Latest image of China’s stealth fighter jet weapons bay is a bad Photoshop work

Well a couple things stick out to me:

1. I’m betting that that lower fuselage is at least half again as wide as the F-22s. And if so, those are not small missiles. Indeed, the fact that there are only two missile shoes per bay suggests that the option of a lot of smaller weapons has been deliberately eschewed in favor of much larger, longer reaching, ones. Certainly the Raptor has always been a six-shooter because the AIM-120C development line predated it’s IOC by years and indeed the C-development process was -driven- by the need for six-not-four combat persistence as shot count.

2. It could just be the shadows but the taper on those nosecones is awfully severe (almost conical) for any kind of articulated seeker. If so, it could well be that we are seeing something more akin to this-

http://english.ruvr.ru/2013_01_18/Russian-air-force-puts-X-38-air-to-surface-missile-into-service/

Which is to say a very high speed air to surface weapon which uses the Dragon’s supercruise or sprint to boost it’s own kinematic as a 100nm+ loft to 100,000ft and a Mach-5 or even 7 endgame. In this, you -have- to have a fully tailored missile as opposed to ‘bomb with wings’ design because of the high thermo-acoustic conditions and the terminal threat (PAC-3 ERINT) which would basically tear a glide-ballistic weapon up.

Since everyone knows what a SLAM Harpoon, HARM and SRAM are; I find it rather strange that they cannot envision this as a large warhead ASM to do things like center-punch command bunkers and HAS clusters or detonate over open ramp spaces. Because at the kinds of speeds we’re talking about, it would be quite capable of doing so, probably in fewer total shot-count numbers than an equivalent weight (but not carriage box) of Sino-SDB would require.

3. Of course, it could just be shadows as the missiles both have a large body duct and usually that means someone is sending signals from a tail receiver (datalink or SARH tether) up to the GCS section, receiving pure parent RF as antijam or giving TVM handoff updates at the end of midcourse.

In this, it’s fair to state that the design also reminds me a great deal of the R-37 AAM or the Buk SAM for some reason-

https://en.wikipedia.org/wiki/File:9M38M1_9M317.svg

If so, you are indeed looking at some massive ISR-killer AAMs which likely use the same profile: generating a large downrange increment at very high altitude (as low drag) for Mach number, before the target can retrograde out of the way and it’s escorts charge forward to take down or distract the shooter.

The thing to remember here is that ballistic lobshots like this tend to have midcourses measured in minutes even as they are -highly- vulnerable to target ‘unexpected moves’. Such as generating a large cross-track displacement which eats up missile energy in compensation. This is why, in the Iran:Iraq war, the AIM-54 Phoenix was a 40-20nm weapon rather than a 100-70nm weapon most of the time when IRIAF Tomcats engaged tactical targets rather than Backfire bombers.

Indeed, if you want to go hunt other hunters, you need a weapon which offers flexibility on crossing or opening targets (40-60nm) and that typically means a ramjet capability with constant impulse over absolute peak Mach as a rocket can provide.

PL-12D and PL-21 match this need for high midcourse trajectory flexibility with a Meteor like shape as propulsion method and rather smaller size which means that they can generate a Mach 2.5 overtake and if need be, be launched in multiple Shoot-Shoot-Look overlaps, with the missile cutting the corner or running up the fighter-targets exhaust, no matter what it does.

A terminal boost via a screw-valve in the gas generator throat (higher combustion pressure = hotter/faster propellant grain burn at heightened impulse for any given duct flow) providing a Mach 4’ish boost for those conditions where you are fighting a 20-10nm and in need of a faster terminal flyout to A-Pole rather than absolute F-Pole as launch distance.

Such flexibility also helping the pilot avoid the problematic ballistic trajectory vs. radar scan cone divergent condition on saturating targets that go -> <- 'this way!' out of the edges of the radar coverage volume.

Drawings show PL-21 as a pretty big weapon, roughly R-27 Alamo-C sized. PL-12D is more a straight up BVRAAM equivalent and either should fit 3+ per main bay if these weapons are as big as they look. Or at least they -would- fit, if the twin launch shoes were not so obviously self-limiting.

CONCLUSION:

People tend to deal with new concepts in a strangulative fashion of associating 'known with similar' conservatism until the actual behavior of an idea or it's representative object is displayed.

In this, I think it is dangerous to see the J-20 as either an F-111 or a MiG-31 with stealth as a -platform- driven mission design.

Because the nature of LO is one of COE. Or Contempt Of Engagement.

You hit the targets you need to to leverage a larger fight and ignore the ones you don't because that is the nature of military thought: not to take on all but only the essential. Dealing Death In Detail.

In this, I tend to see the J-20 as something like an SS-21 Spyder crossed with a 40N6 S-400 SAM. As these are the closest match to the Kinetic -effects- that such large weapons could theoretically achieve.

Indeed, because of it's likely fuel load as well as stealth, the J-20 is going to get the hard targets like Kadena or Andersen as much as an E-3 orbiting off Taiwan behind a screen of escorts. As home plate is where the ISR platforms themselves and the logistics base to support them are open-ramp colocated, as much as 60% of the day.

At the same time, because of the operating range it is going to be working at, the Dragon literally cannot afford to engage in long burner sprints as 'air combat maneuvering' in a battle of equals with other fighters.

So it's going to leverage -just enough- of what the Chinese know of VLO technologies. And -just enough- of what they can put together in high temperature CFD thermodynamics to support an engine thrust curve sufficient to sprint for about 100nm (on burner or in IRT). And finally, -just enough- total platform size to provide the fuel for that throttle setting to overcome the drag of pushing a weapons bay carriage volumetric that allows the weapons do the terminal attack hard work.

Whether air to air or air to ground, the J-20s pilot is not looking for a fight, 1,200-1,500nm from base, he can't afford to. He is trying to stay alive just long enough to get to WEZ and then retire from the fight using COE doctrine.

As proof of this, look at the difference in likely poles between the side mounted self defense weapons and these centerline monsters. There is no way, any self respecting fighter pilot is going to press an attack into <10nm heat envelope across 40+nm of last-LRAAM shot interval with an opponent firing 20nm+ AMRAAM at him.

Not if he has the gas to turn and extend rather than take 1-2 individually timed-out (Shoot-Look-Shoot) shots on the way to the merge fight.