Editing Solid-propellant rocket (section)

===Black powder (gunpowder) propellant===
[[Gunpowder|Black powder]] (gunpowder) is composed of [[charcoal]] (fuel), [[potassium nitrate]] (oxidizer), and [[sulfur]] (fuel and catalyst). It is one of the oldest [[pyrotechnic]] compositions with application to rocketry. In modern times, black powder finds use in low-power model rockets (such as [[Estes Industries|Estes]] and Quest rockets),<ref>{{cite web|url=https://www.apogeerockets.com/Rocket_Motors/Estes_Motors|title=Model Rocketry Resources and Components|access-date=16 Aug 2017}}</ref><ref>{{cite web|url=http://www.asp-rocketry.com/ecommerce/Quest-Black-Powder-Model-Rocket-Engines.cfm?cat_id=88|title=Quest Black Powder Model Rocket Engines|access-date=16 Aug 2017|archive-url=https://web.archive.org/web/20170816190952/http://www.asp-rocketry.com/ecommerce/Quest-Black-Powder-Model-Rocket-Engines.cfm?cat_id=88|archive-date=16 August 2017|url-status=dead}}</ref> as it is cheap and fairly easy to produce. The fuel grain is typically a mixture of pressed fine powder (into a solid, hard slug), with a burn rate that is highly dependent upon exact composition and operating conditions. The [[specific impulse]] of black powder is low, around {{convert|80|isp |abbr=on}}. The grain is sensitive to fracture and, therefore, catastrophic failure. Black powder does not typically find use in motors above {{convert|40|N|lbf|abbr=off}} thrust.