Shenyang FC-31 / J-31 Fighter Demonstrator

manqiangrexue said:

Brat was claiming that J-20 likely cannot supercruise in its given state with WS-10 or AL-31X. He was not saying that it did not have the potential to do so with WS-15. I think we all agree that J-20 was designed to supercruise with WS-15. Only question is whether J-20 could attain limited supercruise with its current engines. For reference, F-22 supercruises at mach 1.8 with engines that give 120kN in dry thrust, though with squint nozzles, I don't know how much that amounts to. Early AL-31 has dry thrust of 74.5kN and AL-41 has 86.3kN while early WS-10X was reported to have 89kN (possiby due to it being derived from a civilian engine). So whether J-20's current engines could pop it to over mach 1 in its current weight is uncertain, though for practical purposes, mach 0.99 or getting in just under breaking the sound barrier is not much worse than very low supercruise.

It's really both in combination. If your frame was less optimized for supercruise, you can supplement it with extra engine power and if you lacked engine power, you could design a frame more around supercruise. Flanker frames couldn't supercruise until the Russians pumped extra juice into the Su-35 with the AL-41 and now it can.

Can J-31 carry anti-shipping missiles internally? I'd like to see a source. Which missiles? What it their range and payload?

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Exactly, and I wasn't intending to condemn the J-20, just pointing out that as good as it is, it likely will not supercruise until the WS-15 comes along, but it is still a quantum leap over 4th generation fighter aircraft, thanks Bub for clarifying my intent.

Air Force Brat said:

Exactly, and I wasn't intending to condemn the J-20, just pointing out that as good as it is, it likely will not supercruise until the WS-15 comes along, but it is still a quantum leap over 4th generation fighter aircraft, thanks Bub for clarifying my intent.

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Still not sure that it can’t with its current engines. Super cruise isn’t just determined by thrust to weight ratio.

latenlazy said:

Still not sure that it can’t with its current engines. Super cruise isn’t just determined by thrust to weight ratio.

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Still, viable supercruise requires lots of it.
Especially on a stealth fighter with an internal weapons bay.
For Mig-29 powered fc-31(but with much fatter cross) - it is just unrealistic.

Gloire_bb said:

For Mig-29 powered fc-31(but with much fatter cross) - it is just unrealistic.

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I want to add keeping a consistent area size of cross section throughout is important to reduce drag during supersonic flight.

manqiangrexue said:

Do you know of any Chinese anti-shipping missiles that are 500kg or less and within the given length of the bomb bay? If so, what is the range and how much damage is it mean to do (sink a 2,000 ton ship, a 4,000 ton ship, etc...)? Because I think that's too small for a powerful anti-ship missile; maybe they meant air-to-surface for killing tanks, radars, SAMs, etc... For reference, YJ-12 (launched by J-16 and JH-7) is 2,500kg, 6.3 meters with 400km range for killing 5,000 ton ships.

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You do realize that there are factors besides the size of the warhead that determines its chances of incapacitating a ship, right? Flight profile, its ability to strike the waterline, warhead composition, kinetic energy, etc., are all independent of how massive its warhead is. In fact, a NSM-sized missile would be a perfect fit for the FC-31 and would provide it with Harpoon-level AShM capabilities.

Additionally, note that the bay could carry four 500 kg-class weapons, which could potentially allow for two 1-ton missiles, not just 500 kg-class AShMs.

SinoSoldier said:

You do realize that there are factors besides the size of the warhead that determines its chances of incapacitating a ship, right? Flight profile, its ability to strike the waterline, warhead composition, kinetic energy, etc., are all independent of how massive its warhead is. In fact, a NSM-sized missile would be a perfect fit for the FC-31 and would provide it with Harpoon-level AShM capabilities.

Additionally, note that the bay could carry four 500 kg-class weapons, which could potentially allow for two 1-ton missiles, not just 500 kg-class AShMs.

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kinetic energy if shaped properly and enough velocity is enough to take down even the biggest ships. no explosives needed. that's essentially what rail guns are.

SinoSoldier said:

You do realize that there are factors besides the size of the warhead that determines its chances of incapacitating a ship, right? Flight profile, its ability to strike the waterline, warhead composition, kinetic energy, etc., are all independent of how massive its warhead is. In fact, a NSM-sized missile would be a perfect fit for the FC-31 and would provide it with Harpoon-level AShM capabilities.

Additionally, note that the bay could carry four 500 kg-class weapons, which could potentially allow for two 1-ton missiles, not just 500 kg-class AShMs.

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NSM is a subsonic missile with 185kM range designed to do far less damage than YJ-12. It has far less kinetic energy due to slow speed. Larger missiles on the same technical level typically impart greater range, greater kinetic energy, greater warhead with no disadvantages to smaller missiles other than being more difficult to carry. So yes, I realize that warhead size isn't the only factor that determines a ship-killing missile's lethality, but it is a huge determinant, as is overall missile size.

So I see two ways to go here:
1. Use J-15 or J-15 stealth(ier) variant to lob YJ-12 at enemy ships from 400km away with 500kg of warhead at mach 4.
2. Use stealthy J-31 to lob Sino-NSM missiles at enemy ships from 185km away with 125kg of warhead at subsonic speeds. Bring a lot more missiles since in addition to dealing considerably less damage, subsonic missiles are far more prone to CIWS interception than missiles moving at mach 4.

PLAN's call. I have to note also that, the strike range of the missiles should be added to the range of the jets so J-15+YJ-12 should confer a strike radius from the carrier that is much much longer than that of the J-31+Sino-NSM combo. And if it had the option to build a new large stealth fighter that could carrying YJ-12, I think it would jump at the chance.

Carrying two 1,000kg missiles instead of four 500kg missiles would only work if those 1,000kg missiles were the same length at the 500km ones. Chubby missiles indeed.

manqiangrexue said:

NSM is a subsonic missile with 185kM range designed to do far less damage than YJ-12. It has far less kinetic energy due to slow speed. Larger missiles on the same technical level typically impart greater range, greater kinetic energy, greater warhead with no disadvantages to smaller missiles other than being more difficult to carry. So yes, I realize that warhead size isn't the only factor that determines a ship-killing missile's lethality, but it is a huge determinant, as is overall missile size.

So I see two ways to go here:
1. Use J-15 or J-15 stealth(ier) variant to lob YJ-12 at enemy ships from 400km away with 500kg of warhead at mach 4.
2. Use stealthy J-31 to lob Sino-NSM missiles at enemy ships from 185km away with 125kg of warhead at subsonic speeds. Bring a lot more missiles since in addition to dealing considerably less damage, subsonic missiles are far more prone to CIWS interception than missiles moving at mach 4.

PLAN's call. I have to note also that, the strike range of the missiles should be added to the range of the jets so J-15+YJ-12 should confer a strike radius from the carrier that is much much longer than that of the J-31+Sino-NSM combo. And if it had the option to build a new large stealth fighter that could carrying YJ-12, I think it would jump at the chance.

Carrying two 1,000kg missiles instead of four 500kg missiles would only work if those 1,000kg missiles were the same length at the 500km ones. Chubby missiles indeed.

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Why are you persistent in that the YJ-12 is the be-all and end-all for all of their anti-shipping needs? The NSM not only has a smaller profile and stealthier fuselage compared to the YJ-12, but its smaller size would allow the FC-31 (or similarly-sized platform) to carry multiple rounds. The NSM may not have as big a warhead or the velocity of the YJ-12, but there is no indication that the former would be insufficient for the needs of the PLAN; note that the PLANAF still operates the C-802 series which is comparable in kinematics and payload.

Regarding your proposals:
1. There is nothing much that can be done to make the J-15 "stealthy", especially when it's carrying a monster like the YJ-12. A J-15 equipped with a centerline-mounted YJ-12 will be sluggish and its combat radius drastically decreased. What you'll end up with is a fleet of slow, immobile J-15s fitted with YJ-12 that will require fighter escort against enemy defenses that will spot you from hundreds of kilometers away.
2. The FC-31 would be able to release its weapons much closer to the enemy than could the J-15. This decreases the reaction time of the enemy, which itself is an advantage that the YJ-12 hopes to equally fulfill with its supersonic dash.

You also need to keep in mind that a J-15 and YJ-12 combo would have a much smaller operating envelope than a FC-31 + NSM/YJ-XX combo and would require a lot more supporting platforms such as escorts or ECM. Chubby missiles exist (e.g. KEPD-350, Storm Shadow), and if the Chinese can develop a similarly-sized missile with a 400-600 km range, you will essentially negate any range advantages a YJ-12 & J-15 tag team has.

SinoSoldier said:

You do realize that there are factors besides the size of the warhead that determines its chances of incapacitating a ship, right?

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And warhead size is the main one among them, with larger combatants being able to absorb, even while rapidly loosing combat capability, more than a few hits.

Against, say, carrier 500kg subsonic/supersonic ASCM will not justify losses to get it go the target, if there is anything else.

Tonot let offtop in, fc-31

1.range gives little, we don't know conditions. Say, 4000 km range suspiciously reminds somewhat improved(we know fc-31 carries more fuel inside, it isn't hard to guess) mig-29m2(mig-29k,mig-35). Latter does it with 5(!) external tanks, it obviously isn't combat relevant configuration. Same with combat radius(3 for MiG, though)
Given the same size and engines - FC-31 numbers are quite likely to also use drop tanks.

2.Special bombs or armament w/o names. Do we know them?
Are they developed for FC-31, or customer is shown what "everything can happen, just add some $"? Or are they are from J-20(about a2g of the latter we don't know much, btw)?