Chengdu J-20 Stealth Fighter

Viktor wrote:

Never mind that, I think his arguments are valid.

Considering it is nothing but a tech demonstrator, it doesn't mean much of anything as APA suggests.

Some Chinese fan boys from another Defense forum said that there are in fact 2 Prototypes of the J-20, one with Al-31s and another with WS-10s.

Would certainly make sense to test both engines.

Of course the real issue will be weapons.

...to be a stealth fighter the J-20 will need weapons that can be stored and fired from internal bays.

ARH AAMs are not a big problem... the R-77 was designed from the outset for the rear grid fins to fold forward and for the launch rail it is launched from the catapault the weapon downwards 3-5m before the engine starts up so it is clear of the aircraft when it speeds off to the target. It also has a datalink and can be fired to fly to an intercept point and discover its target after launch.

The problem is the IR short range guided missiles as most earlier missiles needed a lock on before launch and the FOV from inside a weapon bay is too restricted for a lock on before launch weapon like R-73 or R-60 to be used.

Hense the development of the 9M100 missile that is going to be their universal short range missile. It is going to be used on the T-50 and Su-35 and Mig-35, on the ground as part of the Vityaz system (as a 10km range IIR guided SAM) and as a Naval weapon also as part of the Naval Vityaz system where it will be the Russian equivelent of Sea RAM.
It would be like the US used AIM-9X in aircraft, and replaced Chapparal with AIM-9X and of course used AIM-9X instead of SEA RAM as a replacement for Phalanx.

Of course I think the Russian Navy will not replace the Kashtan-M completely with 9M100... I think they will also use a stealthy version of the Duet twin AK-630 and also on some vessels will use a 57mm stealthy gun system with laser directed shells to also deal with large scale attacks.

Why replace Kashtan-M? It isn't stealthy.

There should be lots of savings in using unified missile systems across all the services too... they have already standardised on the 30 x 165mm shell.

See the warplane profiles.J-20 do have some large canards!!



Closer look at landing gears


It has one-piece canopy; T-50 has two piece if I recall correctly

As Legendary Aerospacee engineer Kelly Johnson said:" if it looks good, it flies good."
I think J-20 got the best looking out of all the stealth fighters. Gotta fly good as well.

^^Look at the air-intakes; unlike T-50/F-22 they are not below LERX & are DSI intakes

he is the chief designer of JF-17,J-10AS and J-20

http://en.wikipedia.org/wiki/Yang_Wei_(aircraft_designer)

Song Wencong is chief designer of J-10A


http://en.wikipedia.org/wiki/Song_Wencong

nightcrawler wrote:See the warplane profiles.J-20 do have some large canards!!

Large canards mean high drag and increased RCS. It is not conducive to stealth or super cruise... at all.

It has one-piece canopy; T-50 has two piece if I recall correctly

Called bubble canopy, it is stealthier than a two piece.

As Legendary Aerospacee engineer Kelly Johnson said:" if it looks good, it flies good."
I think J-20 got the best looking out of all the stealth fighters. Gotta fly good as well.

If it looks like it flies like a brick and actually lands like a brick, it probably is a brick.

- Vladimir79 RMF

@Garry
your speculations are right. Two models were tested

Interesting that China still does not have full faith in its WS-10As.

Vladimir79 wrote:Interesting that China still does not have full faith in its WS-10As.

China has tested its WS-10 engine as the image dictates; but yes its not that trustworthy!!
Regarding the canopy RCS relationship; this is the best answer I got. Sorry its from another forum; but its informative

I know very well bubble canopies have less RCS. The answ3r is simple. There is no metal.

The problem is that when a canopy has a front frame you can make the front piece of transparency thick to withstand the impact of a bird while the rest of the canopy can be made thinner and easier to see through.
With a one piece bubble it all must be thick and is therefore less transparent.

To reduce RCS a very very thin layer of gold is often added that absorbs radio waves and converts it into a very minor heat increase.

That is why some canopy's seem to have a gold tint.

Regarding engine nozzle_
As you can see the saw-toothed edges on the nozzle of F-35; these are absent in both T-50&J-20

Saw tooth engine nozzle doesn't mean shit. It is just another Iris nozzle. J-20 uses either AL-31Fs or WS-10As. Both engines are inferior to item 117S. WS-10A is inferior in acceleration due to its inferior nozzle.

I would say neither the T-50 or the J-20 have sawtooth engine exhaust petals because they are not flying with their final operational engines... though the T-50 might start service with that engine because it is not just a warmed over Al-31.

We know that the rear end of the T-50 will be reworked and that the current setup is temporary... and that there are plans for new nozzle options that for the moment are not ready. They have a lot of things to get right and doing everything at once introduces problems.

Giving it a proven layout for the rear (similar to the Flanker) they are reducing problem variables to make isolating problems simpler and easier. For instance the IRST is clearly not actually fitted and the stand in is just a place holder. Most likely the final system will be faceted and stealthy, but that is clearly not being tested in the current prototype. When it is time to integrate it and test it once it is tested it will become part of the base prototype and new things will be tested on top of it to check for conflicts.

I am sure they are working on the flight control system first and then they will likely work on system integration and flight characteristics and leave rear end RCS issues to later on... they will have a group working on it right now, but it will be computer tested and hung on wires with real ground based radars pointing at it for testing and tested in wind tunnels to make sure the new shape is both stealthy and aerodynamic.

If they can't manage a rectangular exhaust that is effective and efficient then the spiky round nozzle will likely be the best compromise regarding radar cross section reduction.

Air-inlets- Wing layouts compared


...& a must read article
http://www.aviationweek.com/aw/blogs/defense/index.jsp?plckController=Blog&plckBlogPage=BlogViewPost&newspaperUserId=27ec4a53-dcc8-42d0-bd3a-01329aef79a7&plckPostId=Blog%3a27ec4a53-dcc8-42d0-bd3a-01329aef79a7Post%3a5c50cb01-bdd0-41cc-b216-fdc89354eb19&plckScript=blogScript&plckElementId=blogDest

@Nozzles


China's J-20 stealth fighter engine nozzles


China's J-20 stealth fighter engine nozzles (another view)


F-35 Lightning II engine nozzle

Those are refined Low Observable Axisymmetrical Nozzles and first tested on a F-16 for the JSF programme. The LOAN was developed after the F-22 and that's why the Raptor doesn't have them.

http://www.f-16.net/f-16_versions_article20.html

Stealth Aircraft - Infra-Red Signature Reduction

Electromagnetic radiation, emitted or reflected by the gas turbine exit nozzle contributes significantly to the "signature" of a vehicle. By mounting the exit nozzle within a suitably shaped shroud this signature is reduced. Radar signals are absorbed or diffused by the shroud and infra-red emissions are masked, either by the shroud itself or by cool air ducted by the shroud to pass around the nozzle and the exhaust stream issuing from it. Such an arrangement, by its nature, defines a constraining envelope within which the nozzle must lie in order to be effective. This imposes constraints upon the use of reheat or thrust vectoring of the engine exhaust stream.

Here are comments made by others stating why PAK-FA is not a stealth aircraft.

Features that leap out as being non stealthy on the T-50 include:

- Absence of sawtooth edges on anything but the weapons bay doors
- Absence of edge alignment on skin panels
- Control surface inner edges not aligned with planform edges
- Noisy features like the auxiliary vents on the engine inlets
- Lower fuselage from the inlets rearward is completely conventional, no blending at all of engine nacelles into fuselage
- Upper fuselage from the mid-wing rearward is conventional, no blending of engine nacelles into fuselage (although partially masked from the sides by the empennage)
- Straight-through engine nacelles

What about the IRST ball... it isn't stealthy either.

Perhaps people making these comments perhaps should reconsider what the term first flying prototype means.

Why show the world what the stealthy aircraft will actually look like 5-10 years before it enters service?

All issues you mention are speculative... for instance do you have a photo from the front through the engine inlets that shows the front fan blades of the engine?

The Su-27 has a folding grid door that prevents foreign objects entering the intake... the early Mig-29s had a solid door and air was rerouted through vents in the upper wing surface.

It would be fairly simple to put ramps inside the intake trunk that when opened block the front view of the engine without the continuous issue of a bent intake flow.

This prototype was likely designed to verify the aerodynamics and flight control system. There was a Su-30M used to test the radar. Later prototypes will likely test stealth but what we are seeing may look nothing like the final aircraft... just look at the first flying prototype of the Flanker.

GarryB wrote:What about the IRST ball... it isn't stealthy either.

Perhaps people making these comments perhaps should reconsider what the term first flying prototype means.

Why show the world what the stealthy aircraft will actually look like 5-10 years before it enters service?

Maybe they already have 200 of them refined and built, they are just publicly showing some of the early prototypes off. By the time the F-117 was publicly shown it was already headed to be decommissioned and obsolete. The F-117 was the biggest "bluff" aircraft in military history. Unless it turns out the Chinese are playing a bigger bluff.

Where is the video of the fall 2010 Chinese National Day military parade? It's not on the internet. All they publicly released to the internet is a friendlier China showing people hanging out together. No display of current military technology. (They're mad some of their new hardware was taken from them)

Hence why they shot that Ballistic Missile 30 miles off the coast of California. Displaying they are pee'd off. So far China's losing.

They either better have hundreds of the J-20 built and ready to fly or they're dead.

China's 5G fighter 'a showoff'

RIA Novosti

18:16 20/06/2011 LE BOURGET (France), June 20 (RIA Novosti) - China's fifth-generation fighter program is more for effect than substance, Russia's leading aircraft maker said on Monday.

China carried out its first test-flight of a fifth-generation stealth fighter in January.

"It was more a demonstration than a real program," Mikhail Pogosyan, head of United Aircraft Corporation, said.

The Chinese aircraft industry is developing successfully but it lacks what is required for a breakthrough, he said.

"There will be no breakthroughs here. Great scale and great experience are needed to carry out such programs," Pogosyan said.

Russia is testing its own fifth-generation aircraft T-50 PAK FA developed by the Sukhoi design bureau. The aircraft is expected to become operational in 2015.

China's prototype Black Silk J-20 stealth fighter is thought to be similar to the U.S. F-22 Raptor and the Russo-Indian T-50 jets, although imagery and video footage appearing on the internet suggested the Chinese model is larger. This means it could be capable of flying a longer range and carrying a heavier load.

China has been working on a future fighter program since the mid-1990s, and the J-20 is notionally anticipated to enter service around 2018-2020.


http://www.globalsecurity.org/wmd/library/news/china/2011/china-110620-rianovosti01.htm

http://en.wikipedia.org/wiki/Noshir_Gowadia

China does have the blueprints for the B-2 bomber now. They do have a design/manufacture advantage, they don't have to spend time and money on R&D.

Not even Russia knows what China does now on Advanced Carbon Composites. Which gives them an edge to make a 5th Generation plane really quick and cheap.

They've got a bomber edge over Russia now as well.

Hang on...

They've got a bomber edge over Russia now as well.

No disrespect... but rubbish!

Currently the Chinese have one main bomber type and it is a Chinese made Tu-16 medium bomber that lacks strategic range.

Compared to even the Tu-95 it is slower, much shorter ranged and carries a much smaller payload of much lower performing weapons.
Photos have been released of the Tu-95 carrying Kh-101/102 missiles with flight ranges of 5,500km... which is actually comparable to the unrefuelled flight radius of the Tu-16.

There is also the Blackjack.

Also having the blueprints for the B-2 is nice, but the thing about the B-2 is not only its shape and design, but the materials it is made from and how it is made and also the electronics and equipment it carries.

The Chinese actually have very little use for a B-2.

A large stealth fighter able to carry a long range anti ship missile makes rather more sense for them.

Building a 5th gen fighter is not just about giving it a certain angular look and black paint.

""The Chinese actually have very little use for a B-2""

Aren't they flying their own right now? Their big worry is this:


"""On 13 September 2010 Air Force Secretary Michael Donley said that long range strike would continue cautiously with proven technologies and that the plan to be submitted with the 2012 budget could call for either a missile or an aircraft"""

http://en.wikipedia.org/wiki/Next-Generation_Bomber

If US makes a scramjet bomber or uses scramjet missiles Chinese assets may never leave the ground.

If the US makes a scramjet missile or bomber then the Chinese might consider an ABM agreement with Russia...

The US and China already have very high speed missiles... they are called ICBMs and also IRBMs in the case of China.

The fact that the US wants to put conventional weapons on high speed missiles or bombers might lead to the Chinese vastly expanding their ICBM and IRBM fleets to compensate.

If they can get the accuracy of their weapons down to a few metres then they might use conventional warheads to match the US systems but I suspect for the time being they will need nuclear warheads.

Wonder how much safer the US will feel then...

Scramjet powered missiles and bombers will fly high and will have IR signatures that will allow long range detection, so it actually reduces the risk of a sneak attack.

It looks like the T-50 !

megacombat.net/chengdu-j-20-stealth-fighter-plaaf-first-test-flight/