SAC FC-31 Stealth Fighter: News & Discussions

[Audio]

more to do with its twin engine configuration, which give more space to fit everything inside without creating any bumps.

I meant sensors which are placed on outlying positions in order to have a better view of the sorrounding environment, not that it lacks space inside, stuff like DAS, RWR, etc...

So I guess the F-22 has no instruments inside.

This is the first prototype. Do you know of any other first prototypes that were fully loaded with gear and electronics on first flight?

wants to "clone" garbage like this.

I guess that's why J-15 doesn't resemble a Russian fighter and J-15 doesn't at all resemble the Russian jet trainer.
Do you think before you post or you operate only in spotting differences on airplane pictures?


As for the rust on the PAK-FA. Why do you think Chinese ones are painted black?

 

[j20blackdragon]

I guess that's why J-15 doesn't resemble a Russian fighter and J-15 doesn't at all resemble the Russian jet trainer.

The J-15/Su-33 are not stealth fighters like the CRAP FA claims to be.

As for the rust on the PAK-FA. Why do you think Chinese ones are painted black?

The rust is the least of the problems.

 

[Audio]

The J-15/Su-33 are not stealth fighters like the CRAP FA claims to be.

Irelevant. It was cloned, and since it is a predecesor to the PAK-FA it should by all accounts be inferior. If you are mocking it, you are mocking all of those Chinese engineers who were painstakingly taking it apart and cataloging all the parts.

The rust is the least of the problems.

If only they could import Chinese black paint to cover it up, right?

 

[gambit]

China should of chose Gambit instead, since Gambit has good knowledge in defense tech. Anyway, he doesn't want to work for them.
BTW, why would the ex-B-2 engineer work for China. Money is it?

Any aircraft will have many engineering disciplines involved, and each discipline have its own subordinate disciplines. So the question is more about what system or subordinate system was this guy working on. This is not meant to downplay what he did but to better focus the discussion on the damages.

So according to the news article...

...when he worked for Northrup from 1968 to 1986, designed the exhaust nozzle for the cruise missile...

The exhaust nozzle is a subordinate system to Propulsion. Under Propulsion, there will be engineers assigned to work on fan blades, fuel injectors, materials, core integration, avionics, and just about anything else whose components cannot be found in the civilian sector. The more advanced the weapon system, the more likely each component for each sub-system will have to be designed and manufactured from paper instead of adapting an existing component.

Quite often an engineer will be assigned to be specialist in two or more specialties simply by virtue of their integration. For example...An air data specialist will be the specialist for both the air data computer and the air data probes, those 'thingies' that sticks out into the air stream. It will be his responsibility to search for available probe designs, adapt them as necessary, or learn to design new ones if necessary.

So what kind of damages can Mr. Noshir Gowadia do? Plenty.

Exhaust nozzles design hints at many vital internal engine designs, everything from core diameter to thrust. Every subordinate system must be optimized, to use that cliche, to produce the best effect for any other sub-system that require its inputs. The best analogy is that every component in every system is either a supplier or a customer of data to another system at any time.

Gowadia may be portrayed as an exhaust nozzle engineer but that could also make him a materials specialist as well. May be not materials for the aircraft's skin but materials that could withstand high temperature for long duration because that is the environment produces by the engine. So now China have additional knowledge on this aspect of aviation in general and of cruise missile engine design in particular. Knowledge that is either new to the Chinese engineers or to correlate/confirm any suspicion/speculation Chinese engineers may have in their own designs. The Chinese engineers working on engine avionics now have data on how to control an engine in a different method thanks to a new (to China) exhaust nozzle diameter, that can withstand a higher temperature, that can be cycled from mil to AB without stalling, etc. Either way, the Chinese engineers benefit and any money spent in bribes was well worth the investment.

 

[siegecrossbow]

Video on the 3D laser printing techniques used to manufacture the stress bearing parts on the J-21.

[3D

 

[Ultima Thule]

i guess this plane is better than j-20 because of it not has canard and ventral fin

 

[j20blackdragon]

i guess this plane is better than j-20 because of it not has canard and ventral fin

But can you briefly explain why canards are detrimental to the aircraft's RCS to begin with, or are you just saying it because everyone else is?

The top and bottom of a canard are flat plates.

The canard has a leading edge.

The canard has a trailing edge.

The canard forms a 120 degree angle with the fuselage.

The canard is a moving control surface, but so are the F-22's stabilators.

So what is it about the canards that make them so horrible from a stealth perspective?

 

[gambit]

But can you briefly explain why canards are detrimental to the aircraft's RCS to begin with, or are you just saying it because everyone else is?

The top and bottom of a canard are flat plates.

The canard has a leading edge.

The canard has a trailing edge.

The canard forms a 120 degree angle with the fuselage.

The canard is a moving control surface, but so are the F-22's stabilators.

So what is it about the canards that make them so horrible from a stealth perspective?

It is their locations that made them significant.

Plus they are not in the same plane as the wings...

As the above image showed. That means the canards' trailing edge diffraction signals will impact the wings' leading edges in a different angle than how the F-22's wings and horizontal stabilators are aligned. Plus they add to the total amount of major structural radiators on the J-20. The J-20 have 8 flight control surfaces. The F-22 have six. All of this have been explained before.

Apparently you have a difficult time understanding how things relate to each other.

 

[Sam1980]

Hmm... Noshir Gowadia! I don't want to Google him! But is he Parsi by any chance?!

 

[j20blackdragon]

That means the canards' trailing edge diffraction signals will impact the wings' leading edges in a different angle than how the F-22's wings and horizontal stabilators are aligned.

This is speculation.

You're describing a speculative interaction between the trailing edge of the canard and the main wing, which you believe will return a radar signal back to the enemy receiver. The main problem with what you said is that you can't know with any certainty that it will happen at all. In other words, it can't be verified.

I challenge you to draw a diagram depicting what you're describing.

 

[hk299792458]

It is their locations that made them significant.

Plus they are not in the same plane as the wings...

They are.

Some colleagues from Dassault have studied this plane.

Henri K.

 

[gambit]

This is speculation.

You're describing a speculative interaction between the trailing edge of the canard and the main wing, which you believe will return a radar signal back to the enemy receiver. The main problem with what you said is that you can't know with any certainty that it will happen at all. In other words, it can't be verified.

I challenge you to draw a diagram depicting what you're describing.

There is nothing 'speculative' about this and I do not need to draw anything. Anyone can do keyword search 'radar cross section edge diffraction interference' and see for themselves. There are plenty of credible sources about this subject, starting with Russian mathematician Ufimtsev, using real physics. Not 'Chinese physics'.

They are.

Some colleagues from Dassault have studied this plane.

Henri K.

Not for the J-20...

Look at the canards' angle again...

 

[hk299792458]

Not for the J-20...

Look at the canards' angle again...

The root of canard is at the same plane as that of the wing.

In a more general way of speaking, the canards, the LERX and the wing are aligned on the same structural side line. The canards have a positive dihedral angle based on this plane, whereas the LERX a negative one.

This is our conclusion after having seen more than 3500 pics of J-20 and around 2h of footage.

We know what we say.

Henri K.

 

[gambit]

The root of canard is at the same plane as that of the wing.

This is our conclusion after having seen more than 3500 pics of J-20 and around 2h of footage.

We know what we say.

Henri K.

Edge diffraction fields are not confined to the root. Most illustrations regarding these behaviors uses straight lines/arrows, which are misleading.

This is what a radar transmission, be it from an antenna or from a diffraction field, look like...

Surface waves travels throughout the structure, losing small packets of specular energy until a surface disruption is encountered. That surface disruption here is between metal and air. Or the canard and free space.

If the goal is to control, as much as possible, these behaviors, then you must confine their radiation angle of approach onto nearby structures, if there are any. One way to do that is to keep the structures in as much alignment as possible. That is why for the F-22, the wings and horizontal stabs are so close together and in complete alignment.

 

[j20blackdragon]

There is nothing 'speculative' about this and I do not need to draw anything.

You can't draw it because it's speculation.

The naysayers/haters/trolls here have been saying time and time again that the trailing edge of the canards will supposedly diffract onto the main wings and fuselage, and generate a radar return.

I want to see how that actually happens.

Please draw the diagram.