J20 Stealth Fighter

MiG-29SMT

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This seems to be prototype 2013. Notice the same band just aft of the radome in these earlier pics of 2013 testing these twin rail AAM missile racks:

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I am an airplane fan, in general I like aircraft regardless of their nationality, sometimes i get in debates but i remember i should cool off, we are all humans, so I like to see J-20 as a technological marvel, I was born in 1971, so when i was young I love MiG-23 and MiG-25, later I discovered I love F-14 a lot, I am an engineer, but not in aviation, but still I love aircraft.

I follow J-20 because I love aerodynamics, I learned a lot talking with people online about aerodynamics, I love IAI Lavi.

I am a western guy because simply i was born in the western hemisphere, and I have to confess you I belittled J-20, with the age you learn to be more humble and honest.
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Now I understand more J-20, it was made less stealthy than F-22 intentionally, the canards we set up there because tailerons push up the nose up, if they are statically instable, I mean the aerodynamic center of the main wing is ahead of center of gravity, the tailerons exert a tail up force so their lift is added to the aircraft if the aircraft is statically instable contrary to a statically stable aircraft where the tailerons reduce lift for a nose up pitch up force.
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If they use canards the canards by being ahead of the wing, exhibit a high pitch up tendency, so they will give a quicker pitch up force.

J-20 was designed with that in mind, so they had to rely less in thrust vectoring control like F-22.

IAI Lavi for example is the best example, it was a F-16 with lower thrust but with higher instataneous turn rate than F-16.

Since Chengdu designed a modified Lavi, they applied that experience to J-20
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MiG-29SMT

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This seems to be prototype 2013. Notice the same band just aft of the radome in these earlier pics of 2013 testing these twin rail AAM missile racks:

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What I mean is you can think F-22 is like F-16 and J-20 is IAI Lavi.

Lavi gets better instantaneous turn rate than F-16 thanks to the canard, the canard and by being statically unstable, make Lavi to have a quicker instantaneous turn rate than F-16 despite has a less powerful engine

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you can see the figure 44 in it they show you the turn rate of IAI Lavi and 2 other aircraft named a and b, they are probably F-16 and F-18, you can see Lavi was not as good sustaining a Turn but initiating a turn aka instantaneous turn rate, it was pretty good, the idea of J-20 probably is the same, lacking Thrust vectoring and knowing China was going to have WS-15 late in the J-20 operational history, they adapted the canards.


F-16XL was superior alsoo to regular F-16 because its large wing gave it very low wing loading

Two additional capabilities of the F-16XL contribute to survivability. First is improved instantaneous maneuver ability coupled with greatly expanded flight operating limits (with bombs), and second is reduced radar signature resulting from the configuration shaping.

Importance of High Turn Rate

For a decade and a half, many fighter tacticians have stressed the paramount importance of being able to sustain a high turn rate at high Gs. The rationale was that with such a capability, enemy aircraft that cannot equal or better the sustained turn rate at high Gs could not get off a killing shot with guns or missiles.

With developments in missiles that can engage at all aspects, and as a result of having evaluated Israeli successes in combat, the tacticians are now leaning toward the driving need for quick, high-G turns to get a “first-shot, quick-kill” capability before the adversary is able to launch his missiles. This the F-16XL can do. Harry Hillaker says it can attain five Gs in 0.8 seconds, on the way to nine Gs in just a bit more time. That’s half the time required for the F-16A, which in turn is less than half the time required for the F-4. The speed loss to achieve five Gs is likewise half that of the F-16A.

All of these apparent miracles seem to violate the laws of aerodynamics by achieving greater range, payload, maneuverability, and survivability. Instead, they are achieved by inspired design, much wind-tunnel testing of shapes, exploitation of advanced technologies, and freedom from the normal contract constraints.




What I mean is if the F-22 and J-20 have similar parameters J-20 with Canards might at least be not so bad for turning, F-22 has the advantage of better thrust to weight ratio and Thrust vectoring ensuring post stall capability, and very good sustained turn rates at least compared to a J-20 with Al-31s
 
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MiG-29SMT

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This seems to be prototype 2013. Notice the same band just aft of the radome in these earlier pics of 2013 testing these twin rail AAM missile racks:

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View attachment 74272
What I am trying to say is summarized here in this Lavi article

After the Cancellation
Although the flight performance envelope was not completely explored, it seems probably that the Lavi would have been at least the equal of the F-16C/D in most departments, and possible even superior in some. It had been calculated that the Lavi could reef into a turn a full half second quicker than the F-16, simply because a conventional tailed fighter suffers a slight delay while the tailplane takes up a download, whereas with a canard fighter reaction is instantaneous. By the same token, pointability of canard fighters is quicker and more precise. Where the Lavi might really have scored heavily was in supersonic maneuverability, basically due to the lower wave drag of a canard delta.


Wing loading: 302 kg/m2 at normal take-off weight and 523 kg/m2 at maximum take-off weight. Sustained air turning rate: 13.2o/s at Mach 0.8 at 4,757 m. Maximum air turning rate: 24.3o/s at Mach 0.8 at 4,757 m. Take-off distance: 305 m at maximum take-off weight. G limit: + 9 g.

So if J-20 more or less is like Lavi if J-20 has similar wing loading difference as IAI Lavi had with F-16 with respect F-22


So J-20 designer followed IAI Lavi philosophy with J-20.

Consider with Al-31 it is highly underpowered so Sustained turn rate will make current J-20s act more like interceptors than Air superiority fighters, If WS-10 is like 117 perhaps might cope with F-22 to some degree, if WS-15 is soon fitted it might be potentially better than F-22, specially since J-10 has tested Thrust vectoring nozzles
 

rockdog

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China was interested with J10 like intake since later 1970s'. This magazine was Youth Secience on 1979.

j10.jpg


The nearest time of similiar intakes came to China was 1987, the thunderbird visited China:

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MiG-29SMT

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China was interested with J10 like intake since later 1970s'. This magazine was Youth Secience on 1979.

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The nearest time of similiar intakes came to China was 1987, the thunderbird visited China:

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that is partially true, I will tell you why that is not accurate.

Any one that knows about aerodynamics, I mean the basics, knows that aerodynamic studies take thousends of hours of research and development.

To put it simple, a wing or a taileron has many, many posible configurations.
These are for example distance between taileron and wing, vertical and horizontal distance.
aspect ratio, you can divide canards by aspect ratio, for example.
Wing position with respect the fuselage, trailing edge sweep or leading edge sweep, camber distance, wing airfoil shape and so on.

So that resaearch takes too much time and money, add avionics, structure, etc etc, and you find the average aircraft takes 5 to 8 years to be designed and 8 to 14 years to be flight tested.

the first evidence of IAI Lavi being the basis of J-10 is the visit J-10 design team made to IAI, this type of visit is not to drink tea but to exchange data, why? simple research takes time, so with money you buy data that reduces design and research time
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this shows the original J-10 had several configuratoins studies but look at the main wing and you see it is very similar to the IAI Lavi wings
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this shows you that IAI went to study several wing airframe configurations just to get to Lavi final shape
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An early IAI Lavi configuration with a boxy intake, racked inlet lips shape like J-10
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J-10 mockup with Lavi type pitot intake

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The strongest admission of Israeli involvement in the J-10's development by Israeli authorities appeared in a statement made by an official as American authorities investigated alleged Lavi technology transfers to China. Without mentioning either Lavi or J-10, the Director General of Israel's Ministry of Defense David Lari "acknowledged in an Associated Press interview that 'some technology on aircraft' had been sold to China and that some Israeli companies may not have 'clean hands'".
In May 2008, Jane's Information Group reported several interviews with Russian sources claiming to be involved with various Chengdu military projects. A number of engineers, designers and technical specialists described their visits to Chengdu and other areas of China in the 1980s. A source alleged that high-level Chengdu officials described the possession of a single Lavi prototype at one of Chengdu's facilities. They also claim that in 2000, two years after the J-10's maiden flight, aerodynamic models were sent to Russian wind tunnel testing facilities to study the J-10's aerodynamics.

During the 2006 Farnborough Airshow, the Russian Siberian Aeronautical Research Institute (SibNIA) confirmed its participation in the J-10 program. According to the article, this participation was limited to observation and instruction as "scientific guides." The sources also called the J-10 "more or less a version of the [Israel Aircraft Industries] Lavi", but also a "a melting pot of foreign technology and acquired design methods" Left unelaborated is the degree of Israeli participation - if any - in J-10 development.
Kommersant's reporter Kostantin Lantratov affirmed that Russian consent was required to export the J-10, given its Russian AL-31 engine.

It has been reported that composite materials tested in the Delsen Testing Laboratories in Glendale, California during the year 1990 were related to the J-10 project.




This Yakolev prpject was ahead of its time, but if you see it shows you the path J-20 had, canards were chosen due to the advantages they offer over tailerons in terms of instantaneous turn rate.

Now for J-20 in order to be designed needed not 1 or 2 configurations but many configurations, it is obviously they copied and studied F-35 and MiG 1.44, but definitively the Lavi experience left some inprint on J-20
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So to put it simple J-10 has a wing and landing gear position repeating the same configuration. the ventral fins and trailing edge wing extension are the same configuration, in order to be that similar they needed direct participation from IAI.

Lavi had many innovative solutions in structure and aerodynamics with respect the wing arragement, these were Israeli solutions, J-10 took over those studies there is ample evidence of it.
 
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MiG-29SMT

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while not a stealth fighter this AFTI configuration shows aerodynamic studies and a configuration similar to J-20

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american studies that show early Lavi configuration

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JSF studies configuration C160 shows similarities to J-20

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MiG-29SMT

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Designers of J-10 and J-20, Song weng cong leading head deputy of J-10 Program with Chief designer of J20 Yang wei

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He also had some Russians helping him

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Probably he said Camarad, when I worked for MiG ...........da camarad set two ventral and dorsal fins in booms like our MiG

 

MiG-29SMT

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Deliveries Chengdu J-10C seems to have been stopped.

A visit to Chengdu Aerospace Corporation (CAC) at Chengdu/Huangtianba (China) early January 2021 revealed that deliveries of the Chengdu J-10C fighter aircraft to the People's Liberation Army - Air Force (PLAAF, China Air Force) seem to have stopped.

Over thirty J-10Cs were noted outside on the tarmac, fully covered by camouflage tarpaulin waiting for things to come. Google Earth shows only a dozen, but that is the situation as it was in February 2020.

Also, during the visit in January, it became clear that production of the Chengdu J-20 is in full swing, with aircraft for the 1st Brigade at Anshan being produced (serials 61x2x), where they will replace the Shenyang J-11s.

 

Marliii

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J20 looks like a big cruise missile.there were some reports of j20 not having a internal gun for close range fights.is that issue addressed now?
 

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