General Electric I-16 / J31 / J39
The General Electric J31 was the first working jet engine produced in the United States and also the first jet engine to be produced in quantity there.
The J33 was originally developed by General Electric as a follow-on to their work with the designs of Frank Whittle during World War II. The J31 was essentially a production version of the prototype Whittle W.1 that had been sent to the US after the Tizard Mission successes. General Electric's extensive experience in turbocharger production made them the natural choice for producing the engine, which they initially referred to as the I-16, I-A referring to the original prototype. After major changes to adapt it to US production and to increase thrust, it started limited production as the I-16 in 1942, the 16 referring to its 1,600 lbf (7,100 N) thrust. The United States Army Air Forces later decided to standardize all their jet engine naming, at which point the I-16 became the J31. Full production started as the J31.
Like the W.1, the I-16 produced 1,650 pounds force (7.3 kN) of thrust and weighed about 850 lb. Production started for the P-59 Airacomet in 1943, and by the time the lines shut down in 1945, a total of 241 had been built. GE also used the basic design to produce the much larger I-40 with 4,000 lbf, but this design was passed on to Allison as the J33, much to GE's chagrin and another derivative of the J31, the General Electric I-20, given the military designation J39, was ordered but later cancelled.