Editing Torpedo (section)

==== Wet heater ====
{{Anchor|Wet heater|Wet-heater}}A further improvement was the use of water to wash and cool the [[combustion chamber]] of the fuel-burning torpedo. Water would be injected into the combustion chamber, at a rate commensurate with the fuel supply rate. This water would flash to steam, with stray condensate carrying the soot combustion byproducts out through the engine. An early example was the wet heater system developed by Lieutenant Sydney Hardcastle at the [[Royal Arsenal|Royal Gun Factory]], in 1908.<ref>{{cite book|chapter=The Officers of the Royal Navy Before 1918|chapter-url=https://link.springer.com/content/pdf/10.1057/9781137481962_2.pdf|website=Springer Link|date=2015 |doi=10.1057/9781137481962_2 |access-date=4 October 2024|chapter-url-access=subscription |last1=Farquharson-Roberts |first1=Mike |title=Royal Naval Officers from War to War, 1918–1939 |pages=8–23 |isbn=978-1-349-57163-5 }}</ref> The compressed air bottle was partially filled with water, with an outlet at the bottom leading into the combustion chamber. This would guarantee that compressed air and water would be injected into the combustion chamber at the same pressure. The system not only solved heating problems so more fuel could be burned but also allowed additional power to be generated by feeding the resulting steam into the engine together with the [[combustion]] products. Torpedoes with such a propulsion system became known as ''wet heaters'', while heated torpedoes without steam generation were retrospectively called ''dry heaters''. Most torpedoes used in World War I and World War II were wet heaters.