Dr. Hans von Ohain and Sir Frank Whittle are both recognized as the co-inventors of the jet engine. von Ohain designed the first operational turbojet engine and Whittle was the first one to register a patent in 1930. However, Whittle could not afford the £5 renewal fee for his jet engine patent when it became due in January 1935, and because the British Air Ministry refused to pay it the patent was allowed to lapse.
When Whittle first came to know about von Ohain’s engine, he was initially upset as he believed von Ohain’s engine had been developed after seeing his patent. Eventually he became convinced that von Ohain’s work was, in fact, independent. The two became good friends and often toured the U.S. giving talks together.
According to patentyogi