Hypersound problems
Despite the fact that the further fate of the X-51A was not so successful, the US military made absolutely victorious reports. The head of the relevant program, Charles Brink (Charlie Brink) said: “We are extremely pleased to report on the completion of most of the tasks set for the tests. This breakthrough can be compared with what happened after the Second World transition from screw aviation to reactive. "
However, in some places the officials, nevertheless, blurted out. The same Brink says: “Now we must return and once again carefully examine all the circumstances. There are no perfect tests, and I am sure that we will find problems that we will try to fix for the next flight. ” Independent commentators are more cautious that those who passed the tests were "partially successful."
But the problems were quite expected. Hypersonic flight is not even a supersonic. It is believed that hypersound starts somewhere at speeds around Mach 5, and the technical difficulties associated with such a furious movement are very numerous. The pressures, temperatures, mechanical overloads that affect the apparatus are too high. Conventional jet engines do not provide sufficient power and are not reliable enough. Developers poetically compare their task with the need to light a match in the heart of a hurricane - and maintain its burning.
The X-51A itself is 4,2m long and has virtually no wings. Technically, it flies by straddling a chain of shock waves that it creates itself in flight - hence its second name, Waverider. With its sharp nose, it rips apart the surrounding air, generating sound waves - and reflecting them at a strictly defined angle. So that the excess pressure is directed under the apparatus, creating a lifting force and accelerating the flow of air entering the engine. The engine here is also unusual, an experimental Pratt & Whitney Rocketdyne SJY61.
These tests were the third during the work on the system, and the first of its independent flight, until X-51A flew only fixed on the aircraft carrier. After being dropped from the plane, in the first 4 seconds of the flight, the X-51A used conventional solid-fuel engines, modified versions installed on American tactical missiles. They dispersed it to Mach 4,8, lifting almost 20 km to an altitude, after which they were dropped to make room for the main engine, the SJY61 engine.
This is a hypersonic ramjet engine - like all similar systems, it requires an increased pressure in the combustion chamber, which is achieved by braking oncoming airflow. But to achieve a sufficient amount of pressure, the air flow itself must be supersonic, and therefore it was necessary to preliminarily accelerate the apparatus with the help of a solid-fuel engine. Interestingly, unlike their “colleagues”, SJY61 operates on conventional aviation kerosene, and not on hydrogen or methane, which is achieved using special catalysts.
Initially it was planned to get much more from the tests: to reach speed in Mach 6, to work 300 seconds. But at the 120 second, information from the sensors began to arrive irregularly (according to other data, the thrust was lost), so that a signal was sent to the 200 th device for destruction.
In any case, 200 seconds of flying at this speed is, after all, a significant success. Let's see what the following tests show; at least the 3 test launches are scheduled for this year.
Of course, it is assumed that such missiles will not have a peaceful purpose. Flying at such an incredible speed, they will not even require warheads, just the kinetic energy of the device itself.
Information