一路 BBS

 找回密码
 注册
搜索
查看: 720|回复: 2

歼10B将亮相珠海航展

[复制链接]
发表于 10-30-2018 16:44:00 | 显示全部楼层 |阅读模式
乌龙防务评论 (author name), 矢量航发版歼10B亮相 喷管活动范围超F22与苏35航发. 新浪军事, Oct 30, 2018
mil.news.sina.com.cn/jssd/2018-10-30/doc-ihnaivxq7541086.shtml
("军迷们发回了很多歼-10B推力矢量验证机降落珠海机场的特写照片。这种在涡扇-10B改进型太行发动机上研发的推力矢量发动机,是一种采用轴对称矢量喷管的先进TVC发动机,喷管可上下左右活动 * * * 要知道,一架代号2021的歼-20的批生产型原型机,正装上推力14吨级的涡扇-10B发动机进行测试,它还是采用红外隐形喷管的改进型")

Note:
(a) "A force has both magnitude and direction, making it a vector quantity."  en.wikipedia.org for Force.

So, the issue is not thrust vectoring or vectored thrust (both terms found in the Web), but how to change the direction of thrust when desired. See thrust vectoring
https://en.wikipedia.org/wiki/Thrust_vectoring
(also thrust vector control or TVC)

(b) VTOL
https://en.wikipedia.org/wiki/VTOL
("Besides the ubiquitous helicopter, there are currently two types of VTOL aircraft in military service: craft using a tiltrotor, such as the Bell Boeing V-22 Osprey, and another using directed jet thrust, such as the Harrier family and new F-35B Lightning II Joint strike Fighter (JSF). * * * [photo caption:] The Harrier and the Yak-38 were the first operational examples of VTOL fixed-wing aircraft")
(i) V-22 uses two turboshaft engines, one on each wing.
(ii) Turboprop and turboprop are almost identical. See the second illustration in
What are the differences between a helicopter engine (turboshaft) and an aircraft engine (turboprop)?  Stackexchange.com, June 2015
https://aviation.stackexchange.c ... haft-and-an-aircraf

Turboshaft is also used in helicopters.
回复

使用道具 举报

 楼主| 发表于 10-30-2018 16:44:54 | 显示全部楼层
本帖最后由 choi 于 10-30-2018 16:46 编辑

(c)
(i) Each Harrier (in service 1969- (UK retired it but US Marine Corps likes and retains it) ) has one (turbofan) engine, with four rotating nozzles (a pair of front nozzles and a pair of read nozzles).
(A) The engine is Rolls-Royce Pegasus.

Kevin Richardson, Vectored Thrust Jet Engines. MIT (2.972 is an undergraduate course; in the series "Reports on How Things Work")
http://web.mit.edu/2.972/www/rep ... _thrust_engine.html

View only the first pair of illustration: Left is top-down view (the front of engine/Harrier on the left; note blue-colored cold air through entry and combustion chamber red; the four parts jutting upward and downward are nozzles) and right is lateral view (showing nozzles tilting downward when taking off or landing).
(B) About the rotating nozzles again. See Harrier Hover Capability. Aerospaceweb.org, undated
www.aerospaceweb.org/question/planes/q0042.shtml
(view the top illustration only)
(C) Sheldon M Gallager, Coming: Jump Jets That Break the Sound Barrier.  Popular Mechanics, June 1984, pages starting at 59
https://books.google.com/books?i ... egasus+rolls+royce+"front+nozzles"&source=bl&ots=4G8z4ZabXq&sig=M0QLg5lKXiNkp5cUQY_YP5gTW_Y&hl=en&sa=X&ved=2ahUKEwiDiMLsgq_eAhXET98KHTMjBjEQ6AEwDHoECAEQAQ#v=onepage&q=pegasus%20rolls%20royce%20"front%20nozzles"&f=false
(page 96: "(continued from page 62) * * * In the present Pegasus, fuel is burned only in the main combustion chamber leading to the two rear exhaust nozzles. The two front nozzles discharge compressed but unburned air supplied by the low-pressure fan. This provides sufficient thrust for vertical lift, but not enough for supersonic flight")  

This page talked about "Plenum Chamber Burning" (PCB) to make Harrier supersonic (from subsonic) and compared PCB with afterburner. The project was canceled. So there is no need to read it.
(D) Harrier (BAe/McDonnel Douglas). School of Aeronautics and Astronautics, Purdue University, undated
https://engineering.purdue.edu/A ... ts/advanced/pegasus
("What gives the Harrier its capability is its thrust vectoring. Remarkably, there is no computer control of the nozzles. This means the Harrier has a fatally high learning curve, which has meant heavy losses over the years, but those who get through training are the best and most capable pilots in the world")
(ii) Yakovlev Yak-38 (in service 1976-1991l said to be a failure)
(A) https://en.wikipedia.org/wiki/VTOL

On the left of margin of this Wiki page is an illustration whose caption is "The Soviet Union's VTOL aircraft, the Yakovlev Yak-38 [where blue arrows signify cold air]."  What one can not tell is the position (it appears two front nozzles on each side) -- and hence, the number -- of front nozzles.
(B) "The Yak-38 uses a main engine with two aft rotating nozzles and a set of small lift engines."  from the Web.
(C) It turns out that the two front nozzles in Yak-38 is positioned midline. See the illustration (there is only one illustration) in
Yak-38 -- $3.95. Fiddlers Green (a site selling "paper models"), undated.
www.fiddlersgreen.net/models/aircraft/YAK-38.html
(D) Michael J Hirschberg, Soviet V/STOL Aircraft: The Struggle for a Shipborne Combat Capability. American Institute of Aeronautics and Astronautics, , at page 12
https://books.google.com/books?i ... &dq=The+Yak-38+"lift+nozzles"&source=bl&ots=HVJxUYcQPr&sig=QAy3dL9UZchPqYdfSBX_MCAH9Is&hl=en&sa=X&ved=2ahUKEwjkydO8ja_eAhVQt1MKHX-1CAAQ6AEwB3oECAkQAQ#v=onepage&q=The%20Yak-38%20"lift%20nozzles"&f=false
("III. Yakolev YAK-36M/YAK-38 FORGERS  A. Overview[:] The Yak-38 Forger [NATO reporting name] was basically conventional design, utilizing a lift plus lift/cruise engine configuration (Fig. 10). Immediately behind the cocket were two nearly vertically oriented lift engines. The cruise engine was located along the fuselage centerline")

The three engines in Fig 10 are all topped with a black disc punctuated in the center with a white cone.
回复 支持 反对

使用道具 举报

 楼主| 发表于 10-30-2018 16:45:21 | 显示全部楼层
(d) Yesterday in my posting 雲峰中程飛彈, I stated my belief in Note(a)(i): "For a decade, I could not figure out whether the thrust came from compressor or combustion. Today I learn the answer is mostly, but altogether -- the latter -- (see (a)(iv) below) ), the energy released from fuel combustion (as in gas-engine car; fuel is packed with energy)."  But the following says it is the compressor that dominates the role. See Navy BMR (which stands for "Basic Military Requirements" I believe), undated, at page 1-4
http://navybmr.com/study%20material/14008a/14008A_ch1.pdf
("The compressor is the greatest single reason the gas turbine engine runs and produces the thrust needed by modern aircraft")

See also Compton's Interactive Encyclopedia
http://www.fem.unicamp.br/~em313/paginas/consulte/jet.htm
("Modern axial-flow compressors can increase the pressure 25-fold in about 16 'stages,' each stage consisting of a set of rotor and stator blades" without mentioning how many folds the combustion increases pressure)

(e)
(i) F-35B uses Pratt & Whitney F135
https://en.wikipedia.org/wiki/Pratt_%26_Whitney_F135
("The F135 family has several distinct variants * * * The F135 team is made up of Pratt & Whitney, Rolls-Royce and Hamilton Sundstrand. Pratt & Whitney is the prime contractor for the main engine, and systems integration. Rolls-Royce is responsible for the vertical lift system for the STOVL aircraft. * * * The lift for the STOVL version in the hover is obtained from a 2-stage lift fan (about 46%) in front of the engine, a vectoring exhaust nozzle (about 46%), and a nozzle in each wing [for the fighter to roll] using fan air from the bypass duct (about 8%)" )
Rolls-Royce Three Balling Swivel Model
(ii) the preceding quotation is schematically represented by
Eric Adams, Jumping into Action; Fresh off the assembly line, the leapfrogging, stealthy F-35B fighter jet prepares for liftoff. Popular Science, Apr 16, 2008
https://www.popsci.com/military- ... 8-04/jumping-action
(second illustration)

Again, the blue arrows signify cold air, pink arrows lukewarm.
回复 支持 反对

使用道具 举报

您需要登录后才可以回帖 登录 | 注册

本版积分规则

快速回复 返回顶部 返回列表