Pre-flight tests: X-59 QueSST successes
X-59 in flight - so far only in the picture
Over the past few years, NASA and Lockheed Martin have been engaged in the QueSST (Quiet SuperSonic Technology) research program. Its goal is to create a fundamentally new look for a supersonic aircraft with optimized aerodynamics that reduce the shock wave and noise in flight. The program has recently gone through the development and prototype stages. Now the prototype X-59 aircraft is entering the first ground tests.
Work in progress
The contract for the development and construction of the future X-59 aircraft was signed in April 2018. In the following months, NASA and Lockheed Martin conducted the remaining studies, as well as determined the final shape of the aircraft and completed its design. At the end of the year, the production of the first parts and assemblies began at the Lockheed Martin plant in Palmdale, California. The assembly of the future X-59 began six months later, in June 2019.
The main part of the airframe elements of the new aircraft was manufactured by the end of 2020, after which their docking began. NASA and Lockheed Martin regularly posted photos from the assembly shop, showing how the prototype takes on a design look. The last pictures of this kind were revealed in December. By that time, the assembly of the airframe was almost completed. Part of the skin and some internal units were missing.
Aircraft under assembly, 2021
The assembly of the X-59 airframe with part of the on-board systems was completed by mid-December. After that, the aircraft was partially dismantled and prepared for transportation to another plant. The glider in a polymer film was transported by road to the Lockheed Martin plant in Fort Worth (Texas). There it was unpacked and reassembled for new work.
The plant in Fort Worth has not only assembly facilities, but also its own test base. Since the end of December, preliminary tests of an experimental glider have been carried out on it. If he passes the checks and confirms the design characteristics, he will be sent back to Palmdale to complete the construction and prepare for flight tests.
Preliminary tests
First of all, the Fort Worth plant conducts static testing of the design. With the help of a stand with hydraulics, the loads on the glider during flight, takeoff and landing, maneuvering, etc. are simulated. It is curious that before the arrival of the experienced X-59, the test bench had to be finalized. In the original configuration, it could not work correctly with an aircraft of similar geometry. In the updated form, the stand is fully consistent with the tasks of the QueSST program. In addition, it can be used in other projects with similar technical features.
Latest construction phases, end of 2021
It is reported that the static tests of the X-59 airframe are taking place in a fairly gentle mode. Compliance is established with the maximum design flight loads, incl. with an excess of 25%. At the same time, they do not plan to determine the breaking loads - such checks are not required, because the aircraft is experimental, not serial. In addition, test equipment is able to identify risks in time, and studies will not lead to breakdowns even if there are prerequisites for them.
The prototype aircraft is equipped with a set of sensors to collect data on loads on various structural elements. Using the existing stand, they are calibrated before future flight tests.
The following checks will affect the fuel system of the aircraft. The tightness of tanks and pipelines will be checked. They will also check the operation of the remaining fuel sensors. They must work in any position of the aircraft, when maneuvering, etc.
A few days later, NASA reported that preliminary tests of the X-59 were moving forward successfully. By the end of January, about 80% of the required work had been completed. At the same time, all tests are going according to plan and without any problems. However, the testers are not yet able to give an exact date for the completion of activities and the return of the aircraft to Palmdale for completion and flight tests.
Aircraft prepared for transportation to another plant
Plans for the future
The first flight of an experienced X-59 is scheduled for this year, but the exact date has not yet been determined. It will be affected by the progress of ongoing work, the presence or absence of any difficulties, as well as the progress of subsequent final assembly and ground testing. The QueSST program is progressing according to schedule so far, and it is very likely that the first flight will take place on the indicated dates.
During the first stage of flight tests, the general flight characteristics, aircraft stability, etc. will be checked. They will also test new models of avionics and control systems. Then the main research will begin - the X-59 will show how much it was possible to reduce the supersonic impact due to new aerodynamic and other solutions. Tests of this kind, with a positive development of events, may take place as early as 2022.
Upon receipt of positive results, comprehensive full-scale tests will start in 2023. In particular, the aircraft will be presented to the ICAO, and new technologies may be approved for use in promising civil engineering projects. aviation. All these activities are expected to be completed no later than 2025.
X-59 in Fort Worth, December 2021
Technical features
The purpose of the QueSST program is to reduce the noise of aircraft flying at supersonic speeds. This problem was solved with the help of a special aerodynamic shape of the airframe, reminiscent of a standard scheme. The new look does not exclude the formation of shock waves and shock waves, but does not allow them to add up to a powerful sonic boom. As a result, the sound pressure of a supersonic impact drops significantly.
According to calculations, during a high-altitude flight, a sonic boom of no more than 60-75 dB will reach the ground. For comparison, the Concord liner gave at least 100-110 dB. Such noise reduction will allow flights not only over the ocean, but also over land, incl. near populated areas. Reduced supersonic impact should not interfere with people or harm the environment, as it was before.
In accordance with the theoretical foundations of the project, the prototype X-59 aircraft is distinguished by a thin fuselage of high elongation. About a third of its total length is accounted for by a nose cone with a flat bottom and a curved top. It is he who must "breed" the shock waves in space. Behind the fairing is a cabin, without a protruding canopy, and the tail section is made in the form of a nacelle for one General Electric F414 engine.
Prototype on the static test bench
The aircraft is equipped with a front horizontal tail unit of a small area. Behind it is a mid-range delta wing with a break in the leading edge. A traditional stabilizer and a keel with an additional horizontal plane on top are also provided. The shapes, sizes and arrangement of the planes are also calculated taking into account the reduction of shock waves.
The X-59 received a single "glass" cockpit. There are four monitors of different sizes on the dashboard. Three are used to provide a variety of information, and the fourth combines the functions of a windshield and an indicator on it. The fact is that a long nose cone blocks the view forward and down from the pilot's seat, making it difficult to take off and land. This problem was solved by using a set of cameras that output a signal to a separate monitor. In addition, they got rid of the usual windshield, improving the design of the airframe.
In the development and construction of the X-59, ready-made and available components were actively used. So, the main part of the cockpit elements, with the exception of new instruments, was taken from the T-38 training aircraft. The chassis was taken from the F-16 fighter, and the F414 engine is actively used on carrier-based F / A-18E / F aircraft.
Dashboard with monitor instead of windshield
The X-59 aircraft has a length of 29 m and a wingspan of 9 m. The maximum takeoff weight should not exceed 15 tons. With the help of a single-engine power plant, it will be able to reach speeds of up to 1590 km / h at altitude, which will allow all the necessary research to be carried out.
Great future
NASA and Lockheed Martin continue preliminary tests of their experimental aircraft, and their results are not yet known. However, the authors of the project are already showing some optimism and expect that the experienced X-59 will cope with the tasks set, and QueSST as a whole will give the desired results.
As a result of the current QueSST program, NASA and related organizations will have new developments in the field of supersonic aviation at their disposal, which can be used in practice in the civilian sphere. The development of passenger supersonic aircraft has long stopped for objective reasons, and the new research program allows us to overcome negative factors. The possibility of military application of new technologies has not yet been reported.
However, the real prospects of the QueSST project and the entire direction are still unknown. They will be determined in the future, based on the results of all necessary tests. Now their first ground stage is being carried out, and flights will begin in a few months. And only after conducting part of the flight tests, the developers will be able to draw preliminary conclusions.
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