Monday, 11 April 2011

What China's New J-20 Stealth Fighter Means for the F-35 JSF and F/A-18E/F Super Hornet

First prototype of the Chengdu J-XX or J-20 Very Low Observable (VLO) fighter aircraft. A large high performance design with excellent stealth shaping, this aircraft is expected to be become the centrepiece of the PLA-AF fighter fleet. It combines supersonic cruise, large range and persistence, and stealth (Chinese Internet).

Chengdu J-XX [J-20] Stealth Fighter Prototype
A Preliminary Assessment
Technical Report APA-TR-2011-0101

The latest monograph by Dr Kopp, as published in the peer reviewed APA Analyses journal, is an in-depth and broad scientific study of what exponential growth laws - like Moore's Law - mean for current and future combat aircraft. It is, and intentionally so, a scientific paper, and confines itself to the technical dimensions of this problem. What do exponential growth laws mean for Western nations in terms of strategy and national policy? That is the subject explored in this NOTAM1.

Let us start with a familiar situation and one for which you already know the end-result. Suppose you are driving down a road on a dark night, not looking in the rear-view mirror, but admiring the fancy digital display of the dashboard, with the moving GPS map, the instruments telling you about speed, range, altitude, engine condition, cabin temperature, while the iPod interface slips soothing songs into your brain. The mobile phone rings and you reach to tap the control column to take the call. This is a fatal distraction because a sharp turn appears ahead, you miss it, and in an instant, there is a violent disintegration of these marvellous technological displays as the car leaves the road and rolls end-over-end down a steep embankment.

Over the past few days, images have emerged of the new Chinese Stealth Fighter, the J-XX or the J-20. On the 29th January 2010, the Russians first flew the PAK-FA, and the Su-35S, which first flew on 28th February 2008, is expected to achieve IOC in early 2011. Meanwhile, back at the US fighter-farm, the JSF which first flew on 15th December 2006, has experienced continuing difficulties with the STOVL version and is likely to enter a substantial re-design programme in 2011, adding more years and even greater costs to the already frequently-extended development phase.

By the time the F-35 makes IOC (if it ever does) it will be, to use that well-known technical term, ‘toast’.

Even if an extensive redesign produces an aircraft that meets the March 2000 Joint Operational Requirements Document (JORD), the
Su-35S, PAK-FA, J-20 world of 2015-2020 will be much different than the Su-27S, MiG-29 world that existed when the JORD was first released. Most astonishingly, when gross cost overruns forced a review of the program, the JORD specifications were not updated to encompass the 2015 - 2025 air combat environment. Instead, during the ensuing process that followed the Nunn-McCurdy Breach, the Joint Requirements Oversight Council (JROC) re-verified and re-validated the F-35 JSF Operational Requirements Document of March 13, 2000, as representing a capability “essential to the national security” (refer JROCM 078-10 dated May 20, 2010). And people wonder why some refer to the Nunn McCurdy process as the “codification of silliness, if not mendacity and misfeasance”?

And if the F-35 is ‘toast’ that makes the F/A-18E/F ‘cinders’ – this 1985 ‘old wine in a new bottle’ aircraft has some fancy new electronics, but none that will save it from destruction in combat. Like the distracted car driver, the crews of the F-35 and the F/A-18E/F can be fully informed by watching the dancing digital displays, but they cannot avoid the inevitable crash.

Why has this calamity fallen on the US fighter design teams? Perhaps the answer can be found in that now infamous phrase: ‘Manoeuvre is irrelevant – let the missiles do the turning!’. These simple words speak volumes about what is deeply flawed in the US development of those aircraft on which it will depend to protect its sovereignty, keep its fleets on top of the water, and project power. The Internet source has now been censored, but the attitude that led to this statement remains deeply ingrained.

Firstly, it assumes that the aircraft firing the missiles will have survived to the point where they achieve a firing solution and get their missiles in-flight. A fundamental tenet of combat is that you must be alive to enter the fight. The superior kinematics of the Su-35S, the PAK-FA and the J-20, the signature reduction of the latter two aircraft, and the (highly likely – we have not seen the final list) improved sensor suites of all three, severely reduce the F-35 and F/A-18E/F’s chance of even making it first to a weapon release point. Each of the threat aircraft will be operating at times more than two miles higher and 700+ knots faster, giving their ‘look-down, shoot-down’ missiles substantial kinematic ‘shoot-first’ advantages in the engagement.

We need to make special mention of the profound effect that signature reduction will have on future air combat, as the stealth ‘catch-up’ by the Russian and Chinese aircraft has grave consequences for the USA, as it has a tactical advantage to lose and nothing to gain.The situation is best shown by injecting ‘reasonable and representative’ figures into the mathematically exact radar-range equations to get an indication of the magnitude of the change to the operating environment.


RCS ~ 3 m2

PAK-FA / J-20
Best Case
RCS ~0.1 m2
PAK-FA / J-20
Worst Case
RCS ~0.001 m2
F-35 / APG-81~82.8 NMI~35.4 NMI
~11.2 NMI
F/A18-E/F / APG-79~111.9 NMI~47.8 NMI~15.1 NMI

Aircraft such as the PAK-FA and the J-20, with ‘Low Observability’ from the front aspects, can be guided by (say) a HF-band Skywave radar and SATCOM system, or VHF-band GCI radar, into a merge ‘cold nose’ and passive, but still searching on IRST and ESM. Having an aircraft first appear on the F-35 APG-81 at 20 NMI would be a very nasty surprise, demonstrated by ‘first-look, first-shot, first-kills’ by the enemy. But back to the ‘Let the missiles do the turning’ statement.

Secondly, and perhaps more dangerously, the statement assumes that the missiles ‘turning’ will actually achieve a terminal missile-to-aircraft distance where the fuses detonate the warhead. Nothing is mentioned about these missiles being kinematically defeated during the ingress, and/or being confused by electronic countermeasures such as cross-eye-jamming, and/or being seduced by towed or released decoys, let alone rendered blind by the effects of the respectable stealth technology employed in the T-50 PAK-FA and J-20.

The Sukhois' missile countermeasures are far superior to those employed in the F-35, probably because nobody believed the stealth advantage would be penetrated and that countermeasures, like manoeuvre, would therefore be ‘irrelevant’. However, it is reasonable to expect these countermeasures to be included in the large and spacious PAK-FA and J-20 airframes, both of which will have a credible stealth capability.

The third deadly mis-assessment is that, with the missiles doing the turning and presumably the killing, egress from the fight will be a leisurely affair, with the pilots congratulating themselves on their kills. When the enemy has a first-shot and first kill advantage, and our missiles miss because of effective opposing countermeasures and genuine stealth technology, the truth is starker. When our people fly aircraft not designed for high Mach and with the prodigious fuel flows required to offset enormous drag at high speed, an enemy with a 500 - 700 knot closure rate and internal fuel reserve advantage will quickly run-down and dispatch the survivors. If the aircraft are separated at 50 NMI when the egress is started, it only takes 6 minutes with an over-take speed of 500 KTAS for the aggressors to reach guns-range, less for a WVR missile shot. As shown above, with signature reduction in the PAK-FA and the J-20, the chase-distances, fuel requirements and run-down times will, most likely, be considerably less.

So, why have these non-viable US designs been allowed to persist, and the corollary question, why has the production of the USA’s only aerodynamically and kinematically competitive fighter, the F-22A Raptor, been killed?

The answers can be found in Dr Kopp’s comprehensive paper. Observing the seemingly inexorable development of high-tech boxes, as shown by examples such as Moore’s Law, seems to have led US military capability planners and developers, and US air combat fighter development in particular, into a deadly evolutionary trap:
“All we need is to employ our (temporary) technological advantage into systems that ‘let the missiles do the turning’. Since ‘manoeuvre is irrelevant’, we don’t need to turn our attention to designs that make our aircraft fly faster, further, longer, higher, and in combat, able to change energy state, attitude and location rapidly to be the first to get to a firing position, or to avoid incoming missiles”
What turns this intellectual sloth into a toaster, is that eventually the enemy, applying the same exponential growth laws, only this time faster and with a much reduced learning time, catches up and then surpasses the efforts of the USA. Even more dangerous is their use of multi-spectral sensors employed across Infra-Red, Ku-Band, X-Band, L-Band, VHF and HF frequencies.

The other dangerous illusion is that these exponential growth laws also apply to other elements of air combat design, such as sensor ranges, power-aperture, engine thrust, manoeuvrability, controllability and, consequently, agility.

They don’t, because in these areas of design, the fundamental and more enduring Laws of Physics apply.

Over-estimation of a capability leads to an under-estimation of the likely losses in future air combat. As Dr Kopp points out in his paper, exponentially improving internal electronics does not result in exponentially increasing sensor range – at best an incremental advantage is gained. When the opponent introduces a significant stealth capability, as seen in the T-50 PAK-FA, then that incremental advantage rapidly erodes, driving combat from paradoxically perceived to be information dominated Beyond Visual Range engagements to agility dominated air combat engagements, whether in the close combat or Beyond Visual Range arenas.

The net result is that the Su-35S, the PAK-FA and the J-20 will, over their operational life, severely reduce the relative survivability and lethality of the F-35 and F/A-18E/F, and any other legacy fighters dressed up in new garb. Here is a table that shows the overall effect:

(Lost a few, did not do much with the survivors)
(Lost a few, did a lot with the survivors)
(Lost a lot, did little with the few survivors)
(Lost a lot, did some with the few survivors)
Table 1: Combat Effectiveness: The ability of air combat aircraft to deliver the intended combat result in a combat environment.

To conclude with a familiar scene, the F-35 and F/A-18E/F pilots of the future will have exquisitely crafted digital cockpits which will give them a crystal-clear picture of their combat environment, such that they know with unprecedented precision the moment at which they will die – assuming that Russian and Chinese stealth technology can be easily defeated.

And their opponents will have the same but a more enduring view, without such high and final costs, thanks to the inexorable merging of exponential growth laws and superior aerodynamic/kinematic design into their air combat machines.

Chengdu J-XX [J-20] Stealth Fighter Prototype
A Preliminary Assessment
Technical Report APA-TR-2011-0101

Chengdu J-20 stealth fighter. This design outperforms the F/A-18E/F and F-35 JSF in every important respect (Chinese Internet).


1 Kopp C., Assessing the Impact of Exponential Growth Laws on Future Combat Aircraft Design, Air Power Australia Analysis 2010-04, 31st December 2010, URI:

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