J-35 carrier fighter (PLAN) thread

[manqiangrexue]

My point about the engines is that I'd be surprised if the J-35 was lighter than an F-35 carrying comparable armaments and fuel.

Engines are a very small percentage of a fighter jet's weight. China has said before that while the F-22 an F-35 are welded, the massive application of 3D printing coupled with increased composite incorporation to the airframes of the J-20 and J-35 save a great deal of weight and would much more than offset some 350kg in the J-35/F-35 comparison. I don't remember specifics but I remember that the number was shockingly high for many people when it was revealed.

 

[taxiya]

My point about the engines is that I'd be surprised if the J-35 was lighter than an F-35 carrying comparable armaments and fuel.

J-35's manufacturing methods reduce lots of weight than F-35 could do. The following example is one-piece wing/fuselage integral part, it reduces weight by 38% compared to traditional method (welding or fixers). There are two such pieces per plane. The overall weight reduction of the whole wing/fuselage is 26%.

We also know that the bulkhead around the weapons bay is 3D printed titanium, again it reaches equal strengh with lighter (thiner) structures compared to tranditional method (forging and welding).

 

[Deino]

Another image of the J-35 mockups at the carrier aviation training facility.

but still the two mock ups most likely?!

 

[by78]

but still the two mock ups most likely?!

They probably don't need more at this point.

 

[Deino]

They probably don't need more at this point.

would be interesting to know for sure

 

[by78]

would be interesting to know for sure

Me too, and I'm also interested in knowing J-35's turning radius while taxiing, as it has a great impact on flight deck handling and launch/recovery cycles.

 

[ACuriousPLAFan]

The F-4 Phantom II was the heavy interceptor and multirole air superiority/attack aircraft of its era. The sources I can find online place the empty weight of USN F-4B/J variants in the range of 12,700-13,500kg, somewhat less than today's "medium" F/A-18E/F Super Hornet at 13,700-14,500kg. Super Hornet is heavier despite the Phantom's two J-79 engines weighing 1300kg(!) more than Super Hornet's two F414s. If the F-4 Phantom II were re-engined with F414, this "heavy" aircraft would weigh 11,400-12,200kg empty. Incorporate the half-century of materials and manufacturing advancements that Super Hornet benefits from and one could undoubtedly reduce the weight of a notional reborn Phantom by a further several hundred kilograms.

The F-14 is indeed an outlier. But that outlier should not distract from the clear record of carrier-based aircraft becoming heavier and heavier over time. The "light" carrier-based aircraft of the past have disappeared while the "medium" aircraft of today are the heavyweight aircraft of yesteryear. I don't know if USN's NGAD program will deliver an aircraft of equal or even greater weight than the F-14, but it is very likely to come in well above the 15,700kg of F-35C. Boeing's own 2009 NGAD concept had a notional empty weight of 18,000kg.

As such I think it is entirely reasonable to question the wisdom of PLAN investing in J-35 as the centerpiece of its future carrier air wing. My own view is that I think it makes sense for PLAN to take this relatively modest, low-risk approach to delivering a modern, VLO carrier-based combat aircraft and that such an aircraft, paired with upgraded J-15, will suffice in the medium-term, but that it will ultimately need to be augmented by a probably larger, higher-performance platform to debut by the late 2030s.

One of the key considerations is the weight limitations on carrier-based aircrafts that the EMALS on Fujian and future Chinese CVs can launch. This also heavily depends on the maximum available energy that can be provided for launching carrier-based aircrafts, and the intended launch speed for said carrier-based aircrafts.

For instance, the EMALS on Ford is said to be capable of launching (at most) a 45-ton aircraft at a speed of 130 knots.

The heaviest carrier-based aircraft to actually enter active service is the A-3 Skywarrior, with a max takeoff weight of ~37.2 tons. The F-14 Tomcat has a max takeoff weight of ~33.7 tons. In the meantime, the heaviest aircraft ever (catapult-) launched from a carrier is the F-111B at nearly 40 tons. The F-111B never entered service, whereby its role was then replaced by the F-14.

Assuming that the EMALS on Fujian has the exact same parameters as the EMALS on the Ford-class, that means future carrier-based aircrafts shouldn't weigh anywhere significantly more than 40 tons.

Besides, there's the problem regarding the size of carrier-based aircrafts, which translates directly to aircraft footprints on both flight and hangar decks. Nobody is going to fit a B-52-sized aircraft on a carrier, even if the wings can be made to fold more than once (which also adds to more weight and greater complexity).

 

[Lethe]

One of the key considerations is the weight limitations on carrier-based aircrafts that the EMALS on Fujian and future Chinese CVs can launch. This also heavily depends on the maximum available energy that can be provided for launching carrier-based aircrafts, and the intended launch speed for said carrier-based aircrafts.

For instance, the EMALS on Ford is said to be capable of launching (at most) a 45-ton aircraft at a speed of 130 knots.

The heaviest carrier-based aircraft to actually enter active service is the A-3 Skywarrior, with a max takeoff weight of ~37.2 tons. The F-14 Tomcat has a max takeoff weight of ~33.7 tons. In the meantime, the heaviest aircraft ever (catapult-) launched from a carrier is the F-111B at nearly 40 tons. The F-111B never entered service, whereby its role was then replaced by the F-14.

Assuming that the EMALS on Fujian has the exact same parameters as the EMALS on the Ford-class, that means future carrier-based aircrafts shouldn't weigh anywhere significantly more than 40 tons.

Besides, there's the problem regarding the size of carrier-based aircrafts, which translates directly to aircraft footprints on both flight and hangar decks. Nobody is going to fit a B-52-sized aircraft on a carrier, even if the wings can be made to fold more than once (which also adds to more weight and greater complexity).

The performance of the catapult system is certainly one limiting factor on the weight and design of carrier-based aircraft. Footprint dimensions are another, relating to hangar space, flight deck management, elevators. A further constraint is the requirement to bring the aircraft back aboard safely. Hence the emphasis on maintaining full controllability at the lowest possible airspeed requiring solutions like the F-14's variable geometry wing, the canards on J-15, the enlarged LERXs on Super Hornet, etc. Several aircraft in USN service, including the F-14, have had "bring back" limits whereby they simply cannot land (on a carrier deck...) with certain combinations of payload and fuel state. At least on paper, EMALS offers the potential (to what extent it has been realised is another question) to loft heavier aircraft into the air while subjecting the pilots and airframe to lower peak loads as the total force imparted is more evenly distributed over the entire catapult run, rather than front-loaded as with a Steam catapult. I believe that the Advanced Arresting Gear system on Ford is intended to offer similar benefits (i.e. reduced peak loads) upon landing though, again, who knows how much of this has survived contact with reality, given the tortuous development of AAG in particular.

 

[Totoro]

Is there an estimate for the empty weight of J-35? Considering that the J-35 is a twin engine aircraft, it'd be surprising if the J-35 is significantly lighter than the F-35C.

Sure, here's my personal estimate on the empty weight of J-35.

FC-31 was advertised as having MTOW of 25 tons. Later, possibly with better engines, that got changed to 28 tons.

MiG-29 had empty weight of 11 tons and MTOW of 18 tons.
MiG-29M and MiG-35, the redesigns with more powerful engines and new internal structure had empty weight of anywhere from 11 to 13 tons and MTOW of 24.5 to 26.5 tons. Exact values are not clear and are not properly sourced.

F-35A has empty weight of 13.1 tons and mtow of 32 tons
F-35C has empty weight of 15.7 tons and mtow of 32 tons.

Rafale C has empty weight of 9.9 tons and mtow of 24.5 tons
Rafale M has empty weight of 10.6 tons and mtow of 24.5 tons

Using all those values to extrapolate a weight estimate, and given that J-35 is a larger and heavier plane than FC-31 due to its role,
I'd estimate J-35 to have an empty weight anywhere from 12 to 15 tons.
With closer to 12 rather than 15 if its design is not meant to haul a lot of heavy weapons around and if it's not designed to last for more than 6000 hours or so.

Since I do believe that to be likely, then I can further narrow the weight estimate down to 12 to 14 tons empty. MTOW is unknown but I see no reason for it to be below 28 tons, given it's launched by catapult. Operationally, of course, it's almost never gonna reach 25 tons, if that.

 

[Atomicfrog]

Sure, here's my personal estimate on the empty weight of J-35.

FC-31 was advertised as having MTOW of 25 tons. Later, possibly with better engines, that got changed to 28 tons.

MiG-29 had empty weight of 11 tons and MTOW of 18 tons.
MiG-29M and MiG-35, the redesigns with more powerful engines and new internal structure had empty weight of anywhere from 11 to 13 tons and MTOW of 24.5 to 26.5 tons. Exact values are not clear and are not properly sourced.

F-35A has empty weight of 13.1 tons and mtow of 32 tons
F-35C has empty weight of 15.7 tons and mtow of 32 tons.

Rafale C has empty weight of 9.9 tons and mtow of 24.5 tons
Rafale M has empty weight of 10.6 tons and mtow of 24.5 tons

Using all those values to extrapolate a weight estimate, and given that J-35 is a larger and heavier plane than FC-31 due to its role,
I'd estimate J-35 to have an empty weight anywhere from 12 to 15 tons.
With closer to 12 rather than 15 if its design is not meant to haul a lot of heavy weapons around and if it's not designed to last for more than 6000 hours or so.

Since I do believe that to be likely, then I can further narrow the weight estimate down to 12 to 14 tons empty. MTOW is unknown but I see no reason for it to be below 28 tons, given it's launched by catapult. Operationally, of course, it's almost never gonna reach 25 tons, if that.

It's always fun to compare numbers but it's very hard to get real conclusions only with empty weight and MTOW numbers even if they are true.

Taking into account other variables, comparing empty weight is kinda flawed and it's better to compare payload and range vs mtow than empty weight... Some aircraft need quite a lot of fuel in the tank for cooling just to have their avionics running on the ground and it's not taked into account in the empty weight..

An airplane that cool is avionics with air or separated system will have an empty weight disadvantage in number compared to one that use fuel for cooling. Carrier aircrafts tend to have bigger emptyweight because of strutural needs and arresting hook.

For example, we can take F-35 empty weight with a grain of salt... it's cooling most of its internals system with fuel and while you can weight it empty, a good amount of fuel is required to make it works and need to stay in the tank. So this dead weight is not accounted for.

Even fuel temperature is troublesome when refueling on the ground because it change the time for the avionics to work before liftoff. Imagine taking a pause during liftoff preocedure because your computer take longer time to boot... or think about your avionics starting to cook when landing because you are below minimum requirement.

We forget that quite a portion of fuel need to be preserved for landing when looking at fuel capacity of an aircraft. We talk about multiple thousands of pounds of fuel to be able to do a turn around or having some time for loitering. Some aircraft need a lot more than other because of low speed consumption or minimum fuel requirement for cooling.

Quite hard to compare stuff....