Monday, June 1, 2009

PIPER PA-31 “NAVAJO”


1967–84



STANDARD DATA: (C) Seats 5-8. Gross wt. 6,500. Empty wt. 4,003. Fuel capacity 187. Engines two 310-hp turbocharged Lycomings.
PERFORMANCE: Top mph 261. Cruise mph 248. Stall mph 81. Initial climb rate 1,220. Range 1,125. Ceiling 24,000. Takeoff distance (50') 2,290. Landing distance (50') 1,818.

STANDARD DATA: (CR) Seats 5-8. Gross wt. 6,500. Empty wt. 4,099. Fuel capacity 183-237. Engines two 325-hp turbocharged Lycomings, counterrotating.
PERFORMANCE: Top mph 265. Cruise mph 253. Stall mph 80. Initial climb rate 1,220. Range 1,082-1,485. Ceiling 24,000+. Takeoff distance (50') 2,440. Landing distance (50') 1,818.

STANDARD DATA: (Chieftain) Seats 5-10. Gross wt. 7,000. Empty wt. 4,221. Fuel capacity 182-236. Engines two 350-hp turbocharged Lycomings, counterrotating.
PERFORMANCE:
Top mph 267. Cruise mph 254. Stall mph 85. Initial climb rate 1,120. Range 1,018-1,392. Ceiling 27,200. Takeoff distance (50') 2,780. Landing distance (50') 1,880.

STANDARD DATA: (Pressurized) Seats 6-8. Gross wt. 7,800. Empty wt. 4,842. Fuel capacity 192-242. Engines two 425-hp turbocharged Lycomings.
PERFORMANCE: Top mph 280. Cruise mph 272. Stall mph 83. Initial climb rate 1,740. Range 995. Ceiling 29,000. Takeoff distance (50') 2,200. Landing distance (50') 2,700.

Taking to the air for the first time in 1964, the Piper Navajo was the first of a series of large executive airplanes to be produced by Piper. The Navajo is known for its excellent performance, easy-to-fly characteristics, and dependable systems. It was the first in its class to offer factory air-conditioning and the longest cabin interior available: 16 feet. Piper’s exclusive engine nacelle was designed to house an extended shaft that put the prop blades well ahead of the cowling. This allowed the blades to bite into undisturbed air for greater propulsion efficiency.

Another feature of the Navajo was Altimatic VF/D, a truly automatic flight control at an economical price. To simplify flight operations, the Navajo’s full-time turbochargers have no special controls, and safety devices prevent overboost or turbine overspeeding. The early Navajos were powered by 310-hp turbocharged Lycoming engines.

At one time, the Navajo family of aircraft included four models. The Navajo C, powered by 310-hp Lycomings, has accommodations for five passengers plus pilot in a standard or executive arrangement and up to eight persons with its optional commuter interior. The Navajo CR, introduced in 1975, offers stepped up performance during takeoff, climb, and cruise, due to the increase in power brought about by its 325-hp Lycomings. Counterrotating three-blade props neutralize torque and eliminate the “critical engine.” With either engine feathered, equal rate of climb and ceiling are assured. The Pressurized Navajo is powered by twin 425-hp Lycomings and provides executive class travel for six to eight. Optional pressurization was first offered in 1970.

The Chieftain’s super-stretched 18-foot cabin allows it to perform as either an executive transport or light airliner. Powered by 350-hp Lycomings, it offers seating for six in an executive configuration or up to 10 in a commuter configuration. This latter aircraft was initially introduced as simply the PA-31-350 in 1973. The Navajo line was recertified for flight into icing conditions under newer more stringent standards in 1980. The Navajo family of aircraft was eventually trimmed to three models: basic Navajo, CR, and the Chieftain. Optional nacelle tanks on the Navajo CR and Chieftain in 1981 offered 54 gallons of extra fuel capacity, increasing the range of the Chieftain by 391 miles to a maximum range of 1,485 miles and boosting the range of the Navajo CR by 432 miles for a maximum range of 1,628 miles. The system incorporates two bladder tanks with non-icing fuel vents. The fuel simply gravity-feeds into main inboard tanks.



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