Piper's Short-Lived Star: The PA-50 Cayuga
The Piper PA-50 Cayuga was an American single-engined training monoplane designed by Piper for military and commercial markets.
The PA-50 grew out of Piper’s exploration into two-seat trainers in the late-1950s and early-1960s that initially culminated in the PA-29 Papoose. The Papoose proved that the PA-28 airframe could be successfully adapted into a two-seat trainer, but the all-composite construction proved to be too expensive for serial production and Piper quietly discontinued the project. In 1965, company executives decided to restart design work on a similar trainer, this time intended for the military market. The US Air Force had just recently decided to retire the T-34 Mentor and Piper’s management saw an opening for a similar aircraft with the USAF and foreign T-34 operators. Desperate to avoid the skyrocketing costs that the PA-29 experienced, the new design was to be all-metal and retain as much of the existing PA-28 airframe as possible. The PA-28R-180 Arrow, which was also currently on the drawing board, was determined to be the perfect starting point for the new aircraft (soon designated PA-50).
Designers began by removing the four-place cabin and replacing it with a sliding bubble canopy seating student and instructor in a side-by-side configuration. The landing gear was strengthened to support repeated hard landings by new student pilots and the fuselage was reinforced to increase G limits to +6/-3. The 180 horsepower Lycoming IO-360-B1E engine from the Arrow was quickly identified as too weak and Piper chose to fit the 300 horsepower Lycoming IO-540-K1A5 engine from the PA-32-300 instead. This engine gave the PA-50 excellent performance for an aircraft its size and gave it speed comparable to that of the T-34 it was intended to replace.
The first PA-50 rolled out of Piper’s Lock Haven facility in April 1969 and took flight on 1 June. Test pilots reported excellent visibility and an aircraft that was both stable and responsive. Marketing tours began in the fall and both the USAF and USN tested the aircraft in early 1970. The USAF, however, was not interested in purchasing the design as the Cessna T-37B had already become their standard primary trainer and replaced the T-34. Piper was simply too late to the party. The US Navy was similarly uninterested, having decided to retain the T-34 and develop the turboprop-powered T-34C. This left Piper without obvious domestic operators and focus shifted to foreign markets. Orders finally came in the summer of 1970, with Mexico placing an initial order for 15 aircraft and the Philippines ordering 48 aircraft to replace their T-34s. The line at Lock Haven went into full swing in early 1971 and serial production aircraft began rolling off the line in the summer. The US Army approached Piper in August 1971 about purchasing a small handful of aircraft to provide fixed-wing training for their pilots, a role that was at the time being fulfilled by the USAF. An order was finalized in early September for five PA-50s, to be operated by the US Army Aviation Center at Fort Rucker.
The US Army and Mexican Air Force orders were complete by spring 1972, but the larger Filipino order was still underway in early June when disaster struck. Torrential rains from Hurricane Agnes caused massive flooding along the Susquehanna River which drowned Piper’s facility in over 16 feet of water and destroyed over 100 aircraft. Tooling for several aircraft was completely destroyed, including equipment for the PA-24 Comanche and the PA-50 Cayuga. Production never resumed, and the Philippine Air Force sold their incomplete order to civilian operators and smaller militaries including several African nations. The Mexican Air Force and US Army remained the only original military operators of the PA-50, though Mexico retired their aircraft by 1980 in favor of a larger order of SIAI-Marchetti SF.260s. The US Army flew the type well into the early 1990s, before they too divested their fleet. Only 37 PA-50s were ever built.
Capacity: One Passenger
Length: 7.5 m
Wingspan: 9.2 m
Height: 2.9 m
Wing Area: 15 m2
Airfoil: NACA 652-415
Empty Weight: 1,605 lb
Gross Weight: 2,650 lb
Max Takeoff Weight: 2,650 lb
Powerplant: 1x Lycoming IO-540-K1A5 6-cylinder air-cooled horizontally-opposed piston engine, 300 hp
Propeller: 2-blade constant speed propeller
Never-Exceed Speed: 215 KIAS
Cruise Speed: 165 KIAS
Stall Speed: 55 KIAS (Flaps/Gear Extended)
Range: 375 nmi
Service Ceiling: 15,200 ft
Rate of Climb: 1,230 ft/min
Below is an excerpt of Sections I and II from the PA-50's Pilot Operating Handbook (1971 revision).