Pneumatic drive of ground catapult with free piston

Аuthors

Sereda V. A.

National Aerospace University «Kharkov Aviation Institute», KhAI, 17, Chkalova St., Kharkiv, 61070, Ukraine

e-mail: sereda_vlad@ukr.net

Abstract

Purpose
To obtain the optimal dynamic performance of the pneumatic ground launching device, which reduce the length of the guide by upgrading expansion engine.
Design / methodology / approach
To identify the negative factors of pneumatic ground launching device workflow. To determine the path for modernization of expansion engine to get the best dynamic performance. To develop the conjugate model of catapults and optimization method aimed to reduce the length of the rail. To perform a series of experiments and carry out the results analysis with respect to the efficiency of using additional piston.
Findings
An improved scheme of expansion engine of ground pneumatic catapult, which is protected by a patent for utility model, is proposed. Comprehensive physical- mathematical model of the launching device is compiled. Method for the optimization and evaluation of the criterion of excellence dynamic characteristics is developed. The analysis of physical fields in the cylinder catapults is carried out and considerable intensity of oscillation process is shown.
Practical implications
Software package in the language Fortran 6.6 for numerical studies is created. The optimum characteristics of the proposed catapult, namely the mass of the intermediate piston and its initial position, are calculated. Synchronization move master and slave pistons are able to fix the front of the compression wave in the center of pneumatic chambers. Obtained traction law closed to the constant reduces the length of the guide by 25%.
Originality / value
Scheme of expansion engine of circuit ground launching device with an intermediate piston, which is confirmed by a patent for utility model, is firstly used. Method of dealing with the negative factors of the oscillatory process in the cylinder is first proposed. Presented range of changes in the characteristics of the proposed catapult allows to obtain optimal parameters of unmanned aircraft vehicle launch from the surface.

Keywords:

catapult, unmanned aircraft vehicle, pneumatic drive, law thrust, wave process, free piston

References

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