In 1937 James Hart Wyld presented a regenerative rocket engine, cooled by liquid fuel circulating between the walls of the combustion chamber.

- When the fuel circulated between the walls of the chamber there was a preheating that helped the combustion process when the fuel entered the combustor.

“J. Hart's rocket engine”

-James Hart belonged to the American Rocket Society.

-James Hart along with three other members of the ARS founded RMI (Reaction Motors Inc.) in 1941.

-RMI made JATO until later it intervened in the 6000C-4 engine that was used by the Bell X-1A, the first aircraft that passed the sound barrier.