Abstract:
The first aerospace modeling flight test named MF-1 in China was carried out aiming at studying fundamental problems in hypersonic aerodynamics. By employing a cone-cylinder-flare configuration in the payload modules, the main objective of this test is to investigate the boundary layer transition on the cone surface and the shock wave/boundary layer interaction at the compression corner. The structure and thermal protection system of experimental vehicle need to satisfy not only the basic requirements of flight safety, but also the special surface precision requirements regarding transition studies. According to the deformation control requirements of the tail fin, the cruciform strengthening structure was optimized to the shape of British 'Union Jack', which effectively suppressed the maximum deformation and flutter of the tail fin. To satisfy the control requirements of the installation deflection of four tailfins, an improved method for the tail fin installation and positive and negative offset for the deflection installation were used to ensure the total installation deflection less than 7' and effective suppression of the projectile rolling. The integrated design of structure/thin wall temperature measurement module and a second precision machining scheme were proposed for the requirement of surface precision control. These methods effectively inhibit the interference of the temperature measurement module on the boundary layer flow. Thermal-vibrational joint test of the ground temperature measurement component, tail/tail-fin static test, and model vibration test show that the structure and thermal protection system for the MF-1 flight test are safe and reliable. Flight test results show that the structure and thermal protection of the MF-1basically successfully resolve the key issues. However, the coaxality differences between the nose cone and the front cabin of test model lead to out-of-tolerance in meridian steps, further induce a forced transition phenomenon in the meridian plane. This behavior highlights the importance of surface accuracy control to the research on boundary layer transition.