The F-5G / F-20 Tigershark; Northrop’s Bane

May 18, 2021

The F-20 Tigershark remains a controversial topic even to this day. Offering good capability in a cheap and neat package, it is surprising for many that the aircraft never achieved any success. To understand why Northrop’s interesting little fighter never made it, let’s take a dive into the history of both the aircraft and its predecessors.

In the 1950s, the Northrop Corporation began development of a new fighter which was very much intended to be a reversal of trends. In contrast to the bigger and heavier designs that were being built or on the drawing boards, the new design was going to be small, lightweight, easy to maintain and cheap.


The decision proved extremely smart as in 1962 the Kennedy administration, wanting an aircraft that met these requirements, ordered the aircraft into production for supply to America’s allies under the Military Assistance Program.

Designated the F-5A Freedom Fighter, this replaced older, first-generation subsonic jets and was a learning step in providing greater experience to Western-orientated air forces by giving them a modern supersonic, yet simple, attack fighter. With additional two-seat and dedicated reconnaissance variants built, including license production in Canada and Spain, 1223 of the early F-5s were built.


By 1970, the limitations of the F-5A were apparent and a new competition was launched to provide a more sophisticated aircraft to foreign allies, though again with the emphasis on simplicity, reliability and cheapness.

Northrop once again won this with its F-5E Tiger II, which entered production in 1972. This basically updated the F-5A with radar, more powerful engines and sophisticated electronics, and the ability to use more advanced weapon systems.


The Tiger II proved even more successful than its predecessor, with a total of 1,417 of the various models of the series being built in the USA, South Korea, Switzerland and Taiwan. In fact, the aircraft continues to serve in a frontline capacity with several countries still in 2021!

But though the F-5E was an improvement on the -A model, it was still a limited aircraft. Its radar was basic, and though it was a formidable dogfighter – as was proven by its use as a favoured mount for the USAF Aggressor squadrons and the US Navy’s TOPGUN teachers – it was outclassed by modern Soviet fighters that had Beyond Visual Range (BVR) missile capability.

One American ally, Taiwan, was particularly concerned about having this capability, as its air force was focused on defending the waters of the Taiwan Strait from incursions by the Peoples Republic of China. Here we have our first example of the where US government departments clashed on policy in regard to this aircraft.

The Taiwanese wanted a BVR-capable aircraft, which essentially meant one able to operate the AIM-7 Sparrow medium-range missile. However, after Nixon’s visit to China in 1972, the US State Department was very keen to explore improving relations with the People’s Republic and selling advanced weapons to Taiwan was absolutely the worst thing in that regard.

So, they blocked any possibility of supplying to Taiwan aircraft like the F-4 Phantom, which was the primary American BVR-fighter available.

However, the US Department of Defense, with an apparent disregard of State’s wishes, did think that supplying the Taiwanese Air Force with such a capability was a good idea. As the Taiwanese were beginning licence production of the F-5E, the DOD suggested to Northrop that it might be useful for them to develop a variant of the Tiger that had an emphasis on air interception and the ability to use Sparrow missiles.

Northrop promptly began development of what they designated the F-5G to fulfil exactly this role. This project proceeded nicely along and looked like it might represent another great success in the Northrop model of fighter aircraft sales – cheap and cheerful and basically a technological step up from their previous offering.

Then in 1977 President Carter banned the export of advanced American aircraft. I talk more about the ban and the subsequent effects in my previous article on the F-16/79, so if you want to know more, I suggest you check that out. But suffice to say, American aircraft manufacturers were not too thrilled at this.

Except, ironically, Northrop. As far as they were concerned, the F-5G for Taiwan was approved. In fact, with the sales of potential rivals blocked by Carter’s policy, Northrop was looking at being the only game in town when it came to providing American aircraft to the long list of allies and friendly nations.

Their optimism turned out to be ill founded.

In 1978, Carter personally blocked any sale of the F-5G to Taiwan. Northrop were, to put it mildly, shocked. They suspended development of the F-5G and the company diverted it’s attentions to the F/A-18 Hornet that they were working on with McDonnell Douglas and a possible export version of that aircraft, the Northrop F-18L.

But Carter’s vision of encouraging peace through restricting arms proved short sighted when no other country followed his example and, instead, rushed in to sell their aircraft to anyone who could pay. In 1979 the administration initiated the FX program, which was intended to develop a lower-capability export aircraft that the United States could supply to its allies.

It sounds just like the previous programs that Northrop had done so well out of in the past. But this time, the development costs would be borne entirely by the manufacturer, with no government funding to assist. Though this had paid off on the simple F-5A, the new aircraft would be a much more sophisticated aircraft – and correspondingly expensive to develop.

As a result, only two competitors would be built for the FX program; the afore-mentioned General Dynamics F-16/79 and the Northrop F-5G / F-20. Interestingly the companies approached the problem in opposite directions – one updating an old design, the other downgrading a modern one.

With an apparent green light, Northrop went back into action. The -5G was resurrected and substantially updated to provide a candidate for America’s new export fighter.

Anyway, like the Tiger II, the F-5G focussed on improving engine, flight performance, radar, electronics and the sophistication of the weapons capable of being used. But where the previous model had been an incremental upgrade in design, the new aircraft was vastly superior to its forebear.

The primary visual design change between the earlier F-5E and the F-5G was the use of a single General Electric F404 engine, the same as was used on the F/A-18 Hornet. This put out 17,700 lbs of thrust, a 60% increase on the combined output of the F-5E’s two General Electric J85s, which hugely improved the aircraft’s thrust-to-weight ratio. The F-5G/20 had a top speed of over Mach 2.0, a ceiling over 55,000 ft and an initial climb rate of 52,800 ft per minute.


Though the aircraft looked like the earlier F-5s aerodynamically, in fact Northrop made it inherently unstable and added a fly-by-wire control system. This made the F-20 extremely agile, a match in many aspects to the F-16, itself an extremely manoeuvrable aircraft.

The electronics suite was probably where the biggest enhancement came. The radar was now a General Electric AN/APG-67 multi-mode radar, a thoroughly modern design that provided the F-20 the ability track fighters at 75 kms away and, most importantly, engage them with Sparrow missiles.


The F-20 was also able to use most of the standard weapons then in US service, including the AGM-65 Maverick air-to-ground-missile, latest variants of the AIM-9 Sidewinder heat-seekers and the Mk.80 series of bombs. A total bombload of 8,000lbs could be carried on seven hardpoint, and this was backed up by two 20mm cannon in the nose.

The first aircraft flew on August 30, 1982 and demonstrated excellent performance and reliability over hundreds of test flights. A second prototype took to the skies a year later, this one with the full avionics suite fitted. This would demonstrate in testing the ability to use Sparrow, Sidewinder and Maverick missiles.


By now Northrop had dropped the F-5G designation and had an official USAF one applied – the F-20. This drew the line that the new aircraft, while looking like its forebears, was a completely new machine. Northrop also added to their marketing by applying a new name to the F-20 – the ‘Tigershark’.

All this effort seemed to be paying off. In November 1982 Bahrain placed a small order, and multiple countries were queuing up to test fly the competent little fighter.

But looks can be deceiving. Because while Northrop had delivered an excellent aircraft that fulfilled the requirements of the FX contract, politics had moved on.

In 1981 Ronald Reagan had become President of the United States. His foreign policy, and that of the Soviet Union, was more aggressive and meant that the arms control measures introduced by Carter were gradually reduced. Instead of having to buy the downgraded FX fighter, more and more exemptions were being made, allowing American allies to buy the same aircraft in service with the United States – principally the F-16 and F-18.

In contrast, the F-20 was still struggling to find purchasers, despite all the interest in it. In essence, no one wanted to commit to an aircraft that the United States were not going to buy. In fact, for most prospective customer it seemed that if they waited long enough and complained hard enough, they would, sooner or later, be able to buy the F-16 or F-18. This ultimately proved correct.

Northrop were desperate to sell the aircraft, the small Bahraini order not enough to start production, but here Northrop’s participation in the FX program proved a curse.

Because it was an FX-fighter, selling the F-20 was under the jurisdiction of the State Department. They, with no real experience or interest in managing a fighter export program, didn’t really bother, something that Northrop complained bitterly about.

In fact, during a congressional enquiry into the whole affair, Northrop asked why they as an independent contractor had had to bear the entire burden of developing the F-20 when it was the State Department that was going to sell it – or not, as the case turned out.

This was in sharp contrast to the Department of Defense’s and United States Air Force’s attitude. They were under pressure to reduce the costs of US service aircraft acquisition. The best way to do that was to encourage export sales of these types, as the greater the production run on an aircraft, the less per-unit cost to the DOD and USAF. So naturally, they pushed the F-16, or else the F-15 or F-18.

This issue with the USAF cropped up again when, in what was a bit of a desperate throw of the dice by Northrop, the F-20 was offered to the Air National Guard as a new interceptor for defending US airspace. The F-16 was not, at that time, capable of BVR missile use, a prerequisite for the role. As it was a key feature of the F-20, Northrop argued that their aircraft should get the job.

But for DOD, the financially sound decision was to purchase a variant of the F-16 modified to use the AIM-7 – the F-16 ADF. Again, why split the order and add to your expense when an upgrade – one that would become a standard feature in time – could do the job?

The same reason also explains why the USAF and the US Navy turned down the F-20 as a new dissimilar aircraft for service in their respective aggressor training programs. Congress made the two services evaluate the Tigershark for the job but ultimately, they went with the F-16.

There have been allegations since that the Navy’s choice was the result of them getting their TOPGUN F-16s at a below cost rate from General Dynamics, a ploy to further undermine the F-20. Considering the level of mendacity that seems to permeate some of the deals involving US fighter contracts, I would not dismiss the idea.

But at the end of the day, the issues of any limited purchase for the United States were the same as those which put off foreign buyers. Why open an entire production line for a limited run which would prove more expensive in the long run than using existing in-service aircraft?

And despite making noises in support of the F-20, Congress was not much of a friend to the Tigershark either. In 1983 when the House approved both funding and technology transfers to enable Israel to develop the IAI Lavi – a cutting edge multirole fighter that would have directly competed against the F-20.

Again, Northrop made loud noises about how they had paid for the whole program completely out of their own pockets, but that American taxpayers were now funding a foreign competitor; a very legitimate beef, and once again shows the vagaries of American policy.

Worse came when tragedy struck. Two of the prototypes crashed in two separate occasions, resulting in the deaths of both pilots.

Though both events were attributed to the pilots blacking out while performing hard-gee stunts, it still raised questions. The second loss, in May 1985, pretty much marked the end of the F-20, though technically it staggered on until 1986 when Northrop finally gave up. The whole venture cost the company $1.2 billion of their own money, a staggering sum.

In a lot of ways, the financial realities of differing US policies explain both the success of Northrop’s early export fighters, and what ultimately killed the F-20.


The F-5As-through-F were basically given away as military aid. They might not have been the most advanced and capable aircraft, but they were better than what many of the operators were flying, they were new, and they were cheap – or even effectively free. As a result, their addition to air forces all over the globe was welcomed. And Northrop didn’t have to worry too much about the finance as the USA was picking up the tab.

But in the mid-70s, that had changed. America largely wanted its allies to buy their aircraft from them, not subsidise them. And if those allies had to buy their new aircraft, then why would they settle for second best, especially if that aircraft had no real future.

With no purchase by a US service, or even a large foreign buyer, the F-20 was not going to receive any major updates in the future. Indeed, it would prove much more expensive to operate in the long run due to the limited numbers in service meaning spare parts would not be available or else must be custom made.

In contrast, with the Reagan administration permitting sales of the F-16, customers could get a USAF standard fighter. These would receive long term support and upgrading and you could be assured of a ready supply of parts.

And here is the thing about the F-20. Yes, it WAS an excellent aircraft.

But the United States already had three of those available – the F-15, -16 and -18.

All of these would prove export successes and to have the necessary capability and growth potential to make them truly great aircraft. That is why they’re still being built in new variants today.

Because if we are brutally honest, when you compare the Tigershark to its contemporaries, with its smaller size and likely more limited potential, it really does shape up as the worse of the bunch.

But that isn’t to denigrate the F-20. It’s a recognition of how good the other ‘teen-fighters’, its ultimate competition really were and are. It was not any Soviet fighter that proved capable of killing the F-20, it was its national rivals – which was exactly what it was designed for under the FX program, to be inferior to contemporary US fighters.

Add in the vagaries of politics and management by a government department – something that is rarely noted for its ability to act well in a commercial environment – and you have the quite frankly complete mess that was the F-20 project.

And that really is not fair, neither to the aircraft nor Northrop. Because if one thing must be said about the F-20, it’s to give kudos to the designers at Northrop who produced such a brilliant design.

Truly, one of the ultimate “what-if’ aircraft.


Hushkit – F-20 versus Lavi: The Tigershark, the Young Lion and the Viper

The Westland Wyvern; Outdated Monster

The Westland Wyvern; Outdated Monster

There are a literal host of aircraft that, despite apparent good design, were doomed by the failure to provide them with a decent engine. But occasionally you come across one that manages to succeed despite repeated failures by powerplant manufacturers to get their...

Varga RMI-1 X/H; The First Turboprop…almost

Varga RMI-1 X/H; The First Turboprop…almost

In the run up to the start of the Second World War, air forces across the world were not just building up their respective strengths, they were exploring new concepts and designs that they hoped would give them the edge when conflict broke out. And the twin-engine...

Big Moves in Myanmar; The Hpapun Offensive and Drones Hit Naypyitaw

Big Moves in Myanmar; The Hpapun Offensive and Drones Hit Naypyitaw

There have been some major developments in Myanmar, also known as Burma, as anti-junta forces have struck several significant blows against the military regime that seized power in a coup in February 2021. On the 30th of March the Karen National Liberation Army (KNLA)...

American Tiger; The Northrop F-5C

American Tiger; The Northrop F-5C

Bit of an unusual one today as the Northrop F-5 is far from a forgotten aircraft and the particular model we are looking at was only built in tiny numbers and has so few differences from the original production aircraft that the redesignation is barely warranted. But...

A Big Miss? The Gloster F.9/37

A Big Miss? The Gloster F.9/37

When you look at the primary fighter aircraft that the Royal Air Force (RAF) started the Second World War with in 1939, one really does look like an anomaly; the Gloster Gladiator. Very much an aircraft from a previous era to its illustrious stable mates, the...