The McDonnell Douglas F-4 Phantom II is widely acclaimed as the most significant Western fighter jet of the Cold War. In its time, it was the workhorse and backbone of US airpower. The aircraft redefined what a fighter jet was able to be through technological complexity, versatility, and sheer power. By the time the program ended, over 5,000 Phantom IIs had been built for the US and export customers around the world.

The F-4 Phantom II was originally built for the US Navy to protect the aircraft carrier groups from Soviet threats. In Marine Corps service, it served a close air support and strike mission, and in Air Force service, it was used for air superiority, strike, reconnaissance, and SEAD roles. Here is what to know about the impact of the F-4 Phantom II and how it was designed for a new age of combat.

Development Of The F-4 Phantom II

McDonnell Aircraft Corporation was founded in 1939 and lasted until 1967, when it merged with Douglas Aircraft Company to form McDonnell Douglas. The 1950s were a difficult time for McDonnell, with demand for its twin-engine McDonnell F2H Banshee fighter drying up following the conclusion of the Korean War. The Banshee was first flown in 1947, and a total of 895 were built.

Adding to its woes was that it had gone all in on designing a single-engine successor called the Demon, an effort that had almost bankrupted the company. But it was beaten out by Vought for US Navy contracts, with Vought eventually building 1,219 Vought F-8 Crusaders, while McDonnell built just 519 McDonnell F3H Demons.

McDonnell struggled to find an answer for the F-8, as well as the Grumman F-11 Tiger, to meet the Navy’s changing requirements. McDonnell got to work on a new aircraft, which they called the Satan, but would later rename the Phantom II. The first F-4 prototype was delivered in 1958 by McDonnald Aircraft Corporation. The US Navy could not ignore the twin-engine, supersonic, all-weather, long-range fighter designed to operate from US carriers and set up a protective screen against emerging Soviet threats against the carriers.

How The F-4 Offered A New Way Of Fighting

Whereas previous aircraft were focused on nimble aerial dogfighting, the F-4 Phantom II was designed around its radar and missile technologies to engage enemy targets beyond visual range. The F-4 was so enthusiastic about this new way of warfare that it even scrapped the autocannon. It was soon realized this was a mistake, and missiles and radars had a long way to go before fully replacing guns. The United States Air Force quickly added guns to their Phantoms, although the Navy didn’t due to the constraints of operating the aircraft from aircraft carriers.

In an unusual move for a fighter jet, the Phantom was designed with a crew of two in order to cope with the additional workload of all its new equipment. The aircraft was soon exported to US allies around the world, including the RAF. A former RAF Phantom II pilot told the Imperial War Museums, « In an ‘intercept’ in a Phantom, you can basically identify an aircraft over 20 miles away. And if you knew what you’re up against, then you’ve won the battle, really.« 

Emily Charles, a curator at the American Air Museum, said, « Some described the Phantom as a ‘flying brick’, but its unorthodox design made it versatile. The Phantom’s size and power gave it a large carrying capacity of almost 16,000 pounds. » The aircraft was also fast, with a top speed of around Mach 2.2. The aircraft focused on speed for defense, although the later F-14 Tomcat would later improve on this by adding a good deal more maneuverability.

Speed: A Dead End

The F-4 Phantom II was fast at around Mach 2.2, which was around the same speed as the contemporary MiG-21. Up until that time, it was assumed that a more advanced fighter meant a faster one. According to Not What You Think, after 20 years in Vietnam, military analysts reviewed the flight data of more than 100,000 sorties by the Phantom II over North Vietnam, and they found that in not one of those sorties was there even a single combat second spent with the F-4 over Mach 1.8.

They found there were a few minutes flown over Mach 1.4 and only a few hours at or about Mach 1.2. This was an incredible revelation, seeing that it was reviewing 100,000 sorties over a 20-year period. The reason for this was partly due to the pilots flying the aircraft at a speed that optimized their maximum turn rate, and this drives the speed down to around Mach 0.7. The Mach 2.2 dash speed to get into the conflict zone quickly was also mostly seen as useless, as it just guzzled the fuel, collapsing the aircraft’s combat radius and time in the air.

While the F-15 would be designed with a greater speed of around Mach 2.5, after these findings, having an even higher top speed ceased to be a leading priority. The F-22 has a classified top speed of over Mach 2, perhaps Mach 2.2, but the F-35’s top speed was slowed to just Mach 1.6. The F-14 Tomcat was a bit faster at around Mach 2.3, but it put more emphasis on maneuverability.

Beyond Visual Range (BVR): The Future

Where the F-4 really set the standard for future air warfare was in Beyond Visual Range (BVR) engagements. Since the Phantom II, this is where successive fighter jets have sought to push the envelope. The major fundamental difference between the F-4 and modern 5th-generation jets is stealth, which allows aircraft to remain hidden from sight for much longer, allowing them to get the first look and first shot.

The F-4 was designed to fight at distances where pilots couldn’t see the enemy and was built with the understanding that the age of dogfighting was over, although this was later partially retracted. As a carrier-based interceptor, the aircraft emphasized long-range interception of bombers, heavy missile armament, and a powerful radar. It was designed around the AIM-7 Sparrow radar-guided missile, the AIM-9 Sidewinder infrared missile, and the AN/APQ-120 radar.

Still, it takes time for technology to mature, and at the start, the aircraft’s BVR performance was disappointing, with a kill probability of less than 10% with its Sparrow. This was partly due to the Rules of Engagement requiring pilots to visually identify a target, negating the benefit of being able to engage beyond visual range, and the limits of early radars struggling to see low-flying targets against the clutter of the ground.

Versatility Leading To Multirole Fighter Jets

Before the F-4 Phantom II, it was typical to develop separate aircraft types for specific missions like interception, strike, close air support, etc. But the airframe of the F-4 was large and versatile, allowing variants of the same aircraft to be built for each mission. The F-4 never became a multirole aircraft, as it couldn’t do all those things at once; it was a family of aircraft with variants able to do them individually.

But it was so successful that it influenced later programs like the F-16 and F/A-18 that were designed from the ground up to do multiple missions like air-to-air and air-to-ground. The F-15 followed the F-4’s lead in having a powerful airframe able to carry future munitions not developed when the aircraft first flew.

Today, any F-35 can carry out missions like electronic warfare, ground strikes, air-to-air missions, and more without needing a separate variant. Another area where the F-4 set a new gold standard was its comparatively long combat radius for the era. This has been progressively extended with modern aircraft, and further extending the combat radius is one of the design priorities of the upcoming 6th-generation fighters.

Refining The F-4’s BVR

The F-4’s early BVR limits were overcome, and the technology improved, while the Rules of Engagement changed with developments like IFF (Identification Friend or Foe). The Phantom II can be considered a « rough draft » for BVR, something that 4th and 5th-generation jets have been able to refine. The aircraft’s biggest weakness was ground clutter. But this was overcome by the F-14 Tomcat and F-15 Eagle with their Pulse-Doppler radars that were able to filter out the moving ground and track targets from above.

The Phantom helped to shape three major post-Vietnam principles. One is that having multirole aircraft is not an option, and another is that doctrine needs to evolve with technology (e.g., adjusting the rules of engagement). A third principle was that fighter jets can’t just rely on their speed and missile armament; they also need situational awareness, maneuverability, and the ability to use different weapons.

The Phantom was a 3rd-generation fighter, but it helped set the stage for 4th-generation fighter jets. As a dogfighter, the F-4 had limitations after all; being called a « flying brick » was a reference to being fast but not maneuverable. Like almost all fighter jets, the F-4 evolved over the course of its lifetime and was able to achieve positive victory ratios over highly maneuverable MiG-17s and MiG-21s. Aircraft evolve overtime, and one excellent example is the famous A-10 Warthog that started as a tank hunter, but in its twilight years is at least partially pivoting into a drone hunter platform.