Key Points and Summary – This article provides a rare inside look at how Iran’s industry reverse-engineered the American F-5 fighter after being cut off by sanctions following the 1979 revolution.
-Based on exclusive interviews with a lead Iranian engineer on the project, the author reveals the step-by-step process.
-While copying the airframe and sourcing engines was relatively simple, the real challenge was the internal systems.
-Iran’s solution was to create a “hybrid” aircraft, combining smuggled Western components with available Russian systems to create indigenous fighters like the now-famous twin-tailed Saeqeh.
Iranian Industry’s Experience Copying the US F-5 Fighter
In 2002, when I was preparing to head off to Iran for what was to be the country’s first major international air show, a colleague of mine from a NATO country’s air force said to me, “Hey, you will get to see the twin-tailed F-5. Let me know what you think about it.”
The phrase “twin-tailed” F-5 was a reference to the several slightly different reverse-engineered versions of the Northrop lightweight fighter.
Under the rule of the Shah of Iran, the country acquired 104 single-seat F-5A and 23 F-5B two-seaters. These were later supplemented by 166 F-5E/F models, 26 F-5Fs, and 15 RF-5As, totaling 352 combined models of this type.
When the Shah’s government fell and the Islamic Revolution created the current Iranian state in 1979, the country found itself with a large number of US-made F-5s, plus F-4s and the F-14 Tomcat.
However, the embargos imposed on the new Iranian state by the US left the new Islamic Republic of Iran Air Force (IRIAF) without any source of spares, maintenance, or technical support for these aircraft.
The Iranian engineers and technicians were tasked with finding a way to utilize their knowledge of the US equipment they had been working with for years and keep their air force operational. Iranian designers soon began to learn the art of reverse-engineering from the Chinese. Once they felt proficient with this technique, they began exploring the possibility of copying American-made systems.
The Twin-Tailed F-5
One of the first Iranian-modified copies of the F-5 was the Iran Aircraft Manufacturing Industrial Company (HESA) Saeqeh fighter, which has also been referred to as the “Saeqeh-80”, which first flew in 2004. There were three later versions of this HESA aircraft shown on Iran state television on 23 September 2007. Those aircraft were shown on this instance as being inspected by then-Iranian President Mahmoud Ahmadinejad, and are designated as the “Saeqeh”, “Azarakhsh” and “Tazarv”.
Speaking more than a decade later at Iran’s own Persian Gulf Air Show with one of the lead Iranian engineers who worked on this program to copy the American aircraft, he described how the reverse-engineering process was carried out.
“We knew basically the aerodynamics and structure of the aircraft, and our industry was capable of fabricating the sections we needed to develop this modified design of the F-5. The configuration was not too complicated and there was no heavy use of composite materials as you see in today’s aircraft,” he said. “So from a materials standpoint this was not a huge challenge.
“The engines were not a major issue either,” he continued. “We had a large number of J-85 engines from all of the F-5s we had procured on our own, plus there were many places in the world that you could buy them and also obtain spares for them.
“What was the major technical problem was developing the configuration of the on-board systems. What we did was of course list them all out and determine what we needed on board the aircraft to have it operate like the US aircraft,” he explained. “Then we went out to look at what was available to buy from where. Basically, what we did was to buy the original US system or some analogue from a Western nation wherever we could.
“But where we could not buy what we needed from the US or one of its allies then we would buy something Russian. We could usually find something that would perform the same function as the US subsystem or components that we could not acquire from anywhere without complications.”
We were assisted by the history of the F-5. Specifically, there were a lot of them were left behind when North Vietnam invaded the South and captured them. Some of those F-5 systems were later copied by the Russians, who were still making them for their own aircraft years later and gave us an easily-accessible source.”
Impact on Iran’s Modern Aircraft Industry
This is how this fighter ends up being a “hybrid” aircraft—by combining the systems sourced from both Cold War-era protagonists. However, the Russian influence is also evident in the cooperation between Russia and Iran in the 2000s, which led to joint design proposals, such as the Shafaq program, which never advanced beyond the prototype stage.
The most notable feature that the Iranian design team developed in copying the F-5 was to change the configuration from a single, vertical tail to twin, outwardly canted tails. This design feature was not only used in the design of the Saeqeh but also all subsequent variants. It was also the tail design for the Shafaq and for other Iranian homegrown design concepts that have been seen over the years.
When I asked if this tail configuration was to aid the performance at high angles of attack, the answer I received was “yes, that was one of the considerations from the beginning.”
“However,” one of the designers on the program I also spoke to continued, “this was also because with this kind of a tail the aerodynamics engineering team said that this greatly increased the stability of the aircraft at different flight regimes and altitudes as well.”
This is a sign that one of the tendencies that had rubbed off on Iran was the dominant position of aerodynamicists in Russian fighter design that has been seen for decades. This is one of the factors that has driven designs of later Russian models like the Su-35 and Su-30SM and the Russian use of supermaneuverability.
Interestingly enough, when Iranian designers talk about the performance of the Saeqeh and the other models, they do not compare them with Russian designs. They instead speak about it being a “cross-breed” with the older McDonnell-Douglas F/A-18C/D design. (It is not a coincidence that the F/A-18 has a similar tail design.)
This telegraphs what I have heard from Iranian designers for many years, namely that, regardless of the years that have passed since they were in close cooperation with the US, they still prefer American-made fighters to anything else. This preference persists to this day, despite the ongoing hostility between the two nations.
About the Author: Reuben F. Johnson
Reuben F. Johnson has thirty-six years of experience analyzing and reporting on foreign weapons systems, defense technologies, and international arms export policy. Johnson is the Director of Research at the Casimir Pulaski Foundation. He is also a survivor of the Russian invasion of Ukraine in February 2022. He worked for years in the American defense industry as a foreign technology analyst and later as a consultant for the US Department of Defense, the Departments of the Navy and Air Force, and the governments of the United Kingdom and Australia. In 2022-2023, he won two awards in a row for his defense reporting. He holds a bachelor’s degree from DePauw University and a master’s degree from Miami University in Ohio, specializing in Soviet and Russian studies. He lives in Warsaw.
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