Chengdu J-20 5th Generation Aircraft News & Discussions

[SyrianChristianPatriot]

Good Job China to bad won't be exported for a while.

 

[marshall]

Each turn was over 10 second... How did you calculate that? Each 180 degree turn (the one with reference) was around 9 seconds tops. Not bad for AL-31 engines.

Also I was talking about figure 8s, a type of maneuver, at not 8 second turns.

Looked like 10-11 seconds to me, hard to be sure. 9 seconds is good but completing a full turn at that rate is the issue. I was talking about figure 8s not 8 second turns. It can't maintain good turn performance at speed if it continued from a 180 to a 360. It was carrying no load while at low altitude. Unless the pilot was holding back or throttled the engines, the J-20 is way underpowered. These rumours about the fast development of the WS-15 haven't produced any concrete news yet except for a publicly declared milestone. Unless it is ready for first flight by 2014, there's no way the J-20 will be competitive in a dogfight in its first iteration. I don't buy the malarky about the existence of the ethereal WS-10G engine.

 

[FairAndUnbiased]

there's a materials solution to everything.

canards holding back stealth? make radio transparent canards. it can be done. they're also extremely strong to boot. ceramics are just too heavy but that can be done away with through weight reduction elsewhere. machining the ceramics is easy for the low curvature canards.

Refractories and Industrial Ceramics, Volume 43, Numbers 3-4 - SpringerLink

 

[amalakas]

there's a materials solution to everything.

canards holding back stealth? make radio transparent canards. it can be done. they're also extremely strong to boot. ceramics are just too heavy but that can be done away with through weight reduction elsewhere. machining the ceramics is easy for the low curvature canards.

Refractories and Industrial Ceramics, Volume 43, Numbers 3-4 - SpringerLink

perhaps .. but right now noone has made a widely produced and used dielectric control surface. There must be a reason for it.
And although I do believe the strides the chinese industry is making, I don't think they have gotten to the point where they made such a material.

 

[amalakas]

Here are the 2 messages I wrote relating to this specific sub-topic...




Like I have pointed out before, you have a chip on your shoulders and you increasingly rely on lies and deception. Why am I not surprised given the level of integrity you demonstrate with many of your messages. You don't understand the tactical requirement to minimize the effects of moving canards in a threat environment and are purposely pretending that canard movements cannot be reduced with corresponding compensatory adjustments from the other control surfaces. This is basic logic that any neophyte can understand. In addition, your umpteenth red-herring that it would reduce maneuverability is irrelevant because such a flight mode would be used in a threat environment, as in before you were detected by any of the probable multiple illuminating enemy radars in the vicinity, stealth would be the primary goal at that juncture not maneuverability, since the objective at that point in time would be to get as close as possible to the engagement zone. Like I said, not your forte. Your attempts to prove 1+3=13 is simply wrong.

I think you take this personally. I don't know how big the IRST probe appears to a radar, but on the other hand you have to think in terms of the russian engineers having a tiny bit of brain too.

if a 12 year old geek from his mums basement can see the IRST, and ***** about it, I guess an engineering team full of PhDs would see it too.

coming to the canards, I don't think you are realising what you are saying.
in normal level flight, the primary control surfaces deflect only a little, there would be no point in limiting them anyway.
don't know how else to put it really

 

[Luftwaffe]

I think you take this personally. I don't know how big the IRST probe appears to a radar, but on the other hand you have to think in terms of the russian engineers having a tiny bit of brain too.

if a 12 year old geek from his mums basement can see the IRST, and ***** about it, I guess an engineering team full of PhDs would see it too.

If Americans and Chinese could hide IRST then russian Phds could have done it before it would have been criticized even that damn Rafale IRST has relatively low observability then pak-fa. We hope russian Phds would grow brains.

 

[Luftwaffe]

Looked like 10-11 seconds to me, hard to be sure. 9 seconds is good but completing a full turn at that rate is the issue. I was talking about figure 8s not 8 second turns. It can't maintain good turn performance at speed if it continued from a 180 to a 360. It was carrying no load while at low altitude. Unless the pilot was holding back or throttled the engines, the J-20 is way underpowered. These rumours about the fast development of the WS-15 haven't produced any concrete news yet except for a publicly declared milestone. Unless it is ready for first flight by 2014, there's no way the J-20 will be competitive in a dogfight in its first iteration. I don't buy the malarky about the existence of the ethereal WS-10G engine.

Seriously.. you expect prototype to perform full fledged aerobatics. You think all critical maneuvers to be perform at public sites they would be far away from the population area just few flights over the air base can't be the conclusion.

 

[amalakas]

If Americans and Chinese could hide IRST then russian Phds could have done it before it would have been criticized even that damn Rafale IRST has relatively low observability then pak-fa. We hope russian Phds would grow brains.

I would disagree, the rafale probes are no different to the PAK-FA ones, the only difference is a fairing that connects the pak fa probe to the front of the cockpit.

I don't think these arguments hold any water, and I don't appreciate you thinking a team of people who make supersonic jets, don't know what they are doing.

 

[Luftwaffe]

I would disagree, the rafale probes are no different to the PAK-FA ones, the only difference is a fairing that connects the pak fa probe to the front of the cockpit.

I don't think these arguments hold any water, and I don't appreciate you thinking a team of people who make supersonic jets, don't know what they are doing.

Don't care if you don't appreciate what has been said is to the point and scientifically proven. I don't need to repeat what Martain2 has already explained in detail in reference to pak-fa's overall huge rcs and design.

To start off with pak-fa complete design is non stealthy. Let me port what Martain2 posted nothing better than to re-posted which is to the point. So pak-fa team actually did not work that hard to design a stealth prototype lets see if in later stages their brains growup.

1. Circular exhaust.
2. Infrared-search-and-track ball on the nose.
3. Canopy frame,
4. Gaps around the inlets.
5. Various unshielded intakes and grilles.
6. Limited use of composites for now. Eventually, 40% of the aircraft will be made using composites.
7. Many surface intersections and flight-test probes that increase the radar signature.

So russians need to work hard to come up with a refined revamp design.

 

[j20blackdragon]

Once again, surface to air missile radars are on the ground looking up at your lower fuselage.

American stealth fighters look like this.

Russian "stealth" fighters look like this.

These pictures speak for themselves.

 

[amalakas]

Don't care if you don't appreciate what has been said is to the point and scientifically proven. I don't need to repeat what Martain2 has already explained in detail in reference to pak-fa's overall huge rcs and design.

To start off with pak-fa complete design is non stealthy. Let me port what Martain2 posted nothing better than to re-posted which is to the point. So pak-fa team actually did not work that hard to design a stealth prototype lets see if in later stages their brains growup.





1. Circular exhaust.
2. Infrared-search-and-track ball on the nose.
3. Canopy frame,
4. Gaps around the inlets.
5. Various unshielded intakes and grilles.
6. Limited use of composites for now. Eventually, 40% of the aircraft will be made using composites.
7. Many surface intersections and flight-test probes that increase the radar signature.

So russians need to work hard to come up with a refined revamp design.

Right.. you believe martian.. conversation ended.. nothing more to say

 

[DARKY]

Right.. you believe martian.. conversation ended.. nothing more to say

He thinks He and Martin2 knows more than the ones who are doing the Job.. may be their respective govt. should enroll them in their next Gen. combat aircraft teams as Brainy engineers.

Yet to see a functioning IRST which is hidden...

 

[j20blackdragon]

Yet to see a functioning IRST which is hidden...

The F-35's Distributed Aperture System would be one example.

 

[gambit]

You're the one who insinuated the non-faceted spheroidal IRST of the PAK FA could be larger according to the lambda rule not me. Nice try at role reversal there Houdini but no cigar. I suggested you had an interesting psychosis at some point but I didn't know it was this bad. LOL Those who have been paying attention know the history behind that statement.

Btw, if, as you suggest, the IRST's curvature already conforms to the lambda rule, what radar bands are you referring to exactly? The IRST looks to be somewhere between 22cm-28cm, typical fighter radar targets X-Band (2.5-3.75cm). Only the lower bound of X-Band somewhat applies and it wouldn't be effective because of the surface discontinuities of the IRST. It would have to be shaped more like a WOK, or better yet like the underwing protrusions of the J-20, for it to be reasonably stealth shaped.

You and that other guy are indeed dense.

The 10-lambda rule applies to ALL wavelengths. The rule is about the RELATIONSHIP between wavelength and diameter and less towards curvatures.

If the wavelength is one meter, as in the HF/VHF/UHF bands, if the diameter is less than 10 meters, then the creeping wave occurs, and if the diameter is greater than 10 meters, then the creeping wave does not occur.

Heck, even the Chinese engineers understand it...

If the wavelength is centimetric, as in the X-band, the rule still applies. As long as the diameter is 10 times greater than X-wavelength, no creeping wave will occur. No creeping wave? No increase in RCS contributorship. So let us take a look at your silly argument again...

Considering the context in which you are referencing the lambda rule, you could propose to the US Air Force that IRST probes should be made much larger...like 5 feet wide...this will make them more stealthy, according to you,

This is outright stupid. If the diameter is 11x the wavelength -- in this case the cm -- why the hell would we need to make it larger? There is already specular reflection REGARDLESS of diameter. So enlarging the diameter to 12x or even 11.5x does not reduce RCS contributorship. The creeping wave already is negated at 11 or 10.5x.

On a non-spheroidal structure like the IRST device, the 10-lambda rule is still highly applicable even though the surface wave will meet a larger structure -- the fuselage. If the curvature is large enough, as in being 10x greater than the impinging wavelength IF it was a sphere, whatever surface wave behaviors that finally meet the fuselage and reflected off it, its energy level may be small enough to make that energy level statistically insignificant to the total RCS.

Get it?

This is why the T-50's IRST device does not need to be any larger nor should we make any declaration on its negative effects on the total RCS or not. Your man did and it was a colossal technical and PUBLIC blunder.

This is why the Chinese boys and their fan club, of which you are a member, continues to make fools out of yourselves. All of you have no interests in learning new things. It is understandable to have misconceptions. We all do about many things. But the honest thing to do is to admit ignorance and correction when evidences and reasonable arguments are presented, especially when those arguments are backed up by unimpeachable sources.

---------- Post added at 10:19 PM ---------- Previous post was at 10:17 PM ----------

Right.. you believe martian.. conversation ended.. nothing more to say

I stopped paying attention to lufty a long time ago. I do believe he is a 12yr old.

 

[gambit]

Like I have pointed out before, you have a chip on your shoulders and you increasingly rely on lies and deception.

Just because you are too stupid to understand dumbed down concepts does not mean they are 'lies and deceptions'.

You don't understand the tactical requirement to minimize the effects of moving canards in a threat environment...

News for you, kid. Aerodynamic requirements trumps any and all tactical desires. Without aerodynamic exploitation, we do not have this thing call 'flight'.

...and are purposely pretending that canard movements cannot be reduced with corresponding compensatory adjustments from the other control surfaces.

Really? Then why bother with canards in the first place? Why not make those other flight control surfaces do the work that includes those compensatory actions?

More news for you, kid...

Delta Wings

A delta wing is a wing whose shape when viewed from above looks like a triangle, often with its tip cut off. It sweeps sharply back from the fuselage with the angle between the leading edge (the front) of the wing often as high as 60 degrees and the angle between the fuselage and the trailing edge of the wing at around 90 degrees. Often delta-wing airplanes lack horizontal stabilizers. Despite the fact that paper airplanes have delta wings and appear to fly quite well when launched from a height, delta wings actually perform poorly at low speeds and often are unstable (i.e., they do not stay in level flight on their own). Their primary advantage is efficiency in high-speed flight.

The J-20 without canards is essentially the old F-102 Delta Dart and F-106 Delta Dagger. Installing canards give the J-20 the medium to low (cruising) speed maneuverability the designers WANT, not need. In other words, the J-20 does not need the canards.

Fly-by-wire you say?

More news for you, kid...

The WW I era Sopwith Camel and its companions, friends and foes, approached the negative stability regime in their designs. In other words, FBW-FLCS was designed to deal with (or in response to) negative stability, not to create or introduced negative stability.

Sukhoi Su-7 - Wikipedia, the free encyclopedia

A Su-7U modified with canards and a longitudinal stability augmentation system. It was designed as a testbed for a fly-by-wire system for the Sukhoi T-4. It was later used in 1973–1974 during the development of the Su-27's fly-by-wire system.

What happened was we both deliberately and accidentally intrude into the negative stability regime throughout aviation history with many designs. We found out we could not handle it, and we backed off. Until the advent of electronics.

The entire idea is called 'control configured vehicle'...

ARTIFICIAL STABILITY & FLY-BY-WIRE CONTROL

The lower the natural static stability of the aircraft, the larger the number of corrections required, thus diverting attention from other tasks. This doesn't last forever, because there comes a point where the pilot himself can no longer respond fast enough to make the appropriate correction, with that degree of instability the aircraft becomes unflyable.

A large number of current applications point to the necessity of lower static stability, for one reason or another, yet the aircraft must remain flyable.

In a Control Configured Vehicle (diagram 2.) corrections to the aircraft's attitude are carried out by a computer. Assuming the pilot is not touching the controls, we shall examine the system's behaviour.

The first paragraph clearly indicated that we do not need FBW in order to design and actually fly a negative stability aircraft. We done that and paid dearly for those experimentations. As the Sukhoi Su-7 source showed, we often used positive longitudinal stability designs to test out the FBW-FLCS intended for newer designs with negative stability. Sometimes we even take the aircraft that was originally designed with positive stability and introduce flight control surfaces to make it more unstable to test out the FLCC that is supposed to go into the newer designs that will be built with negative stability.

Next...

The greater the quantity of flight control surfaces and associated their locations, the greater the increase in stability in all axes, even for a negative stability design, in other words, if we have an aircraft that was originally design with negative stability, if we add more flight control surfaces to it in any axis, we moved the aircraft a further away from the point that gave it its signature negative stability characteristic. Computerized CCV moved the aircraft back to that point. The more flight control surfaces are there, the greater the flexibility we must give the FLC computer, or FLCC, so it can do its job.

So if the J-20 which is pretty much a delta winged design, which have inherent poor cruising speed maneuverability, and added canards to remedy that deficiency, you can bet your next decade's salary that the canards will not be 'locked' in place for ANY reason.

Looks like I have far more respect to the Chinese engineers than you and the Chinese boys do. None of you have even turned a wrench on an aircraft, let alone study its foundations, but you have no problems making declarations. You guys are too damn arrogant and full of yourselves to know to pick up a clue even when it is tossed in front of you.