China’s J-20 Enters Stealth Fray




[Above] 05-May 2012: Since the time of this original writing last year, a second Chengdu J-20 aircraft has appeared designated '2002' as part of a continued PRC flight test program. Pilot-tube on "2002" has been relocated.  [Above] Aircraft "2001" Note pilot-tube location versus aircraft "2002." 

[Below] New photos of the J-20 weapon bay(s). Again valuable airframe real-estate in fighters better used for fuel. An additional door aka American F-22 style for IR missile. It appears the missile can be moved out into the air stream and the door re-closed (before firing). This is necessary for the missile seeker head to have a view of the target before release. All stealth fighters must overcome blocked seeker heads.



[Below] In addition, yet another PRC stealth fighter has appeared in early Sept 2012, the Shenyang J-31. It appears to leverage ideas from American F-35 and F-22A and perhaps the Russian T-50. As more photos emerge a better assessment will be possible. However, even with the appearance, this new aircraft - all Chengdu J-20 and Shenyang J-31 observations and analysis detailed in this writing - will still apply.



[Above] Shenyang J-31. [Below] Chengdu J-20.
(05-Jan, 2011) China’s J-20 "fifth-generation stealth fighter” finally makes an appearance. The aircraft is black, large, has a one-piece canopy, canards, conventional exhaust nozzles, and a shiny nose tip similar to the American F-35 (also under development). New images have surfaced of the aircraft in flight. J-20 and appears heavily influenced / dependent on the Russian Mikoyan MiG 1.42 / 1.44 / MFI of the late 1990s. We're inclined to concur with new observations that J-20 is "a mishmash" of older U.S. and Russian designs.

The best article on J-20 we've seen to-date, graciously brought to our attention by our readers.

Borrowing ideas from elsewhere to influence the design of particular said aircraft is nothing new, but whether J-20 represents any (generational or otherwise) leap in PLAAF capability - remains an open question.

The American/Pro-American defense lobby is sure to interpret the J-20 as a severe threat to the US and regional security posture and call to restart the F-22 production line. We are inclined to reject these threat assessments due to the sobering nature of factors detailed (and hyperlinked) further down the body of this writing.
Note wing shape, particularly the trailing edge angle. J-20 similarity to MiG 1.42 / 1.44 / MFI [below] is obvious.



[Above] MiG. [Below] J-20.
[[Above] Note J-20s not-so-stealthy under-wing bulged control surface actuator housings (two on each wing). Russian T-50 is similar. Note American F-22A [below] with additional rear stabilator actuators as well. How a high altitude flight regime effects exposure of these types of bulged-shapes to hostile radar(s) is unknown.
The Northrop B-2 bomber [below] has no flight-control-related protuberances. Neither did YF-23.

As a separate matter, we've supported offering an export version of F-22 for foreign sale, again for the same reasons outlined in the body of text below.

Direct or indirect Russian assistance on J-20 is unclear due to the “J-11b incident” (international intellectual copyright violation-abrogation by the Chinese State of the Russian Su-27 ‘Flanker’ fighter jet) that surely has had an impact on Sino-Russian relations. The PRC is proceeding with both J-11b and J-15 programs.

To be honest, we were caught off guard by the appearance of J-20. The PRC appears to be resolute at conducting (real or perceived) force modernization – at all possible speed. We would still caution the reader that the design and development of combat aircraft - in particular remains - not a trivial affair – even for nations with long histories of aviation design, development, and technology breakthrough. China will not be immune from any of an array of conflicting and uneven program-platform requirements, design, propulsion, and developmental issues – both seen and unforeseen.

As of yet, we have not been overly impressed with stealth fighters for the reasons described here. When combined with available historical evidence (including the "unseen" attacker) - stealth fighter (fighter) technology does not stand up to (inductive/deductive) critical analysis, particularly against a modern multi-sensor aerial opponent with DFRM and helmet-sighting (unobstructed fields of view for missile seeker heads ) – for which no stealth fighter in existence today - has been tested, evaluated, or pitted against - in any authentic manner. 

Assurances from stealth fighter proponents that under actual combat conditions the merge ("the dogfight") can be avoided because of stealth advantages - is pure nonsense. Here is yet another reason why.

The emphasis on radio-spectrum-airfoils (stealth) for fighters and for reduced drag - can force:
  • Internal weapon bays / carriage restrictions.
  • Reduced space for internal fuel.
  • Which force increased aircraft size / or the use of external tanks.
  • All bad for "the element of surprise" Stealths hallmark feature.
[Below] Lockheed's F-35 (JSF). [Above] Note vertical tails of J-20.
How stealth fighters using only radar (only radar) - overcome the paradox of defeating the same electromagnetic radio-energy they need to detect targets, and for their own communication/coordination / identification-friend-or-foe (and in weather) - has not been addressed in any serious way. In wartime, these issues will emerge – too late for stealth-fighter-aircrews already strapped in their cockpits.
[Above ] J-20 [Below] The MiG-1.44.


[Above] MiG-1.44 [Below] The J-20.
Global aircraft development trends are nothing new. In the early 1950s, most fighter/interceptors aircraft were designed only to use air-to-air missiles. Guns at the time were seen as totally unneeded. Later this would be recognized as an ill-advised miscalculation by the global design community. Guns were (re)fitted sometimes hastily so - to all later aircraft.
[Below] Lockheed's F-35 JSF. Note similar DSI intake design on J-20 to aircraft like F-35. Note J-20 shiny nose tip.
We would simply say that: other than opposing stealth fighters having trouble detecting each other, (the Russian PAK-FA and the American F-35 seem to be aware of the problem by retaining a thermal IRST station), the only real strategic effect of stealth fighter programs is that vast national resources are exhausted on them - rather than elsewhere. Stealth technology is locked in a running pitched battle with sensor technology - a battle the Stealth fighter cannot win.
Some might be underestimating the thirst by the Chinese leadership for international prestige - regardless of any real or perceived aircraft capability?
As some in the Washington defense establishment weighs in on (or just as likely - says nothing of substance?) on the implications of a PRC J-20 class aircraft, the US-Navy is likely viewing the 'forced retirement' of the F-14D Tomcat with new / invigorated concern? Tomcat variant “D” (or further enhanced versions) with her AIM-54 system, would by definition, have dramatically altered the scope of the discussion on whatever threat(s) the Chinese could (hypothetically or otherwise) impose on USN battle groups, now and in the future.

[Below] The authenticity of this chart is unknown. The aircraft circled in green appears to be J-20. Of perhaps greater interest - we count no less than seven (7) examples of the Russian Flanker-series aircraft. In addition, the aircraft depicted just below J-20 is a previously unknown type. Could there soon be unauthorized (not authorized by Russia) Flanker-class proliferation by the Chinese J-11b into South Asia?
Your thoughts?

#china, #military, #stealth, #weapon

- All media found here is for scholarship and research purposes and protected under U.S. Internet ‘Fair Use’ Law - 

Comments

  1. It seems to me that the Chinese are following the Russian doctrine and not investing in all aspect stealth.

    The size of the aircraft while detrimental in terms of stealth, implies that the Chinese are more keen on combat persistence and a larger weapons loadout.

    By the look of the overall frame design, the Chinese are probably investing in high manuverabilty through thrust vectoring. I dont know if the forward carnards imply this, but by the look of things the Chinese intend to outfly rather than out-stealth the U.S

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    1. I would argue that primitive Chinese engine technology in the WS-10 clone of the AL-31F is a major deficit to the airframe design in that it requires a much longer engine bay and a subsequent displacement of the principle airfoil to support same.

      The USAF F-22 has a similar problem but solves them by putting the tails on booms and pushing the shorter F119s as far forward between them as possible while 'integrating' the tail/wing longitudinal occupancy into a more trapezoidal than true delta format (42.5` vs. 48` LE Sweep) which has the associated benefit of stiffening the airframe for sustained maneuver at supercruise.

      The J-20 main weapons bays also look to be between 14-15ft long, a good foot and a half longer than the F-22 equivalents with resulting further displacement of CG/CP.

      The easiest way to offset this is with a canard to both unload the tail controls and allow cooperative CCV modes to minimize body flex stress on the very long boxframe fuselage.

      While LO will undoubtedly suffer for want of multipath reflection off the mixes surface corners, one great advantage is that is allows much larger fuel quantities in both wing and fuselage saddle tanks over the weapons bays. Perhaps as much as the 32,000lbs of the F-111.

      This is important because required engine cycles for supercruise change dramatically and unless you are able to open up mass flow as RPM (with concomitant increases in TIT) you will not be able to sustain the stochiometrics needed for high end compression recovery as thrust needed for SSC.
      In this, the F119s love to run hot but they do so with a combination of lowered stoichiometric efficiencies and fuel cooling which is why the engine has roughly 50% higher (vs. 200% in burner) SFC at operational cruise Mach than the F100, despite similar carcass size and thrust class between say a late F100-PW-232 EFE and the F-119-PW-100.

      The trade off for this capability is using the F-22 as a 'by legs' rather than radius driven aircraft which is to say 600nm to fence at Mach 1.35, tap the tanker, 300 nm to BRL or TARCAP point and release at Mach 1.6. Another 300nm back to fence at Mach 1.78 and another tanker sip. Followed by 600nm, home at 'best Mach' for final fuel offload (tankers do _not_ top off every 'customer', they have other jets to service on the ATO).

      Such an approach works wonders for pilot fatigue as sortie rate generation (doing in three hours what would take an F-35 closer to 8-10) but it requires the ability to project those tankers forward and secure a bastion airspace bubble around them, well out from the combat area, likely with AEGIS.

      The PLAAF know that they cannot survivably match this in prepositioning AAR to support J-20s operating against HVA around Taiwan. Though they might be able to get away with it, once, in support of a strike on Kadena or Andersen Field.

      If their recent 50 billion dollar investment in their aero industry is anything to go by, they don't have the propulsion technology as DSF powder metallurgy and compression path CFD to try for a true supercruise platform capable of this magnitude of operational depth.

      To be fair, it would be very hard for us to achieve this in a B-1R or similar scaled platform.

      Instead the Chinese have likely adopted a huge internal fuel capacity to fly a large delta wing, subsonically but at great height, to within 200-400nm of the target and then execute a dipsydoodle (SR-71 unload into burner to maximize acceleration times) and a Rutowski step climb to whatever Mach point is necessary or possible to deploy the weapons systems before combining the canards and conventional tail controls to bring the airframe oblique and execute a runout that goes as far as fuel will allow on a downhill run to best cruise point for the RTB transit.

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    2. We are talking 40K to 70K and then back to 50K on a very structured profile run because you cannot simply slam throttles closed or use airbraking at Mach 2 to maximize deceleration. You'll blow up the engines trying.

      As a function of this, the jet may actually run -past- a fixed target like Guam or Okinawa before turning for home.

      There is no glamor here it is prosaic in the same way a shuttle launch is, with throttle up here, climb profile to here, throttle back at Mach-X cruise and then rolloff breakaway and -gradual- slowdown after release.

      It is functional and unlike the 7G split-ess capabilities of the F-22 as a SAM defeat, it is likely strictly intended to enable the F-pole boosting of very large LRAAM as ISR/BMC killers (E-3, E-8, RQ-4) or to put strike weapons into open air flightlines whose locations are updated vi overhead imagery handed by satcomms, just before the acceleration phase.

      In the latter case, the J-20's high speed also serves to aid in weapon defense penetration of any THAAD/ERINT layering.

      Provided cockpit automation is up to it, the preferable standoff release points for an aeroballistic weapon are so far out as to render onboard sensor handing impractical for A2G strike and better done by shooter-illuminator wingmen (offset in trail) for HVA sniping.

      The self targeting complexity of these systems however could dictate single seat shoot and scoot or dual seat shoot and update with targeting through one missile seeker and retransmitting precision impact points to followon INS-only weapons using the J-20 as a master node.

      With only four, full length, weapons bay attach points, the J-20 is not going to be useful as a persistent fighter but rather as something which either complicates intercept of other (J-10/J-11/J-15) PLAAF platforms by dashing in and plowing LRAAM into any counter intercept or by downing network enablers in select, high value, SENSECAP attacks offset from the main raid approach lanes before running away.

      Again, a large fuel load as the ability to work the periphery of a fight will help here and the Chinese may well accept first raid losses of 50% (especially if done via UCAV conversions to older fighters) as 'decoys' to help generate the confusion draw off supporting fighters sufficient to break the J-20s into the HAVCAP protected orbits.

      For such missions, topend is assured and indeed superior to the Raptor's by burner, not by IRT thrust and the clean airframe, while lacking somewhat in fineness ratio and ruling is going to be functionally adequate to the task of a platform that behaves more like an F-111B/C than an F-22A.

      Depending on how their propulsion technology base investment goes, if the size of the inlets are anything to go by (as having significant residual massflow capacity), the WS-10G, when fielded, may have thrust ratings much closer to the F119-PW-614 of the JSF X-32 equivalency. Which is to say 36-39,000lbst military and 54,000lbst in afterburner.

      Such an engine would still not provide serious supercruise (might do 1.25 to 1.3 though), due to thermal and stall margin issues but would have so much thrust in burner that the J-20 would be able to accelerate very quickly and then back off a zone or two and still have significant operational range at Mach 2-2.2 or however high the airframe composites will support the thermal soak.

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  2. Incidentally, here is an updated (2010) Air power Association video:

    http://www.youtube.com/watch?feature=player_embedded&v=wE4G_BxlyOk

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  3. Hi Anonymous,

    Good observation. To be perfectly honest we’ve been caught somewhat off guard by PAK-FA and in particular now J-20. Global marketing appears to be taking precedence over true combat capabilities? How these fighter designs will overcome radio-spectrum targeting mechanics and also still be “stealthy to hostile radar” remains unclear. PAK-FA seems to be aware of problem by it’s retention of a thermal-IRST station.

    Thanks for the update from the USAF Association! Good stuff.

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  4. Just speculating here but I think they are pursuing these programs for the following reasons:

    1. Technology demonstration. I.e letting the world know that they are equally competent to create these types of systems.

    2. Military Keynesiam: Investing in cutting edge technology in order to develop primary infrastructure and knowledge base which can then be used in other areas or industries.

    3. Regional force projection: These fighters will probably be utilized in checking smaller states and dealing with legacy systems rather than fighting a on-parity adversary.

    4. Redundancy: Assuming that tommorow some truly game changing technology comes into play - a means to effectively shield the fighters from lower band hostile radar, having a current stealth fighter provide an available test bed and operational capability would seem
    reasonable.

    5. Counter-stealth: The other side of the coin, wherein developing stealth systems allows such countries insights on how to further counter said planes.

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  5. Pure speculation on my part, but the way I see it there can be a number of reasons to pursue stealth:

    1. Technology Demonstration: Just to show the world that Non-western powers can also create stealth aircraft if need be.

    2. Military Keynesianism: Investing in cutting edge technologies in a single form factor in order to develop the neccessary infrastructure, institutions and knowledge base which could then be used in other projects and industries ((materials, avionics, etc).

    3. Regional Force Projection: These fighters will probably be aimed at checking smaller periphery countries which would have legacy systems rather than face on-parity adversaries.

    4. Counter-Stealth: By developing and training with such aircraft, the Chinese and the Russians will also at the same time gain insights into how to counter Stealth technology, rather than merely relying on observation of U.S fighters.

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  6. Also:

    Does it seem to you that the nose cone is pretty damn large? What kind of sensor suite could fit in there? and how large? Does this mean that the Chinese intend to follow through with a "first look, first shoot" loadout? If so what would be the BVRAAMRAM in use?

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  7. Hi Anonymous,

    J-20 is going to need huge radar transmit power regardless - to either:

    a) Burn thru ones own stealth on the nose of the aircraft (to receive own targeting Doppler return signals) or to
    b) promote some reasonable BVR (targeting / mid-course data-link-command) range capability.

    Statistically, missile round hit-performance under actual combat conditions will see no more than 50% of J-20 load out - hitting targets – and THAT’S best (best) case.

    There seems to be some backing away from LPI (low probability of intercept) techniques by the USAF as well – so LPI may also have a shortened life as ‘a technical edge’?

    - The Boresight

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  8. Thought I might bring your attention to this article:

    http://www.atimes.com/atimes/China/MA14Ad02.html


    A thought struck me:

    What if the Chinese J-20 is merely a ruse by the Chinese to panic the United States into continuing to invest in the F-22 and the JSF, thereby leeching ever diminishing resources toward unfeasible and possibly disastrous systems and technologies.?

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  9. Good article on what the J-20 really means.

    http://www.opendemocracy.net/paul-rogers/china%E2%80%99s-military-threat-or-twist

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  10. "How sheath fighters using only radar overcome the paradox of defeating the same radio-energy they need to detect targets, and for own communication/coordination/identification-friend-or-foe (and in weather) - has not been addressed in any serious way. In wartime these issues will emerge – too late for the aircrews already strapped in their cockpits."

    Aren't AESA arrays generally understood to be low probability of intercept?

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  11. Hi Earlydawn,

    In general we would agree with your comment. Because PESA use a central radio frequency source (according to public information) they might be slower (more time delay) changing frequencies compared to AESA? However, there should be nothing stopping PESA from still using a LPI-class pseudo-random-scan ‘scheme’ regardless?

    Thanks for your comment!

    - The Boresight

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  12. No matter what way you spin it; the restarting of the f-22 program just proves how desperate the US desires to maintain its status as world superpower instead of focusing first on internal affairs. The US still has a decent lead besides China's modernization, and yet it takes drastic actions to use its country's budget to maintain its reputation worldwide

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  13. Hello Boresight,

    After reading the first "Anonymous" post and posting something on the Flanker page (Painful Road for Sukhoi).

    The J-20 follows the idea of Figure 2 outline in:

    http://en.wikipedia.org/wiki/Fuselage

    Where the '20 is aiming for speed/acceleration, possibly supercruise included.
    We've seen the weapons bay doors of the '20 and it seems it will carry even less missile rounds than a PAK-FA or a '22 as the premise of the bay's design is to preposition the selected missile in the airflow before releasing it from the aircraft(retractable rail???).

    What good would it be to position a missile in the airflow before launch?

    Why is China wasting space in its first Stealth fighter for a missile launch prepositioning system?

    Aren't they taking enough risks on there own just basing their designe over scrapped/defunct concept designs?

    I had found out about the missile prepositioning system in an APA article (yes the Australian one).

    Just putting it out there.

    -Cameron

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    Replies
    1. By the way, the F-15SE does use a missile prepositioning system like the '20.

      Also this system extends from what used to be considered the FAST packs.

      (Addendum)
      -Cameron

      Delete

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