The first of three Hawkeye prototypes flew on October 21, 1960, the Hawkeye became the primary early warning component of the US Navy carrier air wings.

Grumman E-2 Hawkeye Article

Delivery of the first member of the Hawkeye family, the E 2A (formerly known as the W2F-1) began on 19 January 1964 to the US Navy, entering service in 1965 as a replacement for the Grumman E 1B Tracer, an early warning derivative of the S 2 Tracker. The E 1B carried its radar aerial inside a fixed oval, aerofoil shaped radome, but the E 2 was the first AEW type to adopt the 7.32m diameter ‘rotodome’, with the antennae mounted rigidly inside a radome which itself rotates at 6 rpm in the case of the Hawkeye. Fifty nine E 2As were delivered to the US Navy, and the type quickly proved its worth off the coast of Vietnam. The Hawkeyes were sent out to patrol whenever there was a risk of the naval task force being attacked by enemy aircraft or ships; by extending the force’s detection range well beyond the normal horizon, even against low flying aircraft, the E 2As reduced the need for large numbers of intercepters to be kept on alert throughout the day and night.
In addition to their defensive role, the Hawkeyes were able to relay target information from the aircraft carriers to their distant attack formations. With the E 2A the US Navy began to appreciate the many advantages of a modern AEW aircraft, but the 1950s technology computer had to be physically modified every time the ATDS (Airborne Tactical Data System) needed new software. To overcome this problem the Hawkeyes were fitted with Litton L 304 general purpose digital computers, and several minor modifications were also made; the E 2As thus became E 2Bs, which flew for the first time in February 1969, all having been converted by 1971.
Grumman built 56 E-2As, later updated to E-2B, before introducing the E-2C. The first of the significantly more capable E-2C series flew in January 1971. By mid-1987 97 E-2Cs had been delivered to the US Navy, plus 21 to overseas customers.

Firm orders existed for a total of 47 aircraft, with procurement of 36 more by the end of 1985. Israel has four and in 1979 Japan released funds for the first four of an eventual total of about 15 for the JASDF. The Air Self-Defence Force accepted its first E-2C Hawkeye at Bethpage, Long Island, on 18 May 1982.

The E-2G has an advanced radar that is capable of detecting airborne targets anywhere in a three-million-cubic-mile surveillance envelope. It first entered service with the US Navy in November 1973 and went to sea on board USS Saratoga in late 1974. A training version is designated TE-2C.

By this time the first E 2Cs were flying, the prototype first flew in January 1971. Although virtually identical to its forebears externally, the E 2C is a very different under the skin. The improved APS 120 radar’ can detect and track aircraft over land as well as above the sea, and the APS 125 ARPS (Advanced Radar Processing System) is being incorporated in all E 2Cs to give long range detection of very small targets and automatic overland tracking. The APS 125 also incorporates a digital airborne moving target indicator (AMTI) in place of the E¬2B’s analogue unit. Communication equipment has been improved, and the E 2C has better hot day and single engine performance than its predecessors, and is four times as reliable.

The E 2C entered service in 1974, its arrival more or less coinciding with the introduction of the US Navy’s new generation of carrier based aircraft: the F 14 Tomcat, S 3 Viking, EA 6B Prowler and A 6E Intruder.
The latest APS-138 surveil¬lance radar was introduced on the E-2C airborne early warning aircraft built in 1983, and will be retrofitted to earlier E-2Cs in place of the original APS-125. APS-138 has a low-¬side-lobe active-element-array antenna, an enhanced passive detection system with trian¬gulation and exotic emitter recognition, together with expanded computer memory allowing the simultaneous and automatic track¬ing of up to 600 targets. At an operating height of 9,150m (30,000ft), a Hawkeye can detect and assess any approaching aircraft over a range of 480km (260 nm) in all weathers.
From 1988 new E-2Cs will be fitted with uprated Allison T56-A-427 engines, and will receive the improved APS-139 radar system which can transmit on any one of ten UHF channels. General Electric is also developing an APS-145 radar for service in 1990 which will counteract the problem of overland clutter.
The Hawkeyes work closely with the Tomcats, orbiting on station between 110 km (68 miles) and 185 km (115 miles) from the carrier at heights of 4600 m to 9150 m (15000-¬30000 ft); a typical orbit begins at 7000 m (23 000 ft) and rises to 8500 m (28000 ft) as fuel is burnt off. At a height of 7600 m (24 930 ft) the radar has a horizon range of 375 km (235 miles) and can detect high flying aircraft out to 460 km (285 miles).
The radar can detect and track more than 200 targets simultaneously, supplying alti¬tude, range and velocity information. The crew of five includes three operators in the combat information centre, each of which has a main 25 cm (10 in) radar display and a 12.5 cm (5in) screen giving alphanumeric information. Targets detected by the AWG 9 long range fire control radar in the F 14 can be notified to an E 2C by data link; they are then correlated with the appropriate return on the Hawkeye’s own radar displays or are used to feed in new information, thus effec¬tively extending the range of the AEW cover-age. The intercepter may then be vectored automatically on to the rear of the target for a visual identification, or it can be manoeuvred into the optimum firing position. The US Navy claims that the use of an E 2C for airborne control can double the number of kills made by the intercepter force while substantially reducing losses of friendly air¬craft.
Hawkeyes can also control a carrier’s attack force, supplying navigation and turn¬ing instructions by data link.

Northrop Grumman undertakes production of E-2C Hawkeye in the Hawkeye 2000 form (first flown April 1998).

Gallery

E-2A Hawkeye

E-2B Hawkeye

E-2C Hawkeye
Engine: 2 x Allison T56-A-425 turboprop, 4910 shp.
Installed thrust: 6800 kW.
Span: 24.6 m.
Length: 17.5 m.
Wing area: 699.66 sq.ft / 65 sq.m.
Height: 18.34 ft / 5.59 m
Empty wt: 17,265 kg.
MTOW: 23,560 kg.
Max speed: 600 kph.
Cruising speed: 269 kts / 498 kph
Service Ceiling: 30840 ft / 9400 m.
Initial climb rate: 2519.69 ft/min / 12.80 m/s
T/O run: 609 m.
Ldg run: 439 m.
Fuel internal: 7050 lt.
Range: 320 km.
Endurance: 4 hr on station.
Air refuel: Yes.
Crew: 5

Engines: 2 x turbo-prop Allison T-56 A-8, 2980kW
Max take-off weight: 22450 kg / 49494 lb
Empty weight: 16358 kg / 36063 lb
Wingspan: 24.6 m / 80 ft 9 in
Length: 17.2 m / 56 ft 5 in
Height: 5.6 m / 18 ft 4 in
Wing area: 65.0 sq.m / 699.65 sq ft
Max. speed: 600 km/h / 373 mph
Cruise speed: 500 km/h / 311 mph
Ceiling: 9660 m / 31700 ft
Range w/max.fuel: 3000 km / 1864 miles
Crew: 5

Derived from the E-2A Hawkeye, the first of two Greyhound prototypes flew on November 18, 1964.
19 were completed for the US Navy by the end of 1968, including the two prototypes converted from E-2A airframes. The C-2 shares wings and power plants with the E-2 Hawkeye, but has a widened fuselage with a rear loading ramp and replaced the piston-engined C-1 Trader in the COD role.

Grumman C-2 Greyhound Article

The original C-2A aircraft were overhauled to extend their operational life in 1973.
The C-2A was produced 1965-1968, followed by the C-2A(R) 1985-1989
58 were built at a unit cost of US$38.96 million
C-2As built after production was resumed in 1983 are based on the E-2C, and have the uprated engines and avionics of the latter. Production C-2As also have a new auxiliary power unit to reduce the need for ground support equipment at remote locations.
Grumman received a $678 million multi-year production contract for 39 additional C-2A twin-turboprop carrier on-board delivery (COD) aircraft from the US Navy in 1983. The first of these was delivered in 1985, and production was to run until 1989.
The C-2A was originally powered by two Allison T56-A-425 turboprop engines and four-bladed Hamilton-Sundstrand constant-speed propellers.
An undercarriage with main gears is fitted to each engine nacelle and at the fuselage’s forward-most portion, a nose wheel is fitted. The wing systems are foldable and twist down, and then fold towards the empennage, just outboard of each engine nacelle, thus improving the carrier storage. Fitted into streamlined nacelles, the engines are mounted under each wing.
Straight-in rear cargo loading and downloading are enabled by the inclusion of a large aft cargo ramp and door, and a powered winch in the design to allow for fast turnarounds. A cage system helps to tie down the cargo and restrain it from the arresting and loads during carrier operation.

Northrop Grumman has equipped the aircraft with modified fowler-type flaps, and hydraulically powered irreversible flight controls with an independent hydraulic backup system.

Ultra-high-frequency (UHF) radio navigation aids such as GPS, TACAN (tactical air navigation), dual VOR (VHF omni-directional range), UHF/DF (ultra-high-frequency / direction finder), LF/ADF (low-frequency / automatic direction finder) and weather radar; and communications equipment such as high frequency (HF) and very high frequency (VHF) were provided in the aircraft. The TCAS, TAWS and ARC-210 (airborne radio communication) radios were added later.
The C-2A has open-ramp flight capability which enables airdrop of personnel and cargo or other supplies from a carrier-launched aircraft. Ground power self-sufficiency in remote areas and an auxiliary power unit onboard for starting the engine give the C-2A high operational versatility.

The C-2A is also an approved special warfare asset. It can airdrop the inflatable combat rubber raiding craft of a SEAL (sea air land) platoon out of its ramp. It deploys the platoon after the release has been made, thus enabling the SEALs to operate in close proximity to enemy camps. The airdrop capability also enables the aircraft’s utility as a search and rescue (SAR) platform to airdrop life rafts and provisions.
In 1984, the Navy ordered 39 new C-2A aircraft to replace older airframes. Dubbed the Reprocured C-2A (C-2A(R)) due to the similarity to the original, the new aircraft has airframe improvements and better avionics. The older C-2As were phased out in 1987, and the last of the new models was delivered in 1990.
Powered by two Allison T56 turboprop engines, the C-2A can deliver up to 10,000 pounds (4,500 kg) of cargo, passengers or both. It can also carry litter patients in medical evacuation missions. A cage system or transport stand restrains cargo during carrier launch and landing. The large aft cargo ramp and door and a powered winch allow straight-in rear cargo loading and unloading for fast turnaround.

Its ability to airdrop supplies and personnel, fold its wings, and generate power for engine starting and other uses provide an operational versatility found in no other cargo aircraft.

The fact that this aircraft has four vertical stabilizers is due to aircraft carrier hangar deck height restrictions. Only three of these stabilizers have working rudders. For adequate directional control of an aircraft of this size, a single rudder would have been too tall. It also places the outboard rudder surfaces directly in line with the propeller wash, providing effective yaw control even as the plane’s airspeed approaches zero, as during takeoff and landing.

Between November 1985 and February 1987, VR-24 (the former Navy Transport Squadron) and its seven reprocured C-2As demonstrated the aircraft’s exceptional operational readiness. The squadron delivered 2,000,000 pounds (910 t) of cargo, 2,000,000 pounds (910 t) of mail and 14,000 passengers in the European and Mediterranean theatres. The C-2A(R) also served the carrier battle groups during Operations Desert Shield and Desert Storm, as well as during Operation Enduring Freedom.

Production of the modernised version began in 1985. Delivered in 1990, the aircraft’s modernisation process included several improvements in the airframe and avionic systems over those in the C-2A.

Northrop Grumman is currently working on the resupply of the upgraded C-2A version. In November 2008, the company also obtained a $37m contract for the maintenance, logistics and aviation administration services over five years for the C-2A fleet assigned to air test and evaluation squadron 20 (VX-20) at Patuxent River.
Greyhound service life extension programme (SLEP)

A service life extension programme (SLEP) is being carried out to improve the operating service life of the reprocured aircraft, achieving a viable and economically maintainable platform until it is replaced. The programme will increase its service life from 15,020 to 36,000 landings and from 10,000 to 15,000 flight hours. The SLEP involves structural enhancements to the centre wing, an aircraft rewire, a new propeller system and improvement of the avionics systems.

The eight-bladed NP2000 propeller is another part of this upgrade and was expected to be installed by 2010.
Navigational upgrades such as the addition of a global positioning system (GPS), the dual CAINS II navigation system, crash-survivable flight incident recorders and a ground proximity warning system are also included in the programme.

Further, a mandate issued by Congress and the chief of naval operations provided for incorporation of two passenger-carrying safety requirements, namely the traffic alert and collision avoidance system (TCAS) and the terrain avoidance warning system (TAWS) in the extension programme. The landing limit of most of the airframes is quickly approaching and the SLEP, upon successful completion, will improve the operational life of the aircraft till 2027.

While all the existing fleet of 36 C-2As is being upgraded in the SLEP, the first upgraded C-2A(R) took off from the NAVAIR Depot North Island on 12 September 2005. Development and installation of the SLEP for this aircraft took three and a half years. As of 2009, a second airframe is close to completion, and the rest of the 34 aircraft are anticipated to take off in the following five years.
As of September 2009, the USN was exploring a replacement aircraft for the C-2, including the V-22 Osprey.

The C-2 was operated by Carrier Airborne Early Warning Squadron One Two Zero (VAW-120), Fleet Logistics Support Squadron 30 (VRC-30) and Fleet Logistics Support Squadron 40 (VRC-40). ‘Providers’ at NAS North Island and Detachment Five (at NAF Atsugi, Japan) of VRC-30 are also flying the C-2As. VRC-40 is using the aircraft for its ‘Rawhides’ stationed at NAS Norfolk, while VAW-120 is using the aircraft for its ‘Greyhawks’ stationed at the same location.

VAW-120, the US Navy Fleet Replacement Squadron, was engaged in training aircrew men, naval flight officers and new pilots for the C-2A Greyhound as well as E-2C Hawkeye aircraft.

Variants:
C-2A
C-2A(R)
“Reprocured” C-2A

C-2 Greyhound
Primary Function: Transport
Engines: Two Allison T-56-A-425 turboprop, 4,600hp (3,400 kW)
Length: 56 feet, 10 in (17.30 m)
Wingspan: 80 feet, 7 in (24.60 m)
Folded span: 29 feet, 4 in
Height: 15 feet, 10.5 in (4.85 m)
Wing area: 700 sq.ft (65 sq.m)
Empty weight: 33,746 lb (15,310 kg)
Useful load: 20,608 lb (9,350 kg)
Max takeoff weight: 60,000 lb (24,655 kg)
Payload: 10,000 lb cargo or 26 passengers / 12 litter patients
Wing loading: 77.6 lb/sq.ft (378.9 kg/sq.m
Maximum speed: 343 knots (394 mph, 553 km/h) at 12,000 ft (3,660 m)
Cruise speed: 251 knots (289 mph, 465 km/h) at 28,700 ft (8,750 m)
Stall speed: 82 knots (94 mph, 152 km/h) at idle power
Range: 1,300 nm (1,496 mi, 2,400 km)
Service ceiling: 33,500 ft (10,210 m)
Rate of climb: 2,610 ft/min (13.3 m/s)
Crew: 2 pilots, 2 aircrew

C-2A / C-2(R)
Engines: 2 × Allison T56-A-425 turboprop engines; 4,800shp (3,400kW)
Propeller NP2000 eight-blade propeller
Length 56ft 10in (17.3m)
Height 17ft 2in (5.28m)
Wingspan 80ft 7in (24.56m)
Wingspan Folded 29ft 4in (8.94m)
Wing area: 65 sq.m.
Maximum Gross Take-Off Weight 57,500lb (26,082kg)
Empty Weight 35,000lb (15,875kg)
Internal Fuel 12,000lb (5,443kg)
Payload 10,000lb (4,536kg)
Carrier Landing Weight 49,000lb (22,226kg)
Field Take-Off Weight.60,000lb (27,216kg)
Field Landing Weight 52,000lb (23,587kg)
Airspeed 260kt (true cruising airspeed)
Maximum Speed 343kt
Range 1,300nm
Climb Rate 2,610ft a minute (13.3m/s)
Ceiling 30,000ft (9,144m)
T/O run: 665 m.
Ldg run: 435 m.
Fuel internal: 6905 lt.
Range/payload: 1930 km with 4500 kg.
Crew 4 (two pilots and two air-crew)
Capacity 38 (26 passengers and 12 litter patients)