The F-111B: A Missed Opportunity? (1961-1968)

A prototype F-111B lands on USS Coral Sea (CV-43) during carrier trials in 1968

The saga of the F-111 is well known. In the late 1960’s, the United States Air Force and United States Navy were both looking for a new tactical fighter and the Department of Defense mandated that they cooperate and develop a single airframe with variants for both services. The Air Force variant, a low-level attack plane, entered service in 1967 as the F-111A Aardvark. Fast, long-ranged, and equipped with sophisticated electronics, the F-111A and its later versions served with distinction from the Vietnam War to Operation Desert Storm. It also was modified into a highly effective electronic warfare plane (the EF-111) and Strategic Air Command even operated a version (the FB-111) as a nuclear bomber. However, the Navy’s F-111B variant, a long-range interceptor, was cancelled in 1968 after only seven prototypes had been built.

The stated reasons for this cancellation was that the plane was too heavy, underpowered, and completely unsuitable for carrier operations. Instead, the Navy chose to develop the now legendary F-14 Tomcat, which entered service in 1974. Today, the F-111B is commonly derided as an example of a foolish bureaucracy intent on commonality over mission effectiveness and is held up as an example of the unworkable nature of joint procurement. However, a closer look suggests that there may have been another side to the story.

Many high ranking civilian defense officials held that the Navy’s opposition the F-111B was based less on fact than on emotion. And indeed, the Air Force’s highly successful experience with the F-111A and its derivatives is generally ignored by those who disparage the F-111 program. If it is brought up, the response is usually that the F-111 program prioritized the Air Force’s needs. However, this is somewhat questionable given that the Navy was actually the lead service early in the program. But let us examine the facts ourselves and compare the infamous F-111B with its storied successor, the F-14A.

Comparing the F-111B vs F-14A

Dimensionally, the footprint of the F-111B was rather close that of the F-14A, being 8% longer, 2% wider, and 4% taller. Still, weight was a different story as the F-111B was a full 20% heavier when empty. However, its maximum catapult takeoff weight was only 7% more than that of the F-14A and its maximum arrested landing weigh just 3% more. These figures would seem to indicate that while the F-111B would have had inferior performance to the F-14A, it’s size would not have prevented carrier operations as is commonly portrayed. This is supported by comments that carrier trials of the F-111B proceeded smoothly - unfortunately they were not conducted until after the program had already been officially cancelled. Interestingly, despite its size and weight, when configured for the fleet defense mission, the F-111B actually required slightly less wind over the deck for takeoffs and landings than the F-14A and had a 10% lower approach speed.

With wings swept for high speed flight, the prototype F-111B was much sleeker than the F-14

The real problem with the F-111B was that it was truly underpowered. Despite having a maximum takeoff weight nearly 50% higher than that of the contemporary F-4B Phantom, the combined maximum thrust of the F-111B’s two TF30 engines was just 9% higher than the two J79 engines of the Phantom. However, this is far from the whole story. The F-14 used the same TF30 engines developed for the F-111B, but by the time the Tomcat entered service, the power of these engines had been increased by 13%. The even better engines of the Air Force's F-111F would have actually given the F-111B a higher thrust to weight ratio than the F-14A and were introduced in 1969.

Both the F-111B and the F-14A were interceptors before all else. The Navy considered Soviet bombers armed with long-range antiship missiles to be the greatest threat, and both planes were designed to engage those bombers before they could they could launch their weapons. Interestingly, both planes were built around the same weapons system - the AN/AWG-9 multimode radar and up to six AIM-54 Phoenix long-range air to air missiles. This makes a direct comparison much simpler than would normally be the case. Surprisingly, the F-111B outperforms the F-14A in several key areas.

A Better Fleet Interceptor?

Armed with the maximum load of six Phoenix missiles, the F-111B weighed 13% more that the the F-14A, but carried 16% more fuel. This advantage in fuel capacity was further magnified because the F-111B was much cleaner, with no drop tanks and two of its missiles carried internally. Altogether, this gave the F-111B a fully 33% greater combat range than the F-14A  (1830 nautical miles against the 1375 nautical miles). Not only did this mean the F-111B could range further afield, it also meant that if both planes were stationed the same distance from the carrier, the F-111B could remain there far longer, allowing for greater coverage.

In addition to this massive advantage in range, the low drag nature of the F-111B's combat configuration meant that it was also 16% faster than the F-14A, even after the Tomcat had jettisoned its drop tanks (1260 knots against 1090 knots) - an important feature when trying to intercept Soviet bombers before they could open fire. The one area in which the F-14A was markedly superior to the F-111B was rate of climb. At sea level and loaded with six missiles, the Tomcat could achieve a 62% higher rate of climb than the severely underpowered F-111B (34,000 feet per minute against 21,000 feet per minute). This could have been a serious drawback for fighters on deck alert and even with better engines it is unclear how much this poor performance would have improved.

While the F-111B dwarfed the Midway-class carrier Coral Sea, the F-14 only ever operated from the super carriers

Possibly the most important feature of the F-111B as a fleet interceptor was its ability to actually return to the carrier with all six Phoenix missiles on board, while the F-14's lower landing weight meant that two missiles would have to be jettisoned. Given the extreme expense of the Phoenix, this effectively mean that the six missile loadout was unusable for the F-14, and no more than four missiles were commonly carried. Obviously, having 50% more firepower available would have been a tremendous advantage when faced with dozens of Soviet bombers.

A More Versatile Airwing?

Perhaps the most interesting benefit that might have appeared if the Navy had stuck with the F-111B program was the potential for an all F-111 airwing. While the Tomcat was designed as a pure air to air fighter, the F-111 would have theoretically allowed the Navy to take advantage of the Air Force’s use of the F-111 in other roles. Thus, it would have been possible for an airwing made up of F-111 fighters, A-111 bombers, RF-111 recon planes, and EA-111 electronic warfare aircraft. Such an composition would not only have given the Navy an incredible supersonic deep strike capability, it would have also allowed for the efficiencies in maintenance and mission planning seen in the current Hornet airwings.

Today many detractors draw a comparison between the F-111 program and the F-35 program, claiming that history shows us that joint procurement is destined for failure. However, a deeper reading of history reveals that while the comparison may indeed be apt, the conclusions are far less certain. Instead, the Navy may well have thrown away an excellent aircraft because of service politics - and more importantly may be on the brink of doing so again with an even better aircraft as it continues to delay F-35C procurement in favor of more F/A-18 Super Hornets.