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

S

Skywatcher

Captain
The Russian Object 54C had a MTOW of 100 tons, though it was longer at 35 meters, and had variable geometry wings (which likely would add a fair amount of weight). Its powerplant were two afterburning engines (AL-41F?) with each a total thrust of 40 tons.
 
Blitzo

Blitzo

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latenlazy said:
TBH, I never had problems with that bit. The reason I brought up a point about needing greater kinematics was because we were comparing T:W ratios of other supersonic bombers. This goes back to my general feeling that using WS-10s as interims would be insufficient (I'm essentially saying that a JH-XX should probably have better T:W at loaded weight than the Tu-22M to perform the mission you're describing).
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Erm, I hate to bring up this again (I just realized you actually made a reply to me on this point), but I think my entire argument is still not understood. My position has been that JH-XX's stealth would mean it can have a lower T/W ratio (AKA relatively poorer kinematic capability) compared to a non-stealthy aircraft like Tu-22M, if both were to attempt to conduct egress under the same conditions.

In other words, we're not just comparing T/W ratios of supersonic bombers as the contributors to successful egress, but also the contribution of stealth for JH-XX.
So, if we were to put both JH-XX and Tu-22M into the same egress situation, my position is that JH-XX can afford to have a degree of poorer kinematic capability because its stealth would synergize with its (lower, relative to Tu-22M but still supersonic) kinematic capability to allow it to potentially escape its pursuers, whereas Tu-22M has a very large RCS and is non-stealthy, therefore it must rely only on kinematic capability to escape pursuers, thus meaning it requires greater kinematic capability than JH-XX (ignoring other things such as ECM, etc, that may be available for both aircraft).
[obviously, if JH-XX had equal or greater kinematic capability than Tu-22M on top of its advantage in stealth, that would allow it to conduct successful egress to an even greater degree]

If you can accept that position, then the next logical question (which neither of us can really answer and I don't expect us to seriously know) is to consider just how much stealth would contribute to JH-XX's ability to conduct egress and what the minimum degree of kinematic capability it would need on top of its stealth to successfully egress... and whether WS-10s could potentially successfully meet that minimum kinematic capability.
 
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T

Totoro

Major
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I believe a 80+ ton jh-xx would be a non-starter. It would unnecesarily make the project more expensive, it would result in fewer planes available, it would be limited due to engine options, and limited in perfomance (acceleration and take off distance) and it would step on h6k and h-x territory a bit.

What examples do we have? tu22m, a 120 ton mtow plane with a large weapon bay, swing wing configuration offering good versatility for various mission aspects, using 50 tons of fuel to do 7000 km of ferry range or perhaps some 3000 km of cruise speed range armed with missiles or perhaps 2000-2500 km of range with a supersonic dash. two 250 kn engines.

then we have the already mentioned f111. small weapon bay, again a swing wing configuration, 16 tons of internal fuel plus another 8 or so tons of external fuel. two 112 kn engines. doing 2500 km was doable with a small load and at cruise speed. not high subsonic speed but cruising speed - around mach 0.7. High subsonic speed and high altitude flight would allow a f111 with 24 tons of fuel perhaps some 2200 km of total combat range. Supersonic dash would cut that further, perhaps closer to 1500 km.

Soviet 54c is a paper project with just guesswork for its specifications. taken for granted, that guesswork mentions a 90ish ton mtow plane powered by two near 20 kgf engines and an advanced lifting body design with swing wings. fuel load 37 tons. range is a total guesstimate with astonishing 11.000 km so i'd guess that's just wishful thinking.

There was also a mention of a reduced 54c (45?) project, a 60ish ton mtow plane, 22 tons of fuel, two 13 kgf engines. projected ferry range 8.000 km.

Anyhow, a 3 or 4 engined solution is a non starter, i think. too complex, too constly to maintain, too inefficient for a workhorse plane. Two engined solution is much more sensible. so some variant of ws15 is possible. either close to vanilla ws15 if we're talking about 2025 timeframe or some souped up, high bypass variant if we're talking about 2030 timeframe. 150-180 kn of thrust would be my guess but we really have NO way of knowing for sure.

Discarding the wishful figures for mythical soviet object 54, tu22m and f111 are a decent guide as to what one might expect from jh-xx. so depending on engine thrust, we might see a 65-80 ton mtow plane. with internal fuel fraction compared to its mtow at around 0.3 to 0.4
So a 20-ish tons of internal fuel is plausible, offering perhaps somewhat better range figures than f-111 but only marginally.

I still think a supersonic dash plane with low rcs of such weight class would be hard pressed to reach 2000 km of combat range. (with some 10 tons of external fuel on top of those 20 tons of internal fuel) 80 ton mtow one MAY be able to just reach it. For 66 ton one is about impossible to pull off.

Until we know more about ws15 perfomance it's really a moot point.
 
Blitzo

Blitzo

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Totoro said:
I believe a 80+ ton jh-xx would be a non-starter. It would unnecesarily make the project more expensive, it would result in fewer planes available, it would be limited due to engine options, and limited in perfomance (acceleration and take off distance) and it would step on h6k and h-x territory a bit.
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It's worth repeating again, that 80 tons would only be the MTOW for the plane and as such it includes external weapons load, and I don't think anyone would expect an 80 ton plane to have sufficient supersonic dash/cruise or range for a true high intensity mission... even ignoring the fact that an 80 ton MTOW JH-XX would be unstealthy in the first place and thus not survivable against a capable opponent.

Putting it another way, the supersonic demands and range requirements are only really applicable for JH-XX in its stealthy, internal payload only configuration (at 55-60 tons) and that is the only configuration useful in high intensity environments where the opponent has intact air defences. Its MTOW of 80 tons would be used for less intensive missions or when the opposing side's air defences are already sufficiently degraded.

so, for a 55-60 ton TOW, stealth, internal payload only configuration, I envision JH-XX with a full internal fuel load of slightly over 20 tons, carrying 2 LRAAMs in its two side bays, and for a land attack mission would carry six JSM class 500kg weapons (3 tons) internally, or for a naval strike mission would carry two YJ-12s (assuming each is about 2-3 tons, that would be 4-6 tons) internally. I think that would allow for a combat range approaching 2000km, with some supersonic dash factored in for a couple hundred kms. It would be even better if WS-15 allowed it to supercruise as well, but that's probably asking for a bit too much.
 
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D

delft

Brigadier
Bltizo said:
How so? It is a bomber primarily, after all, it won't have to conduct any high alpha maneuvers, I imagine there should be very little disruption of airflow to its air intake during level flight.
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Air pressure is higher on the underside of a wing or in this case fuselage than on top. Having your air intake in the higher pressure area leads to more efficient propulsion and a lower fuel consumption.
 
T

Totoro

Major
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We don't have to talk about mtow if that's a vague limit open to debate. 150-180 kn engines, for a comparable role of f-111 would yield a plane of empty weigh equaling 28-34 tons. Using similar weight fraction one gets some 21-26 tons of internal fuel and possibly around 6-8 tons of external fuel for a combat mission. Scaling up the plane from f111's 21 tons empty to 28-34 tons would certainly make the internal weapon bays bigger, probably enough for two decently sized (2 tons?) missiles.

So mtow of such plane would, using the 2.1 factor similar to f111 and tu22m yield a plane of 59 to 71 tons mtow. cited mission perfomance for f111 was for a very loaded plane, less than 10% less than its mtow. So realistic long range mission might require TOW of 55-65 tons, while MTOW would be 60-70 tons.

we will see what ws-15 brings...
 
S

Scratch

Captain
I believe using / comparing F-111A vs Tu-22M as an extrapolating base for a notional JH-XX is a bit of a stretch. These two "base" planes are of a completely different category I think, which would bring up the question what we think JH-XX is ment to be in the first place.
The Aardvark is a heavy fighter-bomber, that, in weight numbers, is very similar to todays Su-34.
The T-22M, on the other hand, is a full blown (strategic) bomber comparable to the B-1.

If the JH-XX is to be a JH type, i.e. a (heavy) fighter-bomber, I believe F-111 / Su-34 is the category to think of.

If it's ment to be the, mostly tactical, heavy strike platform / workhorse, I think that and the stealth requirements negate a variable-geometry wing setup and also a variable inlet geometry. It will also be a 2 engine layout.
I guess the combination of all that will mean a top-speed below Mach 2.
In a Su-34 type setup the space between the nacelles, when slightly enlarged, should yield enough space for a usefull main weapons bay. And then some side bays on the outside. (?)
The only issue here is that the "Fullback's" range is probably on the low side.

So at best I think slightly larger than the aformentioned at 25t empty, 50t full is sensible for what I guess JH-XX to be.
To reach the required range, aerial refueling will be a requirement anyway in that part of the world, were distances are quiet significant.

The all aspect stealth to cover the egress will obviously eat into the performance as well. The IR suppression will put a price tag on engine performance. With range and top-speed limited, it would probably have to still go rather quick without afterburner I guess. Or be a full up VLO design.
 
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