The US Air Force is ordering the first eight of 80 new F-15X aircraft from Boeing, which manufactures them in St Louis alongside production of the F-18 Super Hornet.
According to reliable reports, the new F-15’s will have even greater carrying capacity than older F-15 models and will have upgrades found in the F-15 model being sold to Qatar. Deliveries to Qatar are now underway so the production line is active.
The proposed US Air Force acquisition is strongly opposed by Lockheed Martin, which makes the F-35 “stealth” fighter, on the grounds that it would undermine the F-35 program. The Air Force has denied this and claims F-35 purchases won’t be affected by the new procurement.
Meanwhile, the jury is still out on whether Congress will agree to the Air Force request.
Moreover, the “X” version, as currently defined, does not make use of the electronics and sensor integration that is a key feature of the F-35. Whether future F-15 platforms would have the costly electronics of the F-35 is uncertain.
The F-35 is optimized for “stealth” – that is, a very low radar signature, while the F-15X apparently is not.
‘Stealth’ detection capabilities
But Boeing has a “stealth” version of the F-15 on its drawing board, called the Silent Eagle. Israel was very interested in the Silent Eagle for many reasons, including the ability of the heavy F-15 to carry a large payload of precision weapons and a capability to penetrate enemy air defenses.
The US is still on the stealth bandwagon, even though the F-35 is not stealth capable from all directions. But the more important development is the emergence of new stealth-aircraft detection capabilities which are being pursued heavily by the Russians and others. These include much more capable electro-optical systems able to pinpoint threats at greater distances, which rely on visual and non-visual signatures, such as heat profiles in the infra-red bandwidths, and more exotic detection systems including quantum radars and photonic detection systems.
Electro-optical systems and their detectors are being steadily improved and can be integrated into air defense systems. A key advantage is that these sensors are passive: they do not emit any radio energy, meaning they can’t be knocked out with anti-radiation weapons nor can they easily be jammed.
Reportedly, Russia’s S-400 Air Defense System can detect stealth aircraft including the F-22, which may help explain why it is being sold successfully to Turkey, Egypt and Saudi Arabia, countries that normally don’t buy Russian hardware.
Along with electro-optical, lower frequency radars operating in the very high to ultra-high frequencies (VHF, UHF) along with L Band radars are being integrated into new Russian fighter aircraft and ground air defenses. The problem with these systems in the past was that while they can detect a threat at some distance, they could not accurately locate the threat. But there is evidence that this weakness is being overcome.
Most ideas about air combat today are focused on long-range intercept using beyond visual range (BVR) missiles. BVR missiles do not need to be mounted only on stealth aircraft, but stealth allows more protection from enemy counterattacks at long range.
BVR missiles come potentially in three designs: standard missiles, stealthy missiles and hypersonic missiles. Of the three, Russian, Chinese and US defense establishments are increasingly focused on hypersonic weapons, mostly for ground attack. But if hypersonic missile sizes can be reduced, they can perform both the air-to-ground and air-to-air role, creating a major problem for a defender.
One of the reasons the Air Force wants the F-15X is it can carry, in its beefed-up design, hypersonic missiles. These are currently believed to be too large to fit into the F-35, which must carry its weapons – including its air-defense missiles – internally, to maintain its penetration capability.
Another key advantage of the F-15X is that it can fly long-range missions while the F-35 is much more a tactical aircraft optimized for relatively short range missions. Problems such as removing threats in places such as Iran or North Korea would typically need long-range aircraft. While the existing F-22 can do this mission, it has constant readiness problems because the platform is aging and has problems in repairing stealth coatings on the aircraft’s surface. These coatings are eroding and require skill and time for repair.
In 2017 the average readiness level of the F-22 was a poor 49%, compared to an overall fleet average of 71%. There are around 195 F-22’s currently operational, but some 17 were damaged at Tyndall AF base in October 2018 by Hurricane Michael. It is reported it will take years for these aircraft to be repaired, if they can be. Given operational readiness levels that may continue to decline, as priority is given to F-35’s, which have their own maintenance issues, that leaves 89 F-22 aircraft or less that can be used in combat.
The F-15X, missiles
The F-15X like Qatar’s F-15 QA will have a greatly enhanced cockpit with touch screen displays and a new, highly capable and updated heads up display (HUD). Among its significant capabilities is it can operate very well at night because of its terrain following radar, meaning it can penetrate enemy air defenses at low altitude, giving an enemy limited time to react. The F-15X can also carry a load of air-to-air missiles including a capacity of 22 AMRAAMs.
The AMRAAM is a medium-range intercept missile that qualifies it as a BVR system, although it has less range than Russian and Chinese BVR weapons and particularly a new Russian design for a ramjet-powered version of the R-77 air-to-air missile.
An important factor in missile design is the ability to maneuver as the missile heads in for a kill, especially to turn tightly as the targeted aircraft tries to avoid being hit. Here the Russians seem to have advantages in the later designs of their air-to-air systems, especially versions of their R-77 mid-range BVR air-to-air missile. Typical missiles as they hone in on a kill fly entirely on kinetic energy, as the missile engine has already burned out, but a ramjet air-to-air missile does not have this problem and, while slower, is more maneuverable.
But the US Air Force is not looking for the F-15X for air-to-air combat, even though it will be quite capable. Rather, the Air Force wants its long range and heavy load, plus the ability to use ‘smart’ weapons and, eventually, hypersonic missiles.
In the Middle East, using the F-15X has the advantage that support facilities in friendly countries like Saudi Arabia, Qatar and Israel are already in place, with logistics and repair facilities available to enable the US to operate with great ease and close to major threats such as Iran.
Japan, Taiwan better off with the F-15X
In Asia, Japan is a major F-15 operator, and the US Air Force has its own F-15s operating in Japan. These aircraft form a counterweight to China because they can penetrate deeper and cause much more damage than the new F-35 or even the older F-16. If the goal was to take out medium-range ballistic missile sites in either China or North Korea, the F-15X has the range to destroy them.
Japan seems to have gotten sidetracked in its search for new aircraft. Its greatest interest was in buying the F-22, but Congress prohibited its export abroad and, in any case, the F-22 aircraft is out of production and the jigs and forms needed to build new ones no longer exist. Now Japan is working on what it calls the F-3 fighter, which is a tactical fighter linked-back to the F-16. But that is not what Japan needs for a credible long-range capability. A better substitute for the missing F-22 would be the F-15X.
But it is not only Japan that needs a long-range heavy fighter. In fact, as Taiwan searches for a new high-performance aircraft, it should consider the F-15X, if the US will supply it. It would give the US and Taiwan a major defense asset in the region and perhaps counter China’s increasingly aggressive operations aimed at the island. Its big load of AMRAAMs would make it a superb air to airforce multiplier. The presence of the F-15X on Taiwan would be a significant counterbalance.
Will either of these countries buy the F-15X? The jury is still out, but the momentum of an Air Force procurement could shift the balance in favor of buying.