Grumman C-2 Greyhound

The C-2 Greyhound, a derivative of the E-2 Hawkeye, shares the Sto-Wings and engines with the E-2, but has a widened fuselage with a rear loading ramp. The first of two prototypes flew in 1964. After successful testing, Grumman began production of the aircraft in 1965. The C-2 replaced the piston-engine Grumman C-1 Trader in the carrier onboard delivery (COD) role. The original C-2A aircraft were overhauled to extend their operational life in 1973.[2]

Powered by two Allison T56 turboprop engines, the C-2A can deliver up to 10,000 pounds (4,500 kg) of cargo or up to 28 passengers, and is normally configured for a cargo/passenger mix. It can also carry litter patients in medical-evacuation missions. A cage system or transport stand restrains cargo during carrier launch and landing accelerations to prevent weight redistribution, which might adversely affect in-flight stability. The large aft cargo ramp and door and a powered winch allow straight-in rear cargo loading and unloading for fast turnaround. The Greyhound's 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. Some parts commonality with the E-2 Hawkeye and the Grumman A-6 Intruder ease logistics support.[3]

A C-2A taxis prior to takeoff on a flight to USS John F. Kennedy in February 1984. This was the first Greyhound delivered in 1966.

The C-2 has four vertical stabilizers, of which three are fitted with rudders. A single vertical stabilizer large enough for adequate directional control would have made the aircraft too tall to fit on an aircraft carrier hangar deck. The four-stabilizer configuration has the advantage of placing the outboard rudder surfaces directly in line with the propeller wash, providing effective yaw control down to low airspeeds, such as during takeoff and landing. The inner-left stabilizer lacks a rudder, and has been called the "executive tail", as it has nothing to do compared to the other three.[4] A single C-2 (2797) was equipped with an air-to-air refueling probe, but this was not installed in other aircraft.[4][5]

In 1984, the Navy ordered 39 new C-2A aircraft to replace older airframes. Dubbed the Reprocured C-2A or 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.

The 36 C-2A(R)s underwent a critical service life extension program (SLEP). The C-2A(R)'s lifespan was 10,000 hours, or 15,000 carrier landings; plans require the C-2A to perform its mission supporting battle group operational readiness through 2015. The lower landing limit was approaching for most airframes, and the SLEP will increase their projected life to 15,000 hours or 36,000 landings. Once complete, the SLEP will allow the 36 aircraft to operate until 2027. The SLEP includes structural improvements to the center wing, an eight-bladed NP2000 propeller, navigational upgrades including the addition of GPS and the dual CAINS II navigation system, the addition of crash-survivable flight-incident recorders, and a ground proximity warning system. The first upgraded C-2A(R) left NAVAIR Depot North Island on 12 September 2005, after sitting on the ground for three and a half years while the SLEP was developed and installed. All aircraft were to receive the SLEP by 2015.[6]

A VRC-40 C-2A(R) after SLEP on USS Carl Vinson, July 2009

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 VX-20 test and evaluation squadron at Patuxent River. Northrop Grumman worked on an upgraded C-2 version, and offered to modernize the fleet with components common to the E-2D Hawkeye.[7]

The Common Support Aircraft was once considered as a replacement for the C-2, but failed to materialize. The U.S. Navy was exploring a replacement for the C-2 in September 2009.[10] Three options were suggested as replacements for the aging C-2s: a new batch of updated C-2s, a transport version of the Lockheed S-3 Viking, and the tilt-rotor Bell Boeing V-22 Osprey.[11]

The C-2 competed with the V-22 Osprey for use as the future COD aircraft. Northrop Grumman proposed modernizing the C-2 by installing the same wings, glass cockpit, and engines as the E-2D Advanced Hawkeye. Installing the Rolls-Royce T56-427A engines would cut fuel consumption by 13–15% with the same eight-bladed propeller, enabling take-offs with a 10,000-pound (4,500 kg) payload in 125 °F (52 °C) degree heat and a range in excess of 1,400 nmi (1,600 mi; 2,600 km); similar performance by the C-2A requires engine temperatures at 70 °F (21 °C), trading fuel for payload. Adopting the E-2D's cockpit would deliver a 10% savings on lifetime logistical support. One of the Greyhound's most important features is its internal volume of 860 cubic feet (24 m³) of cargo space.[12] Northrop Grumman stated that their approach could cost far less than the V-22, including saving $120 million from C-2 and E-2D commonality.[13]

In February 2015, the Navy's FY 2016 budget confirmed the V-22's selection for the COD mission, replacing the C-2A.[14][15][16] The Navy is to order 44 of the Osprey, designated CMV-22B, with deliveries to start in 2020.[17] The C-2 was originally planned to be retired in 2027, but this was accelerated to 2024.[18] The fleet is expected to be fully transitioned to the Osprey by 2028.[19][20]