I.STEALTH 1. Canards canards are forewings close to the nose of the aircraft that provide maneuverability. According to Mr. Aboulafia, â€œThereâ€™s no better way of guaranteeing a radar reflection and compromise of stealthâ€ than adding canards to the aircraft.canards are generally indicative of a less-than-harmonious design requiring â€˜bolt-onâ€™ fixes. And as they add radar-reflecting edges, theyâ€™re usually not stealthy. Now compare it all other 5th gwn fighters they dont have canards or may be the chinese are the 1 step ahead to US & russia in stealth designing 2.engine nozzles The same goes for the engine nozzles, which were clearly not designed to be stealthy, as well the large overall size of the aircraft.But in a close air combat, thought it has a higher manoeuvrability, it is still vulnerable to heat seeking missiles as the aircraft lacks a stealth design in the nozzle section. Though, the aft section stealth design doesnâ€™t look satisfactory, the tail boom, fins and the engine with a conventional nozzle compromises further the overall stealth characteristics of the aircraft. The F-22, B-2 stealth bomber and now-retired F-117 stealth fighter-bomber all have carefully shaped, angular nozzles meant to scatter radar waves. In the F-22, these nozzles can move, â€˜vectoringâ€™ the engine thrust to boost manoeuvrability. The apparent absence of stealthy nozzles and thrust-vectoring places a hard limit on the J-20â€™s ability to evade radar detection from behind. The design has only two apparent weaknesses, which are the curvature in the slab side shaping, which provides broader reflection lobes than necessary, and the circular exhaust nozzle, a weakness common to the F-35 and T-50. II.ENGINE The J-20 may have lower supercruise speed and less agility than a Lockheed Martin F-22 Raptor or PAK FA, The 117S series has thrust vectoring nozzles and will add to the manoeuvrability of the aircraft. Since it has a conventional nozzle it will have a high infra red signature which makes it vulnerable to missile which have IR homing. The aircraft also lacks super cruise capability, one of the essential aspects of a fifth generation fighter. But the AL-31F isnâ€™t necessarily adequate for a large, stealthy fighter. For the T-50, Sukhoi originally planned to use an up-rated version of the AL-31F, but ended up installing a brand-new (and mostly secret) engine, instead. Since the early 1990s Russian sources have disclosed to the author that Shenyang was experiencing great difficulties in meeting planned thrust goals, while there have been reports and rumors of other specific problems. In August 2009 a Chinese AVIC official admitted there were many problems facing the Taihang but declined to elaborate. In 2004 a Russian official speculated that China would still put this engine into production. Other possible issues include incidents of shedding turbine blades, oil leakage issues, and even one unconfirmed rumor of a new J-11BS fighter disintegrating in flight due to a Taihang engine failure. While having resisted the sale of its current advanced turbofan technology to China, Russia hopes to remain a source for completed advanced turbofans. According to Russian officials China has purchased between 300 and 400 Saturn A-31FN engines for the Chengdu J-10 fighter. This source also noted that China has not yet purchased a thrust-vectored version of this engine despite reports of interest dating back to 2005. However, this source did note that China is interested in the improved more powerful versions of the AL-31. For example, the AL-31F-M1 adds 1,000kg of thrust for a total maximum thrust of 13,500kg, and Russian officials note that future versions could achieve 15-tons of thrust. The PLA may make additional purchases of the AL-31FN if Shenyangâ€™s and Chengduâ€™s engine programs remain problematic. While sale of Russiaâ€™s next generation Saturn Item 117 turbofan remains possible, it may not be likely given that China would prefer that its 4th/5th generation fighter be an indigenous product. However, evidence still suggests that AVICâ€™s engine makers are having trouble maintaining consistent quality control as they scale up production of the WS-10, causing problems with reliability and keeping Chinaâ€™s tactical aircraft heavily reliant on imported Russian engines. Russiaâ€™s defense industry appears to believe that China will continue to be unable to attain reliable mass production of high-performance military turbofans. For example, NPO Saturn, a key Russian military jet engine maker, forecasts that it will continue serving as the primary engine supplier for China J-10 and FC-1 fighter programs through 2019. Saturnâ€™s optimism may stem in part from the fact that is it currently in talks with China over the possible sale of 190 D-30KP-2 turbofans, which could be used on Chinaâ€™s IL-76 aircraft. The lack of a sufficient supply of reliable domestically made jet engines could significantly impede future production of the J-10, J-11, J-15, and J-20 fighter aircraft. The J-20 program especially needs domestic engine development and production breakthroughs because the Russia appears reluctant to sell the 117S series engines that could enable the J-20 to have sufficient power to allow the aircraft to supercruise (sustain supersonic flight without using inefficient afterburners) and match the performance of 5th-generation fighters such as the Lockheed Martin F-22 and Sukhoi T-50/PAK FA. A Russian aerospace expert recently quoted in Huanqiu Shibao says Chinaâ€™s inability to produce world-class high-performance jet engines will be a major barrier to large-scale production of the J-20 and in the meantime will hinder Chinaâ€™s ability to full test the airframeâ€™s capability in the ways that it could with engines making 35,000-40,000 lbs of thrust like the AL-41 and U.S. F119 engines can. The Russian experts statements lead to two core logical conclusions: (1) China is unlikely to want to rely on imported components for its latest generation fighter, and (2) in the wake of the disputes over Chinaâ€™s reverse engineering of Flanker variants (into Chinaâ€™s J-11 and J-15) and subsequent slowdown/suspension of new orders of Russian combat aircraft, Saturn and other Russian jet engine makers are unlikely to receive Kremlin approval for selling substantial numbers of high-end engines like the Saturn S117/AL-41 (used in the T-50) to China. But despite all these if Russia stills sell advance engines to china for J20 then they are digging their own graves. III.MATERIALS To the best of our knowledge, no Chinese sources have published a materials composition breakdown for the J-20. Materials are key in a late-generation fighter for two major reasons. First, the plane must be sufficiently robust to withstand violent maneuvering and the heat generated by sustained high-speed operation. We think Chinaâ€™s aerospace industry now has most if not all of the requisite capabilities. Baoti, one of Chinaâ€™s largest titanium producers, says that it supplies 95% of the titanium used by Chinaâ€™s aerospace complex, suggesting that the company can produce high-grade materials. This is a key point because the other main global suppliers of aerospace grade titanium are all potential competitorsâ€”the U.S., Russia, and Japan. Second, advanced composites and surface coatings (e.g., special radar-absorbing paint) help reduce radar signature. The F-22 and T-50 are each roughly 25% composite by weight. We think it is likely that the early J-20s are more titanium and metal-intensive and that as the design is refined to reduce radar cross section (RCS), the composite content will rise. As China pursues low-observable aircraft and UAVs, we expect significant advances in the domestic composite and coatings industry as the defense complex strives to avoid reliance on key imported components IV.Avionics/electronics Electronic equipment, primarily radar, in China stands at approximately the same level as its engines. Chinese designs fall short of the capabilities of their Russian, European and American counterparts. Although China has been gradually narrowing the gap, it still has to import modern electronic equipment for its aircraft. The best aircraft radar systems are currently made for Russia's Su-30MKK fighters, and China will most likely copy this design. It is not clear how much it will differ in terms of specifications from next-generation Russian or American radar systems.Access to Russian and Israeli active electronically scanned array (AESA) technology has likely accelerated China development of this critical technology for 4+ and 5th generation fighters and new radar aircraft. We are watching carefully for indications that China has developed sensor fusion capabilities and an advanced active electronically scanned array (AESA) radar systems, which allow an aircraft to scan for adversaries while being hard to detect. AESA systems also confer jamming resistance, an important advantage in an intense electromagnetic environment like that which would likely characterize a modern Asian military contingency. CONCLUSION The j20 may be better in stealth than it's russian competitors,but it has no other clear advantage to it's Russian rivals t50 & US rivals f22.