[情報] J20新估計數據

[ryannieh (new)]

http://tinyurl.com/4fs7ary
（註：本文作者似乎是找了專家分析網上照片而得到了
本文的結論。至於分析是否正確或有沒有額外的情報管
道，就有待驗證了。約略翻譯了一下，如有錯誤敬請見
諒wwwww）

New Details On China's J-20 Fighter Provide More
Nuanced View Of Threat
Author:Loren B. Thompson, Ph.D.
Date:Wednesday, March 2, 2011
Tags:F-15, F-22, F-35, J-20

Aerospace experts scrutinizing images of the Chinese J-20
fighter that first began appearing on the internet in late
December have developed a more nuanced view of the
plane's features than what was available in early reports.
Although the J-20 resembles the outline of the stealthy
F-22 Raptor when viewed head-on in its forward aspect, the
plane clearly lacks many of the features that make Raptor
the most capable air-to-air combat system in history. On the
other hand, these same experts believe that over time the
Peoples Liberation Army Air Force can evolve the J-20
into a formidable combat aircraft -- especially given the
fact that it is expected to operate in or near Chinese
airspace, where it will greatly outnumber any attacker's
planes.
航太專家經檢視於去年十二月開始出現於網上的中國
J20的照片得到了較原先更加細膩的了解。雖然J20之
前視外貌類似F22，實際上卻明顯地缺乏許多讓F22成
為史上最有威力之空戰戰機的特點。然而，這些專家也
相信假以時日解放軍空軍能使J20發展為強大的戰機─
─特別是考慮到它的被期望的作戰環境是中國空軍能數
量上壓倒敵人的領空及其週邊。

Early reports that the J-20 exceeds 70 feet in length appear
to be wrong. By comparing the scale of the aircraft with
adjacent reference objects whose dimensions are known,
experts have determined that the fighter is 62 feet long –
the same length as the F-22, and not much different from
the 64 feet of the F-15C fighter. Based on overhead
imagery and other inputs, wingspan looks to be about 41
feet, also similar to F-22 (45 feet) and F-15C (43 feet).
However, the wing area of roughly 630 square feet much
more closely resembles the 608 square feet of the F-15C
than the 840 square feet on the F-22; this matters a great
deal in terms of range since fuel is stored in wing areas.
早期的報告稱J20有超過70英呎的長度似乎是錯的。經
比較其週邊相關已知尺寸的物體，專家判定其長度為62
英呎──和F22相當，而和F15C沒差多少。根據上視
圖以及其它管道了解，其翼展約41英呎，約略相同於
F22 (45英呎)和F15C (43英呎)。然而，其翼面積630平
方呎較接近於F15C的608平方呎而不是F22的840平
方呎。由於油料可儲於翼內，此一較小的翼面積嚴重地
影響了航程。

The J-20's top speed is judged to be below Mach 2,
meaning it is significantly slower than an F-22 or F-15C.
Little is known about the performance features of the J-20's
twin jets, which may be based on technology from the
western CFM-56 commercial powerplant first exported 30
years ago. The steady-state thrust provided by the engines
is probably similar to the 29,000 lbs of the F-15C, but
greatly inferior to the 48,000 lbs generated by the two F119
engines on the Raptor (J-20 maximum thrust of 60,000 lbs
comes closer to the 70,000 lbs of F-22, and surpasses the
48,000 lbs of F-15C). The J-20 does not have the
supercruise feature of the F-22 that allows the latter plane
to fly at high speed without consuming excessive amounts
of fuel, which puts the J-20 at a decided disadvantage given
that it carries about 25 percent less fuel internally than the
F-22. It also does not have the vectored thrust of the F-22
that provides enhanced aerial agility; the Chinese appear to
have modified the fixed exhaust nozzles on the J-20 with an
eye to misleading western observers concerning how
capable the propulsion system is.
J20的極速被認為低於兩馬赫，低於F15C或F22的極
速。（專家）對於J20的可能發展自西方30年前出口之
CFM-56商用引擎的引擎性能所知有限。J20的雙引擎可
能能提供近似F15C引擎的29,000磅穩態推力（註：這
裡指的應該是F100-PW-100的軍用推力），但該推力遠
遜於F22的兩具F119的48,000磅（J20的最大推力
60,000磅接近F22的70,000磅而超過F15C的48,000
磅）。J20沒有如同F22般能高速飛行而不用大量消耗
油料的超巡性能，這讓其處於決定性的劣勢，特別是其
內載油料已較F-22少了25%的情況下。J20亦沒有像F22
採用能提高敏捷性的向量噴嘴；中國方面似乎改動了固
定式的噴嘴試圖誤導西方觀察家對於J20推進系統性能
的看法。

The J-20 airframe incorporates extensive low-observable
(stealth) technology into its forward aspect, although it is
more readily tracked from side and rear angles. However,
even in the forward aspect some design features such as the
engine inlets appear sub-optimized for reduction of radar
cross-section. It is not clear how extensively designers have
used radar-absorbing materials. It is also not clear what
kinds of on-board electronics the J-20 will eventually carry
in its operational configuration. Electronic sensors,
processors and datalinks are the heart of the F-35 Joint
Strike Fighter, greatly surpassing the performance of even
those on the F-22.
J20的機型對前向採用了大量的匿蹤科技，雖然側向和
後向的匿蹤較差。然而，即使是前向匿蹤，有些設計，
像是引擎進氣口，似乎並未對縮減雷達截面積最佳化。
設計者採用了多少雷達吸波材料在J20上未知，最終機
上將採用何種電子裝備於其量產機型亦未知。感測器、
處理器、資料鏈是F35聯打機的心臟，其性能甚至遠超
過F22所使用的。


While the J-20 superficially resembles fifth-generation
fighters such as the F-22 and F-35, experts do not believe
Chinese designers will be able to produce an airframe that
comes close to matching the maneuverability, survivability,
 lethality or situational awareness of an F-22 or F-35.
However, they may not need to if they can lure enemy
fighters into Chinese airspace where they have other "home
court" advantages.
雖然J20表面上形似如F-22和F-35的第五代機，專家
們並不相信中國設計者們能造出一架在機動性、生存
性、攻擊性或狀況意識能力和F-22或F-35相當的飛機。
然而，當他們可引誘敵人進入他們有「主場優勢」的領
空時，他們並不需要那麼做。

Loren B. Thompson, Ph.D.

--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 74.111.48.3
推 aixm        :好久沒有關于j20的消息了
推 icehhh      :專家們不相信j20會問世，結果...
推 aixm        :這篇文章可以讓j20的動力疑問得到解
→ aixm        :釋，j20沒那麼大，還比較瘦，空重小
推 BUMAS       :因該說專家不相信有相近F22戰力的J20
→ BUMAS       :能問世..事實上也是如此
推 aixm        :除非打一次
推 rommel1     :跟F-22差不多大?   太低估了吧
推 rommel1     :引擎應該是AL-31
推 aixm        :很多人都說差不多大
推 zaku7777    :日本人是很不客氣的估了23m級的長度.
重點是空重多少不知道。從正面看來，J20是蠻「厚」的…
※ 編輯: ryannieh        來自: 74.111.48.3          (03/31 20:21)