| 词条 | Pickett-Hamilton fort |
| 释义 |
| name = Pickett-Hamilton fort | partof = | location = Lashenden Air Warfare Museum | image = Pickett-Hamilton Fort Mechanism (x16).gif | image_size = 300px | alt = The restoration of the fort was undertaken by museum members David Wild and Barry Baker. They stripped, rebuilt and refurbished the hydraulic mechanism to working order. They then reassembled everything within the fort, which was then put back together. | caption = Pickett-Hamilton fort excavated and reconstructed above ground for public display{{sfn|Pickett-Hamilton fort, Lashenden Air Warfare Museum}} | map_type = | map_size = | map_caption = | type = Pillbox | coordinates = | code = | built = | builder = | materials = Concrete | height = | used = Second World War | demolished = | condition = | ownership = | open_to_public = | controlledby = | garrison = | commanders = | occupants = | battles = | events = | image2 = | caption2 = }} A Pickett-Hamilton fort is a type of hardened field fortification built in Britain during the invasion crisis of 1940–1941.{{sfn|Wills|1985|p=20}} The Pickett-Hamilton fort was designed to be lowered into the ground while it was not in use, as such it would be inconspicuous and would not interfere with the passage of taxiing aircraft or other vehicles. The fort could be raised to about {{convert|2|ft|6|in|m}} above ground level where it would be a physical impediment to aircraft and vehicles and from where a small crew could fire with rifles or light machine guns.{{sfn|Pickett|Hamilton|1940}} Development{{Quote box| bgcolor = lightblue | align = right | quote = By reason of its forming no obstacle to use of ground for flying or traffic, the post can be sited in places where not even a rifleman or small post can be put, and can bring fire on to ground which otherwise could not be covered at all or only at extreme ranges. | salign = right | source = – Pickett-Hamilton Fort Advisory Committee (1940){{sfn|WO 199/2527}} | width = 25% }} The open spaces of airfields were very vulnerable to attack by airborne troops and it was felt that it was particularly important to defend them effectively. However, conventional defences such as pillboxes and trenches could not be installed without danger to friendly aircraft. At this time a number of private companies contacted the government with their own design ideas.{{efn-lr|See Bison concrete armoured lorry for an alternative portable airfield defence scheme, put forward by Concrete Limited.[1]}} The Pickett-Hamilton fort was designed by Francis Norman Pickett and Donald St Aubyn Hamilton. Pickett (1887–1957){{sfn|Grace's Guide obituary}} was an engineer. He graduated from London University in 1907, and from 1918 to 1931 he was Proprietor of the firm of F. N. Pickett et Fils, engaged on the demolition of ammunition.{{sfn|Poverty Bay Herald 1 July 1920}} This business encountered many difficulties but Pickett made a great deal of money{{sfn|Zanders|pp=201–206}} before the company eventually failed.{{sfn|Times 19 October 1932}} Pickett spent much of the early '20s involved in motor racing.{{sfn|Counting the Akelas}} He subsequently became Managing Director of Kaycee, Ltd., in 1931–35, of Consolidated Rubber Manufacturers, Ltd., in 1935–38, and of Ocean Salts (Products), Ltd., in 1938.{{sfn|Grace's Guide obituary}} Hamilton (1907–1956) was an architect based in London.{{sfn|Belling-Lee Radio Factory}} Later, as part of Donald Hamilton, Wakeford & Partners, he designed many buildings in London and southern England.{{sfn|Pickett|Hamilton|1940}} A friend of Norman Pickett, racing driver Donald Campbell, allowed his workshops to be used to build the prototypes.{{sfn|Pickett-Hamilton fort, Tangmere Military Aviation Museum}}{{sfn|Disappearing pillbox, BBC News}} In early 1940, Campbell attended the operational trials of the prototype at RAF Andover.{{sfn|Pickett-Hamilton fort, Tangmere Military Aviation Museum}}{{sfn|Disappearing pillbox, BBC News}} Winston Churchill wrote to General Ismay on 12 July 1940 saying: "I saw these pillboxes for the first time when I visited Langley last week. This appears to afford an admirable means of anti-parachute defence and it should surely be widely adopted. Let me have a plan."{{sfn|Pickett-Hamilton fort, Lashenden Air Warfare Museum}} This pillbox was adopted by the Air Ministry and became known as the Pickett-Hamilton fort.{{sfn|Francis}} Design{{multiple image| footer = Pickett-Hamilton Retractable Fort on a fighter airfield in Southern England | image1 = Royal Air Force Fighter Command, 1939-1945. CH17893.jpg | alt1 = The turret of a Pickett-Hamilton retractable fort, retracted to ground level on a fighter airfield in Southern England. | caption1 = Retracted to ground level. | width1 = 200 | image2 = Royal Air Force Fighter Command, 1939-1945. CH17890.jpg | alt2 = The turret of a Pickett-Hamilton retractable fort, fully raised and manned by a Bren-gun team of the Coldstream Guards, taken on a fighter airfield in Southern England. | caption2 = Fully raised and manned by a Bren-gun team of the Coldstream Guards | width2 = 200 }} The most common version of the Pickett-Hamilton fort consists of two cylinders of pre-cast concrete each with one end closed. The slightly smaller of the two cylinders slides into the larger and they are kept apart by small guard rollers on the moving part that engaged with grooves.{{sfn|Pickett|Hamilton|1940}} The structure is buried so that the overhanging top of the smaller cylinder lies flush with the ground. Closed in this position the pillbox is inconspicuous and allows aircraft and other vehicles to safely drive straight over it.{{sfn|Pickett|Hamilton|1940}} The interior is accessed via a small hatch and rungs built into the structure. To bring it into action a lifting mechanism was used to raise the inner cylinder by about {{convert|2|ft|6|in|m}} thereby revealing three embrasures. A crew of two men could then operate the fort as a pillbox.{{citation needed|date=May 2017}} Initially, the lifting mechanism consisted of a standard 8-ton aeroplane jack that took three minutes to raise the fort.{{sfn|Francis}} This was soon replaced with a pneumatic ram that was based on a system originally intended for agricultural use.{{sfn|Pickett-Hamilton fort, Lashenden Air Warfare Museum}}{{sfn|Goldup|1938}} The pneumatic system operated with compressed air stored in cylinders: this allowed the fort to be raised and lowered quickly when speed was essential.{{sfn|Francis}} A hand pump was also provided to raise the fort for daily maintenance or as a backup method.{{sfn|WO 199/2527}} An alternative design used counterbalance weights to raise the fort.{{sfn|Pickett|Hamilton|1940}} This allowed the fort to be raised by the physical strength of the garrison. This design had two access hatches and, with a slightly larger underground chamber and the elimination of the central pneumatic ram the fort could have a crew of four men.{{sfn|WO 199/2527}}{{sfn|Pickett Hamilton Pillbox Worthy Down, Derelict Places}} Under consideration in late 1940, this alternative design was not used in significant numbers and only about a dozen were installed.{{sfn|World War II Pickett-Hamilton Fort, Worthy Down Airfield}} The cost of construction was about £240{{sfn|WO 199/2527}} (equivalent to £{{Formatnum:{{Inflation|UK|240|1940|r=-2}}}} in {{CURRENTISOYEAR}}{{Inflation-fn|UK}}). Extant examplesThe forts were prone to flooding and they were not sufficiently strong to bear the weight of the heavy aircraft developed during the war.{{sfn|Francis}} Consequently, many forts were moved to the periphery of airfields and are not in their original location. More recently, some forts have been moved as airfields have been developed for modern aircraft. Records show that there were 335 installations.{{sfn|Francis}} Forty-eight examples of this type remain extant.{{sfn|Ruddy|2003|loc=p. 21, Pickett_Hamilton Fort}} A number of forts are displayed at Museums: Tangmere Military Aviation Museum,{{sfn|Pickett-Hamilton fort, Tangmere Military Aviation Museum}} Lashenden Air Warfare Museum,{{sfn|Pickett-Hamilton fort, Lashenden Air Warfare Museum}} D-Day Museum, Southsea (moved from its original location) and an inner part only at the Imperial War Museum Duxford. Because they retract into the ground inconspicuously, many examples have been lost and rediscovered many years later.{{sfn|Disappearing pillbox, BBC News}}{{sfn|Hidden WWII secrets, North Norfolk News}} The management of Kent International Airport (formerly RAF Manston) donated a Pickett-Hamilton fort to Lashenden Air Warfare Museum. Most of the surviving forts are flooded but the fort at Manston was dry and in superb condition.{{sfn|Pickett-Hamilton fort, Lashenden Air Warfare Museum}} The fort was excavated and restored to working order by museum members over a period of 18 months. Although the fort was originally intended to be buried on an airfield there was concern that putting it in the ground might, over time, degrade the concrete. Therefore, the fort has been placed at ground level and surrounded with a cone of earth and sandbags.{{sfn|Pickett-Hamilton fort, Lashenden Air Warfare Museum}} The lifting mechanism is in working order and can be activated by visitors putting a coin into a slot.{{sfn|Pickett-Hamilton fort, Lashenden Air Warfare Museum}} This is the only fully restored Pickett-Hamilton fort. See also
ReferencesNotes{{Notelist-lr}}References1. ^{{cite journal | year = 1992 | title = Concrete Armoured Vehicles | journal = Wheels & Tracks | volume = | number = 41 | issue = | pages = 42–44 | publisher = Battle of Britain Prints International | ref = {{harvid|Wheels & Tracks|1992}} }} Bibliography
| last = Foot | year = 2006 | first = William | title = Beaches, fields, streets, and hills ... the anti-invasion landscapes of England, 1940 | publisher = Council for British Archaeology | isbn = 1-902771-53-2 | ref = harv
| last = Francis | first = Paul | url = http://www.pillbox-study-group.org.uk/advanced-pillbox-designs/part-2-o-z/pickett-hamilton-fort/ | title = Pickett-Hamilton Fort | work = Pillbox study group | accessdate = 21 September 2016 | ref = harv
| last = Osborne | year = 2004 | first = Mike | title = Defending Britain ... twentieth century military structures in the landscape | publisher = Tempus Publishing | isbn = 0-7524-3134-X | ref = harv
| last = Ruddy | year = 2003 | first = Austin | title = British Anti-Invasion Defences 1940–1945 | series = Official Handbook of the Pillbox Study Group | publisher = Historic Military Press | isbn = 1-901313-20-4 | ref = harv }}
| last = Wills | year = 1985 | first = Henry | authorlink = Henry Wills (writer) | title = Pillboxes: A Study of UK Defences | publisher = Leo Cooper | isbn = 0-436-57360-1 | ref = harv
| url = http://thesaurus.historicengland.org.uk/thesaurus_term.asp?thes_no=365&term_no=123500 | title = Pickett-Hamilton fort | accessdate = 21 September 2016 | work = Thesaurus | publisher = English Heritage | ref = {{harvid|Pickett-Hamilton fort, English Heritage}}
| url = http://www.tangmere-museum.org.uk/artefact-month/the-pickett-hamilton-fort-2 | title = The Pickett Hamilton Fort | accessdate = 21 September 2016 | work = Tangmere Military Aviation Museum | ref = {{harvid|Pickett-Hamilton fort, Tangmere Military Aviation Museum}}
| url = https://www.bbc.co.uk/news/uk-scotland-highlands-islands-25413892 | date = 17 December 2013 | title = Rare war-time 'disappearing pillbox' found at Evanton | accessdate = 21 September 2016 | work = BBC News | ref = {{harvid|Disappearing pillbox, BBC News}}
| url = http://www.lashendenairwarfaremuseum.co.uk/6.html | title = Pickett Hamilton Fort | accessdate = 21 September 2016 | work = Lashenden Air Warfare Museum | ref = {{harvid|Pickett-Hamilton fort, Lashenden Air Warfare Museum}}
| url = http://www.northnorfolknews.co.uk/news/photo_gallery_hidden_wwii_secrets_unearthed_at_raf_coltishall_1_2257069?usurv=skip | title = Hidden WWII secrets unearthed at RAF Coltishall | accessdate = 21 September 2016 | work = North Norfolk News | ref = {{harvid|Hidden WWII secrets, North Norfolk News}}
| url = http://rafburtonwood.org/Phfort.html | title = A Rare Find | accessdate = 21 September 2016 | work = uk.rec.subterranea | ref = {{harvid|A Rare Find, Subterranea}}
| url = http://www.gracesguide.co.uk/Francis_Norman_Pickett | title = Francis Norman Pickett (obituary) | accessdate = 23 September 2016 | work = Grace's Guide | ref = {{harvid|Grace's Guide obituary}}
| title = Manure From TNT | author = | first = | last = | authorlink = | url = https://paperspast.natlib.govt.nz/newspapers/PBH19200701.2.59.9 | accessdate = 23 September 2016 | agency = | newspaper = Poverty Bay Herald | publisher = | location = | date = 1 July 1920 | page = | pages = | ref = {{harvid|Poverty Bay Herald 1 July 1920}}
| title = Mr. F. N. Pickett's Failure | author = | first = | last = | authorlink = | agency = | newspaper = The Times | publisher = | location = London, England | date = 19 October 1932 | page = 16 column e | pages = | ref = {{harvid|Times 19 October 1932}}
| last1 = | first1 = | last2 = | first2 = | date = March 1997 | title = Counting the Akelas | journal = Motor Sport | publisher = | volume = | issue = | page = 64 | url = http://www.motorsportmagazine.com/archive/article/march-1997/64/counting-akelas | accessdate = | doi = | ref = {{harvid|Counting the Akelas}}
| url = http://www.the-trench.org/wp-content/uploads/2013/06/CW-destruction-in-Belgium.pdf | last = Zanders | title = The destruction of old chemical munitions in Belgium | first = Jean Pascal | accessdate = 23 September 2016 | work = The Trench | ref = harv
| last1 = Goldup | last2 = | date = 26 August 1938 | title = Improvements relating to the raising and lowering of agricultural implements | first1 = Cecil Edgar | first2 = | url = https://worldwide.espacenet.com/publicationDetails/biblio?FT=D&date=19380826&DB=EPODOC&locale=en_EP&CC=GB&NR=491130A&KC=A&ND=4 | accessdate = 26 September 2016 | work = Espacenet | ref = harv
| last1 = Pickett | last2 = Hamilton | date = 12 July 1940 | title = An improved means for the protection of aerodromes, aircraft landing fields and other situations (patent) | first1 = Francis Norman | first2 = Donald St Aubyn | url = https://worldwide.espacenet.com/publicationDetails/biblio?FT=D&date=19460606&DB=&locale=en_EP&CC=GB&NR=577933A&KC=A&ND=4 | accessdate = 23 September 2016 | work = Espacenet | ref = harv
| url = https://historicengland.org.uk/listing/the-list/list-entry/1393762 | title = World War II Pickett-Hamilton Fort SU 4681 3512 (NO.1), Worthy Down Airfield | accessdate = 28 September 2016 | work = Historic England | ref = {{harvid|World War II Pickett-Hamilton Fort, Worthy Down Airfield}}
| url = http://www.derelictplaces.co.uk/main/ww2-defences/15958-pickett-hamilton-pillbox-worthy.html#.V-vnQvkrLRY | title = Pickett Hamilton Pillbox Worthy Down | accessdate = 28 September 2016 | work = Derelict Places | ref = {{harvid|Pickett Hamilton Pillbox Worthy Down, Derelict Places}}
| title = WO 199/2527 – Pillboxes | date = November 1940 | url = http://discovery.nationalarchives.gov.uk/details/r/C612610 | work = The Catalogue | publisher = The National Archives | ref = {{harvid|WO 199/2527}} External links{{Commons category|Pickett-Hamilton Retractable Fort}}
| url = http://www.nationalarchives.gov.uk | title = Homepage | accessdate = 2 August 2010 | publisher = The National Archives | location = UK 2 : World War II military equipment of the United Kingdom|20th-century forts in England |
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