 The former became the prototype of first the General Electric I-A and then the General Electric I-16, and by April 1943 the latter had been developed to produce 1,650 pounds thrust (750 kgf).In 1941, experiments with boosting the W.1's thrust by introducing a liquid coolant were initiated, the first fluid tried being liquid ammonia which proved too effective, resulting in the engine overspeeding and pushing the thrust and rpm indicators off the scales, before later trials changed to using water, and water-methanol.A system to trial the technique in the E.28/39 was devised but never fitted.