KJ-600 carrierborne AEWC thread

[Blitzo]

There is no risk reduction here. Everything for the PLAN is new as far as an AEW aircraft is concerned in terms of integrating various systems together. And as far as turbofans go, the PLAN is not exactly new to those. A suitable one could be the ones used on the L-15, or another turbofan purchased from Russia. The point of choosing a turboprop isn't about risk reduction, it's about fuel efficiency.

Relative to developing a turbofan powered carrier AEW&C airframe, I think pursuing the E-2 configuration turboprop driven airframe does have reduced risk. For the record, I'm talking about the physical aircraft (airframe, powerplant, flight controls) rather than the radar system or combat management system aboard the aircraft.

Not only do they have relatively proven turboprops (the ones used aboard Y-9 family) to derive a powerplant from for H-600, but they also have a suitable airframe in the form of Y-7 which is appropriate to substantially modify into a new aircraft for carrier operations. Furthermore, this configuration being a proven one that the USN has been using for decades also likely means it is perceived as more proven for the PLA as well.

OTOH, the PRC aerospace industry do not have an appropriate turbofan powered airframe that they could adapt for carrier operations nor do they have an indigenous (which while not essential, it would certainly be preferable) turbofan in that class available at present that could be derived for a turbofan for a carrier AEW&C.



I think if the PRC aerospace industry happened to have the right pieces that already happened to be in place to allow relatively lower risk development of a turbofan powered AEW&C then they might have considered it in lieu of the E-2 configuration they've chosen. After all, we've seen the PLA take on certain new directions which could be perceived as higher risk but which makes sense given potential benefits of success as well as enjoying the fruits of preceding R&D (e.g. going for EM catapults rather than steam).
However for the carrierborne AEW&C project I think the risk of developing a turboprop driven E-2 configuration aircraft would've been perceived as much lower than developing a turbofan driven aircraft.

Developing a turboprop driven, E-2 configuration carrier AEW&C will be new for the PLA and have an amount of risk -- but developing a turbofan driven carrier AEW&C will also be new for the PLA and likely carry higher risk considering the available existing powerplants and existing airframes they had to work with not to mention choosing an AEW&C configuration that does not have the long service history that the E-2 does.

 

[gelgoog]

I am unsure if in the long run these kinds of radar platforms make sense though. I think something like a drone would probably work better.

 

[Iron Man]

Relative to developing a turbofan powered carrier AEW&C airframe, I think pursuing the E-2 configuration turboprop driven airframe does have reduced risk. For the record, I'm talking about the physical aircraft (airframe, powerplant, flight controls) rather than the radar system or combat management system aboard the aircraft.

Not only do they have relatively proven turboprops (the ones used aboard Y-9 family) to derive a powerplant from for H-600, but they also have a suitable airframe in the form of Y-7 which is appropriate to substantially modify into a new aircraft for carrier operations. Furthermore, this configuration being a proven one that the USN has been using for decades also likely means it is perceived as more proven for the PLA as well.

OTOH, the PRC aerospace industry do not have an appropriate turbofan powered airframe that they could adapt for carrier operations nor do they have an indigenous (which while not essential, it would certainly be preferable) turbofan in that class available at present that could be derived for a turbofan for a carrier AEW&C.



I think if the PRC aerospace industry happened to have the right pieces that already happened to be in place to allow relatively lower risk development of a turbofan powered AEW&C then they might have considered it in lieu of the E-2 configuration they've chosen. After all, we've seen the PLA take on certain new directions which could be perceived as higher risk but which makes sense given potential benefits of success as well as enjoying the fruits of preceding R&D (e.g. going for EM catapults rather than steam).
However for the carrierborne AEW&C project I think the risk of developing a turboprop driven E-2 configuration aircraft would've been perceived as much lower than developing a turbofan driven aircraft.

Developing a turboprop driven, E-2 configuration carrier AEW&C will be new for the PLA and have an amount of risk -- but developing a turbofan driven carrier AEW&C will also be new for the PLA and likely carry higher risk considering the available existing powerplants and existing airframes they had to work with not to mention choosing an AEW&C configuration that does not have the long service history that the E-2 does.

The Y-7 is grossly inappropriate for a carrier-based AEW/C aircraft. I don't think you would have said that had you compared the sizes of the E-2 and Yak-44 to a Y-7 beforehand. It is simply not sensible to "substantially modify" something that large and simultaneously unsuited for catapult ops into a compact carrier-based AEW/C plane. The H-600 mockup also looks nothing like a substantially modified Y-7 but rather a ground-up new design modelled after (or at least inspired by) the E-2 and Yak-44. And just because a turboprop is used on the E-2 doesn't mean there is any kind of risk reduction when designing the H-600 using a turboprop; it would be even worse if you are talking about shoehorning a bastardized Y-7 into the role. As far as the PRC aerospace industry is concerned, I have no doubt that they considered the merits of turboprop vs turbofan in detail and came to the exact same conclusion that both the US and the Soviets did.

 

[Intrepid]

Little novelty about E2 is both props rotate in the same direction this is abnormal and causes the aircraft to be eccentric with power changes.

This is normal for aircraft bigger than general aviation.

 

[TerraN_EmpirE]

The reason for a turboprop over a turbofan is as simple as fuel efficiency, no other explanation needed. The turboprop is far more efficient at low to medium airspeeds than a turbofan, which allows the AEW aircraft to loiter on station far longer than the same aircraft with turbofans. If this were not the case I'm certain the US and Soviet navies would have used/switched to turbofan AEW aircraft long ago.

The Soviet navy never had a carrier capabilities beyond The Kuznetsov which was a very recent development of the late late early 1980s early to mid 1990s. As such they are a very very poor basis of comparison. The vast majority of there Carrier AEW being very recent Rotary wing.

The E2 was developed in the 1960s
Since then the USN has studied and run replacement programs for the E2 series including Jet based AEW a number of times the biggest attempt being the CSA which Lockheed Martin proposed a COD Viking and AEW Viking. The main issues being that the Navy wanted to spend its funding elsewhere and Congress was in the early 90s looking for a "Peace Dividend" investing in even a massive redesign of C2 E2 was subject to that cutting. Recently the Navy finally started a replacement of C2 for V22.

The Y-7 is grossly inappropriate for a carrier-based AEW/C aircraft. I don't think you would have said that had you compared the sizes of the E-2 and Yak-44 to a Y-7 beforehand.

There is a degree of reasonability here. Y7 is larger than optimum. Then again even on a super carrier E2 takes up a large amount of deck space. Even V22 on deck prevents large amount of deck use.

Not only do they have relatively proven turboprops (the ones used aboard Y-9 family) to derive a powerplant from for H-600, but they also have a suitable airframe in the form of Y-7 which is appropriate to substantially modify into a new aircraft for carrier operations. Furthermore, this configuration being a proven one that the USN has been using for decades also likely means it is perceived as more proven for the PLA as well.

In a way what they built was a kitbash of Y7 emulating E2. But the PRC in this case I think was looking to follow E2 as close as they could.

I am unsure if in the long run these kinds of radar platforms make sense though. I think something like a drone would probably work better.

That appears to be the next tract of all AEW not just Carrier based. The evolution of computers, Data links, Low Observable, Long range intigrated Air defense system with equally long range missiles make manned AEW more and more risky and less effective.

 

[Blitzo]

The Y-7 is grossly inappropriate for a carrier-based AEW/C aircraft. I don't think you would have said that had you compared the sizes of the E-2 and Yak-44 to a Y-7 beforehand. It is simply not sensible to "substantially modify" something that large and simultaneously unsuited for catapult ops into a compact carrier-based AEW/C plane. The H-600 mockup also looks nothing like a substantially modified Y-7 but rather a ground-up new design modelled after (or at least inspired by) the E-2 and Yak-44.

The JZY-01 is thought to have been derived from the Y-7, but let's set this aside for now and presume that H-600 has no influence from Y-7/was not derived from it etc.

And just because a turboprop is used on the E-2 doesn't mean there is any kind of risk reduction when designing the H-600 using a turboprop; it would be even worse if you are talking about shoehorning a bastardized Y-7 into the role. As far as the PRC aerospace industry is concerned, I have no doubt that they considered the merits of turboprop vs turbofan in detail and came to the exact same conclusion that both the US and the Soviets did.

I've been talking about the airframe+powerplant. If they wanted a turbofan powered AEW&C, I don't think anyone believes they would use the same airframe as what the E-2/H-600 uses -- and choosing a new airframe configuration vs the proven E-2 arrangement adds risk. This is in addition to having a viable powerplant that they could adapt for it.


Of course, I fully agree that turboprop driven aircraft have their advantages for a carrier based AEW&C and is almost certainly one of the reasons for going for a turboprop driven AEW&C.
But I believe the lower risk of developing a turboprop driven airframe similar to the E-2 was also a factor for the final design they went for.

 

[Iron Man]

The Soviet navy never had a carrier capabilities beyond The Kuznetsov which was a very recent development of the late late early 1980s early to mid 1990s. As such they are a very very poor basis of comparison. The vast majority of there Carrier AEW being very recent Rotary wing.

The Yak-44 was developed with the Ulyanovsk class in mind, which in terms of flight deck size and flight ops was very similar to the Nimitz class, so the basis of comparison is perfectly appropriate as far as ships are concerned. As far as range and fuel efficiency is concerned, it's a matter of physics. Turboprops outperform turbofans at the speeds at which a carrier-based AEW/C aircraft is expected to fly. And in terms of aircraft design, the endurance of a given AEW/C design is one of the most if not the most paramount design criterion. Which means if you're going to design a carrier-based AEW/C aircraft, you will choose turboprop regardless of whether you're American or Russian. I have no doubt it is a pain in the ass to operate a relatively weak turboprop-engined, wide-winged aircraft on a flight deck filled with overpowered jet fighters, so the bar for their inclusion IMO was always going to be pretty high. Despite that both countries chose very similar designs. Why? Because wide, thin (high aspect ratio) wings combined with turboprops allow you to maximize fuel efficiency. And fuel efficiency in an AEW/C is what it's all about.

The E2 was developed in the 1960s
Since then the USN has studied and run replacement programs for the E2 series including Jet based AEW a number of times the biggest attempt being the CSA which Lockheed Martin proposed a COD Viking and AEW Viking. The main issues being that the Navy wanted to spend its funding elsewhere and Congress was in the early 90s looking for a "Peace Dividend" investing in even a massive redesign of C2 E2 was subject to that cutting. Recently the Navy finally started a replacement of C2 for V22.

No. The Viking AEW was a LM-funded proposal to the USN which was not solicited by any USN requirement to replace the E-2 with a specifically turbofan-based AEW. The USN wasn't even remotely interested in the concept.

The JZY-01 is thought to have been derived from the Y-7, but let's set this aside for now and presume that H-600 has no influence from Y-7/was not derived from it etc.

Right, and the PLAN rejected the JZY-01. If it were all about risk reduction, an entirely brand new design certainly doesn't seem to be lower risk than a modification of an established plane. In words, the Y-7 is as I said, unsuitable for modification into a carrier-borne AEW.

I've been talking about the airframe+powerplant. If they wanted a turbofan powered AEW&C, I don't think anyone believes they would use the same airframe as what the E-2/H-600 uses -- and choosing a new airframe configuration vs the proven E-2 arrangement adds risk. This is in addition to having a viable powerplant that they could adapt for it.


Of course, I fully agree that turboprop driven aircraft have their advantages for a carrier based AEW&C and is almost certainly one of the reasons for going for a turboprop driven AEW&C.
But I believe the lower risk of developing a turboprop driven airframe similar to the E-2 was also a factor for the final design they went for.

No, I think they would use a very similar airframe, regardless of choice of turboprop or turbofan. See my answer to terran_empire above. Again, outside of the PLAN obtaining the E-2's blueprints, there is no risk reduction associated with a turboprop over a turbofan, especially in a clean-sheet design for which the PLAN has no prior experience. Just because you can observe the external characteristics of an E-2 doesn't mean you somehow reduced any risk for the H-600 program by choosing a turboprop, just because the E-2 uses it.

 

[Blitzo]

Right, and the PLAN rejected the JZY-01. If it were all about risk reduction, an entirely brand new design certainly doesn't seem to be lower risk than a modification of an established plane. In words, the Y-7 is as I said, unsuitable for modification into a carrier-borne AEW.

To my knowledge the JZY-01 was not intended to be an airframe intended for service but a demonstrator..

No, I think they would use a very similar airframe, regardless of choice of turboprop or turbofan. See my answer to terran_empire above. Again, outside of the PLAN obtaining the E-2's blueprints, there is no risk reduction associated with a turboprop over a turbofan, especially in a clean-sheet design for which the PLAN has no prior experience. Just because you can observe the external characteristics of an E-2 doesn't mean you somehow reduced any risk for the H-600 program by choosing a turboprop, just because the E-2 uses it.

Okay, well in that case the underlined part would explain where our opinions differ.

I personally do not think the airframe of a turbofan powered AEW&C would have a similar configuration to E-2/H-600, partly because I cannot think of any turboprop (or propeller) driven aircraft which had turbofan (or even jet) propelled variants and enjoy meaningful service lives. Things like wing sweep, landing gear arrangement (which in turn could have consequences for fuselage diameter), would likely all be rather different for a turbofan "variant" of H-600 such that it would be a different aircraft.

 

[Iron Man]

To my knowledge the JZY-01 was not intended to be an airframe intended for service but a demonstrator..

Well, you can't have your cake and eat it too. Either it was an attempt to adapt the Y-7 to a carrier-borne AEW role, in which case it failed and my point remains, or it was just a technology demonstrator, in which case the association with the Y-7 is irrelevant to the entire discussion.

Okay, well in that case the underlined part would explain where our opinions differ.

I personally do not think the airframe of a turbofan powered AEW&C would have a similar configuration to E-2/H-600, partly because I cannot think of any turboprop (or propeller) driven aircraft which had turbofan (or even jet) propelled variants and enjoy meaningful service lives. Things like wing sweep, landing gear arrangement (which in turn could have consequences for fuselage diameter), would likely all be rather different for a turbofan "variant" of H-600 such that it would be a different aircraft.

The wing sweep depends on the aircraft's intended role/speed, not the engine. Swing wing fighters are perfect examples, being turbofan-driven aircraft yet with highly unswept modes for maximum lift and fuel efficiency, and highly swept modes for high speed dashes, which an AEW/C aircraft will never experience. As for the landing gear differences, they really wouldn't amount to much at all. If you are claiming that the landing gear would be located in the fuselage for a turbofan AEW/C instead of underneath the turboprop housing, maybe, maybe not. Even if they were located in the fuselage you would still see the same wide, thin, high aspect ratio wing, the same thin fuselage with maybe a bulge at the bottom rear for the landing gear (or not even), and the same multiple stubby aft vertical stabilizers which are an inevitable consequence of the radar dish. In other words, a turbofan-driven AEW/C with the same appearance as the E-2 and the Yak-44. Which again, still gives you no risk-reduction at all because you don't have access to the blueprints for either of these aircraft, so you are starting with a clean-sheet design regardless of whether you chose turboprop or turbofan.

 

[Blitzo]

Well, you can't have your cake and eat it too. Either it was an attempt to adapt the Y-7 to a carrier-borne AEW role, in which case it failed and my point remains, or it was just a technology demonstrator, in which case the association with the Y-7 is irrelevant to the entire discussion.

I think my original point was that H-600 could be substantially modified from the Y-7. At this stage we don't yet know just what exactly H-600 will look like and how much commonality it has with JZY-01, however it almost certainly would have been informed by JZY-01.

The wing sweep depends on the aircraft's intended role/speed, not the engine. Swing wing fighters are perfect examples, being turbofan-driven aircraft yet with highly unswept modes for maximum lift and fuel efficiency, and highly swept modes for high speed dashes, which an AEW/C aircraft will never experience. As for the landing gear differences, they really wouldn't amount to much at all. If you are claiming that the landing gear would be located in the fuselage for a turbofan AEW/C instead of underneath the turboprop housing, maybe, maybe not. Even if they were located in the fuselage you would still see the same wide, thin, high aspect ratio wing, the same thin fuselage with maybe a bulge at the bottom rear for the landing gear (or not even), and the same multiple stubby aft vertical stabilizers which are an inevitable consequence of the radar dish. In other words, a turbofan-driven AEW/C with the same appearance as the E-2 and the Yak-44. Which again, still gives you no risk-reduction at all because you don't have access to the blueprints for either of these aircraft, so you are starting with a clean-sheet design regardless of whether you chose turboprop or turbofan.

What you've just described to me sounds like a very different aircraft in configuration and aerodynamics to the E-2/H-600, so we will just have to agree to disagree here.