I wasn't sure where to post this since there are other threads on or that mention the F12F so I started a new one, particularly since it is a significantly different take on the subject.
The F12F designation has been tied to the Grumman Design 118, a large Sparrow-armed fighter powered by two General Electric J79 engines. It was to have a throttleable rocket engine for additional thrust augmentation. Retractable ventral fins were provided for directional stability at high speed. For low drag, two of the Sparrows were semi-submerged in the lower fuselage and a third, or three Sidewinders, housed in a retractable box. The original proposal called for the two-man crew to enter from below. Because an ejection at Mach 2 was likely to cause severe injuries, if survivable at all, the nose section was to separate first, with the crew using ejection seats following deceleration of the nose to an acceptable speed accomplished with a drag chute.
Grumman proposed this airplane to BuAer in December 1955. According to Hal Andrews, however, the Navy wouldn’t entertain a twin-J79 powered Grumman proposal since they already a similar design, the F4H, under contract. BuAer therefore suggested to Grumman that they compete, along with the rest of industry, for a competitor to the F4H powered by a single engine, the Pratt & Whitney’s big J75. Grumman hastily prepared an updated proposal, adding their Model 118A incorporating the J75, which they provided to the Navy in early May. BuAer’s response to the updated proposal was, in part:
The recent receipt of more up-to-date engine data does not alter their relative standings of your design with others already programmed in the fighter field. The Chief of the Bureau of Aeronautics has therefore determined that the introduction of another design using the same engines and conforming to the same general operation requirements cannot be justified or undertaken.
This version of events would suggest that the Design 118 was never seriously considered for funding by the Navy and would not have received an official designation.
A more likely candidate for the F12F designation is identified in two handwritten notes, both by the same person (initials IMP?), found by Joe Gordon of the Navy’s Aviation History Branch “in some old NAVAIR records, which were inherited from the Bureau of Aeronautics.”
1. F12F
Grumman Design 98J2
Very similar to F11F-1F & with same engine J79
Longer nose; ventral tail fins; slightly different intake duct design
Shoulder mounting of Sparrow missiles & pylon Sidewinders
Orig intention Bu??.Inst h2000.23 of 19 July 1955 provided for 23; 2 were ordered on NOO(g) 56-250 (PR EN11-282-56) cutos 4 August 55)
Contract cancelled 4 Jan 56
BuNos 143401 & 143402
Per Wm H Plant
2. F12F
In a more recent telecon, Bill Plant told me he didn’t know whether a contract for the F12F had been issued. He had PO No., Contract No, and assigned serials, but was unable to obtain a contract file.
From this I presume that the contract was never let and that the program was cancelled in the 3-9 months period between initiation of PO and issuance of contract. Note – assignment of Contract No. occurs very early in this process.
IMP 3/30/36
Note that the date following the contract number in the first note is the same month the RFP was issued that Vought responded to for the F8U-3. It’s also the same month that the Navy reportedly accepted Grumman’s proposal to re-engine the last two production F11Fs with the J79. The cancellation occurred shortly after the F8U-3 mockup review at Vought in December 1955.
A SAC was issued with the designation F12F. See below. However, SAC designations might not be official. For example, Grumman proposed a derivative of the F11F as the "A2F", which was of course, officially assigned to a subsequent proposal.
The assigned BuNos are much lower than those for the F8U-3s and there is an interesting juxtaposition with other aircraft:
143232/143366 Grumman F11F-1 Tiger Contract cancelled
143367/143387 Grumman F11F-1P Tiger Contract cancelled.
143388/143392 McDonnell YF4H-1 Phantom (No 1 was 142259)
143393/143400 Douglas F5D-1 Skylancer Contract cancelled
143401/143402 Grumman XF12F-1 Contract cancelled
It’s possible that everybody’s right. Grumman certainly did do a design study of a twin-J79, Sparrow armed fighter and it might have been informally referred to as the F12F by Grumman and/or the Navy for a time after the Super Tiger was canceled. However, somebody was trying to fund the next phase of the Super Tiger program and these aircraft were designated F12F (F11F-2 might have made more sense but the Navy was not hidebound on their designation practice). The first two were assigned BuNos 143401/2 long before the Design 118 was in play.
