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Optical Landing System to Guide Pilot Landing on Aircraft Carrier

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楼主
发表于 1-7-2017 13:31:37 | 只看该作者 回帖奖励 |倒序浏览 |阅读模式
It was Invented by the British, and adopted by Americans and Chinese.

(1) 解剖航空母舰——'菲涅尔' 助降系统. 新华网. Jan 31, 2008
http://news.xinhuanet.com/mil/2008-01/31/content_7533728.htm

(2) 惊心动魄的30秒; 辽宁舰 '菲涅尔' 透镜光学助降系统曝光. 环球网, Oct 19, 2012 (a gallery of 14 photos).
http://mil.huanqiu.com/mlitaryvision/2012-10/2669591.html

Quote:

"最初使用的是光学助降镜 [mirror landing aid]。"  photo 2/14

"灯箱正中央竖排一组上下5盏方形 '菲涅耳透镜灯,' 由上到下同时发出1-5层光束,每层光束保持不同角度和不同颜色,飞行员位于不同下滑位置(或高或低或正常)只能看到其中一盏。"  photo 11/14

"基准灯 [datum light; green] 和禁降灯 [red] 属于信号告示灯,而 '菲涅耳透镜灯' 才是真正判断下滑角大小、下滑位置高低的校准修正灯。"  photo 12/14

Note: The Latin noun neuter datum has a plural form data.




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沙发
 楼主| 发表于 1-7-2017 13:33:48 | 只看该作者
(3) "Optical landing system" progressed from "mirror landing aid" through "Fresnel lens optical landing system (FLOLS)" to presently "Improved fresnel lens optical landing system (IFLOLS)."
(a) Fresnel lens
https://en.wikipedia.org/wiki/Fresnel_lens
(b) Originally the stack of VERTICAL lights (from yellow to orange (or amber) to red -- top to bottom; a pilot may see just one lighted) were round in shape. The British, inventor, called it ball, whereas later on Americans call it meatball.

(4) Concept is the same throughout the progress of optical landing system.
(a) Maxime Verreault, ENG Approach angle on an aircraft carrier. YouTube.com, uploaded on Jan 3, 2009.
https://www.youtube.com/watch?v=UFiWJkZ2Fws

Note:
(i) The ENG" may represent "engineering."
(ii) The "lipstick" (mentioned in the video a couple of times) will be explained in (5), about the invention of optical landing system.

(b) Chap 11 Optical Landing Syetem and Aeronautical Deck Sighting. In Bureau of Naval Personnel (preparer), Aviation Boatswain's Mate 1 & C. US government Printing Office, 1959, at page 141 and 142 ("Naval Training Courses NAVPERS 10386")
https://books.google.com/books?i ... 0mirror&f=false
("This [correct glide angle, or glideslope] is accomplished by a source light and mirror which creates a reflection that pilot can see. (See fig. 11-1.)  Source light and mirror are so arranged that reflection appears o be at the center-line of the mirror to a pilot who is at the intended glide angle. The centerline reference point is indicated by a row of datum lights on either side of the mirror. When landing the pilot flies a path such that the light image always appears to be at the mirror centerline")

Look at Figure 11-1, and you will suddenly realize that it is simply intuitive
(i) that the position (up or down) of the ball the landing PILOT SEES lighted is simply determined by the relative position (thus angle) of the pilot (hence the landing aircraft) vis-a-vis the mirror and the source light; and
(ii) that a landing pilot at any moment would see just ONE light,, never two or more; and
(iii) that only a reflected light will do. A lighted ball will tell the pilot the spot to land and approximate angle to glide through (like a light beam in a beacon), but can not convey precise information how far off the angle the pilot (hence aircraft) is.

(c) Andrew Faltum, The Supercarriers; The Forrestal and Kitty Hawk Classes. Naval Institute Press, 2014, at page 4
https://books.google.com/books?i ... 0optics&f=false
("The third British innovation leading to the success of the Forestal design was the mirror landing system. To take advantage of the capabilities offered by the angled deck and the steam catapult [the other two British inventions around that time], a new method of controlling aircraft as they came on board had to be developed. A landing signal officer (LSO) could only control one aircraft at a time, and the limitations of human eye made control using paddles limited to no more than a half mile. The British system used a large mirror, concave about its horizontal axis, positioned alongside the landing area at the edge of the angled flight deck. The mirror pointed astern at the angle of the glide path and was mounted on gimbals connected to the ship's fire [gun] control system, which was gyro stabilized. This allowed the mirror to compensate for any motion of the ship. Aft of the mirror a powerful light source was aimed at the mirror so that a cone of light was reflected back along the glide slope. The pilot would see a spot of light, the 'ball,' when he flew in the middle of the beam. To position his aircraft more precisely, a horizontal row of datum lights was mounted on either side of the mirror. If the pilot was high on the glide path, the ball would appear above the reference light.s. Og too low, the ball was below the reference lights. Later, the mirror was replaced by a Fresnel lens and colors added to the ball, but the principle of the Optical Landing System (OLS) was the same")

* aircraft carrier
https://en.wikipedia.org/wiki/Aircraft_carrier

section 3.2 Flight deck: "Aircraft launch forward, into the wind, and are recovered from astern [the fixed-wing aircraft lands at the stern toward the port, or left (facing forward), side]. * * * On the recovery side of the flight deck * * * Non-VTOL [VTOL = vertical take-off and landing] or conventional aircraft cannot decelerate on their own, and almost all carriers using them must have arrested-recovery systems (-BAR, eg CATOBAR [Catapult Assisted Take-Off But Arrested Recovery] or STOBAR) to recover their aircraft. Aircraft that are landing extend a tailhook that catches on arrestor wires stretched across the deck to bring themselves to a stop in a short distance. Post-WWII Royal Navy research on safer CATOBAR recovery eventually led to universal adoption of a landing area angled off axis to allow aircraft who missed the arresting wires to "bolt" and safely return to flight for another landing attempt rather than crashing into aircraft on the forward deck.
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板凳
 楼主| 发表于 1-7-2017 13:38:03 | 只看该作者
(5) Invention
(a) Paul E Fontenoy, Aircraft Carriers; An illustrated history of their impact. ABC-CLIO, 2006, at page 115
https://books.google.com/books?i ... ipstick&f=false
("The higher landing speeds of jet aircraft rapidly pushed beyond the limits of landing signals officers' ability to appreciate the aircrafts' [sic; aircraft is spelled the same singular or plural] motions and make signals to which the pilots could respond. Captain Campbell's assistant, Lieutenant [later promoted to rear admiral] Commander Nick Goodhart, initially proposed an optical landing control system in a paper he wrote in 1951. A gyro-stabilized mirror, surrounded by red and green illuminated datum lines, reflected a fixed light back to the pilot's eyes so that he could tell his position relative to the optimum glide approach path, while an audio tone indicated his airspeed. Goodhart formally presented his concept, which he had tested on a small scale [天平] using his secretaru's pocket make-up mirror with datum lines drawn on with her lipstick, in January 1952. The first very successful full-scale trials took place in November 1953 aboard the carrier Illustrious, leading to the adoption of the mirror landing aid on British and American carriers within less than two years. The later Fresnel lens system replaced the mirror with a lens and moved the light source forward of the unit but operate identically")

* "moved the light source forward of the unit"

See (6)(a) below.

(b) Thomas C Hone, Norman Friedman and Mark D Mandeles, Innovation in Carrier Aviation. Naval War College Press, 2011, at page 125 (Newport Paper No 37)
https://www.usnwc.edu/getattachm ... 5543d78e8d31/37.pdf

Three consecutive paragraphs:

"Campbell and his assistant, Cdr Nicholas Goodhart, polished a scheme of Goodhart's to replace a carrier's landing signal officer with 'visual indication of the optimum approach and landing path * * * [using[ a steady light source.' According to an article in Naval Aviation News in 1955, Goodhart had served as an engineer pilot at the Patuxent Naval Air Test Center in 1948-49, between landing signal officers (LSOs) and pilots of jet aircraft. Engineers at Farnborough had already been working on a mechanical replacement for LSOs, and Goodhart took his idea to them. The first component of his system was a large light placed at the after end of the flight deck. About 150 feet from the stern, Goodhart and the Farnborough engineers set up the second component—a large concave mirror, eventually gyrostabilized, that would reflect the light at an angle suited to the type of aircraft coming in to land. On each side of the mirror would be a row of three green lights. The pilot’s task would be to keep the reflection of the light level with the green lights.   

"Campbell's account of how they tested the idea in the office he shared with Goodhart is classic: 'We borrowed a small vanity mirror from Miss Montgomery, our secretary, and propped it up at a simulated 3 degrees approach angle. . . . [W]e then borrowed Monty's lipstick and stood it on end [upright] a few feet away. Looking at the lipstick in the mirror, we found it easy to keep it in view while we moved forwards and downwards.'

"Campbell and Goodhart realized that it was 'blindingly obvious that the two revolutionary inventions [angled deck and landing mirror] would be complementary.' When this 'visual glide slope system' was tested first at Farnborough and then at sea on HMS Illustrious in November 1953, two US Navy pilots were part of the test team, and one, Lt Cdr Donald D Engen, wrote a report to the [US] Chief of Naval Operations recommending 'that the Navy procure the mirror immediately.' Engen was at that time one of two US Navy exchange pilots at the Royal Air Force's Empire Test Pilots School at Farnborough." (footnotes omitted; brackets in original)

(c) Norman Polmar, Aircraft Carriers; A history of carrier aviation and its influence on world. page number not displayed
https://books.google.com/books?i ... ipstick&f=false

two consecutive paragraphs:

"Jet aircraft approached a carrier at speeds that were too high for a landing signal officer or (British) batsman to provide the pilot with adequate warning if he was approaching too high or too low through the use of 'paddles' or lighted baton. Lieutenant Commander Nick Goodhart, Captain Campbell's assistant, an engineering officer and test pilot, sought a means of letting pilot himself determine his approach angle. Initially using his secretary's pocket mirror and the point of her lipstick, he developed the concept of the mirror landing system in 1951. It was flight tested by British and IS carrier pilots at Farnborough in 1853 and quickly adopted by both navies. Th initial mirror was fabricated of highly polished cast aluminum, formed to a cylindrical concave shape [presumably with an horizontal axis]; it was five feet six inches wide and four feet high.

"As developed, the device, mounted on the port side of the flight deck, was visible to an approaching pilot. I provided a mirror reflecting a circle of light (leading to the term 'meatball') and a datum line of green lights to enable the pilot to see if he was high or low by glancing at the 'meatball' relative to the datum line; the mirror was concave so that the pilot could see it as he turned into the angled deck. A pilot could land a high-performance aircraft on a carrier solely by watching the mirror (which was illuminated at night) and the air speed indicator within his cockpit. The air speed was later provided to the pilot by sound pulses in his headphones.

(d) The Contrail ('The official monthly magazine of the 177th Fighter Wing), September 2014, at page 17 of 25
https://static.dvidshub.net/media/pubs/pdf_23135.pdf
("In the summer of 1951 a Royal Navy pilot, Lt Cdr Nick Goodhart, working for Captain Campbell, came up with the idea of a landing aid based on reflected light. The story goes that he got the idea while 'chatting-up; an attractive squadron secretary. hile the young lady was powdering her nose at her desk with a compact mirror, Goodhart's eye was caught by the reflection of a desk lamp in her mirror. Setting up her borrowee lipstick and mirror on her desk he noted that if he moved his head, keeping the image of the lipstick in the mirror, he could reproducibly approach the desktop at the same spot. Thus came the idea of the mirror landing system!")

* Presumably Mr Goodhart conflated the lamp (light source) and red lipstick tip for the benefit of night landing.
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4#
 楼主| 发表于 1-7-2017 13:40:36 | 只看该作者
本帖最后由 choi 于 1-7-2017 13:52 编辑

(6) To sum up (mostly with figures), Improved Fresnel Lens Optical Landing System (IFLOLS) looks like this.
(a) Stanley C Collyer, Gilbert L Ricard, Michael Anderson, Daniel P Westra and Ricky A Perry, Field of View Requirements for Carrier Landing Training. Orlando, FL: Naval Training Equipment Center, June 1980, at page 15 (file:///C:/Users/kiosk.user/Downloads/ADA087012.pdf)
http://file:///C:/Users/kiosk.user/Downloads/ADA087012.pdf
(a sketch whose heading was "Carrier Glideslope Geometry")
(i) The approaching aircraft must raise its nose so that it (aircraft) may catch the third of four wires.
(ii) The "apparent lens location" is where the light source appears to the pilot.

(b) The details of the above landing:

Training. VFA-141, undated
www.vfa-141.com/training.html
(i) VFA-141 'Wolfpack'
http://www.vfa-141.com/ready-room.html
("The Strike Fighter Squadron One Four One "Wolfpack" (VFA-141) are a United States Navy F/A-18 Super Hornet fighter squadron stationed at Naval Air Station Lemoore. They are a part of Carrier Air Wing 2 and are attached to the USS Carl Vinson")
(ii) "5° Aircraft Pitch"

aircraft principal axes
https://en.wikipedia.org/wiki/Aircraft_principal_axes
("pitch, nose up or down")
(iii) The 5° pitch (relative to the sea level) plus 3° glideslope constitutes 8° angle of attack.

(c) You have read so much that you need not read a text-only article that is not very helpful to a novice like me:

Sam Goldberg, The Meatball; Pilots who make it safely to the deck of an aircraft carrier have seen the light. Air & Space Magazine, May 2005
http://www.airspacemag.com/how-things-work/the-meatball-8421491/
("The IFLOLS unit generates its meatball through an optical trick: A [vertical] stack of 12 light cells produces a single ball-shaped image")
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