March 2005-
In the years immediately after World War II, General Aviation was growing—but not very predictably. Manufacturers were constantly going from feast to famine, and several old, venerable airplane companies had gone broke when they found they couldn’t survive the market fluctuations.
There was one emerging market, however, in which a few of the more far-seeing planemakers were interested—Business Aviation—bigger, faster, more sophisticated (and profitable) equipment that was flown for commerce instead of for enjoyment.
Beech Aircraft had known that since the 1930s. Their Model 18 was the leader in the smaller, owner-flown multi-engine market, and they had premiered the Model 50 Twin Bonanza in 1953. Not coincidentally, Cessna was also at work getting certification for its Model 310.
Back in Lock Haven, William T. Piper reckoned that not all that many folks could afford the $80,000 Model 50, the $100,000 Twin Beech or the upcoming Cessna twin—which was projected to be somewhat north of $50,000.
What Piper needed was a good, inexpensive entry into the lucrative twin market and an easing away from its “Cub” image. The answer was already in the files of the company’s engineering department. In 1948, Piper had purchased the assets of the Stinson Division of Consolidated Vultee, and among the papers they had received was a proposal and plans for a “Twin Stinson.”
A low-wing four-seater, it was to be of steel tube construction with fabric-covered fuselage and outer wing panels, have a high-mounted horizontal tail with endplates and twin vertical tails, would be powered by 125 hp Lycoming O-290s with fixed-pitch props, and would be on fixed tricycle gear. To no one’s surprise, it did not fly well.
Back in the experimental shop, the Stinson was transformed into a Piper. Engine power was increased to 150 hp with Lycoming O-320s and constant-speed props, fabric was replaced with aluminum, a partially retracting gear assembly was fitted and the aft fuselage was redesigned from the cabin rearward to mount a single vertical tail.
The prototype (s/n 23-1) was completed in late July 1953, and a second pre-production aircraft (s/n 23-2) was finished in December. These two aircraft were used for certification, and the TC was issued on February 2, 1954. Deliveries started immediately with s/n 23-04. Annual detail refinements resulted in designation changes.
The 1955 Apache B (s/n 121-375) and C (s/n 376-746) were followed by the D in 1957. After production of the Apache E had begun for the 1958 model year, engine power was increased to 160 hp, and the PA-23-160 began with s/n 1068. The F model was similar, but with new auto control system and the G provided extra cabin windows for the fifth seat passenger.
Beginning in 1962, the Apache became the PA-23-235 with the addition of O-540 Lycomings and a half-ton to its gross weight. Production would continue until 1965, even though the improved and renamed PA-23-250 Aztec had taken over the bulk of sales after its 1960 premiere.
More than merely a name change, the $53,000 Aztec was sleeker than its predecessor. It featured a redesigned swept tail and 250 hp O-540 engines. Aztec had originally been assigned PA-27 in-house, indicating that the company intended to get a new Type Certificate, but that expense was deemed unnecessary and the official designation remained PA-23 (although all Aztec serial numbers are prefixed 27-).
On the B variation of 1962, a longer and more pleasing nose replaced the original rather blunt unit, and marked the debut of fuel injection, and turbocharging gave the model a 236 mph top speed. The Aztec would continue the line into the early 1980s.
Meanwhile, the ever-popular Apache had attracted the attention of modifiers over its lifetime. The Sequin Geronimo featured 180 hp O-360-A10 engines and a modification to the vertical fin and rudder surfaces, and the Miller Apache version fitted it with 200 hp IO-360s.
Over its useful life, the carrying capacity of the PA-23 Twin Stinson/Apache/Aztec grew by 1700 lb, its seating by a third and its speed by nearly 70 mph, and it has delivered good, consistent, economic performance throughout the last half-century.
In 1961, Max Conrad flew a PA-23 around the world in 8 days, 18 hours, 36 minutes for a Class C-1-d (3,858 lb-6,614 lb) record, averaging 123.2 mph for 25,946 miles. In the same class, Frances Bera holds the world altitude mark of 40,154 ft, and in 1984, J. Browne flew from Madras to Singapore at a record 286.92 km/hr (177.9 mph) average.
More than 2,000 Apaches were manufactured at Lock Haven between 1954 and 1965, along with 4,929 Aztecs. The Twin Stinson design had 125 hp engines and fixed gear when it first flew in 1952.
After a serious rework program, s/n 23-01 became the first Apache late in 1953. N1000P, s/n 23-2, had 150 hp Lycoming engines, retractable gear and a conventional tail. Built as a production prototype in December 1953, it flew in certification trials, and the Type Certificate for the PA-23 Apache was issued February 2, 1954.
Daryl Murphy has been writing about and flying a variety of aircraft for 36 years. In addition to this magazine, his work appears in General Aviation News and Aviation International News, and he has written five aviation books and one on automobile racing.
