Due to what we talked about in last substack, I always expected 6th gen fighter to be really large. I had been expecting a twin-engined aircraft like J-20, but with more powerful engines. I’ve been expecting engines thrust to jump 25% from 5th to 6th generation. The more powerful engine will allow larger aircraft that can carry more fuel, more electronics and possibly more payload. For payload, a big question is just how much payload is needed if Loyal wingmen are expected to carry missiles and fly in front of the piloted fighter jet? 6th gen aircraft could just retain J-35A sized internal weapon bay while using most of the humongous interior space for carry electronics and fuel store all over the aircraft.
For the future air warfare, it’s always been said to think about the full platform rather than just a single aircraft. Will manned aircraft still need to carry much attack payload if UCAVs function as attritable bomb/missile trucks. Will the UCAVs be able to keep up in cruising speed and range with fighter jet? In order to achieve that level of performance and be stealthy, they need to be quite large themselves and that will increase cost of that platform. At this point, I don’t think we have seen any UCAVs that could meet these criteria. Certainly, getting rid of spacing & equipment needed to service the pilot(s) allow UCAVs to be smaller and a lot cheaper than the manned aircraft. But it remains to be seen just what they will actually look like.
Which brings us to the moment 3 engine design came about in late November when this was posted by a well known Weibo poster on PLA stuff.
It was followed by the rumor that J-XD will have side-by-side seating like on Su-34. The implication of a such design is a very large fight bomber type of design that will carry a lot of electronics (and have the plumbing and space needed for cooling) as well as fuel needed to go long distance and/or have very long loiter time. While I had previously expected an aircraft with 2000-2500 km combat radius, I had to re-adjust my expectations to a 3000km+ combat radius aircraft. It will be one that favors higher T/W ratio for better supersonic maneuverability and cruise performance over control surfaces that improve subsonic turn rates, but could hurt all aspect stealth. It will be one that likely eschews SRAAM & guns to just carry stealthy LRAAM and attack missiles. Having dual operators side by side naturally makes it more of a command and control type of aircraft that could also carry out attack missions. It will likely operate as a forward AWACS directing a whole bunch of drones and other manned aircraft. Side by side cockpit also likely allow for more interior space and comfort for pilots on long missions. If it needs to fly to Guam or Darwin or Diego Garcia or close to Alaska, then crew comfort has to be a consideration. Similarly, if PLAAF is expecting incoming B-21s from Alaska, then it will need J-XD to perform interception missions far out with a whole bunch of UCAVs. The UCAVs don’t need to consider crew comfort, but J-XD does need to. Basically, this is the ideal aircraft to fight a Westpac conflict where B-2/21s are around, but USAF doesn’t have anything else with similar to really threaten China’s homeland.
And then there is the question of just how much power such an aircraft needs
From a long time ago, it was obvious that as time went out, we needed more power. The future fighter jet need power for radar, electronic warfare, computation, DEW and more.the curious part is that America actually went backward from F-22 to F-35 in terms of power requirement. It got so bad that recent F-35 Block 4 upgrade with 80kW PTMS will likely be delayed to 2032! A lot of that has to do with F-35 not being designed with higher energy consumption in mind.
Interesting enough, USAF’s NGAD project did plan with the expectation of need MW level of power. Now, that is important for radar, EW, communication, DEW and other systems. So, if you think about the type of technology needed to power and then compute the most powerful ever radar using the latest RF technology, then having 1 MW of power, doesn’t seem so crazy. Especially on an aircraft that will have a lot of interior space, surplus engine power and very large nose. In fact, it would provide 60x the amount of power that F-35’s APG-81 currently provides. But that is the difference of having latest GaO-on-Diamond MMIC T/R Modules vs early 2010s GaA modules. Instead of spotting B-21s from 15 km out, you might detect it with a UHF radar carrying drone and then narrow beam it from 70 km out for weapon quality tracking data. This is what the latest RF, computation and AI technology would bring to such a large aircraft.
Which brings us to today and this came out.
and then this
We managed to get what looks to be photos for 2 6th generation fighter jet program’s first flight for the same flight. Based on time stamping, it looks like SAC’s flight happened a few days ago.
CAC to me is the more interesting program. It kind of idealizes the things that I’ve been looking for in 6th gen. It is a true Westpac fighter. With the 3 engines, it will have second Island Chain range and possibly more. It should be able to lead attack missions to Guam, Darwin, Diego Garcia and possibly even Alaska with refueling. It can hang in the air for a long time waiting for B-21s to come over. It has the perfect size for carrying large amount of fuel and electronics + power package needed to do these longer range missions while also having enough power to cruise away at High Mach 2. If any aircraft will have the power needed for Direct Energy Weapon, this is it. It will have the space needed to carry large amount of computation power to do sensor fusion across a large group of aircraft (mostly UCAVs) and also direct electronic warfare against adversaries. The amount of power required for future air combat is astronomical. It will overwhelm anything we have in 5th generation by a magnitude.
Not sure what's the point of a 3rd engine nozzle, unless they have different capabilities
Given generally defensive posture of PRC and need to control large airspace vs expected eventual US hostility, there are a lot of things to explore for 6G which are not evident here. Including very-high-altitude subsonic for patrol, very-high-altitude-fast for getaway, and especially distributed radar. Might just be looking at a design for the purpose of exploring the tailless aerodynamic configuration.
It’s quite similar to the flight control company demo from Zhuhai last year