>>delibe+if
Context: "Sir Frank Whittle, an English engineer, is credited with inventing the jet engine. He patented the design for the turbojet engine in 1930, and his work led to the first operational jet engine in 1937. Independently, Hans von Ohain in Germany developed a similar jet engine, with the first flight powered by his design occurring in 1939. Both are recognized for their pioneering contributions, but Whittle's work laid the foundational concepts."