Northrop Development
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Northrop N-156 family program             Last update 12-04-2024

The US Air Force was engaged in a run to obtain higher and higher performances and armament load from its new fighters up to the sixties, with the consequence of increasing complexity, increase in airframe weight,
spiralling maintenance costs and necessity for long runways.
Northrop studies on lightweight fighters begun in the mid fifties with the N-102 "Fang" project, which was not built. This had no resemblance to the future N-156/F-5.

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        Northrop N-102 Fang mock-up with fictitious serial 22777

Small, lightweight engines with enough power were a problem, solved wth the availability of General Electric's J-85 beginning 1955. A new project was started with the designation N-156 and implied a family of aircrafts,
consisting in a ground based fighter (N-156F), a carrier-borne fighter (N-156N) and a trainer (N-156T, later TZ-156).

The US Air Force needed at the time a new supersonic trainer to replace the Lockheed T-33A; it issued in May 1955 an operational requirement for which it was selected and designated Northrop T-38A.

Northrop went on with development of the fighter version as a private venture, although the US Air Force was not interested in the proposal for its own use, but the aircraft might have been of interest to allied nations.
Official presentation to the USAF of both the single- and double-seater was in January 1956.

Northrop philosophy was for a light-fighter, simple, small, with no special maintenance tools needed, simplified maintenance and service procedures (16 manhours/flight hours compared to 40-65
manhours/flight hours
needed by contemporary fighters
)

Construction go-ahead (with company funding) was given early 1958. On 27-05-58 (rather unusually) an research and development contract with the US Department of Defense was formalized allocating almost
USD 50m (32m to Northrop and 18m to General Electric) for 3 aircrafts
and 1 static test airframe to Norair, the division of the new Northrop Corporation now responsible for building aircrafts and missiles.

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                Mock-up with fictitious 56 (Fiscal Year) 156 (project number) serial.     Photo: Northrop             Colour picture of Northrop N-156F mock-up in March 1957                            Photo: Northrop

Official first prototype roll-out followed
at Hawthorne on 31-05-59. Representatives of forty allied nations attended to the ceremony.
Licence production discussions were held with European aircraft builders: Fokker of the Netherlands, SABCA of Belgium and FIAT of Italy but their governments selected the Lockheed F-104G as their new fighter.
Discussions were also held with Australia and the United Kingdom and several other countries without results while additional ones were held in 1959 at Washington to see whether or not it would be good to fund a cheap
fighter for use by the US allies.
                                                                                                  
                                                                                                               Photo: Northrop
                                                                                         Extreme clean underfuselage shown by the first Northrop N-156F prototype

Short take-of/landing on unprepared runways were essential for the smaller Air Forces, see proposals. 
                                                                                                                       frame 1            Drawings: Northrop
                                                                                                                         
Rocket assisted take-off!!!!!!!!!!!!!!!!!!

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First prototype 94987, before being selected by USAF, with (future) gun bay open           Photos: Northrop           All armament to be carried (serparately) by the N-156F on show

                                                                                                  Design: Northrop
                                           Northrop publicity armament drawing: 2'000 lbs underfuselage bomb, 1'000 lbs bomb inbord pilons, 750 lbs bombs on outward pilons.
                        
First prototype, serial 59-4987, was rolled out on 30-05-59 and the first flight took place on 30-07-59 (without any Air Force insignia and markings, only serial 59-4987) at Edwards AFB, where the aircraft had been
transferred, going supersonic on the first flight despite the low thrust of the installed General Electric YJ-85-1 engine.

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Overflight of Edwards AFB still in company colours (Norair on tail, no nationality markings),                      Partial overwing view of the first prototype, not yet selected by the USA, in mid-1959

                                                                                                      
frame 1      Freedom Fighter nose inscription before selection by the USAF        All Photos: Northrop
                                                                                                            
      Same aircraft with two AIM-9B Sideewinder and two long-range tanks........................                                                                                      and in ferry configuration

                                                                            
                                                                             First Northop project for a reconnaissance aircraft system (based on the Northrop N-156F)
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USAF - F-5A Freedom Fighter development
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        The second protoype at an Edwards AFB open-day with Sidewinders and a full load of tanks.         No cannon armament was originally fitted, but tests with 20mm underwing podded cannons took place.
        No nationality or US Air Force markings yet painted as the type had not been officially accepted.     Photo was taken when already selected by the USAF          Photos: Northrop.

                                     Flight tests proceeded smoothly, a USAF project test pilot flying the aircraft from th
e third flight for preliminary evaluation.
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          First prototype with AGM-12 Bullpup missile underwing.            Photo: Northrop                               Air-to-air and (non USA, quite unusual!) air-to-ground missiles were taken in consideration as
                                                                                                                                                 armament in 1960:
  Nord AA.20 (a-a) AS.20 (a-g), Nord AA.25, AS.25 and AS.30, without follow on.
                                                   
         Front view of third prototype with four bombs and trials nose pitot                                Photos: Northrop              First prototype with a full load of bombs seen from bethind

                                                                                                    Photo: Northrop
                                                                                           Third protottype with four naplam bombs on wing pylons.

                                                                                       
                                                                                            Ease of maintenance is shown her by a manual engine change on the first protottype

More powerful General Electric YJ-85-5, with afterburner, replaced the early version after 32 test flights; the second prototype was foreseen to fly in January 1960.

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Intensive armament trials took place: live 250/500/750 pounds bombs and napalm canisters were dropped,                        The third prototype on a test flight, note long nose pitot tube.
2.75 inch rockets were fired,  AIM-9B Sidewinder air-to-air missiles were carried on the wingtips, a
"special missions" (nuclear) bomb mock-up
under the fuselage.                                      Photos: Northrop
 

US Air Force tests at Edwards AFB were concluded with great satisfaction in August 1960, but this did not lead to an Air Force change of mind. No order for its own use was placed and it seemed the the programm
was going to be stopped, so the construction of the third prototype remained incompleted.


Official interest in the aircraft was renewed when the Kennedy administration beginning 60's decided to suppy it allies with a low-cost fighter under the Military Assistance Program FX; a competition was held involving
the Freedom Fighter, the Douglas A-4 Skyhawk and the Lockheed F-104H, a simplified version of the Lockheed F-104G, this last being preferred by the Air Force.


The Northrop F-5A was anyhow selected as the winner, officially announced on 23-04-62, receiving the USAF designation Northrop F-5A Freedom Fighter in August 1962.The third prototype, designated Northrop YF-5A,
was completed and flew on 31-07-63, being fully representative of production aircrafts. Both earlier prototypes were later brought up to YF-5A standard

           Photos: Northrop     
    Line-up of first, third prototypes and first, second production aircrafts on tests                                                Company trials aircraft Northrop F-5A O-38372, in backgroud, with fictitious (?) radar nose
                                                                                                                                                                  next to Northrop F-5F 00889 after a test flight in the late'70s
.


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F-5B Freedom Fighter trainer development

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       This picture clearly shows the external diffence between the Northrop F-5B (serial 38443,                        Forward fuselage difference between the Northrop F-5A and F-5B
       the company's demonstrator) and the Northrop T-38A trainer.          Photo: Northrop

      First flight of the two-seater Northrop F-5B fighter was on 24-02-64; it was accepted ba the USAF and declared operationa on 30-04-64, some four months earleir than the single-seater. The experience
      with the Northrop T-38 trainer was fruitful.

                                                                              
          Photo: Northrop
                                                                                                   Northrop F-5B 38438 FA-438 on AGM-12B Bullpup trials

                                                                              
            Photo: Northrop                                                                                               
                                                                        Preparing for testflightl Northrop F-5B 38438 FA-438, with nose pitot and underwig bombs in 1964
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F-5A Freedom Fighter development - US Army trials
The US Army's wish to operate its own supportforce led in January 1961 till July 1961 to trials for the possible selection of a jet aircraft. This would have operated in the Forward Air Control and the Close Air
Support role operating from uniproved airfields near front lines. Initial factory tests were held on a grass runway at Hughes airfield, Culver City, not far from the Hawthorne factory, followed at NAS Jacksonville
and NAS Pensacola.


Two Fiat G-91R-3s, two G-91R-4s, one G-91T-1, two Douglas A-4D-2 (A-4B) Skyhawks and the two Freedom Fighters prototypes (59-04987/988) participated at Fort Rucker Army Base to the trials.

 
The Northrop aircraft was preferred by the Army, but the project was cancelled due to US Air Force fierce opposition.

 
    Photos: Northrop   
  Bombs armed Northrop YF-5A 94987 (without guns) in company with its competitors,                               First Northrop YF-5A 94987 on an US Army test carrying two underwing tanks in September 1961.
  Fiat G-91R-3 and Douglas A-4B at Jacksonville.

F-5A Freedom Fighter development - USAF ground trials

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            Soft ground trials at Pensacola in June 1961: the second Freedom Fighter prototype with                  Second prototype Northrop YF-5A 94988 seen on the grass runway in 1961, with external
            larger tires on the main and two-tires on the front landing gear, later removed. Trials in                     fuel tanks and single-tire wheel  on the front landing gear.                       Photo: Northrop
            June 1961included landing in 1300 ft/396m on grass and taking off with a maximum load
           
in less than 2'500 ft/762m. USAF inscription was replaced by "Army" in September 1961 Photo: DoD         

                                                     
All photos: Northrop
                                                                                                                        Aircaft servicing during soft-fields trials

F-5A Freedom Fighter development - Production lines

                                                                                 
frame 1                Photo: Northrop
                                                                                                            Construction line for the Northrop F-5s in 1960s


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F-5A Freedom Fighter - museum exhibitions

                                                                                 
         Photo: Glen E. Chatfield
                                                                             Third prototype Northrop YF-5A serial 94989 aeen at Wright-Patterson on 11-06-90, next
                                                                             to a Boeing B-52. This photo gives an idea of the fighter size.


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US Navy - F-5NN Freedom Fighter



               A certain interest for the Northrop N-156 was shown after World War II by the US Navy, as only their piston engined
            aircrafts could be handled by small escort carriers, at the time used mainly as aircraft transport carriers.


            The first Northrop (paper) light fighter project
for the US Navy was the N-156NN or PD-2706 show in November 1955,
            but
interest vanished when the Navy retired in March 1956 these carriers.

           Left drawing of the poroposed naval Northrop N-156NN