On May 27, the X-51A Waverider rocket was dropped from the B-52 Stratofortress strategic bomber over the Pacific Ocean, south of the California coast, from an altitude of just over 15 km. She successfully launched her hypersonic jet engines, accelerated to a speed of Mach 5 (about 6 thousand km / h), at which she lasted 200 seconds. This is much longer than the previous record holder, the X-43, which lasted only 12 seconds.
Despite the fact that the further fate of the X-51A was not so successful, the American military made absolutely victorious reports. Program Manager Charlie Brink said: “We are delighted to report that most of the test targets have been met. This breakthrough can be compared to the post-World War II transition from propeller-driven to jet aircraft."
However, in some places officials, after all, let it slip. The same Brink says: “Now we have to go back and once again study all the circumstances with particular thoroughness. 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 about calling the passed tests "partially successful."
X-51A under the wing of a carrier aircraft: an artist's view …
… And a real photo
But the problems were expected. Hypersonic flight is not even supersonic. It is believed that hypersound starts somewhere around Mach 5, and the technical difficulties associated with such a frenzied movement are very numerous. The pressures, temperatures, mechanical overloads that affect the device are too high. Conventional jet engines do not provide enough power and are not reliable enough. The developers poetically compare their task with the need to light a match in the heart of a hurricane - and keep it burning.
By itself, the X-51A is 4.2 m in length and is practically devoid of wings. Technically, it flies by riding a chain of shock waves that it creates 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 became the third during the work on the system, and its first independent flight, until then the X-51A flew only fixed on the carrier aircraft. After being dropped from the plane, in the first 4 seconds of flight, the X-51A was powered by conventional solid-propellant engines, modified versions of those installed on American tactical missiles. They accelerated it to Mach 4, 8, lifting it to an altitude of almost 20 km, 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 increased pressure in the combustion chamber, which is achieved by braking the oncoming air flow. But in order to achieve a sufficient value of pressure, the air flow itself must be supersonic, and therefore it was necessary to first accelerate the apparatus with the help of a solid-propellant engine. It is interesting that, unlike its "colleagues", SJY61 runs 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 a speed of Mach 6, to work out for 300 seconds. But at the 120th second, the information from the sensors began to flow unevenly (according to other sources, the thrust was lost), so a signal for destruction was transmitted to the 200th device.
In any case, 200 seconds of flight at this speed is still a significant success. Let's see what the following tests show; at least 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 do not even require warheads, the kinetic energy of the apparatus itself is enough.
