Subject: Number 111 in the Series--General Dynamics F-111 (7 of 13)

From: [email-masked]
Date: 16 Mar 94 17:20:17 GMT

>From [email-masked]

Because of late delivery and protracted development of the F-111D, 94 
F-111Es were ordered with simplified avionics and the TF30-P-3 
turbofan engine, but with the Triple Plow 2 air intakes of the F-111D.  
They were ordered in 1968.  Even though the F-111E had a later series 
letter than the F-111D, the E preceded the D into service.  

As compared to earlier F-111 variable-geometry air intake 
configurations, the Triple Plow 2 air intakes were four inches farther 
from the airframe in order to improve boundary layer "plow", and the 
translating cowl was replaced by a series of three blow-in doors.  
These blow-in doors are a set of auxiliary inlets placed on the sides 
of the main intakes which enable extra airflow to reach the engine 
inlet ducts during takeoff or when the engines are at full power but 
the aircraft is moving slowly.  They are normally sealed closed by 
spring-loaded doors which are pushed open by air pressure when 
additional airflow to the engines is needed.  

The F-111E carries the APQ-113 forward-looking attack radar which is 
used by the navigator for navigation, air-to-ground ranging and 
weapons delivery.  It can also be used in the air-to-air mode, 
although this is not the primary mission of the F-111E.  

The first flight of an F-111E took place on August 20, 1969, and 
deliveries to the Air Force took place from 1969 to May 28, 1971.  A 
total of 94 were built, and serials were 67-0115/0124 and 
68-0001/0084.  

TAC's 27th Tactical Fighter Wing at Cannon AFB reached initial 
operational capability with the F-111E in the fall of 1969.  The wing 
had 29 F-111Es by December, but these flew under restrictions until 
the Air Force was convinced that the wing longerons were safe.  

The F-111E program slipped another six months following the December 
1969 loss of the 15th F-111A.  The Air Force grounded the entire fleet 
and refused to accept the delivery of any more F-111s until the 
problems were fixed.  All F-111Es went through the Recovery Program 
and other structural inspections that stemmed from the December 1969 
accident.  The order that grounded the fleet was finally lifted in 
July of 1970.  

The F-111E had integral radar homing and warning equipment and 
possessed electronic countermeasures capability.  This made the 
aircraft needed in Europe right away.  Despite the program's slippage, 
the first two of the 70 F-111Es slated for the 20th Tactical Fighter 
Wing in Europe were sent to the RAF Upper Heyford base in Oxfordshire, 
England on September 11, 1970.  The wing became fully operational with 
the type in November of 1971.  These F-111Es remained based at Upper 
Heyford up to 1993, when defense cutbacks and the overall decline in 
the threat from the East resulted in their withdrawal to stateside 
bases.  

F-111Es of the 20th TFW were used in Operation *Desert Storm* in early 
1991, flying out of bases at Incirlik, Turkey.  They lacked the 
precision guided munitions capability of the later F-111F, and so they 
carried mainly Mk 82 or Mk 84 standard conventional bombs and other 
conventional ordnance against targets in the northern part of Iraq.  
None were lost in combat, which is a remarkable testament to the 
efficacy of the F-111E in combat.  

The first prototype of the F-111E series (67-0115) was loaned to NASA 
for tests in support of the Integrated Propulsion Control System.  
This was a "fly-by-wire" system installed in the weapons bay which 
automatically controlled the variable-geometry inlet and the 
turbofans.  The first IPCS flight was carried out on September 4, 
1975.  The last flight was on February 27, 1976.  After the tests were 
completed, the F-111E was returned to the Air Force and restored to 
its original configuration.  It later served as a chase plane for the 
Rockwell B-1 strategic bomber.  

Sources:

  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.

  The World Guide to Combat Planes, William Green, Macdonald, 1966. 

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

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

  Flying the Frontiers--NACA and NASA Experimental Aircraft, Arthur
  Pearcy, Naval Institute Press, 1993.

  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