Editing V-1 flying bomb (section)

===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>