Grzegorz Kowaleczko

Influence of atmospheric turbulence on bomb release

Abstract Thermal instability in a horizontal layer of Couple-stress nanofluid in a porous medium is investigated. Darcy model is used for porous medium. The model used for nanofluid incorporates the effect of Brownian diffusion and thermophoresis. The flux of volume fraction of nanoparticle is taken to be zero on the isothermal boundaries. Normal mode analysis and perturbation method is employed to solve the eigenvalue problem with the Rayleigh number as eigenvalue. Oscillatory convection cannot occur for the problem. The effects of Couple-stress parameter, Lewis number, modified diffusivity ratio, concentration Rayleigh number and porosity on stationary convection are shown both analytically and graphically.

Effect of free play in rotor blades hinges on the non‐linear ground resonance of a helicopter

In this paper results of numerical analysis of the ground resonance are shown. This analysis is performed making use of the complete model of the one‐main rotor helicopter. This model is adopted from flight mechanics. For the basic analysis it is assumed that the helicopter fuselage is a rigid body and the main rotor consists of four rigid blades. Each blade performs motions about its horizontal flapping hinge and vertical lagging hinge. The tail rotor is treated as a hingeless and weightless source of thrust, which equilibrates the drag moment and ensures directional control of the helicopter. For analysis of the ground resonance phenomenon, forces and moments produced by the landing gear are taken into account – their rigidity and damping are included into consideration.

Evaluation of the possibility of bomb flight control

This paper presents theoretical model dedicated to a guided bomb. A mathematical description of the six-degreesof-freedom motion of the bomb is shown. Particular attention was paid on aerodynamic forces and moments generated by additional control fins mounted on the front part of the bomb. Exemplary results of a numerical simulation of bombing are submitted and conclusions focused on the possibility of flightpath control are formulated. The paper concerns on the equations of bomb spatial motion and kinematic relations expressed making use of moving coordinate systems, the common origin of which is located at the centre of mass of the bomb. The set of equations of the rotating motion about the centre of mass in the body-fixed reference frame is presented. Aerodynamic forces and moments acting on the bomb are described. Coefficients are determined using the PRODAS software with detailed geometry of the LB-10M bomb. The coefficients were determined for different Mach numbers from 0.4 to 0.8. The important task was research investigations of aerodynamic characteristics with a wind tunnel and a set of experiments in real bombing conditions.

Testing the Catastrophic Recorder Resistance Against the Impact of Catastrophic Factors

Abstract The subject of the research was a catastrophic recorder of the S2-3a system for recording flight parameters, developed at the Air Force Institute of Technology. The article discusses tests of catastrophic recorders’ resilience to factors present at aircraft accidents. The document specifying the requirements for catastrophic recorders of flight parameters includes the defence standard: NO-16-A200, and the European standard: EuroCAE ED-112. According to NO-16-A200 and ED-112 standards, the protective unit should be resistant to: g-forces existing during crash, puncture, compression, fire, underwater pressure and aggressive liquids.

Estimation of the accuracy of laser guided bomb

The main goal of the bomb release is to hit the target with a maximum accuracy. Therefore, special active control systems are utilized to improve this accuracy. Some of the most popular are semi-active laser systems of guidance. Selected target is pointed with high-intensity laser by an airborne or ground laser designator. The laser-guided bomb (LGB) tracks this target using on-board laser seeker and adjusts its trajectory. The main task of the control system is to steer the bomb in the way allowing fixing the reflected laser beam in the centre of photo sensor array. This keeps the bomb axis straight toward the target. The aim of this study is to identify factors influencing on the accuracy of the LGB. It was performed for the prototype of LGB, which was designed in the Air Force Institute of Technology. This is the modernized version of the classical LB-10M bomb. Originally, this bomb has only four rear stabilizers and it has been equipped with four additional fins (Fig. 1). These fins allow controlling the bombs path in active way. Earlier studies have shown that this is the useful method of bomb control both in longitudinal and lateral motions. Analysis proved that range of the bomb can be effectively changed. This paper presents method of flight simulations for released LGB. Calculations were performed using sixdegrees-of-freedom mathematical model of the LB-10M bomb motion. Aerodynamics was calculated using commercial software. Control laws were determined based on signals detected by two pairs of laser sensors. Exemplary results of simulations are submitted and conclusions focused on the main factors influencing on bombing accuracy are shown.