A pulse jet system and method is disclosed. In an example, the pulse jet system includes a combustion chamber, intake ports to deliver combustion agents to the combustion chamber, an expansion chamber to cool a combustion product following combustion of the combustion agents in the combustion chamber, and an exhaust to exit the cooled gas from the expansion chamber. In another example, the pulse jet system includes a combustion chamber with intake ports to deliver combustion agents to the combustion chamber, wherein the combustion chamber is part of a four cycle engine. The pulse jet system also includes an expansion chamber to cool a combustion product following combustion of the combustion agents in the combustion chamber.