Yes the original statement says 10 tons is empty weight I believe.
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Yes the original statement says 10 tons is empty weight I believe.
SinoSoldier
Colonel
A single-engine aircraft powered by a WS-15, of all engines, seems a little hard to believe given the technological immaturity of the turbofan.
The weight and weapons load suggest that it could have been designed to be extremely cheap to produce, augmenting its export prospects, and given the rivalry between SAC & CAC, I would not be surprised if it turned out to be a privately-financed project aimed to take a piece of the FC-31 market's pie.
The weight and weapons load suggest that it could have been designed to be extremely cheap to produce, augmenting its export prospects, and given the rivalry between SAC & CAC, I would not be surprised if it turned out to be a privately-financed project aimed to take a piece of the FC-31 market's pie.
Equation
Lieutenant General
Imagine if it's a drone type or man control, but with a lot of it. Quality with quantity in numbers can easily swarm the enemy and win the day.
It may not be that hard to believe, because we don't know when this supposed aircraft is proposed to be ready to fly, if at all.
If the proposal is a 2020ish maiden flight or even later, WS-15 may well be a viable choice. I wouldn't be surprised if Al-31 is intended as an interim engine for development either.
There's too much we don't know about the supposed proposal to make a real call about it. If it really does have a 10 ton empty weight and only carry 2 MRAAMs internally it may be intended to be a stealth fighter even lower in capability than FC-31... but whether an export customer would respond to an aircraft carrying only two missiles internally is doubtful. However, I think Chinese Air Force may find such an aircraft attractive, if it can be developed and produced cheaply enough, to replace early J-10s and even some the hundreds of J-7s still in service.
It'll depend on the force structure the Air Force is looking to aim for in the late 2020s and beyond.
SinoSoldier
Colonel
I wouldn't say that this proposal would be less capable than the FC-31 just yet; the low payload could very well be a sacrifice for something else (likely maneuverability or speed). Export prospects, by a similar token, would be decided by what the customer wants the most out of the aircraft, which may not necessarily be VLO or a large payload.
SinoSoldier
Colonel
Interesting throwback:
A few years ago, an insider by the name of "huzhigeng", who allegedly worked on the J-20, wrote of a new "pre-5th-generation" single-engined fighter, then designated as the J-2X, that was being developed to satisfy the needs of both the Chinese Air Force and export demand. The size of the aircraft was allegedly comparable to that of the F-35, and it was described as the "J-20's little brother". He also claimed that the design had been presented to the Pakistani Air Force, which was satisfied with it.
A few years ago, an insider by the name of "huzhigeng", who allegedly worked on the J-20, wrote of a new "pre-5th-generation" single-engined fighter, then designated as the J-2X, that was being developed to satisfy the needs of both the Chinese Air Force and export demand. The size of the aircraft was allegedly comparable to that of the F-35, and it was described as the "J-20's little brother". He also claimed that the design had been presented to the Pakistani Air Force, which was satisfied with it.
If it really is meant to be a delta and tailless aircraft, I think it will likely emphasize speed and range as best as a small/medium airframe can.
FC-31 is closer to F-35 weight class aircraft, with a similar internal payload at least for air to air missiles, and a stealthy fighter with an internal payload of only 2 MRAAMs simply won't have the same geometry and volume of an aircraft like FC-31, period.
The only way a single engine, stealthy, tailless delta wing fighter with an empty weight of 10 tons and an internal payload of 2 MRAAMs makes sense, is if one wanted an aircraft which could fulfill competitive but low tempo air defense needs on a stealthy airframe with competent (but not overly ambitious) endurance/range performance and speed. Fortunately, such an aircraft would likely be quite a capable A2G or A2A aircraft when utilizing external stores, for missions which do not require stealth, by virtue of a fairly powerful engine.
Such an aircraft, purchased in large numbers, would truly fit the bill of a "stealthy J-7" for the modern era.
Just a maybe stupid idea, but could it be that this single-engine light-weight fighter is related to CAC's/611's VSTOL-research ?
While rumor itself is just that, a rumor, it's fun to speculate. A plane that would indeed be 10 tons empty, that would use ws-15 class engine (150-180 kn, we don't really know) and carry just two pl-12 sized mraams internally would be quite orientated towards fighter role, aerodynamics wise.
First, the weapons bay volume. Using two missiles modeled on the missile seen inside j-20, we get internal bay volume of some 64*440*36 cm if missiles are arranged in staggered fashion or 69*395*36 if missiles are arranged in line. In line arrangement uses up a bit more volume so it's less likely, even more so since 0.64 meter wide bay of staggered arrangement isn't terribly wide even for a 10 ton fighter.
Two other planes that can help for interpolating other figures are, of course, f-35a and AVIC's estimates for FC-31.
We know F-35a is 13,2 tons empty. It has 8,4 tons of fuel. Its engine has test bench thrust of 191 kn. Its bomb bays together have around 2,6 cubic meters. It's basic weight with all the fuel and four amraams would be around 22,2 tons.
FC-31 is estimated with 17,5 tons of typical take off weight. It's also estimated with around 190 kn thrust. (give or take) As far as we can tell, it's weapons bay is twice the volume i calculated earlier as it seems to carry twice as many missiles (since it too seems to have a central divider between bays) So roughly 2 cubic meters.
It's pretty sure FC31 won't carry 8 tons of fuel as f35a does. But it does has similar thrust installed and potentially/likely more thirsty engines. It has a little less internal space "wasted" on weapons, and potentially less weight invested in airframe lifespan (instead of 8000 hours maybe 4-6 thousand?) and potentially less weight invested in radar absorbing materials. Still, anything around 12 tons empty seems pretty realistic. New Migs29 also weight that much, around 12 tons, without additional internal structure and RAM. Modern materials compensate for increased weight a little but, but overall 5th gen fighters are heavier than their 4th gen counterparts.
Anyhow, that would suggest around 4,5 tons of fuel for fc-31. Avic very optimistically estimated 1250 km combat range which even if we use as PR speak for half of ferry range at 2500 km is A LOT for 4,5 tons of fuel on such a plane. Mig29m with same amount of internal fuel does 2000 km ferry range though so...maybe it's plausible. Maybe there's 5 tons of fuel and plane is somehow super light (super advanced building materials/technique, short airframe life, no support for heavy weapons, little RAM)
Lets get back to speculative new fighter. 10 ton empty, 0,2 tons for pilot, ammo, oil, ancillary equipment and 0,4 tons for missiles gives 10,6 tons without fuel. Fuel can be estimated as fraction. F-35a has 0,35 fuel fraction for its intented strike configuration mission. mig-29m has 0,24 for fighter mission on internal fuel. fc-31 seems to have between 0,26 and 0,29. f-22 has
around 0,28. So one could guesstimate between 0,26 and 0,3 for the new fighter.
Another way to estimate fuel is thrust comparison, for planes of similar role.
High powered hotrod fighters like f22 of eurofighter or su35 seem to have w/t ratio (when full fuel and with missiles) of around 1 to 1 or 1,1 to1. FC31 seems to be aiming also over 1, perhaps closer to 1,1 to 1. J10a seems to have that at around 0,9 or so. One would expect the new fighter not to go below that figure and perhaps more realistically try to be closer to fc-31.
Fighter hotrod like f22 has 38 kn of thrust per every ton of fuel carried. FC31 seems to have 38-42 kn of thrust planned per ton of fuel. f35a is down to 23 kn per ton. So those are values that speculative fighters might also enjoy. Probably 30ish, but also probably under 40. For 150 kn class ws15 that'd be between 4,5 and 6 tons. For 180 kn class ws15 that'd be 5,4 to 7,2 tons.
Earlier estimate based on fuel fraction seems to point towards 4 tons of fuel so I'd personally take 4,5 tons as max high limit.
So we might be looking at a 15 ton fighter mission take off weight.
With all above in mind, having a bay holding two pl12x sized missiles is really very believable. Holding twice as many is simply too much for a fighter of said size. It'd be hard to find almost 1,5 m wide and 4 meters long space on such a fighter. If doable, it'd call for some unusual arrangements, like two bays, one left and other right of the engine. Or even four bays for four missiles in which case they'd probably be snuggling the engine and main landing gear would fold in between of two bays on each side. Or bay for 2 mraams in the bells and 2 pods like pakfa has for short ranged aams on the wings. All those are quite inefficient solutions, engineering wise. Having a single bay on such a small, single engined fighter is the best route possible.
Very roughly speaking, adding two more missiles internally would mean 0,8 tons of fuel less. Which on a 4 or 4,5 tons of fuel total is a lot. fc-31 seems quite short legged as it is.
One of the issues is size of pl-12x and pl-10 missiles. They're bigger than their western counterparts. It may mean they pack more capability per missile but it also means one needs more space to pack the same number of missiles. pl-10 is of particulary greater fin span than aim9x for example. To add just one pl-10 between two pl-12x would require almost 1,5 cubic meters of space, even twough two pl-10 require 1 cubic meters.
For comparison, two amraams and one aim9x in between require some 1,05 cubic meters.
Having 3 missiles for a 10 ton fighter is still doable, thought like i said, something would suffer. It'd be more akin to f35a agility wise. Or it'd have even less range than fc-31. Or it'd have a very short airframe life. Or it'd have very little radar absorbent materials.
Important thing to note is that j10b is fairly new. It will be in production for 10 more years for sure. Also, even if speculative new fighter is unveiled within a few years, serial production would not likely start until 2025. Basically, all or almost all j7 would be gone from plaaf by then. So new figther would really complement or replace j10a. And one has to compare its capabilities to j10a, not j7. Range being of greatest importance here. Would plaaf really accept a plane that offers 70% of j10's range? One that potentially has shorter lifespan? Of all compromises, carrying 2 missiles internally is smallest compromises. Because it's not a compromise at all. If one can achieve same range, agility, lifespan numbers as j10, while having stealth on top of it in missions where 2 aams or 2 bombs are enough- then that's more than an improvement overall. Because that's just one option the plane offers. Other one being losing most stealth for same/greater loadout and similar range. That's a terrific gain overall, having such a choice, really.
So yeah, 2 aams are acceptable for a 10 ton fighter. 3 would be better but chinese missiles are big. But 2 are worth it and expecting 4 or so missiles would simply make other variables of the 10 ton plane unacceptably worse.
First, the weapons bay volume. Using two missiles modeled on the missile seen inside j-20, we get internal bay volume of some 64*440*36 cm if missiles are arranged in staggered fashion or 69*395*36 if missiles are arranged in line. In line arrangement uses up a bit more volume so it's less likely, even more so since 0.64 meter wide bay of staggered arrangement isn't terribly wide even for a 10 ton fighter.
Two other planes that can help for interpolating other figures are, of course, f-35a and AVIC's estimates for FC-31.
We know F-35a is 13,2 tons empty. It has 8,4 tons of fuel. Its engine has test bench thrust of 191 kn. Its bomb bays together have around 2,6 cubic meters. It's basic weight with all the fuel and four amraams would be around 22,2 tons.
FC-31 is estimated with 17,5 tons of typical take off weight. It's also estimated with around 190 kn thrust. (give or take) As far as we can tell, it's weapons bay is twice the volume i calculated earlier as it seems to carry twice as many missiles (since it too seems to have a central divider between bays) So roughly 2 cubic meters.
It's pretty sure FC31 won't carry 8 tons of fuel as f35a does. But it does has similar thrust installed and potentially/likely more thirsty engines. It has a little less internal space "wasted" on weapons, and potentially less weight invested in airframe lifespan (instead of 8000 hours maybe 4-6 thousand?) and potentially less weight invested in radar absorbing materials. Still, anything around 12 tons empty seems pretty realistic. New Migs29 also weight that much, around 12 tons, without additional internal structure and RAM. Modern materials compensate for increased weight a little but, but overall 5th gen fighters are heavier than their 4th gen counterparts.
Anyhow, that would suggest around 4,5 tons of fuel for fc-31. Avic very optimistically estimated 1250 km combat range which even if we use as PR speak for half of ferry range at 2500 km is A LOT for 4,5 tons of fuel on such a plane. Mig29m with same amount of internal fuel does 2000 km ferry range though so...maybe it's plausible. Maybe there's 5 tons of fuel and plane is somehow super light (super advanced building materials/technique, short airframe life, no support for heavy weapons, little RAM)
Lets get back to speculative new fighter. 10 ton empty, 0,2 tons for pilot, ammo, oil, ancillary equipment and 0,4 tons for missiles gives 10,6 tons without fuel. Fuel can be estimated as fraction. F-35a has 0,35 fuel fraction for its intented strike configuration mission. mig-29m has 0,24 for fighter mission on internal fuel. fc-31 seems to have between 0,26 and 0,29. f-22 has
around 0,28. So one could guesstimate between 0,26 and 0,3 for the new fighter.
Another way to estimate fuel is thrust comparison, for planes of similar role.
High powered hotrod fighters like f22 of eurofighter or su35 seem to have w/t ratio (when full fuel and with missiles) of around 1 to 1 or 1,1 to1. FC31 seems to be aiming also over 1, perhaps closer to 1,1 to 1. J10a seems to have that at around 0,9 or so. One would expect the new fighter not to go below that figure and perhaps more realistically try to be closer to fc-31.
Fighter hotrod like f22 has 38 kn of thrust per every ton of fuel carried. FC31 seems to have 38-42 kn of thrust planned per ton of fuel. f35a is down to 23 kn per ton. So those are values that speculative fighters might also enjoy. Probably 30ish, but also probably under 40. For 150 kn class ws15 that'd be between 4,5 and 6 tons. For 180 kn class ws15 that'd be 5,4 to 7,2 tons.
Earlier estimate based on fuel fraction seems to point towards 4 tons of fuel so I'd personally take 4,5 tons as max high limit.
So we might be looking at a 15 ton fighter mission take off weight.
With all above in mind, having a bay holding two pl12x sized missiles is really very believable. Holding twice as many is simply too much for a fighter of said size. It'd be hard to find almost 1,5 m wide and 4 meters long space on such a fighter. If doable, it'd call for some unusual arrangements, like two bays, one left and other right of the engine. Or even four bays for four missiles in which case they'd probably be snuggling the engine and main landing gear would fold in between of two bays on each side. Or bay for 2 mraams in the bells and 2 pods like pakfa has for short ranged aams on the wings. All those are quite inefficient solutions, engineering wise. Having a single bay on such a small, single engined fighter is the best route possible.
Very roughly speaking, adding two more missiles internally would mean 0,8 tons of fuel less. Which on a 4 or 4,5 tons of fuel total is a lot. fc-31 seems quite short legged as it is.
One of the issues is size of pl-12x and pl-10 missiles. They're bigger than their western counterparts. It may mean they pack more capability per missile but it also means one needs more space to pack the same number of missiles. pl-10 is of particulary greater fin span than aim9x for example. To add just one pl-10 between two pl-12x would require almost 1,5 cubic meters of space, even twough two pl-10 require 1 cubic meters.
For comparison, two amraams and one aim9x in between require some 1,05 cubic meters.
Having 3 missiles for a 10 ton fighter is still doable, thought like i said, something would suffer. It'd be more akin to f35a agility wise. Or it'd have even less range than fc-31. Or it'd have a very short airframe life. Or it'd have very little radar absorbent materials.
Important thing to note is that j10b is fairly new. It will be in production for 10 more years for sure. Also, even if speculative new fighter is unveiled within a few years, serial production would not likely start until 2025. Basically, all or almost all j7 would be gone from plaaf by then. So new figther would really complement or replace j10a. And one has to compare its capabilities to j10a, not j7. Range being of greatest importance here. Would plaaf really accept a plane that offers 70% of j10's range? One that potentially has shorter lifespan? Of all compromises, carrying 2 missiles internally is smallest compromises. Because it's not a compromise at all. If one can achieve same range, agility, lifespan numbers as j10, while having stealth on top of it in missions where 2 aams or 2 bombs are enough- then that's more than an improvement overall. Because that's just one option the plane offers. Other one being losing most stealth for same/greater loadout and similar range. That's a terrific gain overall, having such a choice, really.
So yeah, 2 aams are acceptable for a 10 ton fighter. 3 would be better but chinese missiles are big. But 2 are worth it and expecting 4 or so missiles would simply make other variables of the 10 ton plane unacceptably worse.