History
Tactical Fighter Experimental Program
The history of the F-111B development began with Secretary of Defense McNamara’s controversial Tactical Fighter Experimental (TFX) program in 1961.
The TFX program was established to meet the USAF’s and USN’s requirements for new aircraft for their disparate roles: a supersonic, ground-hugging strike aircraft invisible to enemy radar and capable of dodging surface-to-air missiles; a carrier-based interceptor capable of engaging Soviet bombers hundreds of miles away before they deploy long-range anti-ship missiles.
The TFX program decreed that the US Air Force and US Navy use identical airframes with respective purposes to meet their requirements. Secretary McNamara personally selected the F-111 as the bi-service fighter for this program. He had closely supervised this program since the beginning of his term.
Design and Development
On September 29, 1961, the TFX program sent Request For Proposals to Boeing, General Dynamics, Lockheed, Northrop, Grumman, McDonnell, Douglas, North American, and Republic. Boeing and General Dynamics submitted the promising proposals; however, an additional three rounds of updates to the proposals had to be conducted before the final decision. Afterward, Boeing was picked by the selection board, but Secretary McNamara overruled and selected General Dynamics’ proposal in November 1962 due to its proposal of the F-111 airframe sharing more commonality between the Air Force and Navy versions. Compared to Boeing’s proposal, only their versions shared less than half of the major structural components, which the Air Force and Navy military operators favored because two structurally different planes would not be compromised to meet contrasting service performance requirements. Nonetheless, General Dynamics signed the TFX contract in December 1962.
Thus, the TFX program had given birth to the F-111 Aardvark series. The F-111A was designated for the Air Force’s TFX version, and the F-111B was designated for the Navy’s TFX version.
General Dynamics lacked experience developing carrier-based aircraft, so it partnered with more experienced Grumman to develop the F-111B. The F-111B was said to be the most sophisticated design during the 1960s. It became the first aircraft to incorporate afterburning turbofan engines with capabilities of flying at Mach 2 and cruising in an extreme range thanks to its fuel efficiency, along with a variable-sweep wing and AWG-9 Pulse-Doppler radar to detect targets at extremely long range for new AIM-54 Phoenix missiles, ranging up to 100 miles or about 161 kilometers.
Flight Testing
The F-111B launched its first flight in May 1965, registered with Serial Number 151970 and powered with TF30-P-3 engines, and its flight test revealed some problems: underpowered performance in sustained maneuvers, flight control malfunctions, and poor cockpit visibility. Nevertheless, the variable-sweep technology proved remarkable on the aircraft. The engineers upgraded the power plant from TF 30-P-3 to TF30-P-12, providing the F-111B with more thrust. The only two F-111Bs that were upgraded with the TF30-P-12 engines were Serial Number 152714 and Serial Number 152715, designated as the pre-production variant.
In July 1968, the fifth F-111B with Serial Number 151974 was built and flew for its carrier trials, boarding the USS Coral Sea. The trials were proving to be successful without grave problems. However, the Navy and its pilots had shown a general dislike of the aircraft since it was too large and heavy for sustained maneuvers in close-range dogfights.
Four F-111Bs were involved in ongoing Phoenix missile testing. Unfortunately, the flight tests were not without costs: two F-111Bs were destroyed, and one F-111B was severely damaged. The F-111B’s last flight started from California to New Jersey in mid-1971 with Serial Number 151792. The seven F-111Bs flew 1,748 hours over 1,173 flights in total.
F-111B’s Replacement
The lifetime of the General Dynamics F-111B program was abruptly cut short when Secretary of Defense McNamara resigned in February 1968, making the program more unpopular. Along with resistance from the Navy fighter pilots and officers, Congress declined extra funds for the F-111B program. The Navy canceled the planned purchase of 705 F-111Bs into the production stage and shifted its focus to the F-14 Tomcat program, marking the final nail in the coffin for the F-111B.
The F-14 Tomcat inherited critical features of AN/AWG-9 radar, Phoenix missiles, variable-sweep wing, and afterburning turbofan engines from the F-111B. The F-14 Tomcat proved its greater dogfighting capability since it was lighter and more agile than the F-111B at the cost of an increased price. Ironically, the F-14 was the largest and heaviest US fighter to take off and land from an aircraft carrier.
While the F-111B did not reach the final production stage, the land-based F-111 variants continued their service within the USAF for many years and with the Royal Australian Air Force until 2010.
F-111B Subvariants
The first three F-111Bs were initial prototypes, and F-111B # 4 and # 5 were prototypes with lightened airframes. F-111B # 6 and # 7 had lightened airframes and improved TF30-P-12 engines and were built to near production standards, and they were approximately 2 feet longer due to an added space between the cockpit and radome.
The first five F-111Bs had Triple Plow I intakes, and the last two F-111Bs had Triple Plow II intakes. The first three aircraft included individual ejection seats, and the remainder included an escape crew capsule as the whole ejection.
Table of All Registered F-111Bs
| F-111B # |
Serial # |
Description |
Location or Fate |
| 1 |
151970 |
Prototype with heavy airframe, TF30-P-3 engines. |
Scrapped in December 1969 after flight tests. |
| 2 |
151971 |
Prototype with heavy airframe, TF30-P-3 engines. |
Involved in Hughes missile testing. Lost in a crash on September 11, 1968. |
| 3 |
151972 |
Prototype with heavy airframe, TF30-P-3 engines. |
Involved in jet blast testing at NATF, NAES Lakehurst, NJ. Was damaged and retired. Likely scrapped. |
| 4 |
151973 |
Prototype with lightened airframe, TF30-P-3 engines |
Destroyed in double engine failure crash on 21 April 1967. |
| 5 |
151974 |
Prototype with lightened airframe, TF30-P-3 engines |
Crash landed at NAS Point Mugu, CA in October 1968. Scrapped at NAS Moffett Field, CA in 1970. |
| 6 |
152714 |
Pre-production version, TF30-P-12 engines |
Involved in Hughes missile testing. Retired in 1969 and stored at a scrapyard in Mojave, California. |
| 7 |
152715 |
Pre-production version, TF30-P-12 engines |
Retired and stored at NAWS China Lake, CA. |
