Piper PA-23, named Apache and later Aztec, was the first twin-engine
aircraft built by Piper Aircraft.
Originally to be named the "Twin-Stinson"
and designed as a four-seater low-wing all-metal monoplane
with a twin tail, the prototype first flew 2 March 1952. The
prototype was then named the PA-21 to conform to Piper's numerical
nomenclature It was redesigned with a single vertical stabilizer
and an all-metal rear fuselage and renamed to Apache 150 when
it entered production in 1954; 1,231 were built. In 1958,
the Apache 160 was produced by upgrading the engines to 160
hp (119 kW), and 816 were built before being superseded by
the Apache 235, which went to 235 hp (175 kW) engines and
swept tail surfaces (119 built).
Declining sales of the Apache
prompted the redesign dubbed PA-23-250 Aztec, with 250 hp
(186 kW) Lycoming. The first models were delivered with O-540
Lycoming carburetor engines. These first models came in a
five-seat configuration which became available in 1959. The
later models of the Aztec were equipped with IO-540 fuel-injected
engines and six-seat capacity, and continued in production
until 1982. There were also turbocharged versions of the later
models, which were able to fly at higher altitudes.
Among other light twin-engined
airplanes of its generation, the Aztec was known for its good
load hauling, long endurance, stable handling, and respectable
single-engine performance, at the cost of higher fuel consumption
and a draggier (slower) airframe. Part of the drag was due
to use of the same basic wing design (albeit with substantially
different dimensions and construction) as the Piper Cub series
of aircraft. The Piper Cub airfoil gave the Aztec superior
short field operation characteristics at the price of lower
performance at cruising speeds.