Although two prototypes were ordered in 1955, development was cancelled the same year in favor of the F4H Phantom II before any examples were built.
The Grumman Design 118 was a two-seat, twin-engined, rocket augmented, carrier-based all-weather supersonic fighter aircraft.
It had a 45° swept wing, a "T-tail" empennage, two small folding ventral fins, and a landing gear of tricycle configuration.
It also featured a boundary layer control system to improve low speed handling.
Similar to the contemporary Vought XF8U-3 Crusader III, it was designed with an additional throttleable liquid-fueled rocket engine using a mixture of JP-4 fuel and hydrogen peroxide oxidizer which produced 5,000 lbf of thrust.