Subject: Number Eighty-Nine in the Series--Northrop F-89 Scorpion (9 of 10)

From: [email-masked]
Date: 30 Sep 93 16:16:10 GMT

>From [email-masked]

The F-89H (N-138) was an adaptation of the missile-armed F-89D to carry 
the new Falcon air-to-air missile.  It was a direct outgrowth of the 
abortive F-89G program, which had been a proposal to mate the Hughes 
MA-1 fire control system with the Hughes Falcon air-to-air missile.  
With the cancellation of the F-89G project, the Northrop company 
proposed a more straightforward upgrade of the F-89D with the Hughes 
E-9 fire control system (a simplified version of the MA-1).  The USAF 
agreed to the project, and three F-89Ds (52-1830, 52-1939, and 53-249) 
were modified to test the weapons system changes.  Only one of these 
(serial number 52-1939) was redesignated YF-89H.  

The wingtip pods of the F-89D were redesigned and enlarged with the 
forward third of each pod carrying six separate weapons compartments.  
Three of the compartments each held a single Hughes GAR-1 Falcon 
air-to-air missile, and the other three each carried a pack of seven 
2.75-inch FFARs.  So the total weapons load of the F-89H was six 
Falcons and 42 2.75-inch FFARs.  

The Falcons were stored inside the wingtip pods until ready for 
firing.  When ready for firing, the Falcons swung out on individual 
launchers through a pair of fairing doors on the pods.  

The Hughes GAR-1 Falcon was the first guided AAM in the world to enter 
operational service.  The first work on the Falcon had actually gotten 
started back in 1947.  It had actually originally been assigned a 
designation in the fighter sequence: F-98.  However, this was changed 
to GAR-1 in 1950.  The Falcon weighed about 110 pounds at launch, and 
was powered by a Thiokol solid-propellant high-impulse rocket motor.  
The missile was fitted with four delta wings of extremely low aspect 
ratio, set at 90 degrees to each other, and each carrying a powered 
control surface at the rear.  A 29-pound high-explosive warhead was 
carried, and the nose was fitted with a radar homing receiver.  The 
GAR-1 used a semi-active radar homing technique, in which the 
launching aircraft's radar transmitter tracked the target and the 
missile homed in on radar waves reflected back from the target.  
Maximum speed of the Falcon missile was about Mach 2.8, and effective 
range was about 4 miles.  

In 1962, the designation of the GAR-1 Falcon was changed to AIM-4.  

Later, an infrared homing version of the Falcon was developed.  The 
infrared Falcon was known as GAR-2 (later changed to AIM-4B), and it 
became standard practice for the Scorpion to carry three radar homing 
and three infrared-homing Falcons.  Were the Falcons to be fired in 
actual combat, the plan was usually to fire one Falcon of each type at 
the target in order to ensure a high probability of a kill.  

The E-9 fire control system had a "universal computer" which enabled 
the crew to select the best mode of interception.  The F-89H could use 
either a lead collision intercept mode (FFARs only) or a tail chase 
interception mode (Falcons and/or FFARs).  

The USAF accepted the first production F-89H in September of 1955, but 
it was not until March of 1956 that the first F-89Hs became 
operational with the 445th Fighter Interceptor Squadron at Wurtsmith 
AFB in Michigan, almost two years later than originally scheduled.  
The delays were primarily caused by problems which developed with both 
the missile launching pods and with the E-9 fire control system.  Just 
as in the case of the F-89D, there were problems with corrosion in the 
missile launching cavities which could result in an explosion or 
misfire if left uncorrected.  The E-9 fire control system had a host 
of minor technical problems which needed to be worked out before 
maximum performance could be attained from the missile armament.  

Because of the rapid advances being made in the supersonic interceptor 
program, particularly with the Convair F-102A Delta Dagger, the 
service life of the F-89H with the USAF was relatively brief.  In 
November of 1957, the first F-89H was transferred to the Air National 
Guard, entering service with the 123rd FIS of the Oregon ANG at 
Portland.  By September of 1959, all USAF F-89H interceptors had been 
passed along to the ANG.  

Serials of the F-89H: 

54-261/320 	Northrop F-89H-1-NO Scorpion 
54-321/416 	Northrop F-89H-5-NO Scorpion 

Specification of the F-89H: 

Two Allison J33-A-35 turbojets, 5440 lb.st.  dry, 7200 lb.st.  with 
afterburner.  Maximum speed: 636 mph at 10,600 feet, 523 mph at 46,500 
feet.  Initial climb rate 8360 feet per minute.  Altitude of 46,500 
feet could be attained in 18.1 minutes.  Service ceiling 49,200 feet.  
Maximum range 1367 miles.  Dimensions: wingspan 59 feet 8 inches, 
length 53 feet 10 inches, height 17 feet 6 inches, wing area 606 
square feet.  Weights 25,194 pounds empty, 37,190 pounds combat, 
42,241 pounds gross, 46,789 pounds maximum takeoff.  Armed with 42 
2.75-inch folding fin unguided rockets and six Hughes GAR-1 Falcon 
semiactive-homing air-to-air missiles in wingtip pods.  Underwing 
racks could carry 16 five-inch rockets or 3200 pounds of bombs.  

Sources:

  United States Military Aircraft Since 1909, Gordon Swanborough
  and Peter M. Bowers, Smithsonian, 1989.
  
  F-89 Scorpion in Action, Aircraft Number 104, Larry Davis and 
  Dave Menard, Squadron/Signal Publications, 1990.

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

  Fighters of the United States Air Force, Robert F. Dorr and David 
  Donald, Temple Press Aerospace, 1990.

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

  American Combat Planes, Third Enlarged Edition, Ray Wagner,
  Doubleday, 1982.

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