James Hart Wyld (September 10, 1912 – December 3, 1954) was an American engineer and rocket scientist.
He was more impressed with a 1933 regeneratively cooled engine developed by Harry Bull, of Syracuse, NY, and work by Eugene Saenger in Austria.
RMI's first Navy contract produced an engine capable of 1,000 pounds force (4,000 N) in 1942, and it was employed for JATO.
His 6000C-4 engine, producing 6000 pounds of thrust was contained in the Bell X-1 rocket plane, which was the first manned vehicle to break the sound barrier.
Wyld died from a heart condition on December 3, 1954, at Pompton Lakes, New Jersey.