 2,650 lb (1202.02 kg)

Powerplant: 1 × Continental W-670-6A seven cylinder radial, 220 hp (161.81 kW)

Performance

Maximum speed: 128 mph (207 km/h)

Cruise speed: 114 mph (185 km/h)

Range: 400 miles (644 km)

Service ceiling: 14,800 ft (4,511 m)