Editing V-1 flying bomb (section)

==Description==
[[File:V-1 cutaway.jpg|thumb|V-1 cutaway]]
The V-1 was designed under the codename {{lang|de|Kirschkern}} (cherry stone){{sfn|Zaloga|2005|p=6}} by Lusser and Gosslau, with a [[fuselage]] constructed mainly of welded [[sheet steel]] and wings built of [[plywood]]. The simple, Argus-built pulsejet engine pulsed 50 times per second,{{sfn|Werrell|1985|p=53}} and the characteristic buzzing sound gave rise to the colloquial names "buzz bomb" or "doodlebug" (a common name for a wide variety of flying insects). It was known briefly in Germany (on Hitler's orders) as {{lang|de|Maikäfer}} ([[Phyllophaga|May bug]] literally "May" + "chafer") and {{lang|de|Krähe}} (crow).{{sfn|Zaloga|2005|pp=8–9}}

===Power plant===
{{main|Argus As 014}}
[[File:V1 Launcher IWM Duxford.JPG|thumb|left|Rear view of V-1 in [[IWM Duxford]], showing launch ramp section]]
The Argus [[pulsejet]]'s major components included the [[nacelle]], fuel jets, flap valve grid, mixing chamber [[venturi tube|venturi]], tail pipe, and spark plug. Compressed air rather than a [[fuel pump]] forced gasoline from the {{cvt|640|litre}} fuel tank through the fuel jets which consisted of three banks of three [[Atomizer nozzle|atomizer]]s. These nine atomizing nozzles were in front of the air inlet valve system where it mixed with air before entering the chamber. A [[throttle valve]], connected to altitude and ram pressure instruments, controlled fuel flow. Schmidt's spring-controlled flap valve system provided an efficient straight path for incoming air. The flaps momentarily closed after each explosion, the resultant gas compressed in the venturi chamber, and its tapered portion accelerated the exhaust gases creating [[thrust]]. The operation proceeded at a rate of 42 cycles per second.{{sfn|Oliver|2018|pp=19–24}}{{sfn|Cooksley|1979|pp=32–33}}{{sfn|Guckelhorn|Paul|2004|pp=12–19}}

Beginning in January 1941, the V-1's pulsejet engine was also tested on a variety of craft, including automobiles{{sfn|Zaloga|2005|p=5}} and an experimental [[attack boat]] known as the Tornado, in which a boat loaded with a {{cvt|700|kg|0}} warhead was steered towards a target ship either by remote control or by a pilot who would leap out of the back at the last moment. The Tornado was assembled from surplus [[seaplane]] hulls connected in [[catamaran]] fashion. Ultimately insufficient Argus 014 pulse-jets were available as all production was allocated to the V-1 missile program.<ref name=":21">{{Cite book|title=German Secret Weapons of the Second World War|last=Hogg|first=Ian|date=1999|publisher=Frontline Books|isbn=978-1-8483-2781-8|page=270}}</ref> The engine made its first flight aboard a Gotha Go 145 on 30 April 1941.{{sfn|Zaloga|2005|p=5}}

===Guidance system===
[[File:V1Musee.jpg|thumb|A V-1 on display in the [[Army Museum (Paris)|Musée de l'Armée]], Paris]]

The V-1 [[missile guidance|guidance system]] used a simple [[autopilot]] developed by [[:de:Askania Werke#Astronomische und geod.C3.A4tische Instrumente|Askania]] in Berlin to regulate altitude and airspeed.{{sfn|Zaloga|2005|p=6}} A pair of gyroscopes controlled yaw and pitch, while azimuth was maintained by a magnetic compass. Altitude was maintained by a barometric device.{{sfn|Zaloga|2005|p=8}} Two spherical tanks contained [[compressed air]] at {{convert|900|psi|MPa|order=flip}}, that drove the gyros, operated the [[pneumatic]] servomotors controlling the rudder and elevator, and pressurized the fuel system.{{sfn|Oliver|2018|pp=19, 24, 28, 89}}{{sfn|Cooksley|1979|pp=30–32}}{{sfn|Guckelhorn|Paul|2004|pp=12–19}}

The magnetic compass was located near the front of the V-1, within a wooden sphere. Shortly before launch, the V-1 was suspended inside the Compass Swinging Building (Richthaus). There the compass was corrected for [[magnetic variance]] and [[magnetic deviation]].{{sfn|Oliver|2018|pp=27–28}}{{sfn|Cooksley|1979|pp=29–30}} The RLM at first planned to use a [[radio control]] system with the V-1 for [[precision-guided munition|precision attacks]], but the government decided instead to use the missile against London.{{sfn|Levine|1992|pp=137, 139}} Some flying bombs were equipped with a basic radio transmitter operating in the range of 340–450&nbsp;kHz. Once over the channel, the radio would be switched on by the vane counter, and a {{convert|400|foot|m|-1|adj=on|order=flip}} aerial deployed. A coded Morse signal, unique to each V-1 site, transmitted the route, and impact zone calculated once the radio stopped transmitting.{{sfn|Oliver|2018|p=33}}{{sfn|Cooksley|1979|p=39}}

[[File:Launcher of V-1 rocket in Historisch-technisches Informationszentrum Peenemünde (1).JPG|thumb|A reconstructed starting ramp for V-1 flying bombs, [[Historical Technical Museum, Peenemünde]] (2009)]]
An odometer driven by a [[vane anemometer]] on the nose determined when the target area had been reached, accurate enough for [[area bombing]]. Before launch, it was set to count backwards from a value that would reach zero upon arrival at the target in the prevailing wind conditions. As the missile flew, the airflow turned the propeller, and every 30 rotations of the propeller counted down one number on the odometer. This odometer triggered the arming of the warhead after about {{cvt|60|km}}.{{sfn|Werrell|1985|p=54}} When the count reached zero, two [[Pyrotechnic fastener|detonating bolts]] were fired. Two [[Spoiler (aeronautics)|spoilers]] on the [[Elevator (aircraft)|elevator]] were released, the linkage between the elevator and servo was jammed, and a [[guillotine]] device cut off the control hoses to the rudder servo, setting the rudder in neutral. These actions put the V-1 into a steep dive.<ref>{{cite book |last= |first= |date=April 1944 |title=FZG 76 Geräte-Handbuch |trans-title=FZG 76 Equipment Handbook |chapter=Teil 1: Zelle [Part 1: Airframe] |pages=7–8 |language=de|url=http://www.mrsite.co.uk/usersitesv32/101755.mrsite.com/wwwroot/USERIMAGES/V1%20Tech%20Manual.pdf |url-status= |location= |publisher= |isbn= |archive-url=https://web.archive.org/web/20190111094355/http://www.mrsite.co.uk/usersitesv32/101755.mrsite.com/wwwroot/USERIMAGES/V1%20Tech%20Manual.pdf |archive-date=January 11, 2019}}</ref><ref>{{citation |url=http://www.psywarrior.com/V1RocketLeaf.html |title=German V-1 Leaflet Campaign |publisher=Psy Warrior |access-date=20 October 2010}}.</ref> While this was originally intended to be a power dive, in practice the dive caused the fuel flow to cease, which stopped the engine. The sudden silence after the buzzing alerted people under the flight path to the impending impact.{{sfn|Werrell|1985|pp=41–62}}{{sfn|Guckelhorn|Paul|2004|pp=12–19}}{{sfn|Oliver|2018|p=27}}{{sfn|Cooksley|1979|pp=29, 37}}

Initially, V-1s landed within a circle {{convert|19|mi|km|abbr=on|order=flip}} in diameter, but by the end of the war, accuracy had been improved to about {{convert|7|mi|km|abbr=on|order=flip}}, which was comparable to the [[V-2 rocket]].<ref>Kloeppel, Major Kirk M., The Military Utility of German Rocketry During World War II, Air Command and Staff College, 1997.</ref>

=== Warhead ===
The warhead consisted of {{cvt|850|kg|lb}} of [[Amatol]], 52A+ high-grade, blast-effective explosive with three fuses. An electrical fuse could be triggered by nose or belly impact. Another fuse was a slow-acting mechanical fuse allowing deeper penetration into the ground, regardless of the altitude. The third fuse was a delayed action fuse, set to go off two hours after launch.{{sfn|Oliver|2018|pp=28, 85–86}}{{sfn|Cooksley|1979|p=30}}

The purpose of the third fuse was to avoid the risk of this secret weapon being examined by the British. Its time delay was too short to be a useful booby trap but was instead meant to destroy the weapon if a soft landing had not triggered the impact fuses. These fusing systems were very reliable, and almost no dud V-1s were recovered.<ref>{{cite web |title=The Doodlebug Project |url=http://www.asa-be.com/PhotogalleryMuseumV1Project.htm |website=Stampe & Vertongen Museum |location=Antwerp Airport |access-date=27 May 2018 |archive-date=21 January 2019 |archive-url=https://web.archive.org/web/20190121234810/http://www.asa-be.com/PhotogalleryMuseumV1Project.htm |url-status=dead }}</ref><ref>{{cite book |title=FZG 76 Geräte-Handbuch |trans-title=FZG 76 Equipment Handbook |chapter=Teil 4: Zünderanlage [Part 4: Ignition system] |url=http://www.mrsite.co.uk/usersitesv32/101755.mrsite.com/wwwroot/USERIMAGES/V1%20Tech%20Manual.pdf |date=April 1944 |pages=98–118 |language=de |access-date=27 May 2018 |archive-date=11 January 2019 |archive-url=https://web.archive.org/web/20190111094355/http://www.mrsite.co.uk/usersitesv32/101755.mrsite.com/wwwroot/USERIMAGES/V1%20Tech%20Manual.pdf |url-status=dead }}</ref>

===Walter catapult===
[[File:V1 flying bomb on ramp.jpg|thumb|V-1 on Walter catapult ramp at [[Blockhaus d'Éperlecques|Éperlecques]]]]

Ground-launched V-1s were propelled up an inclined launch ramp by an apparatus known as ''{{lang|de|Dampferzeuger}}'' ("steam generator"), in which steam was generated when [[hydrogen peroxide]] (''[[T-Stoff]]'') was mixed with [[sodium permanganate]] (''[[Z-Stoff]]'').{{sfn|Werrell|1985|p={{page needed|date=July 2020}} }}<ref>{{cite web |url=http://www.atlantikwall.org.uk/v1_light_stes.htm |title=V1 Light Sites |publisher=Atlantic Wall |access-date=9 May 2017}}</ref>
Designed by [[Hellmuth Walter Kommanditgesellschaft|Hellmuth Walter KG]], the "WR 2.3" ''Schlitzrohrschleuder'' consisted of a small gas generator trailer, where the T-Stoff and Z-Stoff combined, generating high-pressure steam that was fed into a tube within the launch rail box. A piston in the tube, connected underneath the missile, was propelled forward by the steam. It is a common misconception that the steam launch was to allow the engine to start running but the real reason was that the Argus had insufficient power to propel the V1 to a speed above its extremely high stall speed. The launch rail was {{convert|49|m|ft|abbr=on|round=5}} long, consisting of eight modular sections, each {{cvt|6|m}} long, and a muzzle brake. Production of the Walter catapult began in January 1944.{{sfn|Zaloga|2008|pp=10, 17–18, 24–39, 42, 47–48}}{{sfn|Guckelhorn|Paul|2004|pp=20–23}}

[[File:V1 piston.jpg|thumb|left|V-1 launch piston for Walter catapult]]

The Walter catapult accelerated the V-1 to a launch speed of {{convert|200|mph|km/h|order=flip|abbr=on}}, well above the needed minimum operational speed of {{convert|150|mph|km/h|order=flip|abbr=on}}. The V-1 reached the British coast at {{convert|340|mph|km/h|order=flip|abbr=on}}, but continued to accelerate to {{convert|400|mph|km/h|order=flip|abbr=on}} by the time it reached London, as its {{convert|150|USgal|L|order=flip|abbr=on}} of fuel burned off.{{sfn|Werrell|1985|pp=41–62}}

On 18 June 1943 [[Hermann Göring]] decided on launching the V-1, using the Walter catapult, in large launch bunkers, called ''Wasserwerk'' (the German word for [[water works]]), and lighter installations, called the ''Stellungsystem''. The Wasserwerk bunker measured {{convert|215|m|abbr=on}} long, {{convert|36|m|abbr=on}} wide, and {{convert|10|m|abbr=on}} high. Four were initially to be built: Wasserwerk Desvres, [[Siracourt V-1 bunker|Wasserwerk St. Pol]], Wasserwerk Valognes, and Wasserwerk Cherbourg. Stellungsystem-I was to be operated by Flak Regiment 155(W), with 4 launch battalions, each having 4 launchers, and located in the [[Pas-de-Calais]] region. Stellungsystem-II, with 32 sites, was to act as a reserve unit. Stellungsystem-I and II had nine batteries manned by February 1944. Stellungsystem-III, operated by FR 255(W), was to be organized in the spring of 1944, and located between [[Rouen]] and [[Caen]]. The Stellungsystem locations included distinctive catapult walls pointed towards London, several J-shaped stowage buildings referred to as "ski" buildings as on aerial reconnaissance photographs the buildings looked like a ski on its side, and a compass correction building which was constructed without ferrous metal. In the spring of 1944, [[Oberst]] Schmalschläger had developed a more simplified launching site, called ''Einsatzstellungen'' (meaning ca. "deployed emplacement"). Less conspicuous, 80 launch sites and 16 support sites were located from [[Calais]] to [[Normandy]]. Each site took only two weeks to construct, using 40 men, and the Walter catapult only took 7–8 days to erect, when the time was ready to make it operational.{{sfn|Zaloga|2008|pp=10, 17–18, 24–39, 42, 47–48}}

Once near the launch ramp, the wing spar and wings were attached and the missile was slid off the loading trolley, ''Zubringerwagen'', onto the launch ramp. The ramp catapult was powered by the ''Dampferzeuger'' trolley. The pulse-jet engine was started by the ''Anlassgerät'', which provided compressed air for the engine intake, and initial electrical supply for the engine [[spark plug]], and autopilot. The [[Robert Bosch GmbH|Bosch]] spark plug was only needed to start the engine, while residual flame ignited further mixtures of gasoline and air, and the engine would be at full power after 7 seconds. The catapult would then accelerate the bomb above its stall speed of {{convert|200|mph|km/h|order=flip|abbr=on}}, ensuring sufficient [[ram-air intake|ram air]].{{sfn|Zaloga|2005|p=17–18, 20–21}}{{sfn|Oliver|2018|pp=84, 87–90}}{{sfn|Cooksley|1979|pp=32–35}}