H-20 bomber (with H-X, JH-XX)

[Blitzo]

What are the thoughts on relative efficacy in use cases between a flying wing type subsonic heavy bomber and a "big fighter" conventional layout type (like a bigger J-20 with an internal rotary launcher) with supersonic capability?

For a subsonic flying wing, there's a few issues that may reduce it's efficacy in a peer conflict;

1. Vulnerability to IR tracking and 100% unable to escape if caught
2. Slower response speed to rapidly changing events
3. Lower payload for equal thrust due to higher drag (from thick wing).

Just comparing B2 with B1 - they have equal thrust (4x 77 kN) but B2 has half the payload.

Alot of the advantages of a flying wing - the capability to drop dumb bombs on weak adversaries - isn't useful to the PLAAF. The purpose of a bomber in PLAAF doctrine should be closer to Russian - as a big missile truck.

A conventional layout may have some advantages:

1. Can potentially still escape if caught, particularly at edge of engagement windows
2. Can have high payload for equal thrust
3. Still can have a low RCS since design techniques have vastly improved since the B1 and Tu160.

Assuming one wants to keep costs (developmental, but also procurement and mostly operational) under control, IMO, of the below three characteristics, with current technology, one can only pick two:
1 - Stealthy/VLO
2 - Large size (payload and range)
3 - High speed (supersonic capable)


Trying to develop an aircraft with all three of those characteristics would result in an exorbitantly expensive aircraft.
IMO, any modern clean sheet bomber or combat aircraft must be stealthy/VLO for be appropriate for the modern and future combat environment, meaning criteria 1 already occupies one of the two characteristics.

H-20, from our consensus understanding, should fulfill criteria 1 and 2 (if it is indeed a modern flying wing with a weight class in that of B-2 rather than B-21).

If you want a stealthy/VLO bomber aircraft that was high speed/supersonic, then IMO you inevitably have to downsize your aircraft. I suspect practically speaking you'll end up with something between Tu-22M3 and F-111 in size.
Of course, that is where the interest around the so called JH-XX comes in.

 

[FairAndUnbiased]

Assuming one wants to keep costs (developmental, but also procurement and mostly operational) under control, IMO, of the below three characteristics, with current technology, one can only pick two:
1 - Stealthy/VLO
2 - Large size (payload and range)
3 - High speed (supersonic capable)


Trying to develop an aircraft with all three of those characteristics would result in an exorbitantly expensive aircraft.
IMO, any modern clean sheet bomber or combat aircraft must be stealthy/VLO for be appropriate for the modern and future combat environment, meaning criteria 1 already occupies one of the two characteristics.

H-20, from our consensus understanding, should fulfill criteria 1 and 2 (if it is indeed a modern flying wing with a weight class in that of B-2 rather than B-21).

If you want a stealthy/VLO bomber aircraft that was high speed/supersonic, then IMO you inevitably have to downsize your aircraft. I suspect practically speaking you'll end up with something between Tu-22M3 and F-111 in size.
Of course, that is where the interest around the so called JH-XX comes in.

I agree with this. I believe sacrificing payload is acceptable for a high speed, LO tactical missile striker with 2 engines (low bypass, 75 kN dry class).

Dimensions only need be large enough to fit an internal cruise missile launcher. For example, Tu22M and B1 are both 45 m long but a J11B is 22 m long. YJ12 and Tomahawk are 6.3 m long. To accommodate an internal launcher let's say you need 8 m internal length. Ok, 30 meters total length. That is quite a bit smaller than Tu22 and B1. Some of that extra space can be given to fuel storage since you'll also add some wing area. Let's say it makes up for the added weight and a little extra.

A rough end result: length 30% bigger than a J11 at 30 m, likely 25% heavier than a J11 (16000 kg) at 20000 kg, maximum takeoff weight assume only marginal gains at 40000 kg (still less than F-111 at 45000 kg) So with 10000 kg fuel, it can comfortably carry 10000 kg. That is just enough for 4x 2000 kg class missiles and a 1000 kg launching mechanism.

Use case: stealthily approach inside adversaries naval CAP (typically 500 km out), launch 500 km range missiles at surface targets, turn around and hit the afterburners at Mach 1.8 to outrun certain carrier borne fighters with Max speed Mach 1.6 now looking for you on IRST.

This is assuming that it basically performs no worse than a big Flanker or planes built 50 years ago, which I don't think is bad assumption given what we saw from the J-20.

 

[Atomicfrog]

I agree with this. I believe sacrificing payload is acceptable for a high speed, LO tactical missile striker with 2 engines (low bypass, 75 kN dry class).

Dimensions only need be large enough to fit an internal cruise missile launcher. For example, Tu22M and B1 are both 45 m long but a J11B is 22 m long. YJ12 and Tomahawk are 6.3 m long. To accommodate an internal launcher let's say you need 8 m internal length. Ok, 30 meters total length. That is quite a bit smaller than Tu22 and B1. Some of that extra space can be given to fuel storage since you'll also add some wing area. Let's say it makes up for the added weight and a little extra.

A rough end result: length 30% bigger than a J11 at 30 m, likely 25% heavier than a J11 (16000 kg) at 20000 kg, maximum takeoff weight assume only marginal gains at 40000 kg (still less than F-111 at 45000 kg) So with 10000 kg fuel, it can comfortably carry 10000 kg. That is just enough for 4x 2000 kg class missiles and a 1000 kg launching mechanism.

Use case: stealthily approach inside adversaries naval CAP (typically 500 km out), launch 500 km range missiles at surface targets, turn around and hit the afterburners at Mach 1.8 to outrun certain carrier borne fighters with Max speed Mach 1.6 now looking for you on IRST.

This is assuming that it basically performs no worse than a big Flanker or planes built 50 years ago, which I don't think is bad assumption given what we saw from the J-20.

At this rate, it's better to lobe a salvo of multiple stealth cruise missile from an H-6 at 600 km than carrying only one inside a top of the line aircraft and shotting it at 400km... I don't see the jh-xx carrying less than two missiles, you need to saturate a carrier group with multiple missile if you want to have a chance of a hit, stealth bomber or not. It's why the H-6 is still relevant and a costly wonderland tactical stealth bomber a big question mark.

 

[Blitzo]

At this rate, it's better to lobe a salvo of multiple stealth cruise missile from an H-6 at 600 km than carrying only one inside a top of the line aircraft and shotting it at 400km... I don't see the jh-xx carrying less than two missiles, you need to saturate a carrier group with multiple missile if you want to have a chance of a hit, stealth bomber or not. It's why the H-6 is still relevant and a costly wonderland tactical stealth bomber a big question mark.

That all very much depends on how well defended the target is, and what the overall combat environment is like.

There are absolutely scenarios where H-6s may not even be able to get within 1200km of a target without being detected and intercepted, whereas a stealthy regional bomber may be able to get within 400km of a target or even closer and successfully deploy its payload before RTB.

 

[drowingfish]

i wonder if a new bomber can achieve a higher service ceiling, thus able to shoot further while evade enemy aircrafts. at 30km above sea level not many fighters would be able to get to you except under the most idea circumstances, while ordinance you deliver will gain more speed and range.

 

[FairAndUnbiased]

At this rate, it's better to lobe a salvo of multiple stealth cruise missile from an H-6 at 600 km than carrying only one inside a top of the line aircraft and shotting it at 400km... I don't see the jh-xx carrying less than two missiles, you need to saturate a carrier group with multiple missile if you want to have a chance of a hit, stealth bomber or not. It's why the H-6 is still relevant and a costly wonderland tactical stealth bomber a big question mark.

I believe 4 missiles is a possible loadout. Nowhere did I say it can carry 1 missile only.

H-6 will not be able to approach within 600 km of a highly defended target because adversary CAP detection radius can extend over 1000 km. Nor will 600 km be sufficient. PLAAF and PLAN do not yet have 600 km cruise missiles. I made extremely conservative estimates using only munitions that actually exist and assuming the lowest possible performance. A H-6K loadout is still only 6 cruise missiles as well.

A hypothetical flying wing H-20 may be able to approach within 400 km to launch missiles - maybe 6. But let's just say it misses or the missiles get shot down. Now you have enemy CAP that knows the launch position looking for you. Sure the missiles can do a roundabout path, but then you need to approach closer which does not solve the survival problem. If the H-20 is spotted on IR tracking or a close up radar, it's done. How many H-20 can you afford to lose?

Meanwhile a very conservative JH-20 that assumes absolutely zero technical advancement that we don't already know about can approach within 400 km, launch payload, and escape easily. It'll be stealthy while approaching. Even if detected, it'll be able to outrun CAP aircraft, especially at the edges of their engagement envelopes and after ditching its strike payload.

Again, my estimate was very conservative: Al-31/WS-10C class engines, F-111 level aerodynamic performance, payload only a tiny bit higher than a standard J-11, using the most conservative size for internal weapons bay, assuming shaping and manufacturing techniques already proven to exist. Any advancement would make it far deadlier.

 

[Totoro]

Another important aspect of any strike aircraft is delivery of cheap bombs. That's more important than delivery of million+ apiece stand off missiles (in US costs). While a fairly small production run H-20 might get away with never having to do the mission of cheap bomb delivery - a notional JH-XX, if it's to replace JH7 for example, will not have that luxury. It will have to be made in numbers and it will have to do a much broader set of missions.

Which will sometimes literally mean this: getting to 100 or even less than 50 km away from the target and dropping its munitions. Now, of course, that won't be done on the first days of the war, but later, hopefully when enemy's defenses are softened up a bit. But still, it's a mission that will have to be repeated day in and day out. For weeks against small opponents. Or possibly for months or over a year for big opponents.

Now, will that JHXX be manned or unmanned is completely irrelevant here. Will it be one plane or two different planes is again irrelevant. If anything, the GJ-11 seems to be groomed to become the low end of the JH-XX requirement - not being large enough or having large enough bays to carry big stand off missiles. But still being capable enough to deliver several short ranged and fairly cheap bombs per sortie. Of course, it's not supersonic. Which may warrant another design, somewhat larger, to go in between the GJ-11 and H-20. Or the expenses will be prohibitive and China will make do with just different utilization and higher numbers of H-20 and some strike configured J-20s. But we will see what the future brings.

 

[FairAndUnbiased]

Another important aspect of any strike aircraft is delivery of cheap bombs. That's more important than delivery of million+ apiece stand off missiles (in US costs). While a fairly small production run H-20 might get away with never having to do the mission of cheap bomb delivery - a notional JH-XX, if it's to replace JH7 for example, will not have that luxury. It will have to be made in numbers and it will have to do a much broader set of missions.

Which will sometimes literally mean this: getting to 100 or even less than 50 km away from the target and dropping its munitions. Now, of course, that won't be done on the first days of the war, but later, hopefully when enemy's defenses are softened up a bit. But still, it's a mission that will have to be repeated day in and day out. For weeks against small opponents. Or possibly for months or over a year for big opponents.

Now, will that JHXX be manned or unmanned is completely irrelevant here. Will it be one plane or two different planes is again irrelevant. If anything, the GJ-11 seems to be groomed to become the low end of the JH-XX requirement - not being large enough or having large enough bays to carry big stand off missiles. But still being capable enough to deliver several short ranged and fairly cheap bombs per sortie. Of course, it's not supersonic. Which may warrant another design, somewhat larger, to go in between the GJ-11 and H-20. Or the expenses will be prohibitive and China will make do with just different utilization and higher numbers of H-20 and some strike configured J-20s. But we will see what the future brings.

What's the point of delivering dumb bombs stealthily? Any high value target is too heavily defended for that so you need standoff munitions. For low value targets once you gain air supremacy, unstealthy strikers, drones and helicopters can wipe ground targets.

 

[Chavez]

What's the point of delivering dumb bombs stealthily? Any high value target is too heavily defended for that so you need standoff munitions. For low value targets once you gain air supremacy, unstealthy strikers, drones and helicopters can wipe ground targets.

Back in 2012 zhuhai air show,report that avic is early stsge researching and development of variable cycle engine,more likely connected to jxx program

 

[Blitzo]

What's the point of delivering dumb bombs stealthily? Any high value target is too heavily defended for that so you need standoff munitions. For low value targets once you gain air supremacy, unstealthy strikers, drones and helicopters can wipe ground targets.

I don't think he means dumb bombs but rather unpowered/direct attack PGMs.

For targets that are "softened up" as he describes, it will often become far more economical to use an aircraft to get in closer range of the target to use unpowered/direct attack PGMs rather than standoff powered munitions, in terms of "mass of payload delivered to target".


There certainly can be combat environments in which you want to use a stealth aircraft to conduct bombing raids against a large number of targets with degraded (but not fully eliminated) defenses, and also without being detected by the enemy.



That said, the use of PGMs would be very much a secondary or even tertiary payload category for the kind of weapons that the PLA would want H-20 and a notional JH-XX to prioritize. After all, you only get the privilege of using PGMs if you have sufficient air control and enough SEAD/DEAD to begin with.