Editing Pulsejet (section)

==History==
[[file:Ramon Casanova and the pulsejet engine he constructed and patented in 1917.jpg|thumb|left|Ramón Casanova and the pulsejet engine he constructed and patented in 1917]]

Russian inventor and retired artillery officer Nikolaj Afanasievich Teleshov patented a steam pulsejet engine in 1867 while Swedish inventor [[Martin Wiberg]] also has a claim to having invented the first pulsejet, in Sweden, but details are unclear.

The first working pulsejet was patented in 1906 by Russian engineer V. V. Karavodin, who completed a working model in 1907. 

French inventor Georges Marconnet patented his valveless pulsejet engine in 1908. It was the grandfather of all valveless pulsejets. The valveless pulsejet was experimented with by French propulsion research group Société Nationale d'Étude et de Construction de Moteurs d'Aviation ([[SNECMA]]), in the late 1940s.

Ramón Casanova, in [[Ripoll]], [[Spain]] patented a pulsejet in [[Barcelona]] in 1917, having constructed one beginning in 1913. [[Robert Goddard]] invented a pulsejet engine in 1931, and demonstrated it on a jet-propelled bicycle.<ref>U.S. Patent 1,980,266</ref> Engineer [[Paul Schmidt (inventor)|Paul Schmidt]] pioneered a more efficient design based on modification of the intake valves (or flaps), earning him government support from the German Air Ministry in 1933.<ref name="George Mindling pp6-31">George Mindling, Robert Bolton: ''US Airforce Tactical Missiles:1949–1969: The Pioneers'', Lulu.com, 200: {{ISBN|0-557-00029-7}}. pp6-31</ref>

The valveless pulsejet's first widespread use was the Dutch drone [[Aviolanda AT-21]]<ref name="ReferenceA" />

===Argus As 109-014===
{{Main|Argus As 014}}
[[File:Argus As14 RAFM.jpg|thumb|left|[[Argus As 014]] pulsejet engine of a V-1 flying bomb at the [[Royal Air Force Museum London]]]]

In 1934, [[Georg Hans Madelung]] and Munich-based Paul Schmidt proposed to the German [[Reich Air Ministry|Air Ministry]] a "flying bomb" powered by Schmidt's pulsejet. Schmidt's prototype bomb was rejected by the German Air Ministry as they were uninterested in it from a tactical perspective and assessed it as being technically dubious. The original Schmidt design had the pulsejet placed in a fuselage like a modern jet fighter, unlike the eventual V-1, which had the engine placed above the warhead and fuselage.<ref name=":Kay">{{Cite book |last=Kay |first=Antony L |title=German Jet Engine and Gas Turbine Development 1930-1945 |date=2002 |publisher=Airlife Publishing Ltd |isbn=9781840372946 |pages=239–240 |language=en |chapter=}}</ref>

The [[Argus Motoren|Argus Company]] began work based on Schmidt's work. Other German manufacturers working on similar pulsejets and flying bombs were [[The Askania Company]], [[Robert Lusser]] of [[Fieseler]], [[Fritz Gosslau|Dr. Fritz Gosslau]] of Argus and the [[Siemens]] company, which were all combined to work on the V-1.<ref name="George Mindling pp6-31"/>

With Schmidt now working for Argus, the pulsejet was perfected and was officially known by its [[Reich Air Ministry|RLM]] designation as the Argus As 109-014. The first unpowered drop occurred at [[Peenemünde]] on 28 October 1942, the first powered flight on 10 December 1942 and the first powered launch on 24 December 1942.<ref name=":0">{{Cite book |last=Zaloga |first=Steven J |title=V-1 Flying Bomb, 1942-52 |date=2005 |publisher=Osprey |isbn=978-1841767918 |pages=9–11}}</ref>

The pulsejet was evaluated to be an excellent balance of cost and function: a simple design that performed well for minimal cost.<ref name="George Mindling pp6-31"/> It would run on any grade of petroleum and the ignition shutter system was not intended to last beyond the V-1's normal operational flight life of one hour. Although it generated insufficient thrust for takeoff, the V-1's resonant jet could operate while stationary on the launch ramp. The simple resonant design based on the ratio (8.7:1) of the diameter to the length of the exhaust pipe functioned to perpetuate the combustion cycle, and attained stable resonance frequency at 43 [[cycles per second]]. The engine produced {{convert|2200|N|abbr=on}} of static thrust and approximately {{convert|3300|N|abbr=on}} in flight.<ref name="George Mindling pp6-31"/>

Ignition in the As 014 was provided by a single automotive spark plug, mounted approximately {{convert|75|cm|abbr=on}} behind the front-mounted valve array. The spark only operated for the start sequence for the engine; the Argus As 014, like all pulsejets, did not require [[ignition coil]]s or [[ignition magneto|magnetos]] for ignition&nbsp;— the ignition source being the tail of the preceding fireball during the run. The engine casing did not provide sufficient heat to cause [[Diesel engine#Operating principle|diesel-type ignition of the fuel]], as there is insignificant compression within a pulsejet engine.{{citation needed|date=August 2021}}

The Argus As 014 valve array was based on a shutter system that operated at 47 cycles-per-second.<ref name=":0" />

Three air nozzles in the front of the Argus As 014 were connected to an external high pressure source to start the engine. The fuel used for ignition was [[acetylene]], with the technicians having to place a baffle of wood or cardboard in the exhaust pipe to stop the acetylene diffusing before complete ignition. Once the engine ignited and minimum [[operating temperature]] was attained, external hoses and connectors were removed.

The V-1, being a cruise missile, lacked landing gear, instead the Argus As 014 was launched on an inclined ramp powered by a [[piston]]-driven steam catapult. Steam power to fire the piston was generated by the violent [[exothermic]] chemical reaction created when [[hydrogen peroxide]] and [[potassium permanganate]] (termed [[T-Stoff]] and [[Z-Stoff]]) are combined.

The principal military use of the pulsejet engine, with the volume production of the Argus As 014 unit (the first pulsejet engine ever in volume production), was for use with the [[V-1 (flying bomb)|V-1 flying bomb]].  The engine's characteristic droning noise earned it the nicknames "buzz bomb" or "doodlebug". The V-1 was a German [[cruise missile]] used in [[World War II]], most famously in the [[The Blitz#V-Weapons offensive|bombing of London]] in 1944. Pulsejet engines, being cheap and easy to construct, were the obvious choice for the V-1's designers, given the Germans' materials shortages and overstretched industry at that stage of the war. Designers of modern cruise missiles do not choose pulsejet engines for propulsion, preferring [[turbojet]]s or [[rocket]] engines. The only other uses of the pulsejet that reached the hardware stage in Nazi Germany were the [[Messerschmitt Me 328]] and an experimental [[Jet pack|Einpersonenfluggerät project]] for the German [[Wehrmacht|Heer]].

[[Wright Field]] technical personnel [[reverse engineering|reverse-engineered]] the V-1 from the remains of one that had failed to detonate in Britain. The result was the creation of the [[Republic-Ford JB-2|JB-2 Loon]], with the airframe built by [[Republic Aviation]], and the Argus As 014 reproduction pulsejet powerplant, known by its '''PJ31''' American designation, being made by the [[Ford Motor Company]].

General [[Hap Arnold]] of the United States Army Air Forces was concerned that this weapon could be built of steel and wood, in 2000 man hours and approximate cost of {{US$|600|1943}}.<ref name="George Mindling pp6-31"/>

=== Wave ===
In 2024 University of Maryland spinoff Wave Engine Corporation delivered four of its J-1 engines to a customer. J-1 is a digitally controlled pulsejet engine for use in [[unmanned aerial vehicles]] (UAVs).<ref name=":02">{{Cite web |last=Weiss |first=C. C. |date=2024-07-11 |title=Fire-spitting pulsejet engine delivers bulk thrust at low cost |url=https://newatlas.com/aircraft/wave-pulsejet-engine-deliveries/?utm_source=New+Atlas+Subscribers&utm_campaign=4f284aad95-EMAIL_CAMPAIGN_2024_07_12_04_51&utm_medium=email&utm_term=0_65b67362bd-4f284aad95-%5BLIST_EMAIL_ID%5D |access-date=2024-08-24 |website=New Atlas |language=en-US}}</ref>