Subject: Number Eighty-Nine in the Series--Northrop F-89 Scorpion

From: [email-masked]
Date: 21 Sep 93 16:20:37 GMT

>From [email-masked]

After only eight F-89As had been built, production shifted to the 
F-89B (Model N-35).  It differed from the A only in various items of 
internal equipment.  It carried a Lear F-5 autopilot, an instrument 
landing system (ILS), and a Sperry Zero-Reader (which combined the 
features of artificial horizon, directional gyro, magnetic compass, 
and altimeter).  The armament and the radar were unchanged.  

The first production F-89B was accepted during February of 1951, and 
entered service with the 84th Fighter Interceptor Squadroan, 78th 
Fighter Interceptor Group based at Hamilton AFB, California during 
June of 1951.  

After a rash of engine failures on early F-89Bs, the aircraft were 
reengined with Allison J35-A-21A turbojets, rated at 5100 lb.st.dry 
and 6800 lb.st with afterburning.  These engines had an engine oil 
scavenging system and different kinds of afterburner eyelids, which 
gave smoother afterburner control.  

All F-89Bs had external mass-balanced elevators which were adopted to 
overcome a sever flutter caused by the jet exhaust.  However, they 
were fitted retroactively with elevators having internal mass balance 
after this feature had been developed for the F-89C.  

The service of the F-89B with the USAF was quite brief.  By 1954, all 
F-89Bs had been transferred to the Air National Guard.  The first 
Guard unit to re-equip with the F-89B was the 176th Fighter 
Interceptor Squadron of the 128th Fighter Interceptor Wing of the 
Wisconsin ANG.  

Several obsolete F-89Bs were later modified as DF-89B radio-controlled 
drones.  

Serials:

49-2439/2478 	Northrop F-89B Scorpion 

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.

  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