Design 4 (Air Corps Observation Amphibian)
The second aircraft proposal submitted by the newly created Grumman Aircraft Engineering Corporation was for a two-seat observation amphibian offered to the Army Air Corps in January 1930. Of biplane flying-boat design, this aircaft was proposed with a single radial engine mounted ahead of and beneath the upper wing. It was to have been armed witha forward-firing fixed gun and a rear-firing flexible gun. However, the Army Air Corps had no requirement for this type of observation amphibian and this unsolicited proposal failed to generate official interest.
Design 55 (XTB2F-1)
Seeking to obtain a twin-engined torpedo scout bomber for operations from CV-9 and CVB class carriers, the Bureau of Aeronautics had requested Douglas Aircraft Company to submit a proposal in February 1942. However, after the Douglas design had evolved into the XTB2D-1, a large single-engined aircraft, BuAer sought to obtain a twin-engined design and asked Grumman to submit a proposal. Preliminary and detailed proposals for Design 55 were respectively submitted by Grumman on December 21, 1942 and March 19, 1943, and a Letter of Intent was issued on August 6, 1943, for the procurement of two XTB2F-1 prototypes and related engineering and test data. Mock up inspection took place in early May 1944; however, as the aircraft was judged too heavy and too large for operations even from large CVB carriers, a 'stop work' order was issued on June 14, 1944.
Design 66 (XTSF-1)
When ordering the termination of the XTB2F-1 project, the Bureau of Aeronautics also requested that Grumman prepare and submit a design study of a torpedo bomber modified from the F7F-2 twin-engined fighter. Preliminary data for Design 66 were submitted by Grumman in late June 1944, revisions and additional details were provided on July 21 and on August 17, BuAer requested that the XTB2F-1 contract be amended to conver the procurement of two XTSF-1s. Mock-up inspection took place in October 1944, and detailed engineering proceeded until the end of that year. In January 1945, however, the XTSF-1 contract was terminated as the Navy felt that Grumman's engineering load was already excessive. The XTSF-1 design differed primarily from that of the F7F-2 in incorporating a bomb bay, two seats in tandem, and an enlarged nose (with space being initially provided for an APS-3 or APS-4 radar but later being increased again to house a more powerful SCR-720 set).
Design 77
In January 1946, after the Bureau of Aeronautics showed interest in the use of sweptback wings as a result of the data brought back from Germany by the Naval Technical Mission in Europe and of research undertaken by NACA at the Langley Laboratory, Grumman proposed a research aircraft to obtain data on low-speed handling characteristics oh highly swept wings. To reduce costs, consideration was given to fitting swept wings to either a modified Bell P-63 or to a modified Wildcat. In the end, however, Grumman proposed the all-new Design 77. Neither the modified aircraft nor the new design reached the hardware stage. Intended to be powered by a 450-hp Pratt & Whitney R-985 radial, Design 77 was a low-wing aircraft with a wing box structure arranged to accomodate wings with various degrees of sweepback. Fitted with a non-retractable undercarriage, the aircraft was planned as a single-seater but, if desired, could accommodate an observer aft of the pilot.
Design 97
Design 97 was submitted in February 1953 in answer to a Navy request for proposals for a single-seat carrier-based aircraft capable of supersonic speeds in level flight. To be powered by a 9,220 lb. thrust dry and 14,800 lb. thrust with afterburner Pratt & Whitney J57 turbojet, the Grumman Design 97 had a thin mid-wing with 45 degrees of sweep and moderate aspect ratio, long-span flapersons, and all-movable horizontal tail surfaces. Armament consisted of four 20-mm cannon in the nose and four Sparrow II air-to-air missiles beneath the wings. Alternatively, the cannon could be replaced by fifty-eight 2-in FFAR rockets. Grumman had high hopes of winning the design competition but, in the end, the Navy decided to spread the wealth and awarded the contract for the J57-powered aircraft to LTV (the resulting aircraft being the F8U-1) and the contract for the J65-powered aircraft to Grumman ( which would eventually become the F9F-9 and F11F-1).
Design 118 (XF12F-1)
Conceived in answer to an RFP issued by the Navy in September 1953, Design 118 was a missile-armed all-weather supersonic fighter intended to complement the F8U-1 air-superiority fighter aboard carriers. Two prototypes of the XF12F-1 were ordered in 1955, but the contract was cancelled shortly after because the McDonnell XF4F-1 was more heavily armed and promised to have better performance. Production of F12F-1s were to have been powered by a pair of 18,000-lb. thrust General Electric J79-GE-207 turbojets and fitted with an APQ-50 radar. Proposed armament consisted of three Sparrow radar-guided missles or two Sparrows and three Sidewinder IR missiles flush-mounted beneath the fuselage of trapezes which were to swing down before missile launch.
Design 128G-12
When BuWeps requested proposals for the VA(L) light attack aircraft in June 1963, it specified that manufacturers should only submit designs which were minimum change modifications of existing designs as low cost and early availability were of prime importance. Accordingly, in August 1963 Grumman submitted its Design 128G-12, a derivative of the A-6A. As the VA(L) was intended for day operations in clear weather, the complex integrated navigation and bombing system of the A-6A was replaced by a simpler multimode radar, and a single-seat-on-centreline cockpit was substituted for the two-seat cockpit of the A-6A. The only other significant change was the incorporation of a folding horizontal tail to increase by one third the carrier spotting factor. The Navy finally selected the smaller lighter LTV proposal even though the resulting A-7A had much less commonality with the F-8.
Design 607A
As a potential replacement for its CVSs (Antisubmarine Warfare Support Carriers), in 1971-72 the US Navy contemplated obtaining low-cost SCSs (Sea Control Ships) from which ASW helicopters could operate on convoy escort duty. In addition, each SCS was to embark a few V/STOL fighters for conventional air defense and 'anti-Bear mission' (interception of Tupelov Tu-95 and other Soviet maritime surveillance aircraft) up to 100 nm from the convoy. Proposed in November 1971, Design 607A was a supersonic V/STOL fighter specially conceived for operations from an SCS. It was to have been powered by a Pratt & Whittney JTF22A-30B lift/cruise turbofan with a conventional main exhaust nozzle and a swivelling nozzle on each side of the rear fuselage; afterburning thrust in level flight was 27,500 lb. and maximum VTOL thrust, without afterburner, was 15,650 lb. Two 11, 525-lb. thrust Grumman developed GLE-607A direct lift-turbojets were to have been mounted vertically just aft of the single-seat cockpit. Proposed armament consisted of a 20-mm cannon in the port wing leading edge, Sidewinder missiles on wingtip shoes, and a Sparrow missile beneath each wing.