This is the second of a series of three articles contributing to the debate with professor Robert Farley on the ease and challenges of imitating advanced weapon systems – which stems from our academic article “Why China Has Not Caught Up Yet.” Professor Farley’s pieces are available here: 1, 2, and 3. The first part of our answer is available here.
In this reply, we focus on a second criticism raised by Professor Farley. Namely, he has noted that while it’s true that China is behind the United States in stealth technology, China is still ahead of any other country beside the U.S. We are very grateful to professor Farley. Thanks to his objection, we can address an aspect that for space reasons we could only briefly touch upon in our article, despite being of fundamental importance.
Slow diffusion of stealth
In our “Why China Has Not Caught Up” we explain that what is remarkable about stealth technology is how little it has spread so far. Over time, any technology becomes mature (i.e., it is no longer cutting edge). As a result, its underlying principles become better understood and tend to spread, together with the technological knowledge of how to replicate it. Yet, this process has been exquisitely slow for stealth – despite a myriad of facilitating factors.
The scientific principles of electro-magnetic spectrum date to the 19th century. The first attempts to reduce radar reflections (through radar-absorbing material) date to World War II. The scientific explanation of how to reduce radar reflections was published by a Soviet physicist in 1962 in a scientific journal. Since the 1980s, some American professors of engineers have published the technical insights about stealth technology. In the 1990s, the United States lost one of its stealth aircraft in Serbia – the F-117 Nighthawk, which Russia and China examined extensively. Since the 2000s, China has engaged a massive campaign of industrial and cyber espionage aimed at stealing U.S. secrets on stealth technology.
Yet, the U.S. is still unrivaled in stealth technology. 30 years have gone by since the first stealth fighter and stealth bomber entered service (1987 for the F-117; 1989 for the B-2 Spirit). And 14 years have gone by since the U.S. commissioned the F-22. Yet, no country has yet fielded a stealth bomber like the B-2, and no country has fielded a fifth generation fighter like the F-22. China, the country that occupies the second place in this competition, has fielded an aircraft that on some metrics might be on par and possibly superior to the F-117 (e.g., maneuverability), and that in others is still inferior (e.g., the J-20 does not currently possess air-to-ground capabilities).
The Devil is in the Details
China has obviously achieved impressive results in stealth technology. Yet, in modern military-technological competitions, being the second might mean comparatively little. Modern weapon systems such as fighters, bombers, attack submarines or naval destroyers are intended to compete with enemy’s systems such as radar and sonar (i.e., in the “hider-seeker” competition). As a result, extremely minor defects are sufficient to compromise the low observability of these platforms: this is the case, for example, of small dimples between the sonar section and the rest of a submarine hull or a couple of non-perfectly tightened fasteners in a jet fighter. This, in turn, explains why the last effort towards absolute perfection in the production of modern weapon systems is at the same time the most important and the most difficult and expensive to achieve. In this sense, being second is not enough unless China’s industrial and technological base has truly mastered to perfection the key technologies it is trying to develop. This consideration is particularly important in light of improvements in digital signal processing and sensor acuity, which are making “stealth” increasingly more difficult to achieve – i.e., they are constantly raising the bar.
Too many Devils, and too many Details
Absolute perfection, of course, applies to all the systems and subsystems of military platforms, not just those directly involved in the hider-seeker competition. Consider for example that 0.1 percent probability of failure for a turbofan engine is not acceptable for a single-engine fighter like the F-35. The problem for China is that its industrial and technological base is lagging behind not only in stealth, but also in other key technologies for fifth generation fighters – such as turbofan engines (as other observers, such as Andrew Erickson and Gabe Collins predicted in The Diplomat) and aerospace software engineering.
To contextualize how serious these problems are, in our “Why China Has Not Caught Up Yet,” we discussed those that have plagued also Chinese fourth generation fighters such as the J-15 “Flying Shark.” The engine of the J-15, for instance, is so underpowered that to take off from the short ramp of Chinese aircraft carrier, the J-15 has to sacrifice either range or firepower (by embarking either half fuel load or half missile load). Even more problematic is the flight control software, which has so far been responsible for several fatal accidents – to that point that Chinese authorities decided to look for a replacement of the J-15.
The flight control problems plaguing the J-15 are not necessarily also affecting the J-20, since the two aircraft are produced by two different companies, respectively Shenyang and Chengdu. We know, however, that also the J-20 has problems with the flight control software, which is understandable given that a stealthy design requires much more demanding software and sensors than a non-stealthy design (1 and 2). This is an important aspect in that it can possibly explain China’s decision to opt for a “canard configuration” design (i.e., less stealthy) for the J-20. Stealth is not only a function of the airframe and all the features that reduce its observability to enemy sensors: it is also and foremost about the set of sensors and aircraft-specific software that permit an aerodynamically inefficient aircraft to fly and achieve high maneuverability. Without that set of sensors and software, stealth would have never come about. Consider that by simply adding radar-absorbing material to the U-2, Skunk Work engineers compromised the aerodynamics of the aircraft, which resulted to the loss of an aircraft and of the pilot in the very first test.
Stealth and Military Operations
Of course, this is not to say that countries competing with the United States have no other option than reaching U.S. levels of military-technological proficiency. Electronic warfare and operational planning can in part compensate for deficiencies in stealth. Similarly, military organizations can devise tactics aimed at mitigating their technological inferiority – as Serbia did in 1999. Consider for example the Russian stealth fighter, the Su-57, which might be intended to avoid long-range engagement (where U.S. fighters have a clear advantage), in order to bring the fight where it is competitive – i.e., short-range air-to-air combat. Interestingly, however, this is not the path China has pursued: the J-20 does not have a cannon for short-range engagements and its underpowered engines do not provide the maneuverability required. In other words, with regard to jet fighters, China has not opted for a “second best” strategy, but it has tried to compete with U.S. on its own turf. In this competition, the technical deficiencies of the J-20 inevitably limits its capabilities: flaws in its stealth design increase the range at which the J-20 can be detected; while its underpowered engines represent a constraint in short-range engagements (even in case, later on, Chengdu adds a cannon).
Andrea Gilli (@aa_gilli) is a Senior Researcher in Military Affairs at the NATO Defense College in Rome, Italy and an affiliate at CISAC, Stanford University. The views expressed in this article do not represent those of NATO or of the NATO Defense College.
Mauro Gilli (@Mauro_Gilli) is a Senior Researcher in Military Technology and International Security at the Center for Security Studies of ETH-Zurich.