When Former President Donald Trump came up with the idea of a twin-engine version of the F-35 called F-55 just a short while ago, the defense community was quick to respond. The proposal extends the discussion of the future of American airpower and what measures are necessary to maintain air superiority.
On a business leaders’ roundtable held in Doha, Trump described the F-55 as a “super upgrade” of the F-35. He went on to ask if it was really enough for airplanes with just one engine. He also argued the point that a plane having two engines would be safer, as it would be a case of redundancy. Moreover, he threw in the possibility of an “F-22 Super,” a Raptor of the next level, tapping into his idea of breaking with the convention in the development of U.S. fighters.
The F-55 concept, in the simplest terms, is basically the giving of an additional engine to the F-35. Trump says in this case the aircraft would be way more durable; he even notes that no engine is defect-free. He reasons that multi-engined aircraft are the safest ones to get home following a sortie. He even cited the example of commercial aviation, going to the four engines of a Boeing 747 to illustrate the concept of redundancy.
However, defense and aerospace experts have responded to the idea with skepticism. The ex-Air Force Secretary Frank Kendall referred to the concept as “mystifying” and placed emphasis on the fact that a second engine would almost overhaul the F-35 entirely.
Prominent aerospace analyst Richard Aboulafia was more scathing. He likened the idea to a child’s sketch rather than to a serious engineering plan. What he described as doing is to talk about how the addition of a second engine means an almost new aircraft with all the issues that come with it, including costs, technical problems, and possible accidents.
They are not small issues of engineering to overcome. J.J. Gertler of the Teal Group notes that the way the F-35 is currently designed, there is no space for an extra engine. Any such attempt would require larger wings, a stronger fuselage, redesigned tail, and air intakes—basically, you would get an altogether different airplane, just barely related to the original one.
Staying undetected would also be quite a challenge. Stacie Pettyjohn from the Center for a New American Security says that even the tiniest alterations in form or materials can lead to the low observability of the F-35 being violated, being an Achilles heel that the adversaries will try to exploit.
Strategically, the time at which the idea was proposed is very interesting. The Air Force has already decided to go for the F-47 as its sixth-generation fighter that will be specially designed to meet future operational requirements. The introduction of a twin-engine F-35 would be the closest to the F-47’s role, meaning that the overlapping of capabilities, cost, and size could be a problem.
At the same time, the F-35 program is going through a series of changes. The improvements in engines, power systems, and thermal systems are going to cost quite a few billions. Block 4 upgrades are raising combat performance, too. Lockheed Martin is not just coming up with a “fifth-generation-plus” version but is talking about a variant that will have some of the features planned for the F-47 and will also be at a lower cost. However, there are still enough maintenance, supply chain, and intellectual property issues to continue the complexity of the PAK fighter program to be revealed.
In a way, from the defense industry’s standpoint, Trump’s comments send mixed signals. Though the idea of upgrading the F-35 and the F-22 might be welcomed by contractors such as Lockheed Martin, the concept of the F-55 is so far away from current modernization plans, both technically and strategically, that it is unlikely to move from a conceptual stage to further development. The companies that go ahead with such a project without government support would be taking a huge financial risk, as Aboulafia warns.
To sum up, the F-55 debate is a real showcase of the conflict existing in U.S. Air Power’s strategy, i.e., the struggle between the desire for revolutionary and transformative capabilities versus the feasibility of engineering, cost, and strategic harmony. As the Department of Defense is carrying on with its fighter modernization and grappling with the F-35’s long-term sustainment issues, the F-55 idea serves as a reminder that it is not quite enough to be visionary and, above all, grounded in what is technically and financially feasible.
