Annotation: The use of servo drives on flying vehicles determines the requirements to their dynamic characteristics. The problems of dynamics of drive with jet motor are not practically covered in publications. The task arises of selection of structure and parameters of devices consisting of several subsystems whose dynamic characteristics must be brought into agreement with each other in optimal way. The purpose of this work is to develop mathematical dependences for calculation of dynamic characteristics. The functional arrangement of the drive is considered consisting of jet motor based on Segner wheel with de Laval nozzle, mechanical transmission, pneumatic distributing device – jet pipe controlled by electromechanical converter. The layout is presented of mechanical segment of servo drive with jet motor with screw-nut transmission. The dynamic model is presented and the algebraic relations to determine natural frequencies of the drive are given. The motion equations of output rod at full composition of load are given. Using Lagrange transformation as applied to ball screw transmission, the expression for reduced mass of output element was derived. The reduced mass of load depends on the jet motor design and exerts basic influence on the drive’s natural frequencies. The evaluation is given of reduced mass change from the jet motor moment of inertia and reducer transmission coefficient. Based on the proposed algorithms, the dynamic characteristics of servo drive were constructed: transient process and amplitude-frequency characteristic. The drive has relatively low pass band, which is explained by the value of reduced mass of load.

Annotation: The differential equations of the gas-jet control system two-stage hot gas distributor are considered.

Annotation: The semi-empirical technique of evaluation of external acoustic loads during lift-off is a modification of the known NASA SP-8072 technique based on empirically determined universal dependencies of jet section acoustic power on normalized coordinate and frequency (Strouhal number). The proposed technique was updated in respect of evaluation of mechano-acoustic effectiveness of supersonic jet, determination of spatial scale of sound generating zone in jet, and formation of sound radiation direction towards rocket’s head module. A detailed presentation of the sequence of solving the task set is provided. A comparative analysis of the NASA SP-8072 technique and the proposed modification is made.

Annotation: The solid rocket motors thrust is measured according to the developed measurement procedure; fulfilment of its requirements guarantees obtaining the results with required accuracy parameters. Compliance of this procedure with the measurement accuracy requirements is confirmed by way of its validation that can be performed according to different algorithms. The proposed article deals with two validation algorithms of measurement procedure for solid rocket motor thrust up to 30 tf – end-to-end and link-by-link validation methods. The composition of measurement channel, the experimental works performed at each validation algorithm are described, the calculation formulas to evaluate the limits of absolute measurement error and the obtained numerical values of the latter are presented. The comparative analysis of the results of validation procedure of solid rocket motor thrust measurement procedure obtained during metrological investigations of thrust measurement channel by end-to-end and link-by-link validation methods shows that to ensure the required measurement accuracy, the algorithms of end-to-end method is preferable, at which the lower values of reduced error can be obtained as compared with the algorithm of link-by-link validation.

Annotation: The article considers the procedure for evaluation of acoustic stressing parameters at the observation point nearby the launch vehicle nose cone when passing the sectors with maximum velocity heads and close to 1 Mach numbers. And the problem is set to determine the overall sound pressure level and the corresponding levels in octave and 1/3-octave frequency bands. Procedure under consideration is based on the semi-empirical dependency of characteristics of the wideband aerodynamic noise, which occurs during the launch vehicle flight at high velocities due to the turbulent pressure fluctuations and dimensionless aerodynamic parameters of the main stream. General idea of this approach is to establish relation of the velocity heads with wall pressure fluctuations in the boundary layer, calculating shear stress (friction) on the shell surface based on relationships applicable in the boundary layer theory and engineering experience. Attempts of development of similar calculation models go back to the early efforts, dedicated to the study of the aeroacoustics of the launch vehicle in flight. Main advantages of the procedure are its simplicity and versatility since it can be used to determine the acoustic loads around the payload fairings of launch vehicles of different sizes and shapes within the wide range of flight velocities and altitudes.