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Light Observation Helicopter

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Title: Light Observation Helicopter  
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Subject: Fairchild Hiller FH-1100, Bell 206, Bell OH-58 Kiowa, Bell YOH-4, Utility helicopter
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Light Observation Helicopter

An OH-58 Kiowa, winner of the LOH competition's second round

The Light Observation Helicopter (LOH) program was a United States Army program to evaluate, develop and field a light scout helicopter to replace the Army's aging OH-13 Sioux. The program gained impetus with the advent of the Vietnam War and was aided by advances in helicopter technology, specifically the development of the turboshaft engine. Three of the aircraft evaluated for the program would eventually enter military service, one as a training helicopter and two as observation helicopters used for battlefield reconnaissance missions.

History

In July 1953, the Office of Lieutenant General John Dahlquist, Chief, Army Field Forces (AFF), forwarded desirable military characteristics for a two-place reconnaissance helicopter to Army Headquarters. Nearly a year later, in May 1954, Dahlquist's office once again emphasized the need for replacement aircraft and recommended procurement of troop test quantities of the YH-32. Preliminary evaluation of the YH-32 design revealed that the aircraft was unsuitable for the mission, and the tests were canceled.[1]

In 1955, the Army Field Forces were transformed into the Continental Army Command (CONARC). Dahlquist, who had been promoted to 4-star General on 18 August 1954, continued in command. On 11 October 1955, CONARC recommended that the Department of the Army initiate a program to develop a replacement observation helicopter for the aging OH-13 Sioux and OH-23 Raven. Army's Chief of Research and Development agreed to include the requirement for a new helicopter in the budget for fiscal year 1957 on 19 March 1956, after CONARC highlighted the continued lack of development for replacement aircraft.[2]

During the course of the next three years, three helicopters would be evaluated as candidates to replace the OH-13 and OH-23; the Sud-Ouest Djinn, the Hughes 269, and the Brantly B-2. The aircraft were designated the YHO-1 DJ, YHO-2 HU, and YHO-3 BR, respectively. By October 1958, service testing of Sud Aviation YHO-1 DJ was completed. The following year saw the completion of the desert and temperate temperature testing of the YHO-2 HU. The YHO-3 BR did not complete user testing after engineering evaluations revealed significant deficiencies. Service testing demonstrated that the YHO-2 had been the most capable, but due to a limited load capability, it was deemed not suitable to replace the OH-13.[3]

LOH

On 14 October 1960, the United States Navy Bureau of Weapons issued Technical Specification 153, a request for proposals (RFP) for a four-seat, turbine-powered, light observation helicopter capable of fulfilling various roles: personnel transport, escort and attack missions, casualty evacuation and observation.[4] 25 aircraft manufacturers were solicited for the program on behalf of the Army Chief of Transportation. By January 1961, 12 manufacturers, including Cessna, Hughes Tool Co. Aircraft Division, Hiller Aircraft and Bell Helicopters, had responded with 19 designs.[3][5]

The United States Navy provided technical expertise to assist the Army in evaluating the design proposals.[6] In October 1961, the Army selected three of the designs for a flight evaluation. Bell's D-250 design[7] was recommended by the Army team[6] and designated the YHO-4 (later YOH-4),[8] Hiller's Model 1100 was recommended by the Navy team[6] and became the YHO-5 (later YOH-5), and Hughes' Model 369 was added to the competition[6] and became the YHO-6 (later YOH-6). Each manufacturer submitted 5 test and evaluation prototypes of their designs to the Army for flight test evaluation at Camp Rucker, Alabama.

As a result of the flight evaluation, Hiller's YOH-5 and Hughes' YOH-6 were selected to compete in a program cost analysis bid for the contract. The Hughes bid won the contract, although Hiller protested the contract award, and in 1965, the YOH-6 was redesignated as the OH-6A Cayuse.

In 1967, the Army reopened the LOH competition for bids and Bell resubmitted for the program using their model 206A design. Fairchild-Hiller failed to resubmit their bid with the YOH-5A, which they had successfully marketed as the FH-1100.[9] In the end, Bell won the contract and the model 206A was designated as the OH-58A. Following the Army's naming convention for helicopters, the OH-58A was named Kiowa for the Native American tribe.

See also

References

Notes

-- Module:Hatnote -- -- -- -- This module produces hatnote links and links to related articles. It -- -- implements the and meta-templates and includes -- -- helper functions for other Lua hatnote modules. --


local libraryUtil = require('libraryUtil') local checkType = libraryUtil.checkType local mArguments -- lazily initialise Module:Arguments local yesno -- lazily initialise Module:Yesno

local p = {}


-- Helper functions


local function getArgs(frame) -- Fetches the arguments from the parent frame. Whitespace is trimmed and -- blanks are removed. mArguments = require('Module:Arguments') return mArguments.getArgs(frame, {parentOnly = true}) end

local function removeInitialColon(s) -- Removes the initial colon from a string, if present. return s:match('^:?(.*)') end

function p.findNamespaceId(link, removeColon) -- Finds the namespace id (namespace number) of a link or a pagename. This -- function will not work if the link is enclosed in double brackets. Colons -- are trimmed from the start of the link by default. To skip colon -- trimming, set the removeColon parameter to true. checkType('findNamespaceId', 1, link, 'string') checkType('findNamespaceId', 2, removeColon, 'boolean', true) if removeColon ~= false then link = removeInitialColon(link) end local namespace = link:match('^(.-):') if namespace then local nsTable = mw.site.namespaces[namespace] if nsTable then return nsTable.id end end return 0 end

function p.formatPages(...) -- Formats a list of pages using formatLink and returns it as an array. Nil -- values are not allowed. local pages = {...} local ret = {} for i, page in ipairs(pages) do ret[i] = p._formatLink(page) end return ret end

function p.formatPageTables(...) -- Takes a list of page/display tables and returns it as a list of -- formatted links. Nil values are not allowed. local pages = {...} local links = {} for i, t in ipairs(pages) do checkType('formatPageTables', i, t, 'table') local link = t[1] local display = t[2] links[i] = p._formatLink(link, display) end return links end

function p.makeWikitextError(msg, helpLink, addTrackingCategory) -- Formats an error message to be returned to wikitext. If -- addTrackingCategory is not false after being returned from -- Module:Yesno, and if we are not on a talk page, a tracking category -- is added. checkType('makeWikitextError', 1, msg, 'string') checkType('makeWikitextError', 2, helpLink, 'string', true) yesno = require('Module:Yesno') local title = mw.title.getCurrentTitle() -- Make the help link text. local helpText if helpLink then helpText = ' (help)' else helpText = end -- Make the category text. local category if not title.isTalkPage and yesno(addTrackingCategory) ~= false then category = 'Hatnote templates with errors' category = string.format( '%s:%s', mw.site.namespaces[14].name, category ) else category = end return string.format( '%s', msg, helpText, category ) end


-- Format link -- -- Makes a wikilink from the given link and display values. Links are escaped -- with colons if necessary, and links to sections are detected and displayed -- with " § " as a separator rather than the standard MediaWiki "#". Used in -- the template.


function p.formatLink(frame) local args = getArgs(frame) local link = args[1] local display = args[2] if not link then return p.makeWikitextError( 'no link specified', 'Template:Format hatnote link#Errors', args.category ) end return p._formatLink(link, display) end

function p._formatLink(link, display) -- Find whether we need to use the colon trick or not. We need to use the -- colon trick for categories and files, as otherwise category links -- categorise the page and file links display the file. checkType('_formatLink', 1, link, 'string') checkType('_formatLink', 2, display, 'string', true) link = removeInitialColon(link) local namespace = p.findNamespaceId(link, false) local colon if namespace == 6 or namespace == 14 then colon = ':' else colon = end -- Find whether a faux display value has been added with the | magic -- word. if not display then local prePipe, postPipe = link:match('^(.-)|(.*)$') link = prePipe or link display = postPipe end -- Find the display value. if not display then local page, section = link:match('^(.-)#(.*)$') if page then display = page .. ' § ' .. section end end -- Assemble the link. if display then return string.format('%s', colon, link, display) else return string.format('%s%s', colon, link) end end


-- Hatnote -- -- Produces standard hatnote text. Implements the template.


function p.hatnote(frame) local args = getArgs(frame) local s = args[1] local options = {} if not s then return p.makeWikitextError( 'no text specified', 'Template:Hatnote#Errors', args.category ) end options.extraclasses = args.extraclasses options.selfref = args.selfref return p._hatnote(s, options) end

function p._hatnote(s, options) checkType('_hatnote', 1, s, 'string') checkType('_hatnote', 2, options, 'table', true) local classes = {'hatnote'} local extraclasses = options.extraclasses local selfref = options.selfref if type(extraclasses) == 'string' then classes[#classes + 1] = extraclasses end if selfref then classes[#classes + 1] = 'selfref' end return string.format( '
%s
', table.concat(classes, ' '), s )

end

return p-------------------------------------------------------------------------------- -- Module:Hatnote -- -- -- -- This module produces hatnote links and links to related articles. It -- -- implements the and meta-templates and includes -- -- helper functions for other Lua hatnote modules. --


local libraryUtil = require('libraryUtil') local checkType = libraryUtil.checkType local mArguments -- lazily initialise Module:Arguments local yesno -- lazily initialise Module:Yesno

local p = {}


-- Helper functions


local function getArgs(frame) -- Fetches the arguments from the parent frame. Whitespace is trimmed and -- blanks are removed. mArguments = require('Module:Arguments') return mArguments.getArgs(frame, {parentOnly = true}) end

local function removeInitialColon(s) -- Removes the initial colon from a string, if present. return s:match('^:?(.*)') end

function p.findNamespaceId(link, removeColon) -- Finds the namespace id (namespace number) of a link or a pagename. This -- function will not work if the link is enclosed in double brackets. Colons -- are trimmed from the start of the link by default. To skip colon -- trimming, set the removeColon parameter to true. checkType('findNamespaceId', 1, link, 'string') checkType('findNamespaceId', 2, removeColon, 'boolean', true) if removeColon ~= false then link = removeInitialColon(link) end local namespace = link:match('^(.-):') if namespace then local nsTable = mw.site.namespaces[namespace] if nsTable then return nsTable.id end end return 0 end

function p.formatPages(...) -- Formats a list of pages using formatLink and returns it as an array. Nil -- values are not allowed. local pages = {...} local ret = {} for i, page in ipairs(pages) do ret[i] = p._formatLink(page) end return ret end

function p.formatPageTables(...) -- Takes a list of page/display tables and returns it as a list of -- formatted links. Nil values are not allowed. local pages = {...} local links = {} for i, t in ipairs(pages) do checkType('formatPageTables', i, t, 'table') local link = t[1] local display = t[2] links[i] = p._formatLink(link, display) end return links end

function p.makeWikitextError(msg, helpLink, addTrackingCategory) -- Formats an error message to be returned to wikitext. If -- addTrackingCategory is not false after being returned from -- Module:Yesno, and if we are not on a talk page, a tracking category -- is added. checkType('makeWikitextError', 1, msg, 'string') checkType('makeWikitextError', 2, helpLink, 'string', true) yesno = require('Module:Yesno') local title = mw.title.getCurrentTitle() -- Make the help link text. local helpText if helpLink then helpText = ' (help)' else helpText = end -- Make the category text. local category if not title.isTalkPage and yesno(addTrackingCategory) ~= false then category = 'Hatnote templates with errors' category = string.format( '%s:%s', mw.site.namespaces[14].name, category ) else category = end return string.format( '%s', msg, helpText, category ) end


-- Format link -- -- Makes a wikilink from the given link and display values. Links are escaped -- with colons if necessary, and links to sections are detected and displayed -- with " § " as a separator rather than the standard MediaWiki "#". Used in -- the template.


function p.formatLink(frame) local args = getArgs(frame) local link = args[1] local display = args[2] if not link then return p.makeWikitextError( 'no link specified', 'Template:Format hatnote link#Errors', args.category ) end return p._formatLink(link, display) end

function p._formatLink(link, display) -- Find whether we need to use the colon trick or not. We need to use the -- colon trick for categories and files, as otherwise category links -- categorise the page and file links display the file. checkType('_formatLink', 1, link, 'string') checkType('_formatLink', 2, display, 'string', true) link = removeInitialColon(link) local namespace = p.findNamespaceId(link, false) local colon if namespace == 6 or namespace == 14 then colon = ':' else colon = end -- Find whether a faux display value has been added with the | magic -- word. if not display then local prePipe, postPipe = link:match('^(.-)|(.*)$') link = prePipe or link display = postPipe end -- Find the display value. if not display then local page, section = link:match('^(.-)#(.*)$') if page then display = page .. ' § ' .. section end end -- Assemble the link. if display then return string.format('%s', colon, link, display) else return string.format('%s%s', colon, link) end end


-- Hatnote -- -- Produces standard hatnote text. Implements the template.


function p.hatnote(frame) local args = getArgs(frame) local s = args[1] local options = {} if not s then return p.makeWikitextError( 'no text specified', 'Template:Hatnote#Errors', args.category ) end options.extraclasses = args.extraclasses options.selfref = args.selfref return p._hatnote(s, options) end

function p._hatnote(s, options) checkType('_hatnote', 1, s, 'string') checkType('_hatnote', 2, options, 'table', true) local classes = {'hatnote'} local extraclasses = options.extraclasses local selfref = options.selfref if type(extraclasses) == 'string' then classes[#classes + 1] = extraclasses end if selfref then classes[#classes + 1] = 'selfref' end return string.format( '
%s
', table.concat(classes, ' '), s )

end

return p
  1. ^ Weinert 1991, p. 205.
  2. ^ Weinert 1991, pp. 205-206.
  3. ^ a b Weinert 1991, p. 206.
  4. ^ Apostolo 1984
  5. ^ Remington, Steve. The Cessna CH-1 Helicopter. Collectair.com. Accessed on 30 June 2009.
  6. ^ a b c d Spangenberg, George A. "George A. Spangenberg Oral History". edited by Judith Spangenberg-Currier. pdf. Spangenberg.org. pp.187-190
  7. ^ Holley and Sloniker, p. 7.
  8. ^ Beechy, Robert. "U.S Army Aircraft Acquisition Programs". Uncommon Aircraft 2006. 18 November 2005. Accessed on 19 September 2006.
  9. ^
Bibliography
  • Apostolo, Giorgio. The Illustrated Encyclopedia of Helicopters. New York:Bonanza Books, 1984. ISBN 0-517-43935-2
  • Holley, Charles, and Mike Sloniker. Primer of the Helicopter War. Grapevine, Tex: Nissi Publ, 1997. ISBN 0-944372-11-2
  • Weinert, Richard P., Jr. A History of Army Aviation – 1950 - 1962. Fort Monroe, Virginia: Office of the Command Historian, U.S. Army Training and Doctrine Command, 1991.
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