Fairuz Izzuddin Romli

Analytic solutions for Tethered Satellite System (TSS) subject to internal and external torques undergoing a spin-up and spin-down maneuvers

Purpose – The purpose of this paper is to develop analytic solutions for a tethered satellite system (TSS) subjected to internal tether tension moment and external aerodynamic torque for spin-up and spin-down manoeuvres. Design/methodology/approach – Analytic solutions for TSS based on the approximation of Euler’s equations of motion via Fresnel integrals and sine and cosine integrals. Test simulation was performed for two cases (spin-up and spin-down manoeuvres). The conclusion is based on graphical interpretation. Findings – The effects of angular velocities on X, Y and Z axes of the TSS under the influence of combined torques from internal tether tension and external aerodynamic drag influenced during spinning manoeuvres are shown graphically. Research limitations/implications – This research focuses only on a circular orbit, which is one of the simplest orbits without many variables taken into account such as flight path angle and true anomaly. It could get quite complex for other orbit types like ell...

Use of Monte Carlo method to estimate subsystem redesign risk for complex products: aircraft redesign case study

Purpose – The purpose of this paper is to achieve the capability of redesigning complex products system with enhanced efficiency and effectiveness. Design/methodology/approach – It is noted that, by changing one subsystem in a complex product design architecture, the change effects can be propagated to other subsystems through their interrelationships. This condition has to be taken into account when deciding on which subsystems to be modified in the redesign plan because the subsequent effects might be too risky for the development process. Estimating redesign risk for complex product architectures is not an easy task, thus designers often need a decision-making aid to efficiently select the best “change initiating” subsystems. This can be done by providing the designers with a ranking of subsystems based on their estimated redesign risk. Moreover, this decision-making process is taking place during early redesign stages whereby the uncertainties related to the actual level and type of changes to be made...

Travel Time and Cost Analysis of PAVE Application in Malaysia

Transportation has already become a huge necessity in peoples life today. As the world progresses, transportation systems will have to undergo paradigm shifts to adapt with the changing requirements. Personal transportation is typically preferred to the public transportation and to date, most domestic travels have been made on the ground through roads. However, with the increasing traffic volume, the average time spent travelling on roads has significantly increased for the same amount of distance travelled. It has been proposed that utilization of the possible third dimension of transportation system, which is the air transportation, can aid personal transportation and alleviate this problem. This notion gives birth to the design concepts of the personal air vehicle (PAVE) that is envisioned to operate synergistically with the existing ground and air infrastructures. This paper aims to preliminarily study and analyze the potential benefits of having PAVE option in Malaysia for domestic travel and how its performance fares in comparison to existing transportation options. The results of travel time and cost comparisons highlight the potential of PAVE application for the domestic transportation in Malaysia, particularly for personal travel need.

Aerodynamic Interference Correction Methods Case: Subsonic Closed Wind Tunnels

The approach to problems of wall interference in wind tunnel testing is generally based on the so-called classical method, which covers the wall interference experienced by a simple small model or the neo-classical method that contains some improvements as such that it can be applied to larger models. Both methods are analytical techniques offering solutions of the subsonic potential equation of the wall interference flow field. Since an accurate description of wind tunnel test data is only possible if the wall interference phenomena are fully understood, uncounted subsequent efforts have been spent by many researchers to improve the limitation of the classical methods by applying new techniques and advanced methods. However, the problem of wall interference has remained a lasting concern to aerodynamicists and it continues to be a field of active research until the present. The main objective of this paper is to present an improved classical method of the wall interference assessment in rectangular subsonic wind tunnel with solid-walls.

Emissions Performance Study for Conventional Aircraft Designs

Conventional aircraft designs have been highly successful within commercial passengers transport markets for a very long time, as evident from current fleet of many airlines. However, with the anticipated stricter environmental regulations to be imposed on future flight operations by the related governing bodies, the relevance of conventional aircraft designs to remain competitive has been questioned. On the other hand, some research ventures have been made to pursue revolutionary designs like blended wing body (BWB). This study aims to preliminarily assess the comparison of expected future emission performance between conventional aircraft design and blended wing body design. It addresses the ongoing debate on whether conventional aircraft designs can be expected to be able to cope with impending stricter environmental regulations and/or whether the venture into revolutionary designs is really necessary. Analyses done are largely based on the historical trends of conventional aircraft designs with regards to the lift-to-drag ratio and fuel consumption parameters. As for the blended wing body, its projected emissions performance is based on published data in the literature. The outcome from these analyses solidifies the belief that conventional aircraft designs will face tougher chances to remain operational under new environmental regulations and the search for revolutionary design with better aerodynamic efficiency such as blended wing body is becoming rather necessary.

A Preliminary Study of Baseline Design Architecture Effects on Aircraft Redesign Risks

Aircraft redesign process normally does not start from scratch and requires a well-defined reference baseline design as the starting point for redesign changes. In general, the baseline design is often chosen based on the closeness of its existing performance capability to the driving requirement. This practice essentially presumes that such condition guarantees a minimum amount of required redesign changes, hence the least development risk. However, it is argued here in this study that such notion can be misleading because risk also depends on the type and the extent of the changes. Instead, it is believed that the existing baseline design architecture is an important element that will influence its suitability for the redesign task at hand. Through a sample aircraft redesign case study, the possible effects of existing design architecture on the redesign process is demonstrated and highlighted.

A Preliminary Study on Translational Kinetic Energy Absorption Using Coconut-Fiber (Coir) Sheets as a Potential Impact-Worthy Constituent in Advanced Aerospace Material

Known as “coir”, the fibrous husk of the coconut fruit has potential for integration as a constituent in impact-resisting aerospace materials. As a preliminary study, kinetic energy absorption of this natural fiber is studied prior to further testing, for instance; a non-ballistic surface impacted at high velocity by a small mass is the equivalent mock-up to runway debris. The purpose of this study is to find the relationship between the thickness of the fiber with the kinetic energy absorption. Fabricated fiber panels measuring 10×10×t cm with various thickness are subjected to mild steel projectiles launched by a light gas gun at a constant pressure. The velocity of the projectiles is set to be consistent with the velocity range of typical transport-category aircraft. The impact response of the panels aids in predicting the required amendments where plies of coir sheets are increased to which perforation is impossible. The relationship established from the experimental results is then used to predict the amount of layers required for total translational kinetic energy absorption.

Subsystems Change Ranking Methodology (SCRaM) for Complex Product Redesign Process

Product redesign is hardly a straightforward process, especially for complex products. The existence of intricate interrelationships between different components of product design architecture makes it more susceptible to change propagation phenomenon. In this case, redesign risk is not easy to predict since the change effects are being propagated to other components from the initiating change component. Because of this condition, choosing the right initiating change component is essential to control redesign process risks, apart from being able to successfully satisfy the product requirements. With this notion, this paper proposes a method that systematically ranks all components of an existing product design based on their estimated redesign risk. By having this information, designers can make a better redesign planning. The demonstration of this method is presented through an example aircraft redesign case study.

Mould design and manufacturing considerations of honeycomb biocomposites with transverse fibre direction for aerospace application

Sandwich structures with honeycomb core are known to significantly improve stiffness at lower weight and possess high flexural rigidity. They have found wide applications in aerospace as part of the primary structures, as well as the interior paneling and floors. High performance aluminum and aramid are the typical materials used for the purpose of honeycomb core whereas in other industries, materials such as fibre glass, carbon fibre, Nomex and also Kevlar reinforced with polymer are used. Recently, growing interest in developing composite structures with natural fibre reinforcement has also spurred research in natural fibre honeycomb material. The majority of the researches done, however, have generally emphasized on the usage of random chopped fibre and only a few are reported on development of honeycomb structure using unidirectional fibre as the reinforcement. This is mainly due to its processing difficulties, which often involve several stages to account for the arrangement of fibres and curing. Since the use of unidirectional fibre supports greater strength compared to random chopped fibre, a single-stage process in conjunction with vacuum infusion is suggested with a mould design that supports fibre arrangement in the direction of honeycomb loading.

Usability Evaluation Survey for Identifying Design Issues in Civil Flight Deck

Ergonomics assessment for cockpit in civil aircraft is important as the pilots spend most of their time during flight on the seating posture imposed by its design. The improper seat design can cause discomfort and pain, which will disturb the pilots concentration in flight. From a conducted survey, it is found that there are some issues regarding the current cockpit design. This study aims to highlight potential mismatches between the current cockpit design and the ergonomic design recommendations for anthropometric dimensions and seat design, which could be the roots of the problems faced by the pilots in the cockpit.