T700-GE-701: The improved T700-GE-701A, -701B, -701C,-701D versions have also been developed from the original -700.[1]
T700-GE-401: Navalised version for SH-60 Seahawk helicopters.
T700-GE-401C: Universal application version of the -401.
T700-GE-701C: Universal application version of the -701.
T700-TEI-701D: Licensed produced version of Tusaş Engine Industries of Turkey. Developed for use in the Sikorsky/Turkish Aerospace Industries T-70 utility helicopter.[2]
CT7 turboshaft: Commercial version of T700.
CT7-2A: Basic model
CT7-2D: Higher flow compressor and surface coatings to improve resistance to wear and corrosion
CT7-2D1: Similar to the CT7-2D but uses a CT7-6 type hot section
CT7-2E1
CT7-6/-6A: The CT7-6/-6A turboshaft engines are upgraded commercial variants of the successful T700/CT7 engine family. The turboshaft engine powers the entire development fleet of AgustaWestland AW101 helicopters with thousands of flight hours of operation.[3]
CT7-8: The CT7-8 is a family of powerful engines in the 2,500 to 3,000 shp class. They are more powerful and more efficient versions of its predecessors.[3]
CT7-8A: A version of the CT7-8 family used to power older Sikorsky S-92/H-92 helicopters.
CT7-8A1: A more fuel efficient version of the CT7-8A. It is used to power newer Sikorsky S-92/H-92 helicopters. The CT7-8A1 produces 2,520 shp.
CT7-8A5
CT7-8A7: Developed by GE as a more powerful, more efficient and more reliable version of the CT7-8A1 engine for the Royal Canadian Air Force's Sikorsky CH-148 Cyclone helicopters. It is the most modern version of the CT7/T700 engine family. The CT7-8A7 produces 3,000 shp.
P-3 Orions from Japan, Canada, Australia, Republic of Korea and the United States at MCAS Kaneohe Bay during RIMPAC 2010.
In 1963, the U.S. Navy Bureau of Weapons (BuWeps) contracted Univac Defense Systems Division of Sperry-Rand to engineer, build and test a digital computer (then in its infancy) to interface with the many sensors and newly developing display units of the P-3 Orion. Project A-NEW was the engineering system which, after several early trials, produced the engineering prototype, the CP-823/U, Univac 1830, Serial A-1, A-NEW MOD3 Computing System. The CP-823/U was delivered to the Naval Air Development Center (NADC) at Johnsville, Pennsylvania in 1965, and directly led to the production computers later equipped on the P-3C Orion.[5]
Three civilian Electras were lost in fatal accidents between February 1959 and March 1960. Following the third crash the FAA restricted the maximum speed of Electras until the cause could be determined. After an extensive investigation, two of the crashes (in September 1959 and March 1960) were found to be caused by insufficiently strong engine mounts, unable to damp a whirling motion that could affect the outboard engines. When the oscillation was transmitted to the wings, a severe vertical vibration escalated until the wings were torn from the aircraft.[6][7] The company implemented an expensive modification program, labelled the Lockheed Electra Achievement Program or LEAP, in which the engine mounts and wing structures supporting the mounts were strengthened, and some wing skins replaced with thicker material. All the surviving Electras of the 145 built at that time were modified at Lockheed's expense at the factory, the modifications taking 20 days for each aircraft. The changes were incorporated in subsequent aircraft as they were built.[6]
Sales of airliners were limited as the technical fix did not completely erase the "jinxed" reputation, turboprop-powered aircraft were soon replaced by faster jets.[8] In a military role where fuel efficiency was more valued than speed, the Orion has been in service over 50 years after its 1962 introduction. Although surpassed in production longevity by the Lockheed C-130 Hercules, 734 P-3s were produced through 1990.[9][10] Lockheed Martin opened a new P-3 wing production line in 2008 as part of its Service Life Extension Program (ASLEP) for delivery in 2010. A complete ASLEP replaces the outer wings, center wing lower section and horizontal stabilizers with newly built parts.[11]
In the 1990s, during a U.S. Navy attempt to identify a successor aircraft to the P-3, the improved P-7 was selected over a navalized variant of the twin turbofan-powered Boeing 757, but this program was subsequently cancelled. In a second program to procure a successor, the advanced Lockheed Martin Orion 21, another P-3 derived aircraft, lost out to the Boeing P-8 Poseidon, a Boeing 737 variant, which entered service in 2013.
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