The Pacer and the Tri-Pacer were the first post-
World War II Piper designs with
flaps and a
control yoke instead of a
center stick, and they belong to a sub-group of Piper aircraft popularly called "short wing Pipers," reflecting their shorter wingspans compared to the earlier
J-3 Cub and
PA-18 Super Cub. The
PA-20 Pacer is a
tailwheel aircraft and thus has somewhat limited forward visibility on the ground and relatively demanding ground-handling characteristics. To help introduce more pilots to easier, safer flying, from February 1951, Piper introduced the
PA-22 Tri-Pacer with a
nosewheel instead of the tailwheel landing gear. Additionally, the Tri-Pacer offered higher-powered engine options in the form of and , whereas the largest engine available to the original Pacer had an output of . At that time the tricycle undercarriage became popular and 1953 saw the PA-22 Tri-Pacer outsell the Pacer by six to one. Due to the geometry of the nosewheel, the aircraft is sometimes called the "Flying Milk Stool." In 1959 and 1960, Piper offered a cheaper, less well-equipped version of the Tri-Pacer with a
Lycoming O-320 designated the
PA-22-150 Caribbean. Over 9400 Tri-Pacers were produced An unusual feature of the Tri-Pacer is
bungees linking the
ailerons and
rudder to facilitate
coordinated flight. The system can be easily overcome by the pilot as needed and allowed the installation of a simple Mitchell Industries transistorized
autopilot marketed by Piper under the name
Auto-control. It has roll and yaw data derived from a modified AN5735-1 Direction Indicator and AN5736-1 Gyro Horizon, boosted by a piggyback amplifier on the direction indicator driving a Globe Motors bi-directional motor/servo clamped to the top of the control column via the aileron control chains. A trainer version of the PA-22 Tri-Pacer, the
PA-22-108 Colt, was introduced to compete directly with other popular trainers such as the
Cessna 150, and was powered by a
Lycoming O-235. Quickly designed in late 1960, the two-seat Colt was offered at a substantially lower price than the Tri-Pacer, and omitted the four-seat aircraft's flaps and second wing tank along with the rear side windows and door. The Colt otherwise closely resembles the Tri-Pacer, using the same front seats and door, landing gear, engine mounts, windshield, tail surfaces, struts and instrument panel. Over 2,000 Colts were manufactured and it was the last Pacer variant—and thus the last short wing Piper—to be dropped from production. The last batch of 12 PA-22-150s were built for the
French Army in 1963 and the last of the family, a PA-22-108 Colt, was completed on 26 March 1964. The type was replaced on the Vero Beach production line by the
PA-28 Cherokee 140. Some PA-22s have been converted to a tailwheel configuration, resulting in an aircraft very similar to a PA-20 Pacer, but retaining the refinements and features of the PA-22. These conversions are often referred to by owners as
PA-22/20s and are often listed in classified aircraft ads as such, although officially such converted aircraft continue to be designated by the FAA as PA-22 Tri-Pacers. When this conversion is made, disc brakes are usually installed in place of the original
drum brakes, and the Lycoming O-360 180 HP engine is the preferred upgrade. Some PA-22s have a
Hartzell constant-speed controllable propeller or Koppers Aeromatic propeller. These installations improve performance and economy at the sacrifice of payload. A few Colts have also been converted to tailwheel configuration, although this is not as popular. ==Operational history==