The new space race to seize the high ground－4 cylinder 3.5 turbo

Human pursuit of speed during the Cold War began to move toward the extreme - in order to break each other's air defense interceptor for reconnaissance and bombing, and in order to intercept such invaders, the two superpowers, T3 turbocharger the Soviet Union launched a competition on the flight velocity.
Turbo-ramjet is the focus of this competition. The mid-1960s, the Americans successfully flight SR-71 "Blackbird" spy plane, started the turbojet and ramjet fusion applicability attempt. Despite its J58 turbine engine is not really punching combinations, but the resulting three times the speed of sound flight speed, or sparked interest in turbo ramjet.
Currently, the US turbo ramjet major development in the innovative Turbo Accelerator program. The immediate objective of the program is such J58 turbine engine, based on the 2015 to flight speed increased by 35%. The beginning of this century, Americans have repeatedly emit X-43A, X-51A and other unmanned aerial vehicles, the technology for verification.
Other countries are not far behind. Russia in the 1970s and 1980s, they were a full-size turbine engine ground test punching combinations; Japan from 1989 began supersonic / hypersonic transport propulsion system program, and in March 1999 when the end of the program, on the ground the world's first turbo-ramjet operation. France, T3 turbocharger Britain, Germany, Australia and India also scramjet aspects of a lot of basic research.

Technical feasibility, engineering sad Off
Currently turbo ramjet concept has been clear for more than a country via ground tests to prove the feasibility of this technology.

However, these tests are only "There is ample evidence that turbo ramjet is technically feasible, but there is no evidence that it is feasible on the project." Japan's turbo ramjet completed only high-altitude table test; the United States on the X-43B unmanned aircraft test engine combination has not achieved its combined cycle engine technology program is just one on the ground to verify the ability to fly six times the speed of sound turbo punching combinations propulsion systems.
In fact, to won turbo ramjet "ripe fruit", people have to skip several steps. For example, support aircraft from takeoff climb quickly accelerate to a height of 20 km, the speed of 2.5 times the speed of sound, high-speed, high thrust to weight ratio of the turbine engine, can work at the same time stable sub-combustion, supersonic combustion ramjet two states, as well as in speed about 2.5 times the speed of sound from the engine turbo state modal smooth transition state for punching a highly reliable mode conversion technology ...... from this perspective, the human ideal "somersault cloud", in fact, still hanging in the far horizon yet.