The Navajo was introduced 1964 as the - in these times - largest airplane of Piper. It was meant for business travelers and as air taxi and probably represents the maximum, which can be still flown by private pilots. 1967 began the distribution of the basic version with IO-540-K-Triebwerken with 224 KW each (305 HP), which as standard -, commuter and Executive execution were offered.
At the same time also the PA31-T turbo Navajo with TIO-540-A- engines with 231 KW (314 HP) came on the market, starting from 1970 then the PA-31P "Pressurized Navajo" with TIGO-541-E1A-engines with 317 KW (431 HP) and pressurized cabin. Navajo production was stopped 1972, as Piper the PA-31-350 Navajo Chieftain (later only "Chieftain") with one around 0.61 m. longer trunk and larger achievement presented. The PA-31-325 turbo Navajo C/R differed only by its achievement-weaker engines, which propelled propellers moving in opposite directions.
In the PA-31P-350 Mojave of 1983 one combined the cell of the Cheyenne II with the engines of the PA-31-350 Navajo. The airplane has depending upon cab interpretation six to eight seats. The very successful, twin-engine Navajo with a cab for six to eight passengers was taken up by a large number of commuters, charter flight companies, air taxi enterprises, light freight and transportation flight enterprises and was gone through a set of advancements, which finally led to the improved Piper Cheyenne 400LS. The PA 31 was developed as desired the companys' founder, William T. Piper, and the development program for a new, larger twin (multi-engine) was given the project name "Inca".
The prototype PA 31, which could start on 30 September 1964 to its first flight, was the largest airplane, which was built from Piper to these times, in the middle of the 60's. A small number of prototypes of the type PA31300s, equipped with first engines with an output of 225 KW (300 HP), before series production were built, before the production of the final sample was then taken up. The PA 31-310 manufactured in series Pipers "tiger shark" engine holding parts, alternatively also with a lockable cell, was equipped as well as with TIO-540 engines with an output of 230 KW (310 HP) with five cabin windows per side. In addition it had a higher maximum takeoff weight. The Pa 31-310 was developed further and improved, the development finally led still several times anschliessendn to the versions Navajo "B" and "C", and to the model Navajo "C/R" with moving in opposite directions turning propellers.
The Navajo PA31P (whereby the "P" stands for "pressurized"), equipped with a pressurized cabin, had three windows per side of the cabin, a new chassis, turbo-charged as well as TIGO 541-E1A of engines with fuel direct injection (contrary to normal carburetor engines), a higher takeoff weight, an intensified structure and a chassis, alternatively also still auxiliary tank, in order to carry extra fuel forward and to still increase thus the range of this twin, an extended nose and, which was most important probably, a pressurized cabin. The first PA-31 "Navajo" was flown in March 1968, the first deliveries took place from 1970 on, and the Navajo remained afterwards 14 years long in production, until the end of the year 1984. Meanwhile one year before the production end, 1983, was stopped the production of the turbo-charged version.
Further developments of the Navajos, including the "Chieftain", the "Mojave" and the "Cheyenne" are represented still separately (see below). back to the index of Piper airplanes Models "Mojave" and "Chieftain" These two models of the Piper PA-31 are equipped with eight to ten seats. The PA31P350 "Mojave" was the last version of the PA-31-Serie, which were equipped with a pressurized cabin, while the PA-31-350 could follow "Chieftain" the success of the "Navajos" within the range of the smaller air traffic, e.g. for pendulum and charter traffic.
The extended version Navajo "Chieftain" appeared first in 1973, in order to become fair the desire of the customers for a larger available space. After Piper had begun 1971 to sketch this model there was a larger delay (this by an inundation in the hauptbetrieb by the Piper was caused, which in June 1972 to the destruction of the second prototype and the first manufactured models led) in the development. Originally the model "Navajo II" was called and laid out in such a way by Piper regarding price, achievements and equipment that the Piper Navajo Chieftain could begin against the competition model Cessna 402 and partly also against the turbo-rehearse-propelled Beech 99.
As times went by, there were still many changes at the fundamental model of the "Navajo", including a 61 cm (2 foot) broader trunk (with appropriate increase regarding available space), six lateral cabin windows for the passengers, larger doors (an extra door for the pilots and the crew could be inserted alternatively likewise still with) and more efficient, likewise moving in opposite directions turning TIO-540 engines, it brought an achievement of full 260 KW (350 HP). From model year on 1980 the PA 31-350 became simply as "Chieftain" admit, and this airplane remained until October 1984 in production.
A further model, which was optimized for airlines (charter flights) and called "T1020", built Piper in smaller numbers of items, this by two Pratt and Whitney engines, type "Canada PT6" was propelled. Another version of the PA-31, the "Mojave", was a development of the Piper PA-31-P (Navajo), and its trunk was essentially the turbo-propane-driven PA-31T "Cheyenne I" similar. The changes, which Piper made with this model, covered less efficiently, engines moving in opposite directions of the type IO-540V-A, this brought it on 260 KW (350 HP), a lower cab pressure differential (thus changes at the cabin pressure adjustment) and bearing areas with larger span. The "Mojaves" was built between 1983 and 1986.