Editing Hypergolic propellant (section)

=== Less common or obsolete ===

Less-common or obsolete hypergolic propellants include:
* Aniline + nitric acid (unstable, explosive) is used in the [[WAC Corporal]].<ref>{{cite web
|url=https://airandspace.si.edu/collection-objects/rocket-liquid-fuel-sounding-wac-corporal/nasm_A19590009000
|title=WAC Corporal Sounding Rocket
|url-status=live
|archive-url=https://web.archive.org/web/20220107072025/https://airandspace.si.edu/collection-objects/rocket-liquid-fuel-sounding-wac-corporal/nasm_A19590009000
|archive-date=7 January 2022}}</ref> 
* Aniline + hydrogen peroxide (dust-sensitive, explosive)
* [[Furfuryl alcohol]] + [[red fuming nitric acid]] – [[Copenhagen Suborbitals]] SPECTRA Engine<ref>{{cite web |title=Project SPECTRA - Experimental evaluation of a Liquid storable propellant |url=http://copenhagensuborbitals.com/public/spectra.pdf |archive-url=https://web.archive.org/web/20131104140052/http://copenhagensuborbitals.com/public/spectra.pdf |archive-date=4 November 2013 |url-status=dead}}</ref><ref name="Ignition"/>{{rp|27}}
* Furfuryl alcohol + [[Nitric_acid#Anhydrous_nitric_acid|white fuming nitric acid]]<ref name="Ignition"/>{{rp|27}}
* Hydrazine + nitric acid (toxic but stable) was abandoned due to lack of reliable ignition. No engine with this combination ever went into mass production.<ref>{{cite web|title=Nitric acid/Hydrazine|url=http://www.astronautix.com/n/nitricacidhydrazine.html|publisher=Astronautix.com|access-date=January 13, 2023}}</ref>
* Kerosene + (high-test peroxide + catalyst) is used in [[Gamma (Rocket engine)|Gamma]], with the peroxide first decomposed by a catalyst. Cold hydrogen peroxide and kerosene are not hypergolic, but concentrated hydrogen peroxide (referred to as high-test peroxide or HTP) run over a catalyst produces free oxygen and steam at over {{Convert|700|C|F|-2}}, which is hypergolic with kerosene.<ref>{{Cite web|url = http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=31490.0;attach=519423|title = High Test Peroxide|access-date = July 11, 2014|format = pdf}}</ref>
*[[Tonka (fuel)|Tonka]] (TG-02, about 50% [[triethylamine]] and 50% [[xylidine]]) typically oxidized with nitric acid or its anhydrous nitric oxide derivatives (AK-2x group in the Soviet Union) e.g. [[red fuming nitric acid|AK-20F]] (80% HNO<sub>3</sub> and 20% N<sub>2</sub>O<sub>4</sub> with [[Reaction inhibitor|inhibitor]]).<ref name="Ignition"/>{{rp|14-15,116}}
* ''[[T-Stoff]]'' (stabilized >80% peroxide) + ''[[C-Stoff]]'' (methanol, hydrazine, water, catalyst) was used in [[Messerschmitt Me 163]] World War II German rocket fighter aircraft, for its [[Walter HWK 109-509|Walter 109-509A]] engine.<ref name="Ignition"/>{{rp|13}}
* Turpentine + red fuming nitric acid (flown in French Diamant A first-stage)<ref>{{cite web
|url=http://www.b14643.de/Spacerockets/Specials/European_Rocket_engines/engines.htm
|title=European space-rocket liquid-propellant engines
|url-status=live
|archive-url=https://web.archive.org/web/20210723223834/https://b14643.de/Spacerockets/Specials/European_Rocket_engines/engines.htm
|archive-date=23 July 2021}}</ref>
* UDMH + red fuming nitric acid is used in the [[MGM-52 Lance]] missile system,<ref>{{cite web
|url=http://www.astronautix.com/p/p8e-9.html
|title=P8E-9
|url-status=live
|archive-url=https://web.archive.org/web/20220512200958/http://www.astronautix.com/p/p8e-9.html
|archive-date=12 May 2022}}</ref> [[RM-81_Agena|Agena]] and [[Able_(rocket_stage)|Able]] Upper Stages, and Isayev-built maneuvering engines.<ref>{{cite web
|url=http://www.astronautix.com/n/nitricacidudmh.html
|title=Nitric Acid/UDMH
|url-status=live
|archive-url=https://web.archive.org/web/20220701200932/http://astronautix.com/n/nitricacidudmh.html
|archive-date=1 July 2022}}</ref>