The Lockheed P-7 was a four
turboprop
A turboprop is a turbine engine that drives an aircraft propeller.
A turboprop consists of an intake, reduction gearbox, compressor, combustor, turbine, and a propelling nozzle. Air enters the intake and is compressed by the compressor. ...
-engined patrol aircraft ordered by the
U.S. Navy as a replacement for the
P-3 Orion
The Lockheed P-3 Orion is a four-engined, turboprop Anti-submarine warfare, anti-submarine and maritime patrol aircraft, maritime surveillance aircraft developed for the United States Navy and introduced in the 1960s. Lockheed Corporation, Lockh ...
. The external configuration of the aircraft was to be very similar to that of the P-3. Development had not progressed very much before the program was cancelled in July 1990.
Development
In the mid-1980s, the U.S. Navy made plans to replace the large number of Lockheed P-3 aircraft which would reach the end of their useful service lives during the 1990s. To limit costs the U.S. Navy envisioned a modified P-3 with increased payload and updated avionics. This aircraft became known as the "P-3G" of which 125 should be procured over a period of five years up to 2001. However, the U.S. Navy was unwilling to select Lockheed's P-3G without any competition and issued the final "Request for Proposals (RFP)" in January 1987. For the airplane named the P-7A "LRAACA" (Long-Range Air ASW-Capable Aircraft), Lockheed's competitors were:
*
Boeing
The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and ...
- proposal using a modified
757
*
McDonnell Douglas
McDonnell Douglas was a major American aerospace manufacturing corporation and defense contractor, formed by the merger of McDonnell Aircraft and the Douglas Aircraft Company in 1967. Between then and its own merger with Boeing in 1997, it ...
- proposal using a modified
MD-90
In October 1988, the U.S. Navy announced that Lockheed won the competition,
as the company's proposal was significantly cheaper than that of the competitors. The U.S. Defense Acquisition Board (DAB) recommended a full-scale development of the LRAACA on 4 January 1989. The costs were planned to be about $600 million, with a maximum cost limit of $750 million. However, in November 1989, Lockheed announced a cost overrun of $300 million due to the tight schedule and design problems. On 20 July 1990, the U.S. Navy stopped the P-7A program contract for default, "citing Lockheed's inability to make adequate progress toward completion of all contract phases".
The program was finally cancelled by the DAB in late 1990.
Design
The P-7 was designed as an enlarged version of the original P-3C. The fuselage, of similar cross-section to that of the P-3, was lengthened by 2.40 m (8 ft), and the wingspan by 2.10 m (7 ft). The wing center section was increased in length, which moved the engines farther away from the fuselage to reduce noise levels in the cabin. The tailplane was increased by about 25% in area, but shortened in height compared to that of the P-3. The P-7A was to be powered by four
General Electric T407-GE-400 turboprops with 5-blade propellers.
Initial plans included the Update IV electronics equipment of the P-3C. The cockpit was to be fitted with eight
CRT displays and a stowable
HUD for weapons delivery. Other equipment included search radar,
MAD,
decoy flare launchers, electro-optical detector,
radar warning receiver
Radar warning receiver (RWR) systems detect the radio emissions of radar systems. Their primary purpose is to issue a warning when a radar signal that might be a threat is detected, like a fighter aircraft's fire control radar. The warning can ...
s,
IR suppression on the engine exhausts and laser deflection screens on the windows. The primary submarine detection sensor was to be the
sonobuoy
A sonobuoy (a portmanteau of sonar and buoy) is a relatively small buoy – typically diameter and long – expendable sonar system that is dropped/ejected from aircraft or ships conducting anti-submarine warfare or underwater acoustic resea ...
, of which 112 were carried internally; 38 more could be stowed for in flight reloading. Another 150 could be carried in 10 underwing pods.
The design had an internal bomb bay for a maximum of 3,400 kg of weapons and 12 underwing pylons.
[Bowers, Peter M. ''United States Navy Aircraft since 1911''. Annapolis, MD: Naval Institute Press, 1990, pp. 313-314. .]
Specifications (P-7A, as designed)
See also
References
Bibliography
*
{{US patrol aircraft
P-007
Cancelled military aircraft projects of the United States
P-7, Lockheed
Low-wing aircraft
Four-engined turboprop aircraft
P-7