Editing Lockheed P-3 Orion (section)

===Origins===
In August 1957, the U.S. Navy called for proposals for replacement of the [[piston-engine]]d [[Lockheed P2V Neptune]] (later redesignated P-2) and [[Martin P5M Marlin]] (later redesignated P-5) with a more advanced aircraft to conduct [[maritime patrol]] and antisubmarine warfare. Modifying an existing aircraft should save on cost and to allow rapid introduction into the fleet. Lockheed suggested a military version of its [[Lockheed L-188 Electra|L-188 Electra]], then still in development and yet to fly. In April 1958, Lockheed won the competition and was awarded an initial research-and-development contract in May.{{citation needed|date=October 2023}}

[[File:Lockheed YP3V-1 Orion aerodynamic prototype in flight, in 1958.jpg|thumb|The first Orion prototype was a converted [[Lockheed L-188 Electra|Lockheed Electra]].]]

Lockheed modified the prototype YP3V-1/YP-3A, Bureau Number (BuNo) 148276 from the third Electra airframe c/n 1003.{{sfn|Reade|1998}} The first flight of the aircraft's aerodynamic prototype, originally designated YP3V-1, took place on 19 August 1958. While based on the same design philosophy as the  Electra, the aircraft differed structurally; it had {{convert|7|ft|m}} less [[fuselage]] forward of the wings with an opening bomb bay, and a more pointed nose [[radome]], a distinctive tail "stinger" for detection of submarines by MAD, wing hardpoints, and other internal, external, and airframe-production technique enhancements.{{citation needed|date=October 2023}}

The Orion has four [[Allison T56]] [[turboprop]]s, which give it a top speed of {{convert|411|kn|lk= on}} comparable to the fastest propeller fighters, or even to slow high-bypass [[turbofan]] jets such as the [[Fairchild Republic A-10 Thunderbolt II]] or the [[Lockheed S-3 Viking]]. Similar [[patrol aircraft]] include the Soviet [[Ilyushin Il-38]], the French [[Breguet Atlantique]] and the British jet-powered [[Hawker Siddeley Nimrod]] (based on the [[de Havilland Comet]]).

The first production version, designated P3V-1, was launched on 15 April 1961. Initial squadron deliveries to [[VP-8|Patrol Squadron Eight]] ([[VP-8]]) and Patrol Squadron Forty-Four (VP-44) at [[Naval Air Station Patuxent River]], Maryland, began in August 1962. On 18 September 1962, the U.S. military transitioned to a unified designation system for all services, with the aircraft being renamed the P-3 Orion.{{citation needed|date=October 2023}} Paint schemes have changed from early 1960s, gloss seaplane gray and white to mid-1960s/1970s/1980s/early 1990s gloss white and gray, to mid-1990s flat-finish low-visibility gray with fewer and smaller markings. In the early 2000s, the paint scheme changed to its current overall gloss gray finish with the original full-sized color markings. However, large-sized BuNos on the vertical stabilizer and squadron designations on the fuselage remained largely omitted.<ref>[http://www.history.navy.mil/avh-vol2/chap3-3.pdf "Second VP-9."] {{Webarchive|url=https://web.archive.org/web/20070327075802/http://www.history.navy.mil/avh-vol2/chap3-3.pdf |date=27 March 2007 }} ''Dictionary of American Naval Aviation Squadrons'' — Volume 2, p. 74. Retrieved: 7 July 2012.</ref>