Editing RP-1 (section)

== RP-1-like fuels ==
[[Robert H. Goddard]]'s initial rockets used gasoline.

While the RP-1 specification was being developed, [[Rocketdyne]] was experimenting with [[diethyl cyclohexane]]. While superior to RP-1, it was never adopted for use{{snd}} its formulation was not finished before development of Atlas and Titan I (designed around RP-1) leading to RP-1 becoming the standard hydrocarbon rocket fuel.<ref name="Ignition">{{Cite book |last1=Clark |first1=J. D. |author-link1=John Drury Clark |url=https://archive.org/details/ignitioninformal0000clar |title=Ignition! an informal history of liquid rocket propellants |last2=Asimov |first2=Isaac |date=1972 |publisher=Rutgers University Press |isbn=978-0-8135-0725-5 |page=[https://archive.org/details/ignitioninformal0000clar/page/105 105] |url-access=registration}}</ref>

Soviet formulations are discussed above. In addition, the Soviets briefly used [[syntin]] ({{langx|ru|link=no|синтин}}), a higher-energy formulation, used in [[Multistage rocket|upper stages]]. Syntin is 1-methyl-1,2-dicyclopropyl cyclopropane ({{chem|C|10|H|16}}).  Russia is also working to switch the [[Soyuz-2]] from RP-1 to "naftil"<ref>{{cite web |url=http://russianspaceweb.com/soyuz_lv_2017.html#vostochny |title=Vostochny launches on schedule for 2017 |publisher=Russian Space Web |access-date=February 5, 2018}}</ref> or "naphthyl".<ref>{{Cite news |url=http://russia-now.com/en/114967/will-russias-1st-carrier-rocket-firing-naphthyl-blast-off/ |title=When will Russia's 1st carrier rocket firing naphthyl blast off? |date=October 11, 2016 |work=Russia Now |access-date=January 29, 2018 |language=en-US}}</ref><ref>{{cite web| url=https://www.ruaviation.com/news/2019/2/22/13007/?h| title=Russia completes engine tests of Soyuz rocket's second stage using new fuel|date=February 22, 2019|publisher=Russian Aviation}}</ref>

After the RP-1 standard, RP-2 was developed. The primary difference is an even lower sulfur content. However, as most users accept RP-1, there was little incentive to produce and stock a second, even rarer and more expensive formulation.

The [[OTRAG]] group launched test vehicles using more common blends. In at least one instance, a rocket was propelled by [[diesel fuel]]. However, no OTRAG rocket came even close to orbit.{{citation needed|date=November 2018}}