| P-7 | |
|---|---|
 | |
| P-7 LRAACA drawing | |
| Role | Maritime patrol aircraft |
| National origin | United States |
| Manufacturer | Lockheed Corporation |
| Status | Cancelled |
| Number built | None |
| Developed from | Lockheed P-3 Orion |
The Lockheed P-7 was a four turboprop-engined patrol aircraft ordered by the U.S. Navy as a replacement for the P-3 Orion. 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. [1]
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:
In October 1988, the U.S. Navy announced that Lockheed won the competition, [4] 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". [5] The program was finally cancelled by the DAB in late 1990.
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. [6] Other equipment included search radar, MAD, decoy flare launchers, electro-optical detector, radar warning receivers, IR suppression on the engine exhausts and laser deflection screens on the windows. The primary submarine detection sensor was to be the sonobuoy, 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. [7]
General characteristics
Performance
Related development
Aircraft of comparable role, configuration, and era
The Lockheed P-3 Orion is a four-engined, turboprop anti-submarine and maritime surveillance aircraft developed for the United States Navy and introduced in the 1960s. Lockheed based it on the L-188 Electra commercial airliner; it is easily distinguished from the Electra by its distinctive tail stinger or "MAD" boom, used for the magnetic anomaly detection (MAD) of submarines.
The Lockheed EP-3 is an electronic signals reconnaissance variant of the P-3 Orion, primarily operated by the United States Navy.
A propfan, also called an open rotor engine, or unducted fan, is a type of aircraft engine related in concept to both the turboprop and turbofan, but distinct from both. The design is intended to offer the speed and performance of a turbofan, with the fuel economy of a turboprop. A propfan is typically designed with a large number of short, highly twisted blades, similar to the (ducted) fan in a turbofan engine. For this reason, the propfan has been variously described as an "unducted fan" (UDF) or an "ultra-high-bypass (UHB) turbofan".
The Rolls-Royce AE 2100 is a turboprop developed by Allison Engine Company, now part of Rolls-Royce North America. The engine was originally known as the GMA 2100, when Allison was a division of former corporate parent General Motors.
The Boeing X-32 is a concept demonstrator aircraft that was designed for the Joint Strike Fighter competition. It lost to the Lockheed Martin X-35 demonstrator, which was further developed into the Lockheed Martin F-35 Lightning II.
The Boeing 7J7 was an American short- to medium-range airliner proposed by American aircraft manufacturer Boeing in the 1980s. It would have carried 150 passengers and was touted as the successor to the successful Boeing 727. It was initially planned to enter service in 1992. This was intended as a highly fuel-efficient aircraft employing new technologies, but it was postponed indefinitely as the price of oil dropped during the 1980s.
The Lockheed/Boeing/General Dynamics YF-22 is an American single-seat, twin-engine fighter aircraft technology demonstrator designed for the United States Air Force (USAF). The design was a finalist in the USAF's Advanced Tactical Fighter competition, and two prototypes were built for the demonstration/validation phase of the competition. The YF-22 won the contest against the Northrop YF-23, and the design was developed into the Lockheed Martin F-22 Raptor. The YF-22 has a similar aerodynamic layout and configuration as the F-22, but with differences in the position and design of the cockpit, tail fins and wings, and in internal structural layout.
The Pratt & Whitney Canada PW100 aircraft engine family is a series of 1,800 to 5,000 shaft horsepower turboprops manufactured by Pratt & Whitney Canada. Pratt & Whitney Canada dominates the turboprops market with 89% of the turboprop regional airliner installed base in 2016, leading GE Aviation and Allison Engine Company.
The McDonnell Douglas MD-94X was a planned propfan-powered airliner, intended to begin production in 1994. Announced in January 1986, the aircraft was to seat between 160 and 180 passengers, possibly using a twin-aisle configuration. An all-new design that was investigated internally since at least 1984, the MD-94X was developed in the mid-1980s to compete with the similar Boeing 7J7. The price of oil would have to be at least US$1.40 per gallon for McDonnell Douglas to build the plane, though. Configuration was similar to the MD-80, but advanced technologies such as canard noseplanes, laminar and turbulent boundary layer control, side-stick flight control, and aluminum-lithium alloy construction were under consideration. Airline interest in the brand-new propfan technology was weak despite claims of up to a 60% reduction in fuel use, and both aircraft were canceled.
The Allison T56 is an American single-shaft, modular design military turboprop with a 14-stage axial flow compressor driven by a four-stage turbine. It was originally developed by the Allison Engine Company for the Lockheed C-130 Hercules transport entering production in 1954. It has been a Rolls-Royce product since 1995 when Allison was acquired by Rolls-Royce. The commercial version is designated 501-D. Over 18,000 engines have been produced since 1954, logging over 200 million flying hours.
The General Electric GE36 was an experimental aircraft engine, a hybrid between a turbofan and a turboprop, known as an unducted fan (UDF) or propfan. The GE36 was developed by General Electric Aircraft Engines, with its CFM International equal partner Snecma taking a 35 percent share of development. Development was cancelled in 1989.
The Yakovlev Yak-46 was a proposed aircraft design based on the Yak-42 with two contra-rotating propellers on the propfan located at the rear. The specification of the Samara turbofans was in the 11,000 kg thrust range. Though proposed in the 1990s, production of the Yak-46 never commenced.
The Embraer/FMA CBA 123 Vector was a 1990 turboprop aircraft designed for regional flights, to carry up to 19 passengers. The program arose from a partnership between the Brazilian company Embraer and the Argentine FMA. The project was an advanced turboprop aircraft for its time, including advanced technology in avionics, aerodynamics, and propulsion.
The Progress D-27 is a three-shaft propfan engine developed by Ivchenko Progress, and manufactured by Motor Sich in Ukraine. The gas generator was designed using experience from the Lotarev D-36 turbofan. The D-27 engine was designed to power more-efficient passenger aircraft such as the abandoned Yakovlev Yak-46 project, and it was chosen for the Antonov An-70 military transport aircraft. As of 2019, the D-27 is the only contra-rotating propfan engine to enter service.
The General Electric GE38 is a gas turbine developed by GE Aviation for turboprop and turboshaft applications. It powers the Sikorsky CH-53K King Stallion as the T408.
The NAC Fieldmaster was a British agricultural aircraft of the 1980s. A turboprop powered single-engined monoplane, it was built in small numbers and used both as a cropsprayer and a firefighting aircraft.
The Honeywell T55 is a turboshaft engine used on American helicopters and fixed-wing aircraft since the 1950s, and in unlimited hydroplanes since the 1980s. As of 2021, more than 6,000 of these engines have been built. It is produced by Honeywell Aerospace, a division of Honeywell based in Phoenix, Arizona, and was originally designed by the Turbine Engine Division of Lycoming Engines in Stratford, Connecticut, as a scaled-up version of the smaller Lycoming T53. The T55 serves as the engine on several major applications including the CH-47-Chinook, the Bell 309, and the Piper PA-48 Enforcer. The T55 also serves as the core of the Lycoming ALF 502 turbofan. Since the T55 was first developed, progressive increases in airflow, overall pressure ratio, and turbine inlet temperature have more than tripled the power output of the engine.
The Douglas 1211-J was a bomber aircraft design developed by American aircraft manufacturer Douglas to compete with the Boeing B-52 design for a major United States Air Force contract between 1946 and 1954. The Model 1211-J design was 160 feet long with a wingspan of 227 feet, and was powered by four turboprop engines. The aircraft was designed around a new 43,000-pound conventional bomb but could carry nuclear weapons as well. It could also carry its own fighter escorts, as parasites under its wings. These fighters' jet engines were to be powered up to assist the carrier bomber during takeoff; refueling of the fighters was to take place while they were stowed on the mothership's underwing pylons.
The Progress D-236 was an experimental aircraft engine, a hybrid between a turbofan and a turboprop known as a propfan. Also known as the Lotarev D-236T, the three-shaft geared engine was designed in the 1980s and 1990s to power proposed propfan aircraft such as the Tupolev Tu-334, Ilyushin Il-118, and Ilyushin Il-88.
The Allison T56 turboprop engine has been developed extensively throughout its production run, the many variants are described by the manufacturer as belonging to four main series groups.