Saturday, March 15, 2014

Green Dreams – The U.S. Army Evaluates the N-156F

My early articles did not feature footnotes because I was still expanding the envelope of what I could do in the space allotted to me, which was initially 500 words. I soon surpassed that, but it would be several months later before I would hit my stride. What helped was the shift to a purely digital format with Engineering's Airspace on-line magazine.

Unfortunately this piece was written for VelocitE, the name of the magazine that preceded Airspace. VelocitE was a duel track publication with both a digital and a hard copy issue. The hard copy feature meant there were limitations to what I could do.

I remember being very disappointed that not all of the photos I picked for this article (and the Apollo 13 article before it) could be included in the physical issue. Fortunately they were all in the digital issue, which was important because none of the black and white photos featured had been seen before to the best of my knowledge. Even more important to me were the color photos, most of which have not been seen before except as black and white images.

In short this article started me on the path of doing more independent research into Northrop Grumman programs and proposals and into discovering the history behind them. It's been quite a journey and a satisfying one at that. I hope to continue on that path in retirement.

This article originally appeared in the Northrop Grumman Engineering Department's in-house magazine VelocitE, Volumn 2, Number 10, July 2010. It is posted here with permission and has Approved for Public Release number 12-1492. 

Green Dreams – The U.S. Army Evaluates the N-156F

By Tony Chong

The early years of the N-156F were ones of uncertainty. The single-seat, light-weight fighter variant of the successful design that produced the two-seat T-38A Talon trainer was not backed by the U.S. Air Force. While built with an eye towards the proposed foreign military sales program under development by the Department of Defense, the use of the N-156F for that purpose was not a foregone conclusion.   

Despite its lukewarm reception to the small fighter concept, the Air Force was tasked with initial flight tests of the N-156F, which occurred concurrently with the T-38A in 1959 and 1960. Three prototypes were ordered, but only two were completed.  The Air Force suspended construction of the third aircraft as it decided two were sufficient for the test program.

At the conclusion of the tests the Air Force declined to pursue the design any further. Northrop was left with two flyable aircraft and one partially-built vehicle in storage, but no customers. However, an opportunity arose in 1961 from an unlikely source: the U.S. Army.

Since the formation of the Air Force and the division of responsibilities outlined in the document “Functions of the Armed Forces and the Joint Chiefs of Staff,” also known as the Key West Agreement, the Army was forbidden to operate jet-powered fixed wing combat aircraft. While the Air Force saw the roles as clearly defined, the Army chafed at the restrictions. Close Air Support (CAS) was vital to the service’s successful land operations and the Army lacked confidence that the Air Force would make supporting the Army a high priority. As such they cast about for ways around the agreement.

Rebuffed in an earlier attempt to purchase Cessna T-37 Tweetybirds as an operational forward-based aircraft, the Army decided in 1961 that it needed to acquire a light jet for the Forward Air Controller/Tactical Reconnaissance role. Artillery fire support is an Army function, so they reasoned the ability to accurately direct those fires must be in their purview as well.

Three aircraft were chosen for evaluation. Among them was the foreign-made Fiat G-91R light tactical fighter/reconnaissance aircraft. Another competitor was the Douglas A4D-2N Skyhawk light attack jet (re-designated as A-4C in 1962). The N-156F Freedom Fighter was also selected and became the only twin-engine competitor in the trials.

Both N-156s participated in the tests, with the number two aircraft (59-4988) outfitted for unimproved field operations. This eventually consisted of larger tires for the main gear and a twin-tire arrangement for the nose gear.

Sod field operations were conducted at NAS Jacksonville and NAS Pensacola, FL in June and July of 1961 with the other two modified competitors. Initial results were very favorable for all aircraft, with the N-156F receiving high marks for its easy field maintenance and load-carrying capabilities.

The number one N-156F (59-4987) later acquired U.S. Army markings for some additional tests and publicity functions. These were carried out in September of 1961 and provided a unique appearance for the Freedom Fighter.

Despite the promising results, the Air Force made its objections known and the Army backed down. The competition was cancelled. The remaining G-91R returned to Europe, the other one having crashed during the evaluation, killing its Italian Air Force test pilot Riccardo Bignamini. The two A4Ds were brought back to standard configuration and returned to the U.S. Navy.

Its hopes dashed, Northrop renewed the hunt for customers. Its faith in the N-156F was borne out in 1962 when the aircraft was chosen to be the U.S. export fighter of choice under the new Military Assistance Program. The newly designated F-5A would be the progenitor of a line of successful fighters. A total of 2,603 were built of all variants.

The Army would make one more attempt at acquiring a jet-powered, fixed-wing combat aircraft before finally ceding the role to the Air Force in exchange for control over rotary-winged aircraft in an accord known as the Johnson-McConnell Agreement of 1966.

My thanks to Kristi Harding of Records Management for her help in this article.

For a short history on the development of the U.S. Unified Command Structure go to:

For a pdf of the Functions of the Armed Forces and the Joint Chiefs of Staff document click on number 17 at this site:

For a synopsis of the Johnson-McConnell Agreement go to this link:

For a color photo of the Fiat G-91R in U.S. Army markings see this site:

Photo Captions


N-156F #2 during initial sod field tests at NAS Jacksonville (later NAS Cecil Field) FL. Note the large single-tire nose gear with mud guard. Photo credit: Northrop Grumman


Close up of the large, single-tire nose gear and the trench it dug during the test. The mud guard is quite apparent. Photo credit: Northrop Grumman


A view of the ramp at NAS Jacksonville, FL, with all three competitors. The N-156F is 59-4987, the number 1 Freedom Fighter. It was not modified with the special tires. The two Douglas A4D-2Ns directly behind the N-156F are modified with duel-tire main gear. The Italian-built G-91R-1 (serial # 0042) on the right also has larger tires for unimproved field operations. Photo credit: Northrop Grumman


Duel-tire nose gear and large main gear tires were outfitted to N-156F 59-4988 at NAS Jacksonville. Photo credit: Northrop Grumman


A close up of the main gear tires on N-156F #2. The tires appear to have minimal tread.  By this time sod field tests were moved to NAS Pensacola, FL. Note the partial USAF markings on the main gear door. 59-4988 carried standard USAF markings throughout the evaluation. Photo credit: Northrop Grumman



The duel-tires on the nose gear of the N-156F were substantial. Subsequent tests showed the arrangement worked quite well. Photo credit: Northrop Grumman


The West German-built Fiat G-91R-3 (serial # 0065) sits in front of the Italian-built G-91R-1 (serial # 0042). The G-91Rs flew in U.S. Army markings throughout the tests, but wore standard German and Italian color schemes. Photo credit: Northrop Grumman


Douglas A4D-2N, Bureau Number (BuNo) 148483, sit on the sod field with BuNo 148490 in the background. The A4Ds retained their standard markings and colors for most of the tests. International Orange panels were added to denote them as test aircraft and at some point the BuNos were temporarily removed. Note the duel-tire main gear and the sleek, wheeled power cart. Photo credit: Northrop Grumman



Later in September 1961 the first N-156F (59-4987) appeared in U.S. Army markings at NAS Pensacola, FL. Nearly all published photos of this aircraft are in black and white. The full color image is quite striking. Note the yellow tail markings and the white Army (minus U.S.) on the nose. Photo credit: Northrop Grumman


A close up view of N-156F #1 with “ARMY” prominently displayed on the nose. The man in the cockpit is possibly Northrop test pilot Hank Chouteau who was attached to the evaluation program. Photo credit: Northrop Grumman



A right rear quarter view of N-156F #1 at NAS Pensacola. Pensacola Bay is in the background. Photo credit: Northrop Grumman

Approved for Public Release: Northrop Grumman case # 12-1492, 9/4/2012