Subject: Number 111 in the Series--General Dynamics F-111 (3 of 13)

From: [email-masked]
Date: 12 Mar 94 18:31:13 GMT

>From [email-masked]

In the late 1960s and early 1970s, the Air Force was shopping around 
for possible replacements for its Douglas EB-66 electronic warfare 
aircraft.  Although the EB-66 still continued to fly combat missions 
over North Vietnam, it was rapidly beginning to show signs of age.  

The Air Force rejected the development of a completely new type of 
aircraft for this role as being economically impractical because of 
the small number of aircraft required.  At one time, some thought had 
been given to acquiring the Grumman EA-6B Prowler carrier-based 
electronic warfare aircraft, but the Air Force was reluctant to 
acquire yet another aircraft originally developed for the Navy.  After 
some thought, the Air Force concluded in 1972 that the modification of 
some existing F-111A strike fighters would be the most cost-effective 
solution.  

However, the EA-6B was a four-seat aircraft, and it was concluded that 
it was impractical to adapt the F-111A to a four-seat configuration 
because it would reduce internal capacity too much.  The only 
alternative was to develop equipment similar to the Tactical Jamming 
System of the EA-6B, but capable of being operated by a single 
electronics warfare officer.  

In December 1974, the Grumman Aircraft Corporation of Calverton, Long 
Island was selected as the prime contractor for this conversion.  On 
January 30, 1975, Grummann was awarded a contract for the modification 
of two F-111As (serials 66-0041 and 66-0049) as EF-111A prototypes, 
the E prefix standing for "Electronic".  

The modifications included the installation of an AN/ALQ-99E jamming 
subsystem.  Exciters, antennae, and other items were mounted on a 
pallet inside the internal weapons bay.  Other components were mounted 
inside a 16-foot ventral "canoe"-shaped radome.  A fin-tip pod 
accommodated the electronic countermeasures receivers.  The 
self-protection subsystem consisted of a jamming system and a 
countermeasures dispensing set.  A terminal threat warning subsystem 
was installed which consisted of infrared and electronic 
countermeasures receiver sets.  The vertical fin had to be reinforced 
in order to support the fin-tip pod, new electrical wiring had to be 
installed, 60 kVA generators were replaced by 90 kVA units, and an 
improved environmental system for electronic equipment cooling was 
fitted.  The cockpit had to be rearranged to accommodate the new 
electronic warfare officer position, with the flight controls being 
removed from the right-hand cockpit, the navigation equipment being 
relocated so that could be used by the pilot in the left-hand seat, 
and the controls and displays for the electronics warfare officer 
being installed in the right-hand cockpit.  

These modifications resulted in an increase of empty weight from 
46,172 pounds for the F-111A to 55,275 pounds for the EF-111A.  
However, since the EF-111A carried no weapons, its maximum takeoff 
weight was only 88,848 pounds as compared with 98,850 pounds for the 
F-111A.  The Pratt & Whitney TF30-P-3 turbofans of the F-111A were 
retained.  

Grumman first flew a partially-modified F-111A fitted with a mockup of 
the ventral canoe in December of 1975.  The first EF-111A prototype 
(serial number 66-0049) flew at Calverton on March 10, 1977.  It was 
complete with fin-tip pod and ventral fairing, but still lacked most 
of its electronic equipment.  

The first flight of a fully-equipped EF-111A (serial number 66-0041) 
was made on May 17, 1977.  This aircraft was delivered to the Air 
Force to be used by Detachment 3 of the Tactial Air Warfare Center at 
Mountain Home AFB in Idaho for operational test and evaluation.  

Satisfactory results from these tests led to the issuance of a 
contract for the modification of six more aircraft.  Later, 34 more 
conversions were ordered.  

The name *Raven* was officially adopted for the EF-111A.  

First deliveries of EF-111A Ravens were made to the 390th Electronic 
Combat Squadron of the 366th Tactical Fighter Wing at Mountain Home 
AFB in Idaho in November 1981 and to the 42nd ECS of the 20th TFW at 
RAF Upper Heyford in February 1984.  42 Ravens had been delivered to 
the 366th TFW and the 20th TFW by December of 1985.  Mountain Home AFB 
received most of them.  

The first operational mission for the Raven took place during 
Operation *Eldorado Canyon*, the retaliatory attack on Libya on the 
night of April 14-15, 1986.  During that mission, the 42nd ECS 
provided three EF-111As plus two spare aircraft to jam the Libyan 
radar network.  

In 1986, General Dynamics was given a contract to install more 
powerful TF30-P-9 turbofans in the EF-111A.  

In May of 1988, a contract for the update of the AN/ALQ-99E by the AIL 
Division of the Eaton Corporation was cancelled due to cost overruns.  

Under an Air Force contract awarded in January 1987, Grumman and TRW 
Inc. developed the Avionics Modernization Program (AMP) kit for the 
EF-111A.  These kits provided the EF-111A with improved terrain 
following and navigational radars, a ring laser gyro inertial 
navigation system, the capability for using the global positioning 
system, two digital computers, improved cockpit displays, and upgraded 
communication systems.  The first AMP kit was installed in EF-111A 
66-0018 in January of 1989.  Most existing EF-111As were later to 
receive this upgrade.  

Eighteen EF-111A Ravens were deployed in support of Operation *Desert 
Storm* in 1991.  They flew over 900 sorties.  None were lost in 
combat, but one was lost in a non-combat related accident and both 
crew members were killed.  

The EF-111A Raven was even credited with a "kill" during *Desert 
Storm*.  On the night of January 17, 1991, an Iraqi Mirage F.1 flew 
into the ground while chasing EF-111A serial number 66-0016.  Even 
though the Raven is unarmed and has no air-to-air capability, the 
Raven crew was given credit for the kill.  

Serials of the EF-111A Raven (all conversions from F-111A blocks): 
66-0013/66-0016, 66-0018/66-0021, 66-0023, 66-0027, 66-0028, 66-0030, 
66-0031, 66-0033, 66-0035/66-0039, 66-0041, 66-0044, 66-0046/66-0051, 
66-0055/66-0057, 67-0032/67-0035, 67-0037/67-0039, 67-0041, 67-0042, 
67-0044, 67-0048, 67-0052.  

Specifications of the EF-111A Raven: 

Two Pratt & Whitney TF30-P-3 turbofans, 10,750 lb.s.t. dry, 18,500 
lb.s.t. with afterburning.  Maximum speed: 1377 mph at 40,000 feet.  
Initial climb rate 11,000 feet per minute.  Service ceiling 45,000 
feet.  Normal range 929 miles.  Dimensions: wingspan 63 feet 0 inches 
(maximum), 31 feet 11 1/2 inches (minimum), length 76 feet 0 inches, 
height 20 feet 0 inches, wing area 525 square feet.  Weights: 55,275 
pounds empty, 70,000 pounds loaded, 88,948 pounds maximum takeoff.  

Sources:

  Grumman Aircraft Since 1929, Rene J. Francillon, Naval Institute
  Press, 1989.

  United States Military Aircraft Since 1909, Gordon Swanborough and
  Peter M. Bowers, Smithsonian, 1989.

  The Fury of Desert Storm--The Air Campaign, Bret Kinzey, McGraw-
  Hill, 1991.

  General Dynamics Aircraft and their Predecessors, John Wegg, 
  Naval Institute Press, 1990.

  Post-World War II Fighters: 1945-1973, Marcelle Size Knaac,
  Office of Air Force History, 1986.

  The American Fighter, Enzo Angelucci and Peter Bowers,
  Orion, 1987.

  Modern Air Combat, Bill Gunston and Mike Spick, Crescent Books, 1983.

  The Illustrated Encyclopedia of Aircraft Armament, Bill Gunston,
  Orion, 1988. 

  F-111 Aardvark--USAF's Ultimate Strike Aircraft, Tony Thornborough,
  Osprey Aerospace, 1993.

  F-111 Aardvark, Hans Halberstadt, Specialty Press, 1992.

Joe Baugher		AT&T Bell Laboratories   	
2000 North Naperville Road      Naperville, Illinois 60566-7033