Key Points – President Trump’s recent proposal for a new “F-55” fighter, described as a twin-engine “super upgrade” of the F-35, faces skepticism regarding its strategic necessity, technical feasibility as an “upgrade,” and immense potential cost.
-With the sixth-generation F-47 NGAD already in development, critics argue an “F-55” risks being an expensive and redundant program.
-Transforming the single-engine F-35 into a twin-engine platform would require a complete, costly redesign, essentially creating a new aircraft.
-This concept would also compete for limited funding with other vital, high-cost modernization efforts like the F-47, F-15EX, F/A-XX, and B-21 Raider.
The F-55 Might Already Be Doomed
Earlier in May, President Trump expressed interest in upgrading the F-35 into what he called the “F-55.”
Earlier this year, Lockheed Martin also proposed upgrading the F-35 into a “supercharged” version of the aircraft.
Some of these upgrades include adding a second engine, improving the avionics, and so on.
However, when looking at all the other projects that the US Air Force is currently working on, the question arises as to whether there is any room in the budget for a new “super F-35.”
“Supercharging” the F-35
The ”super F-35” (let’s just call it the F-55) is envisioned as a twin-engine evolution of the F-35, addressing what President Trump described as a critical flaw in the current design: its reliance on a single engine. He expressed a clear preference for twin-engine aircraft, citing concerns about safety and performance.
While the F-35 has proven itself as a capable and versatile multirole fighter, its single Pratt & Whitney F135 engine has long been a point of contention among military analysts. A twin-engine configuration could theoretically enhance survivability in combat, especially in hostile environments. It could also offer increased thrust, improving speed, climb rate, and payload capacity.
It is important to note that F-55 would not be a simple upgrade. Integrating a second engine into the F-35’s stealth-optimized airframe would likely require a complete redesign of the aircraft’s structure, avionics, and flight control systems.
This makes the F-55 less of a variant and more of a new aircraft inspired by the F-35’s design philosophy. However, the question arises as to whether this new aircraft is something the US needs at this current time.
What About the F-47?
Meanwhile, the F-47 was supposed to be the centerpiece of the Air Force’s sixth-generation fighter initiative. Developed under the NGAD program and awarded to Boeing, the F-47 is designed to surpass current fifth-generation capabilities.
It is expected to incorporate advanced stealth features, AI-assisted piloting, and sensor fusion, along with collaborative combat capabilities that allow it to operate alongside unmanned wingmen. These drone wingmen, such as the YFQ-42A and YFQ-44A, are already undergoing ground testing and are integral to the F-47’s operational concept. With the announcement of the F-55, where does this put the F-47?
Balancing Too Many Projects?
The proposal for the F-55 raises important questions about whether this choice is the best allocation of resources. One of the central concerns is whether the F-55 is a necessary enhancement or an expensive redundancy. While a twin-engine F-35 might offer incremental improvements, it is not a generational leap in capability. Critics could argue that it risks becoming a costly stopgap between the F-35 and the F-47, diverting funds and attention from more transformative technologies.
The F-47 is not the only high-cost project in the works. The F-15EX Eagle II is another project that the USAF has been working on for some time. This project aims to massively modernize the US’ F-15 fleet, replacing the internal electronics and avionics, completely reassembling the aircraft from the ground up. The DoD has already appropriated approximately $1.2 billion appropriately into the project. At $90 million per aircraft, the F-15EX is more expensive than an F-35A. In addition to the F-47, the F-55 has to compete against the F-15EX for funding.
The F/A-XX is another project that is currently underway. In association with the F-47, the US Navy has been working on a carrier-based version of the NGAD fighter. This project is important as it provides the USN with a carrier-based next-generation stealth fighter capable of competing with the latest fighters from China. However, the fate of the F/A-XX is currently in limbo due to funding constraints, and resistance from the Pentagon.
The B-21 is one of the DoD’s top projects at the moment. The B-21 Raider is the US’ first sixth-generation aircraft, and the newest stealth bomber to take to the skies. With next-generation stealth technology and state-of-art avionics, the B-21 may well be the most advanced manned aircraft that is currently flying. However, the project comes at a staggeringly high cost. With an estimated cost of around $700 million per aircraft, the total cost of the project comes out at around $13.1 billion over the course of its lifetime.
No Room for Another F-35 (Unless the F-55 Is ‘Made Up’)
With all of these projects in mind (there are many others I haven’t mentioned), where exactly is the F-55 supposed to slot in?
The F-35 program has already cost over $1.7 trillion over its lifetime, making it one of the most expensive defense programs in history. Developing a twin-engine variant would involve extensive research and development, flight testing, and production retooling, all of which could significantly increase costs and delay procurement timelines. Pursuing the F-55 alongside all the other projects could very well exhaust the budget and waste taxpayer dollars
With the ‘announcement’ of this new fighter, the Air Force must balance this new billion-dollar project with the numerous other costly endeavors currently underway, unless Trump mispoke and this is not happening.
That is, of course, a real possibility, or that he had some other reason for announcing a fighter project that may or may not exist. So far, the Pentagon has neither confirmed nor denied the F-55 as a real program.
Nonetheless, the project is not without its potential merits. Proponents argue that a twin-engine F-35 could provide a valuable bridge between current and future capabilities, offering enhanced safety and performance while the F-47 matures. It could also appeal to international partners who have experienced the F-35’s qualities firsthand.
On the other hand, opponents contend that the F-55 is a redundant effort and risks undermining the momentum of the F-47 program. Retrofitting a second engine into the F-35’s airframe would likely require a complete redesign of the airframe, thus resulting in another massive fund guzzling program.
Moreover, some argue that the possible proposal reflects a short-sighted desire for incremental improvements rather than a coherent and comprehensive vision for future air dominance.
About the Author
Isaac Seitz, a Defense Columnist, graduated from Patrick Henry College’s Strategic Intelligence and National Security program. He has also studied Russian at Middlebury Language Schools and has worked as an intelligence Analyst in the private sector.
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