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eble

Chinese J20 Stealth Fighter revealed

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The eurofighter uses software canard control to manage and reduce the radar cross section its canards present. I'd imagine that such a feature is present in this aircraft. Moreover, the canards appear highly swept. It seems like the canard flutter, if indeed the software controller will behave in such a way, can be design for so as not to present a specular reflection in its regular stability tasks in terms of shape or software.

Looking at the lighting on the rear of the aircraft in those photos, it looks like the fuselage contours abruptly change shape near the engine nozzles. It seems like maybe they changed that for these current engines and maybe will fit more stealthy nozzles at some later point.

Edited by Max Power

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The eurofighter uses software canard control to manage and reduce the radar cross section its canards present. I'd imagine that such a feature is present in this aircraft.

I believe this was part of the argument that Walker was making arguing that the J-10 flight controls were used in the development of the J-20s, that were derived from IAF Lavi development, and such consultation was a violation of technology export regs. As for including an optimization parameter for reducing radar cross section in the flight control system, I doubt the Eurofighter had RCS as a feedback to the canard cylinder controller or other control surfaces. The flight stability equations are hard enough to deal with, factoring in estimations for RCS based on the many permutations of distance, incident angles of waves, at varying amplitude, and wavelengths, coupled with varying flight conditions would be a night mare to develop. Not saying it is impossible, but just doubt it was developed for an aircraft, Eurofighter, which design criterion did not include low-observability.

Moreover, the canards appear highly swept....

I suspect that that the reason the canard are swept at an angle similar to the wing is to take advantage of the interaction of vortices from canard to the leading-edge of the wing, which increases its strength and therefore augments the lift.

Edited by XDMerciless

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I believe this was part of the argument that Walker was making arguing that the J-10 flight controls were used in the development of the J-20s, that were derived from IAF Lavi development, and such consultation was a violation of technology export regs. As for including an optimization parameter for reducing radar cross section in the flight control system, I doubt the Eurofighter had RCS as a feedback to the canard cylinder controller or other control surfaces. The flight stability equations are hard enough to deal with, factoring in estimations for RCS based on the many permutations of distance, incident angles of waves, at varying amplitude, and wavelengths, coupled with varying flight conditions would be a night mare to develop. Not saying it is impossible, but just doubt it was developed for an aircraft, Eurofighter, which design criterion did not include low-observability.

All I can say in response to this block of nonsense is that it was a criterion.

I suspect that that the reason the canard are swept at an angle similar to the wing is to take advantage of the interaction of vortices from canard to the leading-edge of the wing, which increases its strength and therefore augments the lift.

So the outward facing angles of the f117 were obviously *only* drag related.... :thumbs-up:

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I'm not really interested in this but it might interest you:

http://www.wired.com/dangerroom/2011/01/old-school-jet/

;)[/QUOTe]

interesting read, if it's true the US air force is saying no aircraft is stealthy enough and oh by the way we can just update some old jets with a new radar and become stealth killers.

either the F22 is/was a good jet or it isn't, maybe the US airforce didn't think anyone was have there own stealth fighters for many years?

so the russians just need to update the radar's on those Mig31 and no more stealth worries I guess.

Maybe the US airforce just wasted billions on a white elephant and now everyone else is copying?

Edited by Eble

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Maybe the US airforce just wasted billions on a white elephant and now everyone else is copying?

Yeh, thats what ive been wondering now for a few years. It might explain all the various program changes.

For every evolution of "stealth", someone will eventually evolve a new "detector"

Next evolution I'd say, UAV's.

Pretty hard to beat cheaper, smaller, safer and fast ......

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All I can say in response to this block of nonsense is that it was a criterion.

I stand corrected, upon deeper examination, my doubts were wrong with respect to the EAD engineers feeding back an RCS optimization parameter on the canard angle - the Eurofighter was indeed designed with low-observability in mind, and the engineers did implement it as Max Power suggested. ;)

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

Radar signature reduction features

Although not designated a stealth fighter, measures were taken to reduce the Typhoon's radar cross section (RCS), especially from the frontal aspect.[140][141] An example of these measures is that the Typhoon has jet inlets that conceal the front of the jet engine (a strong radar target) from radar. Many important potential radar targets, such as the wing, canard and fin leading edges, are highly swept, so will reflect radar energy well away from the front sector.[142] Some external weapons are mounted semi-recessed into the aircraft, partially shielding these missiles from incoming radar waves.[140] In addition radar absorbent materials (RAM) developed primarily by EADS/DASA coat many of the most significant reflectors, e.g. the wing leading edges, the intake edges and interior, the rudder surrounds, strakes, etc.[140][143] The Typhoon does not use internal storage of weapons. External mounting points are used instead, which increases its radar cross section but allows for more and larger stores.[144]

The Eurofighter operates automatic Emission Controls (EMCON) to reduce the Electro-Magnetic emissions of the current mechanically scanned Radar.[140] The Captor-M was the first NATO-Radar with three rather than two working channels, one intended for classification of jammer and for jamming suppression.[145] The German BW-Plan 2009 indicates that Germany will equip/retrofit the Luftwaffe's Eurofighters with the AESA Captor-E from 2012.[146] The conversion to AESA will give the Eurofighter a Low Probability of Intercept Radar with much better jam resistance.[147][148] These include an innovative design with a gimbal to meet RAF requirements for a wider scan field than a fixed AESA.[149] The coverage of an fixed AESA is limited to 120 degree in azimuth and elevation.[150]

According to the RAF, the Eurofighter's RCS is better than RAF requirements. Comments from BAE Systems suggest the radar return is around one quarter of that of the Tornado it replaces.[151] The Eurofighter is thought to have an RCS of less than one square metre in a clean configuration by author Doug Richardson, although no official value is available.[142] This compares with the estimated RCS of the Rafale of 2 square metres,[152] the 20 square metres of the Sukhoi Su-30MKI,[153] the 1 square metre of the Su-35BM[154] and the American F-117 of 0.025 square metres.[152] The manufacturers have carried out tests on the early Eurofighter prototypes to optimize the low observability characteristics of the aircraft from the early 1990s. Testing at BAE's Warton facility on the DA4 prototype measured the RCS of the aircraft and investigated the effects of a variety of RAM coatings. Another measure to reduce the likelihood of discovery is the use of passive sensors, which minimises the radiation of treacherous electronic emissions. While canards generally have poor stealth characteristics,[155] the flight control system is designed to minimise the RCS in flight, maintaining the elevon trim and canards at an angle to minimise RCS.[156][157]

It seems ultimately you guys convinced me that the Chinese may have implemented successfully an low-observability canard plane design with an RCS on par with our Raptor.

So the outward facing angles of the f117 were obviously *only* drag related.... :thumbs-up:

I was just speculating that the reason for the same shared swept angle of the canard and wing was that the Chinese engineers intended to superimpose the vortices. The canard could have had a different angle, yet still refract the radar waves.

I'm not really interested in this but it might interest you:

http://www.wired.com/dangerroom/2011/01/old-school-jet/

interesting read, if it's true the US air force is saying no aircraft is stealthy enough and oh by the way we can just update some old jets with a new radar and become stealth killers.

either the F22 is/was a good jet or it isn't, maybe the US airforce didn't think anyone was have there own stealth fighters for many years?

so the russians just need to update the radar's on those Mig31 and no more stealth worries I guess.

Maybe the US airforce just wasted billions on a white elephant and now everyone else is copying?

It's not just updating the radar systems on aging aircraft like the F-15, but the ability to employ the tactics that the article mentions with active radar blaring on the 4th gen fighter or other support aircraft, using them as bait or to invite an attacker to move to an unsuspecting area where F-22s/JSF lie in wait working in passive radar mode. Reminds me of scenes from The Hunt for Red October, but instead of sonar its radar. It's interesting article, if I can find it, I remember reading somewhere that a possible new role for the B1 along the same lines of what this article describes with the F15, but carries an complement of entirely air to air missiles. Picturing a B1B coming in supersonic and launching all its missiles would be an awesome sight.

Gnat]Yeh, thats what ive been wondering now for a few years. It might explain all the various program changes.

For every evolution of "stealth", someone will eventually evolve a new "detector"

Next evolution I'd say, UAV's.

Pretty hard to beat cheaper, smaller, safer and fast ......

Always a cat and mouse. Yeah for the immediate future definitely UCAVs (Unmanned Combat Aerial Vehicles). Look forward to seeing what the aviation industry develops with these highly maneuverable planes that won't be held back because of the human factor - from blacking out or redding out while performing high-g-maneuvers, restrictions limited to the structure's ability to withstand limit loads and fatigue. Placing my self in the shoes of our future aerial adversaries, I'd already be scared enough to know I am going against something I can not only see, literally to my naked eye or instruments, but can pull 10+ gs with no sweat, and psychologically knowing that no pilot is physically in the opposing plane(s) either.

Edited by XDMerciless

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It's a bit odd that they seem to have shown no concern with regard to IR suppression. IRST has proliferated in Western aircraft since the days of the Tomcat, and the F-35 does seem to have a very effective EO system...

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It seems ultimately you guys convinced me that the Chinese may have implemented successfully an low-observability canard plane design with an RCS on par with our Raptor.

Well that's also premature. There's no reason to believe anything about this aircraft other than it can fly and that it looks stealth oriented. The Americans say it's a piece of shit, and the Chinese say it can walk on water. It looks kind of cool, canards can be made more stealthy- however, all the fins all over it probably aren't helping.

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What interested me was a lot of wing vortex disturbance / wash as it climbed in the take-off video.

Looking at the shape of the whole thing, had me wondering how much a dog this was at low speed.

.... it looks a little like is meant for fast straight line activity only, no maneuvering.

No surprise I guess if they intend it to be reliant on "stealth".

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As I understand it, the engines for this plane are made in Russia.

China has no jet engine manufacturing capability.

Which is the plane which China stole the design of from Russia? I take it is not this one.

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As I understand it, the engines for this plane are made in Russia.

China has no jet engine manufacturing capability.

Which is the plane which China stole the design of from Russia? I take it is not this one.

They've stolen/licenced several designs from the Russians throughout history. Are you referring to their production of the Su-27 as the Shenyang J-11?

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You foreigners is impossible to fully understand China's things,

like we Chinese people can't fully understand ourself.

Wise person wouldn't be easily assertions anything.

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For some, simply saying 'oh that is impossible to understand' is not enough... and thank God for that. For at least we are able to carry on an interesting discussion in online forums... or perhaps even advance as a civilization.

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You foreigners is impossible to fully understand China's things,

like we Chinese people can't fully understand ourself.

Good to hear we're not alone ;)

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