General Dynamics/Grumman F-111B

The General Dynamics/Grumman F-111B is a long-range carrier-based interceptor aircraft that was planned to be a follow-on to the F-4 Phantom II for the United States Navy.

The F-111B was developed in the 1960s by General Dynamics in conjunction with Grumman for the U.S. Navy as part of the joint Tactical Fighter Experimental (TFX) with the United States Air Force (USAF) to produce a common fighter for the services that could perform a variety of missions.

It incorporated innovations such as variable-geometry wings, afterburning turbofan engines, and a long-range radar and missile weapons system.

Designed in parallel with the F-111 “Aardvark”, which was adopted by the Air Force as a strike aircraft, the F-111B suffered development issues and changing Navy requirements for an aircraft with manoeuvrability for dogfighting.

The F-111B was not ordered into production and the F-111B prototypes were used for testing before being retired.

The F-111B would be replaced by the smaller and lighter Grumman F-14 Tomcat, which carried over the engines, AWG-9/Phoenix weapons system, and similar swing-wing configuration.

The Air Force F-111A and Navy F-111B variants used the same airframe structural components and TF30-P-1 turbofan engines.

They featured side by side crew seating in an escape capsule as required by the Navy, versus individual ejection seats.

The F-111B’s nose was 8.5 feet (2.59 m) shorter due to its need to fit on existing carrier elevator decks and had 3.5 feet (1.07 m) longer wingspan to improve on-station endurance time.

The Navy version would carry an AN/AWG-9 Pulse-Doppler radar and six AIM-54 Phoenix missiles.

The Air Force version would carry the AN/APQ-113 attack radar and the AN/APQ-110 terrain-following radar and air-to-ground ordnance.

Lacking experience with carrier-based fighters, General Dynamics teamed with Grumman for assembly and test of the F-111B aircraft.

In addition, Grumman would also build the F-111A’s aft fuselage and the landing gear.

The first test F-111A was powered by YTF30-P-1 turbofans and used a set of ejection seats, since the escape capsule was not yet available.

It first flew on 21 December 1964. 

The first F-111B was also equipped with ejection seats and first flew on 18 May 1965.

To address stall issues in certain parts of the flight regime, the F-111’s engine inlet design was modified in 1965–66, ending with the “Triple Plow I” and “Triple Plow II” designs.

The F-111A achieved a speed of Mach 1.3 in February 1965 with an interim intake design.

Variants

7 aircraft were built

1

Prototype with heavy airframe, TF30-P-3 engines        

2

Prototype with heavy airframe, TF30-P-3 engines.   

3

Prototype with heavy airframe, TF30-P-3 engines.   

4

Prototype with lightened airframe, TF30-P-3 engines

5

Prototype with lightened airframe, TF30-P-3 engines.   

6

Pre-production version, TF30-P-12 engines.        

7

Pre-production version, TF30-P-12 engines. 

Specifications

Crew

Length

68 ft 10 in (20.98 m)

Height

15 ft 9 in (4.80 m)

Airfoil

Root

NACA 64-210.68 

Tip

NACA 64-209.80 

Empty weight

46,100 lb (20,910 kg)

Gross weight

79,000 lb (35,800 kg)

Max take-off weight

88,000 lb (39,900 kg)

Wing span

Spread

70 ft (21.3 m)

Swept

33 ft 11 in (10.34 m)

Wing area

Spread

655.5 ft2 (60.9 m2)

Swept

550 ft2 (51.1 m2)

Powerplant

2 × Pratt & Whitney TF30-P-3 turbofans, 10,750 lbf (47.8 kN) thrust each dry, 18,500 lbf (82 kN) with afterburner

Performance

Maximum speed

1,450 mph (2,330 km/h, 1,260 kn)

Maximum speed

Mach 2.2

Range

2,100 mi (3,390 km, 1,830 nmi); with 6 AIM-54 missiles and 23,000 lb fuel internal

Ferry range

3,200 mi (5,150 km, 2,780 nmi); with 2 x 450 gal external tanks

Service ceiling

65,000 ft (19,800 m)

Rate of climb

21,300 ft/min (108 m/s)

Thrust/weight

0.47

Wing loading

Spread

120 lb/ft2 (586 kg/m2)

Swept

144 lb/ft2 (703 kg/m2)

Armament

Guns

1× M61 Vulcan 20 mm (0.787 in) Gatling cannon (seldom fitted)

Hardpoints

6 under wing pylons for ordnance and external fuel tanks

Missiles

6 x AIM-54 Phoenix long range air-air missiles

(Four under wings, two in weapons bay)

Avionics

AN/AWG-9 Pulse-Doppler radar.

       

 

 

 

 

 

 

 

 

 

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