View source for ASM-N-2 Bat

{{Short description|U.S. World War II glide bomb}}
{{Distinguish|Bat bomb}}
{{Use dmy dates|date=March 2020}}
{{Infobox weapon
|name= ASM-N-2 Bat
| image= BAT-PB4Y-wingbat.jpg
| image_size = 300
|caption='''Bat''' guided bomb mated to [[PB4Y Privateer]]
|origin=United States
|type= [[Bomb#Types|Conventional]]
<!-- Type selection -->
|is_ranged=
|is_bladed=
|is_explosive=yes
|is_artillery=
|is_vehicle=
|is_UK=yes
<!-- Service history -->
|service         = 1945 ('''Bomb MK 57''')<ref name=dusrm>{{cite web|url=http://www.designation-systems.net/dusrm/app1/asm-n-2.html|title=ASM-N-2|work=Directory of U.S. Military Rockets and Missiles
|access-date=24 December 2007| archive-url= https://web.archive.org/web/20071113195356/http://www.designation-systems.net/dusrm/app1/asm-n-2.html| archive-date= 13 November 2007 | url-status= live}}</ref> – 1953 ('''ASM-N-2''')
|used_by         = [[United States Navy]]
|wars            = [[World War II]]
<!-- Production history -->
|designer        =
|design_date=
|manufacturer    = [[National Bureau of Standards]]
|production_date=
|number          = 2,580<ref name=ausairpower>{{cite web|last=Kopp|first= Dr Carlo|url=http://www.ausairpower.net/WW2-PGMs.html|title=The Dawn of the Smart Bomb|access-date=24 December 2007|publisher=Air Power Australia}}</ref>
|variants=
<!-- General specifications -->
|weight         = Airframe and guidance package only – {{convert|600|lb|kg}}
|length         = {{convert|11|ft|11|in|m}}
|part_length=
|width          = {{convert|10|ft|m}}
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|crew=
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<!-- Explosive specifications -->
|diameter           =
|filling            =
|filling_weight     = 1,000 lb bomb (1,600 lb (727 kg) gross)
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}}
[[Image:Bat missile NAN6-50.jpg|thumb|right|A Bat on its hoist]]

The '''ASM-N-2 Bat''' was a [[United States Navy]] [[World War II]] [[radar-guided]] [[glide bomb]]<ref name=nasm>{{cite web|title=Missile, Air-to-Surface, Bat |url=http://collections.nasm.si.edu/code/emuseum.asp?profile=objects&newstyle=single&quicksearch=A19500104000 |work=Rockets and Missiles |publisher=Smithsonian National Air and Space Museum |access-date=12 May 2009| archive-url= https://web.archive.org/web/20090507212235/http://collections.nasm.si.edu/code/emuseum.asp?profile=objects&newstyle=single&quicksearch=A19500104000| archive-date= 7 May 2009 | url-status= live}}</ref><ref name=nistA>{{cite web|title=Students Help Renovate a Part of WWII-and NIST-History |url=https://www.nist.gov/public_affairs/techbeat/tb2001_02.htm |last=Newman |first=Michael E. |work=NIST Tech Beat – February 2001 – Preservation |publisher=National Institute of Standards and Technology |access-date=19 March 2015 |url-status=dead |archive-url=https://web.archive.org/web/20150402154736/https://www.nist.gov/public_affairs/techbeat/tb2001_02.htm |archive-date=2 April 2015 }}</ref> which was used in combat beginning in April 1945. It was developed and overseen by a unit within the [[National Bureau of Standards]] (which unit later became a part of the [[United States Army Research Laboratory|Army Research Laboratory]]) with assistance from the Navy's [[Bureau of Ordnance]], the Massachusetts Institute of Technology, and Bell Telephone Laboratories.<ref>{{Cite news|url=https://www.airspacemag.com/military-aviation/restoration-the-bat-2925632/|title=Restoration: The Bat|last=Sweeney|first=Jim|date=January 2002|work=Air & Space Magazine|access-date=13 July 2018}}</ref> It is considered to be the first fully automated [[guided missile]] used in combat.<ref name=":0">{{Cite news|url=https://www.nist.gov/nist-time-capsule/giving-new-wings-old-bat|title=Giving New Wings to an Old Bat|last=Materese|first=Robin|date=20 June 2017|work=NIST|access-date=13 July 2018}}</ref>

==Background==
In January 1941 [[RCA]] proposed a new TV-guided anti-shipping weapon, called Dragon, for which an operator would use the TV image sent from the nose of the weapon and operate aerodynamic controls during the weapon's fall. The [[National Bureau of Standards]] (NBS) would provide the airframe for use with a standard [[bomb]], and was the same guidable ordnance airframe design used for the earlier, abortive [[Project Pigeon]] weapons program. The [[Pelican (bomb)|Pelican]] was a June 1942 modification using [[semi-active radar homing]]. By mid-1943, a modification of the design was proposed to use a new [[active radar homing]] system from [[Western Electric]] with a {{convert|2000|lb|0|adj=on}} (one [[short ton]]) [[General-purpose bomb|general-purpose (GP) bomb]], the same basic "AN-M66" ordnance unit as used for the heavier [[USAAF]] VB-2 version of the [[Azon]] radio-controlled ordnance. This Pelican version entered testing in mid-1944 at [[Naval Air Station New York]], where it hit its target ship in two out of four drops.

==Development==
The Bat was the production version which combined the original NBS airframe with a {{convert|1000|lb|0|adj=on}} AN-M65 GP bomb, the same basic ordnance that was used in the contemporary [[Azon]] guided munition, and the Pelican active radar system.<ref name=Fahrney>{{cite web|last=Fahrney|first=Delmar S., RADM USN |title=The Birth of Guided Missiles |url=https://www.usna.com/SSLPage.aspx?pid=2655 |work=United States Naval Institute Proceedings |date=December 1980 |page=60}}</ref> Gyrostabilized with an [[autopilot]] supplied by [[Bendix Aviation]], the steerable tail elevator was powered by small wind-driven generators. The Navy's [[Bureau of Ordnance]]<ref name=Fahrney/> in partnership with the [[Massachusetts Institute of Technology]] (MIT) supervised development and the NBS was in charge of the overall development. Flight tests were conducted at the [[United States Navy shore activities during World War II|Naval Air Ordnance Test Station at Chincoteague Island, Virginia.]] [[Hugh Latimer Dryden]] won the [[President's Certificate of Merit]] for the development of the Bat,<ref name=nasm/> which "was flight tested by a small unit based at Philadelphia against targets in New Jersey."<ref name=Merril>{{Cite web |date=n.d. |work=Your story – Class of 1934 |publisher=USNA Alumni Association and Foundation |url=http://www.usna.com/page.aspx?pid=599#Innovation |last=Merrill |first=Capt Grayson |title=Innovation Wins Wars |access-date=7 January 2013 |quote=BAT was flight tested by a small unit based at Philadelphia against targets in New Jersey.}}</ref> While the NBS developed the Bat's aerodynamic and gyroscopic stabilizing systems, MIT and Bell Labs worked together on its guidance mechanism.<ref name=":0" />

==Deployment==
[[File:Bat radar NAN6-50.jpg|thumb|left|A Bat weapon on a bomb cart, with its nose radome removed]]
The antiship variant of the Bat (SWOD, for "Special Weapons Ordnance Device",<ref>[http://www.designation-systems.net/dusrm/app1/swod.html SWOD]</ref> Mark 9 Modification 0) eventually saw combat service beginning in April 1945 off [[Borneo]], dropped by [[Consolidated PB4Y Privateer]]s<ref name=Fahrney/> (one bomb mounted under each wing) at altitudes of {{convert|15000|to|25,000|ft|m|abbr=off}} at airspeeds of {{convert|140|to|210|kn|km/h|abbr=on}}. Several Japanese ships were sunk and the [[kaibokan]] ''[[Japanese escort ship Aguni|Aguni]]'' was damaged from a range of {{convert|20|nmi|km|abbr=on}}.This vessel is frequently misreported as having been sunk by a destroyer.<ref>{{Cite web|url=http://www.combinedfleet.com/Aguni_t.htm|title = Japanese Escorts}}</ref> Several Bats were also fitted with modified radar systems (SWOD Mark 9 Model 1) and dropped on Japanese-held bridges in [[Burma]] – the same targets that the [[MCLOS]]-guidance, half-ton (AN-M65 GP bomb) weight VB-1 [[Azon]] PGM ordnance was designed to take on – and other land-based targets. The Bat's pioneering radar guidance system was easily confused by radar land clutter, particularly against targets close to shore. A total of approximately 2,600 Bat missiles were deployed.<ref name=":0" />

After the war, the naval designation '''ASM-N-2''' was applied to the unit.

The Privateer was the primary launch platform for the Bat, but other aircraft were also modified to launch the weapon, including the [[Vought F4U Corsair]], [[Curtiss SB2C Helldiver]], and [[Grumman TBF Avenger]]. The primary post-World War II aircraft to carry the weapon was the [[P2V Neptune]].

==Existing missiles==
The original NBS test airframe of the Bat was renovated in 2001 to resemble the real missile and is currently on display at the museum of the [[National Institute of Standards and Technology]],<ref name=nistB>{{cite web |url=http://museum.nist.gov/panels/batmissile/index.html |title=The Bat Missile |publisher=NIST |access-date=7 June 2010 |archive-url=https://web.archive.org/web/20100527090318/http://museum.nist.gov/panels/batmissile/index.html |archive-date=27 May 2010 |url-status=dead }}</ref> the successor to the earlier US National Bureau of Standards. Another example is on display at the [[Pima Air & Space Museum]] in [[Tucson, Arizona]].<ref>{{cite web |title=Designation: ASM-N-2 |url=http://www.pimaair.org/designation/asm-n-2 |website=Pima Air & Space Museum |date=26 November 2019 |access-date=6 July 2023}}</ref>

==See also==
{{Aircontent
|see also=
* [[Fritz X]]
* [[Henschel Hs 293]]
* [[Ruhrstahl X-4]]
* [[Azon]]
* [[VB-6 Felix]]
* [[McDonnell LBD-1 Gargoyle]]
* [[Project Pigeon]]
* [[GB-8]]
* [[Kawasaki Ki-147 I-Go Type1 - Ko]]
* [[Kawasaki Ki-148]]
* [[Ke-Go]]
|lists=
* [[List of anti-ship missiles]]
}}

==References==
{{Reflist}}

==External links==
{{Commons category}}
*[http://www.designation-systems.net/dusrm/app1/asm-n-2.html Andreas Parsch's "Directory of US Military Rockets & Missiles" entry on the ''Bat'']
*[https://web.archive.org/web/20161019160022/http://bathead.com/asmbat.html Family Tree & History of the ASM-N-2 BAT Glide Bomb]

{{USN missiles}}
{{USN early guided weapons}}

[[Category:World War II aerial bombs of the United States]]<!--SUBCATEGORY OF [[Category:World War II weapons of the United States]]-->
[[Category:Anti-ship missiles of the United States]]
[[Category:World War II guided missiles of the United States]]
[[Category:Guided bombs of the United States]]
[[Category:Weapons and ammunition introduced in 1945]]