Chengdu J-20 5th Generation Aircraft News & Discussions

[Pepsi Cola]

Those 3 IL-78s were bought simply to be studied. The future PLAF refueling capability would be on the Y-20 tanker variant.

"PLAAF is not as capable as the US in terms of mastery of the skills involved."
and what is your support for that claim? I can understand if you claim PLAF is technologically inferior, but mastery of the skills? How do you even measure that?

 

[cirr]

So J-20's AESA radar is GaN-based.

 

[randomradio]

My bad. I will rephrase my original thoughts. The original intent for the J-20 was to have less dependency on air refueling than Western fighters primarily because the PLAAF is not as capable as the US in terms of mastery of the skills involved.

Air refueling is not easy like everyone thinks it is.

The PLAAF's air refueling fleet is drogue equipped. This method has serious limitations in terms of refueling rates which affects how many aircrafts, even though they maybe small fighters, per event. Drogue delivers a lower rate of fuel flow than probe. Even though the receiver aircraft is a small fighter, it still consumes its own fuel while it is taking on fuel.

The US uses two methods: probe and drogue.

The probe method delivers a higher rate of fuel flow which is necessary for large receivers like the bombers and cargo jets.

The US Navy is an expeditionary force that must be as self reliant as possible uses the drogue method. Its lower fuel flow rate is adequate for its fleet of small aircrafts which came from aircraft carriers.

Using the US as example. The probe method can transfer up to 6,000 lbs/min. The drogue method is up to 2,000 lbs/min.

You are using incorrect terms.

What the USAF uses is called Flying Boom. Probe-and-drogue is the term that's used as shown in the below pictures.

You forget that 3 aircraft can be refueled at a time using probe-and-drogue.

And to make up for the potential lack of refuelers, the USN also uses buddy refueling, that the USAF can't.

Similar to Flankers.

So drogue offers more flexibility. A J-11 can easily be modified to refuel a J-20. This makes your assertion wrong.

The J-20's size is no accident. The PLAAF realized its shortcomings in the air refueling area, but the need to have a 5th gen platform outweighs the need to have a comprehensive air refueling capability.

As usual, you underestimate your adversary.

How many air refueler modified IL-78s does the PLAAF have in order to support a typical four-ship sortie to patrol the SCS, for example ?

You don't need any. In case it is necessary, a buddy refueler can be used.

A Su-30MKI can conduct surveillance around the A&N Islands for 30 minutes operating from an airbase on the mainland 1700-1800Km away, without requiring support from tankers or from the island infrastructure. But it can do that while carrying a surveillance pod alone. The J-20 has more fuel in comparison, along with possibly more efficient engines, while carrying weapons internally.

Even a J-11 should be able to comfortably stay over the Spratlys for an hour taking off from Hainan.

And now that they are building military infrastructure on disputed islands, the distance has reduced considerably.

You are talking about possessing an advantage that's irrelevant for your adversary. In fact, your reliance on refueling may be your biggest disadvantage. Why don't you look up basic open source information about the new PCA and why the USAF wants the aircraft to have very long range range.

So J-20's AESA radar is GaN-based.

Most definitely. GaN has achieved production status in many countries. The French are already in the process of operationalizing them on Rafales. They are ready to deliver it on the radar as well. The British are selling them to the US for the F-15's EW suite and developing another for the Typhoon's radar. The Russians are testing new missile seekers based on GaN, along with the PAK FA radar.

 

[xunzi]

What else is new in here again? Uncle gambit getting owned does not count. LOL he always talking some nonsense about airefueling even though J20 intention to operate long range but with capability to refuel with Y-20 variant. Why else we build those for? The guy lack logic and use some information he found on the net and speculate false information.

 

[Deino]

What else is new in here again? Uncle gambit getting owned does not count. LOL he always talking some nonsense about airefueling even though J20 intention to operate long range but with capability to refuel with Y-20 variant. Why else we build those for? The guy lack logic and use some information he found on the net and speculate false information.

However I would be careful, to see it only black and white since some of his concerns are correct and some of Your assumptions are plain wrong or not valid; at least not yet.

Fact is, there are only three Il-78 available and only these are able to refuel the Su-30MKK and as such - given its immense load of fuel - the J-20 too. A HU-6 has simply not enough fuel to transfer; that's a fact.

And until a dedicated Y-20 becomes available .... surely not earlier than in a few years. So in consequence he's not completely wrong.

Deino

 

[randomradio]

However I would be careful, to see it only black and white since some of his concerns are correct and some of Your assumptions are plain wrong or not valid; at least not yet.

Fact is, there are only three Il-78 available and only these are able to refuel the Su-30MKK and as such - given its immense load of fuel - the J-20 too. A HU-6 has simply not enough fuel to transfer; that's a fact.

And until a dedicated Y-20 becomes available .... surely not earlier than in a few years. So in consequence he's not completely wrong.

Deino

Refueling is very important for the US, not for the PLAAF.

Anyway, the J-20 is still many years away from being fielded in large enough numbers and that gives Xian enough time to develop the refueler version.

 

[Asoka]

My bad. I will rephrase my original thoughts. The original intent for the J-20 was to have less dependency on air refueling than Western fighters primarily because the PLAAF is not as capable as the US in terms of mastery of the skills involved.

Air refueling is not easy like everyone thinks it is.

The PLAAF's air refueling fleet is drogue equipped. This method has serious limitations in terms of refueling rates which affects how many aircrafts, even though they maybe small fighters, per event. Drogue delivers a lower rate of fuel flow than probe. Even though the receiver aircraft is a small fighter, it still consumes its own fuel while it is taking on fuel.

The US uses two methods: probe and drogue.

The probe method delivers a higher rate of fuel flow which is necessary for large receivers like the bombers and cargo jets.

The US Navy is an expeditionary force that must be as self reliant as possible uses the drogue method. Its lower fuel flow rate is adequate for its fleet of small aircrafts which came from aircraft carriers.

Using the US as example. The probe method can transfer up to 6,000 lbs/min. The drogue method is up to 2,000 lbs/min.

The J-20's size is no accident. The PLAAF realized its shortcomings in the air refueling area, but the need to have a 5th gen platform outweighs the need to have a comprehensive air refueling capability.

Note...

http://www.ausairpower.net/APA-PLA-Tanker-Programs.html

That is not two fighters at a time. But simply -- two fighters. Based upon its MTOW, as a modified platform, the air refueler Badger can carry only enough fuel to service only two fighters.

Remember, the client is burning fuel at the same time he is taking on fuel. If fuel flow rate in equals to fuel flow rate consume, you will NOT be refueling him. Your delivery must be higher than his consumption. If it is not high enough, the refueling time will take longer, but at the same time, you cannot cram fuel down his receptacle.

Assuming the J-20 is in full service. What this mean is that for every J-20 sortie, and we are looking at a typical four-ship sortie, if there is a need to air refuel this sortie, the PLAAF will have to assign its largest air refueler in inventory for that day.

Most people do not know it, but if you cannot provide that air refueling, that strike mission will be cancelled. That happened many times in Desert Storm when planners conflicted each other in terms of scheduling air refuelers.

At the current time, the US have 50 KC-10s, the largest of the air refuelers, and for the smaller KC-135s...

http://www.af.mil/AboutUs/FactSheets/Display/tabid/224/Article/104524/kc-135-stratotanker.aspx


How many air refueler modified IL-78s does the PLAAF have in order to support a typical four-ship sortie to patrol the SCS, for example ?

News Flash: "The first Xian Y-20 military transport aircraft was delivered to the People's Liberation Army Air Force (PLAAF) on June 15. Developed by Xian Aircraft Corporation, the Y-20 has an empty weight of 110 short tons, making it the largest military aircraft currently in production—larger than Russia's Ilyushin Il-76.Jun 20, 2016"

http://www.popularmechanics.com/flight/a21418/chinas-air-force-largest-military-aircraft-y-20/

No evidence, that Y-20 has been modified for Air-refueling. But there is no barrier for that role, and for a AWAC platform.

H-6 is an ancient aircraft and China can't get enough IL-78s from Russia, because of production capacity problem. So I don't expect them to service J-20 as oil tankers in the future.

Probe refueling, while, is faster, but it can only refuel one aircraft at a time.

""PLAAF is not as capable as the US in terms of mastery of the skills involved."
I think Gambit means China is less experienced with air refueling and has a much smaller refueling fleet.

I would say the need for Long Range matched, nicely, the need for High Supersonic Speed and Supersonic Cruise (which calls for a long slender body for lower Supersonic Drag). As we can see in the comparison picture, J-20 has almost the same body length as F-22, without the 4m long canard section.

Normally, a large and heavier aircraft will conflict with Superior Maneuverability, but that has been solved with Delta-Wing Canards, Leading Edge Extension, Whole Body Lift, Vortex-lift Generators, All Moving Tails, Differential Moving TVC nozzles. All these help created extreme Maneuverability, along with extensive use of Titanium alloy and composite materials.

A new powerful engine definitely also helps.

All these aerodynamic innovations would be a nightmare for Flight Control System Designer, before 1980's. But that has been solved in the 1990's with the use of a full digital and electro FCS. Hence, we are seeing the Eurocanards, J-10, J-20, Su-35, Su-37, Su-47, T50, F-22, Gripen. . . with extreme Maneuverability. That would not have happen if there was no fully computer controlled, digital and electro FCS.

The Israel taught the Chinese about modern aircraft design and digital FCS, when they sold the Lavi fighter design to China. They explicitly told the Chinese not to expect other country to sell you their FCS. You must master the technology by yourself.

It is no coincidence that Yang Wei, the chief Flight Control System Designer of J-10 is the Chief Designer of J-20. Only he can fully appreciate the challenges involved in designing J-20 with such leap of extreme Maneuverability.

There was no crash when testing J-10 and J-20, unlike other countries testing a plane with a new digital FCS. In fact, the J-10 test pilots said they were most confident with the FCS.

 

[Asoka]

So J-20's AESA radar is GaN-based.

In the future, if not already happen, AESA radars will have a distributed and networked architecture. There will be M number of transmitters, and N number of receivers installed in different locations on ground, sea and air platforms, all networked together. The radar beams, instead of just a dump beam, each radar beam or packed will encoded and encrypted with the position and time of the transmitter, just like a WIFI packet. Each packet will be unique and spoof resistant. They can join and leave the network like a WIFI network.

Stealth aircrafts works by deflecting most of the radar signal away from the Transmitter, which happen to be also the Receiver, in the current AESA technology. In the networked AESA system, the deflected radar signal will be picked up by different receivers in different locations.

The stealth aircraft will have no where to hide. Even, if the aircraft can absorb 100% of the radar signal, the distributed system will still works, because it will show a moving region in the sky where the radar signal was disturbed or absorbed completely--no reflection and no transmission through that region.

Freaking large and powerful AESA transmitters could be installed on ships and on the ground. Making airborne AESA transmitters less relevant, which are limited by the size of the AESA antenna the plane could carry. The airplanes then just need to receive the composite picture created by the Central Processor to receive full situational awareness.

There could be dedicated AESA ships, which carries only several gigantic, enormous AESA transmitters facing the four directions. The array of networked Receivers could also be arrayed in such a way that emulates how Radio Telescope Array works.

Note: In this kind of distributed AESA, the Transmitter and Receivers are located in widely separated locations.
Passive Anti-stealth radars are already using this principle, but they are using ordinary radio waves, instead of encoded and encrypted AESA packets like WIFI packets.

 

[Ultima Thule]

The US uses two methods: probe and drogue.

you are wrong sir first method used by USAF is not a probe method but flying boom method
Flying boom


A USAF C-5 approaches a KC-135R.
The flying boom is a rigid, telescoping tube with movable flight control surfaces that an operator on the tanker aircraft extends and inserts into a receptacle on the receiving aircraft. All boom-equipped tankers (e.g. KC-135 Stratotanker, KC-10 Extender) have a single boom, and can refuel one aircraft at a time with this mechanism.

History
In the late 1940s, General Curtis LeMay, commander of the Strategic Air Command (SAC), asked Boeing to develop a refueling system that could transfer fuel at a higher rate than had been possible with earlier systems using flexible hoses, resulting in the flying boom system. The B-29 was the first to employ the boom, and between 1950 and 1951, 116 original B-29s, designated KB-29Ps, were converted at the Boeing plant at Renton, Washington. Boeing went on to develop the world’s first production aerial tanker, the KC-97 Stratofreighter, a piston-engined Boeing Stratocruiser (USAF designation C-97 Stratofreighter) with a Boeing-developed flying boom and extra kerosene (jet fuel) tanks feeding the boom. The Stratocruiser airliner itself was developed from the B-29 bomber after World War II. In the KC-97, the mixed gasoline/kerosene fuel system was clearly not desirable and it was obvious that a jet-powered tanker aircraft would be the next development, having a single type of fuel for both its own engines and for passing to receiver aircraft. The 230 mph (370 km/h) cruise speed of the slower, piston-engined KC-97 was also a serious issue, as using it as an aerial tanker forced the newer jet-powered military aircraft to slow down to mate with the tanker's boom, a highly serious issue with the newer supersonic aircraft coming into service at that time, which could force such receiving aircraft in some situations to slow down enough to approach their stall speed during the approach to the tanker. It was no surprise that, after the KC-97, Boeing began receiving contracts from the USAF to build jet tankers based on the Boeing 367-80 (Dash-80) airframe. The result was the Boeing KC-135 Stratotanker, of which 732 were built.

 

[IblinI]

 

[Asoka]

Comparison between J-20, 2001 and 2012.

 

[gambit]

You are using incorrect terms.

You are correct. It was late evening and I was in a hurry.

And to make up for the potential lack of refuelers, the USN also uses buddy refueling, that the USAF can't.

So drogue offers more flexibility. A J-11 can easily be modified to refuel a J-20. This makes your assertion wrong.

Regarding the image above. How many fighters can another fighter serviced ?

Answer: It depends on the situation at hand.

The F-18 Super Hornet external load is 17k lbs. An F-18 Super Hornet internal fuel load is 14k lbs.

In other words, an F-18 air refueler can refuel only one F-18 to full load. It can refuel two F-18s to half load. Or it can refuel more than two F-18s at various loads. Are you going to tell me that based on your own image, a fighter can refuel more than two fighters to their full internal fuel loads ? Are we talking about 'Indian physics' here ?

Strike tankers, like the F-18 Super Hornet version, accompanies the strike package and refuel the other fighters, not to top them off, but to extend their flight time so they can make the trip back to the carrier. That mean the amount of fuel each client receives must be carefully calculated so that no one in the strike package is unrefueled.

Regarding the J-20. This jet supposedly have an internal fuel load of over 20k lbs, up to 25k lbs. Show me which buddy air refueler can refuel a near empty J-20.

As usual, you underestimate your adversary.

Those 3 IL-78s were bought simply to be studied. The future PLAF refueling capability would be on the Y-20 tanker variant.

"PLAAF is not as capable as the US in terms of mastery of the skills involved."
and what is your support for that claim? I can understand if you claim PLAF is technologically inferior, but mastery of the skills? How do you even measure that?

Try this article...

http://foxtrotalpha.jalopnik.com/confessions-of-a-usaf-kc-135-flying-gas-station-boom-op-1578048155

Particularly the section titled Every Receiver Is A Little Different.

 

[gambit]

In the future, if not already happen, AESA radars will have a distributed and networked architecture. There will be M number of transmitters, and N number of receivers installed in different locations on ground, sea and air platforms, all networked together. The radar beams, instead of just a dump beam, each radar beam or packed will encoded and encrypted with the position and time of the transmitter, just like a WIFI packet. Each packet will be unique and spoof resistant. They can join and leave the network like a WIFI network.

Sure...

First...We find the active transmitters.

Then...We destroy them.

Even if each station is dual purpose, meaning it can be both transmitter and receiver when convenient, the disruption in the radar net will be enough for our 'stealth' fighters to slip thru.

Freaking large and powerful AESA transmitters could be installed on ships...

Subs can take care of them.

 

[Pepsi Cola]

Try this article...

http://foxtrotalpha.jalopnik.com/confessions-of-a-usaf-kc-135-flying-gas-station-boom-op-1578048155

Particularly the section titled Every Receiver Is A Little Different.

I mean.. the section basically said that refueling is hard. I do think that experience is very important, so I'll give you that.

Also upon further reasearch I also found article that said

"According to research by the U.S. air force and its aerial refueling troops, China's way of typical grouping would be two H-6U aircraft with twelve J-8D fighters."

http://english.chinamil.com.cn/news-channels/china-military-news/2015-09/08/content_6671974.htm

That means the US air force determined that the H-6U is capable of at least supporting 6 fighters each in a typical mission.

 

[Deino]

...

That means the US air force determined that the H-6U is capable of at least supporting 6 fighters each in a typical mission.

But You have to consider these are 6 J-8s ... I think the fuel volume for a J-20 is at least comparable to a MKK and the HU-6 is simply too small to support even one MKK.

Deino