de Havilland Ghost
The Ghost came about when de Havilland started work on what was to become the Comet in 1943. Frank Halford's first design, the H-1, was just entering production and he was able to meet the power requirements of the Comet by simply scaling up features of the H-1. The resulting H-2 also used ten larger flame cans in place of the Goblin's sixteen smaller ones, using "split intakes" to each can to feed in more air, as if there were twenty cans feeding off the compressor. While the prototype was being built, de Havilland bought Halford's firm and reformed it as the de Havilland Engine Company, renaming the H-1 and H-2 as the Goblin and Ghost respectively.
The Ghost was already being tested in 1944, and flew on 2 September 1945. This was long before the Comet or Venom was ready for flight. By this point the Ghost had been selected for the Swedish "JxR" fighter project, which eventually turned into the Tunnan. During the design of the Tunnan, Sweden received German data on swept wing designs via Switzerland and redesiged the plane to incorporate this planform. The Tunnan first flew in this form in 1948. For production versions of the Tunnan, the Ghost was built under licence by Svenska Flygmotor (later to become Volvo Aero) as the RM2.
The Ghost would next be seen when the Comet finally took to the air on 27 July 1949. This prototype was powered by the 5,000 lbf (22 kN) Ghost 50, although this was an interim measure while more powerful engines could be developed. The "real" version of the aircraft would be the Rolls-Royce Avon-powered Comet 2, but these engines were not yet ready for flight. In order to make up for the low thrust of the Ghost, the Comet was lightened by using thin-gauge skinning. It was this thin skin that was later found to be a contribution to the cause of a number of infamous crashes, due to metal fatigue. Several versions of the Ghost 50 were produced, ending with the Ghost 50-Mk.4 mounted on the Comet 1XB that was built to test new fuselage construction techniques to address the problems in the Comet 1.
During development, the Royal Air Force also asked for an improved version of the de Havilland Vampire with greater load carrying capacity and thus a larger engine. The resulting design was known as the Venom, and shared many features with the earlier Vampire. The Ghost first flew in the Venom on 2 September 1949. By this point the engine had been running for some time and was already at the Mk.103 model of 4,850 lbf (21,600 N). The Venom was used primarily as a fighter bomber, although some were also produced as night fighters. The Venom was later selected by the Fleet Air Arm for their interceptor needs, and was widely used as the Sea Venom.