Editing Turbopump (section)

==History==
[[File:Rocket engine A4 V2.jpg|thumb|right|upright|The [[V-2 rocket]] used a circular turbopump to pressurize the propellant.]]

=== Early development ===
High-pressure pumps for larger missiles had been discussed by rocket pioneers such as [[Hermann Oberth]].<ref>Rakete zu den Planetenräumen; 1923</ref> In mid-1935 [[Wernher von Braun]] initiated a fuel pump project at the southwest German firm ''[[KSB Company|Klein, Schanzlin & Becker]]'' that was experienced in building large fire-fighting pumps.<ref name=Neufeld>{{cite book |year=1995 |last=Neufeld|first=Michael J. |author-link=Michael Neufeld |title=The Rocket and the Reich |publisher=The [[Smithsonian Institution]] |isbn=0-674-77650-X |pages=80–1, <!--THESE PAGES DO NOT HAVE INFO USED IN THIS WIKIARTICLE:116, 157-->156, 172}}</ref>{{Rp|80}} <!--NONE OF THE CITED NEUFELD PAGES APPEAR TO SAY THE FOLLOWING: The key idea to use [[hydrogen peroxide]] ({chem|H<sub>2</sub>O<sub>2</sub>}}) to drive the pump came from collaboration with [[Hellmuth Walter]] and the first turbopump-fed rockets produced by the German Army Ordnance were developed for the second version of the [[Heinkel He 112#He_112R|Heinkel He 112]] flown in [[1939]]-[[1940]]. In [[1941]] Dr. [[Walter Thiel]]'s propulsion group with the aid of [[Walter Riedel]]s design bureau had the basic design of the [[V-2 rocket]] fuel turbopumps ready.ref name=Neufeld/>{{Rp|tbd}}--> The V-2 rocket design used hydrogen peroxide decomposed through a Walter steam generator to power the uncontrolled turbopump<ref name=Neufeld/>{{Rp|81}} produced at the Heinkel plant at [[Jenbach]],<ref>{{cite book |last=Ordway |first=Frederick I III |author-link=Frederick I. Ordway III |author2=Sharpe, Mitchell R |year=1979 |title=The Rocket Team |url=http://www.apogeebooks.com/indices/RocketTeamindex.htm |series=Apogee Books Space Series 36 |publisher=Thomas Y. Crowell |location=New York |isbn=1-894959-00-0 |page=140  |archive-url=https://web.archive.org/web/20120304025247/http://www.apogeebooks.com/indices/RocketTeamindex.htm |archive-date=2012-03-04 }}</ref> so V-2 turbopumps and combustion chamber were tested and matched to prevent the pump from overpressurizing the chamber.<ref name=Neufeld/>{{Rp|172}} The first engine fired successfully in September,<!--ref name=Neufeld/>{{Rp|156}}--> and on August 16, 1942, a [[Test Stand VII|trial rocket stopped in mid-air and crashed]] due to a failure in the turbopump.<ref name=Neufeld/><ref>{{Cite book |last=Neufeld |first=Michael |url=https://www.google.com/books/edition/Von_Braun/cU1UDgAAQBAJ?hl=en&gbpv=1&dq=August+16+1942+rocket+crashed+%22turbopump%22&pg=PA133&printsec=frontcover |title=Von Braun: Dreamer of Space, Engineer of War |date=2017-04-12 |publisher=Knopf Doubleday Publishing Group |isbn=978-0-525-43591-4 |language=en}}</ref> The first successful V-2 launch was on October 3, 1942.<ref>{{cite book |last=Dornberger |first=Walter |author-link=Walter Dornberger |date=1954 |version=US translation from German |orig-date=1952 |title=Der Schuss ins Weltall / V-2  |url=https://archive.org/details/v20000dorn |url-access=registration |location=Esslingan; New York |publisher=Bechtle Verlag (German); Viking Press (English) |page=[https://archive.org/details/v20000dorn/page/17 17]}}</ref> <!--NEUFELD SAYS TURBOPUMPS WERE INITIALLY USED TO REDUCE TANK AND RELATED PRESSURIZATION WEIGHT, I. E, THIS IS AN UNCITED FABRICATION:. Using turbopumps in rockets was a breakthrough; the power of the rocket motors was increased by an [[order of magnitude]], making the lifting of heavy loads practical.-->

Starting from the 1938-1940, [[Robert H. Goddard]]'s team also independently developed small turbopumps.

=== Development from 1947 to 1949 ===

The principal engineer for turbopump development at [[Aerojet]] was [[George Bosco]]. During the second half of 1947, Bosco and his group learned about the pump work of others and made preliminary design studies. Aerojet representatives visited [[Ohio State University]] where Florant was working on hydrogen pumps, and consulted [[Dietrich Singelmann]], a German pump expert at Wright Field. Bosco subsequently used Singelmann's data in designing Aerojet's first hydrogen pump.<ref name=nasahistory>{{cite web |url=https://history.nasa.gov/SP-4404/ch3-18.htm |title=Liquid Hydrogen as a Propulsion Fuel, 1945-1959 |publisher=[[NASA]] |access-date=2017-07-12 |archive-date=2017-12-25 |archive-url=https://web.archive.org/web/20171225233143/https://history.nasa.gov/SP-4404/ch3-18.htm |url-status=live }}</ref>

By mid-1948, Aerojet had selected centrifugal pumps for both [[liquid hydrogen]] and [[liquid oxygen]]. They obtained some German radial-vane pumps from the Navy and tested them during the second half of the year.<ref name=nasahistory/>

By the end of 1948, Aerojet had designed, built, and tested a liquid hydrogen pump (15&nbsp;cm diameter). Initially, it used [[ball bearing]]s that were run clean and dry, because the low temperature made conventional lubrication impractical. The pump was first operated at low speeds to allow its parts to cool down to [[operating temperature]]. When temperature gauges showed that liquid hydrogen had reached the pump, an attempt was made to accelerate from 5000 to 35 000 revolutions per minute. The pump failed and examination of the pieces pointed to a failure of the bearing, as well as the [[impeller]]. After some testing, super-precision bearings, lubricated by oil that was atomized and directed by a stream of gaseous nitrogen, were used. On the next run, the bearings worked satisfactorily but the stresses were too great for the [[brazing|brazed]] impeller and it flew apart. A new one was made by milling from a solid block of [[aluminum]]. The next two runs with the new pump were a great disappointment; the instruments showed no significant flow or pressure rise. The problem was traced to the exit [[Diffuser (thermodynamics)|diffuser]] of the pump, which was too small and insufficiently cooled during the cool-down cycle so that it limited the flow. This was corrected by adding vent holes in the pump housing; the vents were opened during cool down and closed when the pump was cold. With this fix, two additional runs were made in March 1949 and both were successful. Flow rate and pressure were found to be in approximate agreement with theoretical predictions. The maximum pressure was 26 atmospheres ({{cvt|26|atm|MPa psi}}) and the flow was 0.25 kilogram per second.<ref name=nasahistory/>

===After 1949===
The [[Space Shuttle main engine]]'s turbopumps spun at over 30,000 rpm, delivering 150&nbsp;lb (68&nbsp;kg) of liquid hydrogen and 896&nbsp;lb (406&nbsp;kg) of liquid oxygen to the engine per second.<ref>Hill, P & Peterson, C.(1992) Mechanics and Thermodynamics of Propulsion. New York: Addison-Wesley {{ISBN|0-201-14659-2}}</ref>  The [[Electron (rocket)|Electron Rocket's]] [[Rutherford (rocket engine)|Rutherford]] became the first engine to use an [[Electric-pump-fed engine|electrically-driven pump]] in flight in 2018.<ref name=b14643-electronnlvpropulsion>{{cite web |url=http://www.b14643.de/Spacerockets_1/Rest_World/Electron-NLV/Propulsion/engines.htm |title=Electron Propulsion |first=Norbert |last=Brügge |publisher=B14643.de |access-date=20 September 2016 |archive-date=26 January 2018 |archive-url=https://web.archive.org/web/20180126185301/http://www.b14643.de/Spacerockets_1/Rest_World/Electron-NLV/Propulsion/engines.htm |url-status=live }}</ref>