Quickstrike
As the name suggests the Quickstrike was a limited upgrade to the present F-14D. It would have produced a long range strike fighter, capable of replacing the A-6 and thus making up for the cancellation of the A-12. Having learnt from the Air Force's F-15E program how well a 'pure' air-to-air fighter could be transformed into an air-to-ground attack aircraft the Navy proposed doing roughly the same to the F-14 as the Air Force had done to the F-15. The two main upgrades to the Quickstrike were to be extra modes for the AN/APG-71 radar and FLIR pods for navigation and targeting. The extra radar modes were to have included synthetic aperture (SAR) and Doppler Beam Sharpening, allowing for accurate ground mapping. These would allow the radar to generate high quality images of navigation waypoints and targets. The FLIR pods would be very similar to those used in the F-15E, mounted under the fuselage in the aerodynamic fairings that are presently used for the Phoenix missiles. As with the F-15E one pod would have been used for navigation, using a wide angle FLIR, while the other would have been used for targeting, using a narrow angle FLIR and incorporating a laser designator.
To allow the crew to make full use of these upgrades the cockpit would have been improved with the addition of a moving map display, new HUD (presumably compatible with infra red imagery from the FLIR) and head down FLIR displays. The RIO's cockpit would have been changed to allow him to view FLIR imagery and control the laser designator.
The munitions carrying capability of the Quickstrike would have been considerable. Four underfuselage hardpoints would each have carried five substations. The wing glove pylons would each carry two substations. Fully loaded up the Quickstrike would have carried 24 air to ground munitions, probably Mk20's or Mk84 500lb bombs. Heavier weapons would be carried in smaller numbers. Perhaps most important would have been the addition of standoff weapons to the F-14's arsenal. Quickstrike would have added LGB's, AGM-84E SLAM, AGM-84 Harpoon, AGM-65 Maverick and AGM-88 HARM, presumably to be followed at a later date by AGM-154 JSOW and GAM.
While the Quickstrike would have been an impressive improvement to the F-14's capabilities it was killed by the Navy's selection of the F/A-18E/F as the best platform for future long range strike roles.
Tomcat 21
Tomcat 21 was a more far reaching modification to the F-14D. Using ideas from the Quickstrike proposal Grumman developed the design as a lower cost, multi-role alternative to the NATF. Quickstrike was mainly an avionic and systems upgrade, however to this Tomcat 21 added reshaped wing gloves, which roughly matched the profile of a standard Tomcat glove with the vanes extended. These added around 1,134kg (2,500lb) of fuel. Wing flaps were also to be modified, using a single slotted Fowler type flap. Slats and spoilers were also to be modified. This would have provided 33% extra lift on approach to the carrier, enough to make up for the extra fuel and avionics. The all moving tailplanes would also be enlarged, by extending the trailing edge.
With the increased fuel, structural changes and avionics the empty weight of the Tomcat 21 was expected to be only 454kg (1,100lb) than that of the F-14D. Due to the increased fuel capacity gross weight was expected to increase from 33,070kg (72,900lb) to 34,470kg (76,000lb).
Like the Quickstrike Tomcat 21 would carry nav-attack FLIRS, either the LANTIRN system or Night Owl pods from Ford Aerospace. Again these would be mounted in the front of the aerodynamic Phoenix fairings (which house the cooling oil system for early model AIM-54's on the F-14A and B. The D does not have this system). The laser designator for the Night Owl system would be carried in the undernose twin pod.
In addition to the FLIRS the AN/APG-71 would have been further modified, giving it an ISAR (Inverse Synthetic Aperture Radar) capability, improved look down/shoot down capabilities over land and a 20% increase in target acquisition range.
At a time when high cost designs were being killed at a prodigious rate Grumman was quietly confident that the relatively low cost Tomcat 21 would see production. Its anticipated development costs were $989 million, with the first flight in 1993 (if the go ahead was given in 1990). Production models were expected to begin delivery in 1996. 490 Tomcat 21's were projected, a mix of 233 new build (cost $39 million apiece) and 257 remanufactured aircraft from F-14B/D's (cost $21 million apiece). Which FY these prices were calculated for I do not know.
Attack Super Tomcat 21 (ASF-14)
If the Tomcat 21 was a relatively low cost structural modification to the F-14D then the Attack Super Tomcat 21 (hereafter referred to as AST-21) was the most advanced derivative Grumman could make, both in terms of aerodynamics and avionics.
As well as the structural changes mentioned above the AST-21 would have thicker outer wing panels, allowing even more fuel to be carried. Larger external fuel tanks would also be developed. Flaps and slats would be further refined, reducing approach speeds by 18mph.
A new version of the F110, the GE F110-GE-129 would power the aircraft, giving the potential for the AST-21 to supercruise (achieve and sustain supersonic flight without need for fuel hungry afterburners) at up to Mach 1.3. Vectoring nozzles were also considered, but felt unnecessary when the design displayed a 77 degree angle of attack without the vectoring nozzles.
To aid servicing and repairs all maintenance controls would be grouped onto a single panel.
In the cockpit each crewmember would receive colour MFD's and helmet mounted displays. A single piece forward canopy would replace the present windscreen, enabling full all round vision for the first time.
Carrying the nav-attack FLIRS of the other variants the AST-21 would replace the AN/APG-71 with an electronically scanned unit, incorporating a host of air-to-air and air-to-ground modes. This would have twice the power of the AN/APG-71 and be among the biggest leaps in capability. Some reports suggest this radar would have been that developed for the A-12. Defensive electronics would also have been upgraded, with the AST-21 carrying 135 packets of chaff/flares in launchers on the LAU-7 missile rails.
At present it is unclear whether the ASF-14 differed in any notable way from the AST-21, but the former was the designation used when the Navy carried out a serious study of the Grumman proposals in 1994. Unfortunately for Grumman the study decided the ASF-14 to be unaffordable. As a result the Navy moved ahead with its present plans to develop the F/A-18E/F Super Hornet variants.