AiMT Volume 4 (2009), Issue 2

Development of Wax Fuel Grain for Hybrid Rocket Motor

C. Boros and P. Konečný

The paper deals with development of wax fuel grain for testing of small hybrid rocket motor. The possible wax composition is selected as solid fuel which in combination with nitrous oxide as oxidizer creates hybrid propellant. Rotary casting system specially developed for this case and wax grain manufacturing is described. The first practice with such hybrid rocket motor testing is introduced.

Keywords: Hybrid rocket motor, wax fuel, Paraffin, HTPB, SP-1, wax grain manufacture

Pages: 5-11

Virtual Approach to Ground Armoured Vehicles Design

J. Stodola

The paper deals with computer based design tools and processes integration in the development of ground armoured vehicles. The general demands for ground vehicles and for their development are determined by the environment in which they operate. The paper aims at giving the design process of armoured vehicles overview as well as some insight into specific topics important in the process and describes the integration of modelling and simulation into the virtual process, vehicle dynamics, suspension design, mobility, and mine protection using new armoured vehicles.

Keywords: Virtual prototypes, integration, design process, calculations, development process, modelling and simulation tools

Pages: 13-25

Methods for Evaluation of Speech Enhancement Algorithms

J. Hovorka

Communication systems play the key role in contemporary combat operations. These systems, which can be either onboard or man-wearable, are working in very noisy environment. The noise coming from the vehicle itself and onboard combat systems is entering communication channel via microphones of personal headsets and handsets. Thanks to digital speech processing algorithms it is possible to suppress these annoying background signals. This can be done with speech enhancement algorithms. The target is to gain clear speech of high intelligibility and high quality. This paper presents the methods generally recommended for the evaluation of speech enhancement algorithms in terms of speech quality. Thanks to this knowledge, the best speech enhancement algorithm can be found in practice.

Keywords: Combat vehicle, communication system, speech enhancement, speech quality, quality measure, MOS, DAM, ITU-T P.835, Itakura-Saito measure, PESQ

Pages: 27-35

Design of Operational Vehicle Maintenance Programme Based on Life Cycle Cost and Reliability Centred Maintenance

J. Furch

This contribution deals with one possible approach to the determination of the on-going vehicle maintenance programme. This approach is based on life cycle costs and a method called "Reliability centred maintenance". The objective of this method is to maintain system functions within required safety limits, maintain an inherent level of safety and reliability, optimise availability, and perform these objectives with minimal total life cycle costs. The design of the on-going vehicle maintenance programme was based on quantitative, qualitative and economic analyses.

Keywords: Operational (on-going) maintenance programme, vehicle life cycle costs, reliability centred maintenance, vehicle durability time.

Pages: 37-53

Directed Energy Weapons in Modern Battlefield

L. Palíšek

The paper deals with electromagnetic threats caused due to Directed Energy Weapons (DEW). The area of interest is focused on HPM (High Power Microwaves) and UWB (Ultra Wide Bandwidth) as an important part of DEW area. Possible impact on electronic structures which can be part of military systems is considered in this paper. Some practical results achieved during experiments related to assessment of electronic equipment vulnerability is provided with overview of immunity of some equipment to HPM and UWB signals at the end of this study.

Keywords: DEW, HPM, UWB, electromagnetic threats, NEC, vulnerability

Pages: 55-66

Velocity Field Calculation and Measurement at the Inlet of Centrifugal Compressor

P. Kmoch and A. Jílek

The paper is focused on the possibilities of extending the stable operation region of the centrifugal air compressor by modifying its intake system. For various compressor operation regimes and various shapes of the slots, through which the external air enters the main air in the intake system, the flow velocities at the impeller inlet were measured and calculated.

Keywords: Centrifugal compressor, stable operation region, measurement of velocity field

Pages: 67-78

Ballistic's Resistance of Steel Plate Hardox upon Impact of Non Penetrating Projectiles

J. Hub and J. Komenda

A steel plate material Hardox can be used also as a core design material for the production of ballistic barriers or traps at the shooting ranges for small arms. The article deals with the results of experiments with shooting weapon systems of a high ballistic performance and with Finite Element Method simulation of the projectile penetration upon the steel plate using the software Ansys Autodyn. Results and influencing factors are discussed.

Keywords: ballistics, bullet, Hardox, penetration, shooting experiment, simulation model

Pages: 79-91

Anti-Ballistic Missile System
Selected Technical Principles of Function

I. Hamtil and M. Krátký

This paper deals with a probable defence scenario and the USA GMD/NMD Anti-Ballistic Missile system functioning during engagement of Middle Range Ballistic Missile (MRBM), or Intercontinental Range Ballistic Missile (IRBM) in midcourse, exospheric and high phase of the missile flight.

Keywords: anti-ballistic missile, ballistic missile defence

Pages: 93-104

TECHNICAL INFORMATION
Engineer Support in the Hungarian Defence Forces - 2009

E. Kállai

Changes in security environment generated changes in the military doctrines as well in past decades. Europe could witness large scale force reductions and modernisation. In the name of modernisation, several reorganisation processes have taken place in the Hungarian Defence Forces (HDF) recently. In my study paper I examine the real situation of engineer support after the restructuring, whether the new organisations are capable of meeting the latest requirements to engineer support and whether the existing capacities are sufficient. My conclusion is the following. Presuming the use of battalion battle groups and multipurpose preparation the engineer support for the battle groups can be provided through the reallocation of existing forces and assets. Nevertheless in the case of a simultaneous deployment of the forces of the HDF (primarily in conventional military operations) the engineer support to operations is not ensured.

Keywords: Engineer, engineer support, combat support engineering, close support engineering, force support engineering

Pages: 107-116