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

[GTI]

How is cruising at mach 1.2-1.6 any more survivable than cruising high subsonically(M0.8-0.9),

Try

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(page 20) ultimately taken from a 2013 paper by the chief scientist of the US Air Force. It says that speed will be the only key to survivability, but with modest stealth measures, a high-supersonic vehicle is as survivable as a hypersonic one. Speed and [radar] LO are not incompatible, we’re not talking plasma sheath territory here. The combination of high mach and reduced RCS was demonstrated several decades ago.

it's not nearly fast enough to get you away from interceptors or SAM sites these days.

Exactly, we’re aligned. That’s why you’d need ultra long range stand-off weaponry. And why you’re VLO as well.

In fact, you could forget IR stealth because cruising at mach 1.2-1.6 would generate sufficient compression heating to light your aircraft up on any sufficiently advanced EOTS.

issue of ruining IR .. stealth

How much IR reduction would make you feel safe from the massive dual EOTS of the J-36? How far away do you think it needs to be for them to pick up an B-21, possibly a nice view of the engines from above (if it can fly higher)? Also knowing it has a robust kill chain in space, and flying around in the air for days on end like WZ-X? (I’m not going to relitigate the speed != stealth thing).

And the bomber doesn’t need to supercruise or dash the entire time. It would do it to get away from the J-36 (full-sized LockMart NGAD) and its kill web that are hunting it, relentlessly.

There's nothing preventing a subsonic bomber from doing the same, launch a couple of large hypersonic cruise missiles and go home, it also doesn't need a cranked kite planform, large flying wing do just fine with carrying long cruise missiles. H-20 doesn't have to fly directly over CONUS as you mentioned,

stuff like HACM is meant to have a range

Aren’t HGV’s longer ranged? Also, HACMs still typically need boosters. I’m not sure any of the USAF’s hypersonic projects (tested or theorised) can be launched from the IWBs of the B-2, let alone B-21. The PL-17 is already about 81% of a B-2’s bomb bay length!

PS: IMO, the new large drone is a good example. If supercruising solves all of your problems, then why even bother still building large subsonic flying wings especially one that is meant to overfly the enemy directly(While H-20 could just launch long range standoff weapons).

Extremely long loiter time. Massive surfaces perfect for mounting active/passive conformal arrays and antennae… There are a few in this thread who don’t seem to grasp the importance of strategic ISR - the kill web needs redundancy, PLARF needs eyes. IMO a supersonic H-20 is more likely than WZ-X having a meaningful strike or A2A role.

tl;dr: are you sure sacrificing ELO, IR stealth, range, affordability and payload capacity for the dubious advantages of supercruising is a good idea?

- Payload wouldn’t fit in a B-2’s bomb bay.

- The J-36 might still find you in IR spectrum (and radar), so best be fast enough to always keep it at a safe distance away, and possibly even run away from it if given a head start.

- The proposed lifting body cranked-kite planforms actually have greater internal space for fuel.

And like the chief scientist of the USAF said 12 years ago, subsonic speeds have low survivability:

 

[leonzzzz]

How is cruising at mach 1.2-1.6 any more survivable than cruising high subsonically(M0.8-0.9), it's not nearly fast enough to get you away from interceptors or SAM sites these days

Aside from the sortie rate and ETA, You are also squeezing hostile SAM's flight envelope by being faster and VLO.

VLO means late to respond and faster means early to exit AA range.

If you let the them to get a fire control lock on you well in range of their SAMs, then yeah the higher speed won't save you from SAM fire. But the whole point of VLO supersonic is to get either no lock or locked but out of range quickly.

 

[Tomboy]

Try

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(page 20) ultimately taken from a 2013 paper by the chief scientist of the US Air Force. It says that speed will be the only key to survivability, but with modest stealth measures, a high-supersonic vehicle is as survivable as a hypersonic one. Speed and [radar] LO are not incompatible, we’re not talking plasma sheath territory here. The combination of high mach and reduced RCS was demonstrated several decades ago.

Exactly, we’re aligned. That’s why you’d need ultra long range stand-off weaponry. And why you’re VLO as well.


How much IR reduction would make you feel safe from the massive dual EOTS of the J-36? How far away do you think it needs to be for them to pick up an B-21, possibly a nice view of the engines from above (if it can fly higher)? Also knowing it has a robust kill chain in space, and flying around in the air for days on end like WZ-X? (I’m not going to relitigate the speed != stealth thing).

And the bomber doesn’t need to supercruise or dash the entire time. It would do it to get away from the J-36 (full-sized LockMart NGAD) and its kill web that are hunting it, relentlessly.


Aren’t HGV’s longer ranged? Also, HACMs still typically need boosters. I’m not sure any of the USAF’s hypersonic projects (tested or theorised) can be launched from the IWBs of the B-2, let alone B-21. The PL-17 is already about 81% of a B-2’s bomb bay length!

Extremely long loiter time. Massive surfaces perfect for mounting active/passive conformal arrays and antennae… There are a few in this thread who don’t seem to grasp the importance of strategic ISR - the kill web needs redundancy, PLARF needs eyes. IMO a supersonic H-20 is more likely than WZ-X having a meaningful strike or A2A role.

- Payload wouldn’t fit in a B-2’s bomb bay.

- The J-36 might still find you in IR spectrum (and radar), so best be fast enough to always keep it at a safe distance away, and possibly even run away from it if given a head start.

- The proposed lifting body cranked-kite planforms actually have greater internal space for fuel.

And like the chief scientist of the USAF said 12 years ago, subsonic speeds have low survivability:

View attachment 154580

The USAF chief scientist says a speed of Mach 2-3 is required along with VLO to maintain high P(s), Mach 1.2-1.6 supercruise simply is not enough(As you can see how the blue line levels off at the end of M2/55K alt meaning if you want to go slower/lower you're going to need exponential increase in stealth performance over the already "aggressive signature"). If your suggesting H-20 to be a Mach 2+ supercruiser I guess sure, the data here do support it however the cost of such an aircraft is going to be otherworldly as a CBO report(

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) states that for a Mach 2.4 supercruiser that isn't even stealthy is already projected to cost more than twice as much as a subsonic VLO bomber with the same range/payload capacity. Now factoring in getting that aircraft to also come with VLO stealth and other signature enhancements. Resulting aircraft is also very large, according to that study its MTOW is estimated to be twice the subsonic VLO bomber's for the same range and payload capacity.


Having the bomber not cruise supersonically all the time comes with the issue that now you also have to optimise it for subsonic cruise which means variable wings. Concorde as an example was only efficient at supersonic speeds and was terribly inefficient at subsonic speeds. Engines capable of supercruise is also very inefficient at subsonic speeds(Concorde used turbojets), unless of course H-20 is meant to use VCE but that'll definitely push back H-20 by half a decade at the best estimate. This is also why the XB-70 was designed to just cruise at Mach 3 instead of the original proposal that called for it to cruise subsonically before doing a Mach 3 dash because they found out that it was actually more efficient to just have it supercruise all the way to the target and back.

There is also no way a Mach 2+ supercruising aircraft that large would be stealthy at all in the IR spectrum unless some novel way of suppressing IR signature was found. Even if they can't shoot you down, you are detectable enough that the enemy could always scramble fighters to force you to abandon your mission as commented in the same CBO report about the supercruising design.

How are they going to power such a large aircraft anyways(Remember a supercruising aircraft with similar range is projected to have a MTOW twice as large as a subsonic one), no known engine China has come close to powering such an aircraft unless they are going to go the janky way of having like 6 WS-15s(base WS-15s probably aren't even capable of efficient M2+ supercruise unless significantly modified) strapped to it. You are going to require a GE4(A ridiculously large and powerful turbojet meant for the B-2707 project) level engine for such an ambitious aircraft IMO.

This also contradicts what we know of the project so far, that tender we found was calling for a high bypass turbofan S-duct which is indicative of a subsonic ELO aircraft and not a supercruiser as high bypass turbofans are effectively incapable of supersonic flight due to efficiency massively dropping off past Mach 1. I believe we even saw H-20's intended engines being flight tested on a Y-20 here:

(Credits to @sunnymaxi)
Notice how large the engine is compared to the D-30KP-2s mounted aside it proves it's some kind of high bypass turbofan with a moderate bypass ratio in the 5-6 range.

As for weapons bay size, H-20 is projected to be larger than the B-2 by quite a bit due to ambitious range requirements. I believe it could be large enough to provide ample IWB space for long range weapons whether airbreathing hypersonic cruise missile, HGV or air launched BM even as a flying wing.

The thing is with current technology, it's just not feasible within a limited budget. As much as I too want to see a Mach 2 supercruising H-20, it just goes against what we know of the project and what is feasible.

 

[dom146352]

The USAF chief scientist says a speed of Mach 2-3 is required along with VLO to maintain high P(s), Mach 1.2-1.6 supercruise simply is not enough(As you can see how the blue line levels off at the end of M2/55K alt meaning if you want to go slower/lower you're going to need exponential increase in stealth performance over the already "aggressive signature"). If your suggesting H-20 to be a Mach 2+ supercruiser I guess sure, the data here do support it however the cost of such an aircraft is going to be otherworldly as a CBO report(

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) states that for a Mach 2.4 supercruiser that isn't even stealthy is already projected to cost more than twice as much as a subsonic VLO bomber with the same range/payload capacity. Now factoring in getting that aircraft to also come with VLO stealth and other signature enhancements. Resulting aircraft is also very large, according to that study its MTOW is estimated to be twice the subsonic VLO bomber's for the same range and payload capacity.

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would substantially reduce the cost difference per kilogram per kilometer of payload between subsonic and supersonic bombers.

 

[donnnage99]

There could be other designs of flying wings, contrary to most people's belief B-2/B-21's shape is not the most optimal for stealth as it's lambda wing structure from the back forms converging trailing edges which under certain condition could form corner reflectors from the rear, this also is why B-21 only has a single large V shaped trailing edge instead of B-2's many V shaped trailing edge.

A combination of EBG and RAS manipulates the surface radar wave to reflect upward into space at leading edges to avoid them hitting another converging leading edge. That's why you see Northrop Have Blue, a purely stealth demonstrator, have multiple almost 90 degree angles created from converging leading edges.

 

[donnnage99]

Latest satellite photo of a suspected H-20 on the ground? When it compares to the orange vehicle pulling it, the size seems pretty large. Or is it an super large UAV?

before posting check last couple pages. we can't have people posting the same thing asking the same questions every few pages or so.

 

[ACuriousPLAFan]

Some observations and inferences mentioned by the Guancha Trios based on the recent observation of that WZ-X at Malan in one of the latest ChaHuaHui podcast on Bilibili (minute 23:30 - minute 48:40):

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(Please note that they likely aren't necessarily talking about H-20 in-particular.)

Several key points:
#1 - The drone testing and evaluation base at Malan actually has multiple massive hangars with large main spans (widths). They described the spans of those hangars as "shocking".
#2 - China has no problem with developing and building something like the B-2 today (or, alternatively, a H-20-sized aircraft/manned and unmanned flying-wing aircraft with huge wingspans, ranges in the 5 digits of kilometers, and endurance in the 2 digits of hours).
#3 - The above point (#2) is especially when compared to the past when factors like flight control, engines, material science etc's development/maturity are yet to become satisfactory enough to enable such large-sized flying-wing aircrafts.
#4 - The flying-wing design is actually better suited for strategic reconnaissance/ISR UAVs than bombers, relatively speaking (where the various requirements for an ISR UAV isn't as "demanding" as a bomber would - Refer #7 and #8).
#5 - In flying-wing designs, it is actually preferable for the powerplant(s) (i.e. engines) to be placed as close to the aircraft's centerline axis as possible, due to the effects from the differential in engine power outputs on opposing sides (in multi-engine aircrafts) being actually much more impactful/damning in a flying-wing aircraft.
#6 - The IWBs on bombers should be future-proofed (or alternatively, should take future weaponry development in mind), where both payload weight capacity and payload size capacity is crucial (they listed the example where despite the Tu-22M is larger and much heavier than the Tu-16, they both have largely similar IWB sizes).
#7 - Having a bomber based on the flying-wing design means that multiple compromises would have to be made (to put it simply: flying wing design means shorter fuselage -> shorter IWB length -> IWB have to be expanded sideways -> engines have to be placed further away from aircraft centerline axis -> Problems/risks associated with #5, alongside impacts on cruising efficiency).
#8 - On the other hand, a flying-wing design reconnaissance/ISR UAV do not have the associated issues as mentioned above (#7) (namely, engine can be placed along the centerline axis, no IWB demand, radar/EO/IR sensor windows can be conformal to the aircraft body/skin, reduced thickness of the aircraft body etc), meaning that they are technically easier to be designed and developed.
#9 - "Modularity" (i.e. changing/swapping modules for different mission profiles) isn't as nice as it sounds.
#10 - Last-but-not-least, there is one key mention: One of the Horten Brothers' designs (I interpret this refers to the best if not one of the best) isn't being carried forward and realized in Germany or the United States, but in China. (I'm not sure which specific design(s) did they refer to.)

(For #7 - Just take a look at the engine and IWB layout arrangements of the B-2 versus the B-21.)

(Please do correct me if there are any information/points that I missed or mistaken from the podcast on that segment.)

One funny note - The Guancha Trios actually mentioned how @Deino is "calming" the outside (West-based) observers on the WZ-X (basically those observers were like "Look! Large flying-wing aircraft! H-20!", and @Deino be like "No no no, notice how the aircraft is much shorter in length? It's not a H-20, but a UAV").

 

[CMP]

Stupid question but given what the community knows so far, what is the H-20's most likely flight distance without refueling and estimated min and/or max for bomb carrying capacity? How does that compare to B2, B52, and B21 estimates? Forgive the ignorance.

 

[latenlazy]

Stupid question but given what the community knows so far, what is the H-20's most likely flight distance without refueling and estimated min and/or max for bomb carrying capacity? How does that compare to B2, B52, and B21 estimates? Forgive the ignorance.

If it can’t fly to Guam minimum there’s no point.

 

[Tomboy]

#10 - Last-but-not-least, there is one key mention: One of the Horten Brothers' designs (I interpret this refers to the best if not one of the best) isn't being carried forward and realized in Germany or the United States, but in China. (I'm not sure which specific design(s) did they refer to.)

I don't think there is any known Horten projects that aren't some sort of flying wings, however there were some unique design like the Horten parabola. Not sure how well that works with stealth though.