The Engines And Stealth of J-20

Engines

The J-20 entered production powered by a Saturn AL-31 variant, reportedly the AL-31FM2 with a "special power setting" thrust of 145 kN (32,600 lbf).

The Shenyang WS-10 has also powered various aircraft. The WS-10B reportedly powered low rate initial production aircraft. The WS-10 may have replaced the AL-31 in mid-2019. Flights with prototypes powered by the WS-10C were underway by November 2020. In January 2021, WS-10C tests were expected to take a year. The WS-10C is expected to replace the AL-31 as interim engine.

The intended powerplant is the Xian WS-15 with a thrust of 180 kN. The J-20 requires the WS-15 to supercruise. As of August 2019, the WS-15 was in development.

There are conflicting reports concerning the powerplant of the TVC-equipped J-20B. The powerplant has been identified as the AL-31FM2, or a variant of the WS-10; "WS-10C" by Andreas Rupprecht, or "WS-10B-3" by Jamie Hunter. The TVC-equipped WS-10B-3 was demonstrated at the 2018 China International Aviation & Aerospace Exhibition.

The aircraft is equipped with a retractable refueling probe embedded on the right side of the cockpit, to help the fighter to maintain stealth while flying greater distances.

Stealth

Analysts noted that the J-20's nose and canopy use a similar stealth shaping design as the F-22, yielding similar signature performance in a mature design at the front, while the aircraft's side and axi-symmetric engine nozzles may expose the aircraft to radar. One prototype has been powered by WS-10G engines equipped with different jagged-edge nozzles and tiles for greater stealth.

Others have raised doubts about the use of canards on a low-observable design, stating that canards would guarantee radar detection and a compromise of stealth. However, canards and low-observability are not mutually exclusive designs. Northrop Grumman's proposal for the U.S. Navy's Advanced Tactical Fighter (ATF) incorporated canards on a stealthy airframe. Lockheed Martin employed canards on a stealth airframe for the Joint Advanced Strike Technology (JAST) program during early development before dropping them due to complications with aircraft carrier recovery. McDonnell Douglas and NASA's X-36 featured canards and was considered to be extremely stealthy. Radar cross-section can be further reduced by controlling canard deflection through flight control software, as is done on the Eurofighter.

canad: a small winglike projection attached to an aircraft forward of the main wing to provide extra stability or control, sometimes replacing the tail.

The diverterless supersonic inlet (DSI) enables an aircraft to reach Mach 2.0 with a simpler intake than traditionally required, and improves stealth performance by eliminating radar reflections between the diverter and the aircraft's skin. Analysts have noted that the J-20 DSI reduces the need for application of radar absorbent materials.

In May 2018, Indian Air Chief Marshal B.S. Dhanoa claimed that its Su-30MKI fighters could detect J-20 from "several kilometers away" amid reports from the Indian media that the J-20 was undetectable. Analyst Justin Bronk from Royal United Services Institute noted that Chinese are possibly flying the J-20 with radar reflectors during peacetime for safety and training purposes due to the potential for accidents and identification from other aircraft or ground installations.

各国狙击枪最远射程，美国是2286米，英国是1600米，中国射程最远的狙击枪是M99半自动狙击步枪，它最远的有效射程则达到了1500米。

据外国媒体报道，中国正在研发试验名为PL-15的新型远程空空导弹，并成功击落了30千米外的靶机；而歼-16新型多用途战斗机也挂载一枚全新的大型远程空空导弹亮相。 外媒纷纷猜测继PL-12之后，中国开始全力研发新型远程空空导弹，以进一步扩大空军战斗机平台的远程拦截作战能力。

相比枭龙Block2，枭龙Block3在外观和气动布局方面基本没有任何区别，但是内在却得到了脱胎换骨的提升。其中最大的变化便是加装了KLJ-7A型电扫描有源相控阵雷达，工作在X波段，天线直径超过600毫米，集成了约1000个T/R组件。空空模式下的探测距离达到约170公里，可同时跟踪15个目标，并同时引导攻击其中6个目标，对F35A这样的隐身目标的最大探测距离可达80公里以上。整体性能与F-35使用的APG-81雷达相当。

 六级/考研单词: thrust, prototype, interim, aviation, exhibit, equip, probe, embed, cockpit, yield, mature, exposition, radar, tile, detect, compromise, mutual, navy, tactic, carrier, farther, hardware, intake, eliminate, marshal, amid, medium, unite, install