Northrop Grumman E-2 Hawkeye
|An E-2C Hawkeye from |
|First flight||21 October 1960|
(See operators below)
The Northrop Grumman E-2 Hawkeye is an
The E-2 also received the nickname "Super Fudd" because it replaced the E-1 Tracer "Willy Fudd". In recent decades, the E-2 has been commonly referred to as the "Hummer" because of the distinctive sounds of its turboprop engines, quite unlike that of
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Continual improvements in airborne radars through 1956 led to the construction of AEW airplanes by several different countries and several different armed forces. The functions of command and control and sea & air surveillance were also added. The first carrier-based aircraft to perform these missions for the U.S. Navy and its allies was the
In 1956, the U.S. Navy developed a requirement for an airborne early warning aircraft where its data could be integrated into the
The first prototype, acting as an aerodynamic testbed only, flew on 21 October 1960. The first fully equipped aircraft followed it on 19 April 1961, and entered service with the US Navy as the E-2A in January 1964. By 1965 the major development problems delaying the E-2A Hawkeye got so bad that the aircraft was actually cancelled after 59 aircraft had already been built. Particular difficulties were being experienced due to inadequate cooling in the closely packed avionics compartment. Early computer and complex avionics systems generated considerable heat; without proper ventilation this would lead to system failures. These failures continued long after the aircraft entered service and at one point reliability was so bad that the entire fleet of aircraft was grounded.[
After Navy officials had been forced to explain to Congress why four production contracts had been signed before avionics testing had been completed, action was taken; Grumman and the US Navy scrambled to improve the design. The unreliable rotary drum computer was replaced by a Litton L-304 digital computer and various avionics systems were replaced – the upgraded aircraft were designated E-2Bs. In total, 49 of the 59 E-2As were upgraded to E-2B standard. These aircraft replaced the E-1B Tracers in the various US Navy AEW squadrons.[
Although the upgraded E-2B was a vast improvement on the unreliable E-2A, it was an interim measure. The US Navy knew the design had much greater capability and had yet to achieve the performance and reliability parameters set out in the original 1957 design. In April 1968, a reliability improvement program was instigated. In addition, now that the capabilities of the aircraft were starting to be realized, more were desired; 28 new E-2Cs were ordered to augment the 49 E-2Bs that would be upgraded. Improvements in the new and upgraded aircraft were concentrated in the radar and computer performance.[
Two E-2A test machines were modified as E-2C prototypes, the first flying on 20 January 1971. Trials proved satisfactory and the E-2C was ordered into production, the first production machine performed its initial flight on 23 September 1972. The original E-2C, known as Group 0, consisted of 55 aircraft; the first aircraft became operational in 1973 and serving on carriers in the 1980s and 1990s, until they were replaced in first-line service by Group II aircraft. US Navy Reserve used some aircraft for tracking drug smugglers. The type was commonly used in conjunction with
The next production run, between 1988 and 1991, saw 18 aircraft built to the Group I standard. Group I aircraft replaced the E-2's older APS-125 radar and T56-A-425 turboprops with their successors, the APS-139 radar system and T56-A-427 turboprops. The first Group I aircraft entered service on August 1981. Upgrading the Group 0 aircraft to Group I specifications was considered, but the cost was comparable to a new production aircraft, so upgrades were not conducted. Group I aircraft were only flown by the Atlantic fleet squadrons. This version was followed within a few years by the Group II, which had the improved APS-145 radar. A total of 50 Group II aircraft were delivered, 12 being upgraded Group I aircraft. This new version entered service in June 1992 and served with the Pacific and Atlantic Fleet squadrons.[
By 1997, the US Navy intended that all front line squadrons would be equipped, for a total of 75 Group II aircraft. Grumman merged with Northrop in 1994 and plans began on the Group II Plus, also known as the Group II / NAV upgrade. This kept the same computer and radar as the Group II while upgrading the pilot avionics, such as replacing the mechanical Inertial Navigation System (INS) with a more reliable and accurate laser Ring Gyroscope-driven INS, installing dual Multifunction Display Units (MFCDUs) (vice one in the Group II), and the integration of GPS into the weapon system. A variant of the Group II with upgrades to the mission computer and CIC workstations is referred to as the MCU/ACIS, these were produced in small numbers due to production of the Hawkeye 2000 soon after its introduction. All Group II aircraft had their 1960s vintage computer processors replaced by a mission computer with the same functionality via modern computer technology, referred to as the GrIIM RePr (Group II Mission Computer Replacement Program, pronounced "grim reaper").
Another upgrade to the Group II was the Hawkeye 2000, which featured the same APS-145 radar but incorporated an upgraded mission computer and CIC (
In 2004, the E-2C's propeller system was changed; a new eight-bladed propeller system named NP2000 was developed by the
Once considered for replacement by the "
The APY-9 radar has been suspected of being capable of detecting fighter-sized stealth aircraft, which are typically optimized against high frequencies like Ka, Ku, X, C, and parts of the S-bands. Small aircraft lack the size or weight allowances for all-spectrum low-observable features, leaving a vulnerability to detection by the UHF-band APY-9 radar, potentially detecting
Deliveries of initial production E-2Ds began in 2010. On 4 February 2010, Delta One conducted the first E-2D carrier landing aboard USS Harry S. Truman as a part of carrier suitability testing. On 27 September 2011, an E-2D was successfully launched by the prototype
In December 2016, an E-2D flew for the first time fitted with an aerial refueling capability. This feature will allow the aircraft to double its time on station to five hours, and increase total mission time from four to seven hours. The refueling modification will start being built into the 46th plane (out of 75 planned) for delivery in late 2020 costing an additional $2 million per aircraft, and the Navy plans to retrofit the feature on all previous Hawkeyes for $6 million per plane.