AEROTECH V: Progressive Aerospace Research

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Authors: Mohamed Tarmizi Ahmad, Sevda Ahmadian, Amzari Zhahir, Omar Kassim Ariff, Fairuz I. Romli

Research in pulsejet has intensified recently due to its design simplicity that can be developed into efficient small scale propulsive units for new applications such as UAVs and Unmanned Combat Vehicles (UCAV). A major obstacle for its development is low efficiency of the engine. The objective of this research is to investigate the possibility of using pulsejet in certain applications where the pulsejet can trade its low efficiency with low cost, simple design, and light weight. Numerical analysis is used for analysing the pulsejet engine design. The main results drawn from this research is in increasing efficiency and improving performance of engine by improving size of engine, especially diameter of combustion chamber. The computed results show good resemblance with published data.

Authors: Riyadh Ibraheem Ahmed, Harijono Djojodihardjo, A.B.D. Rahim bin Abu Talib, Mohd Faisal Abd Hamid
Abstract: Coandă effect, which has been widely utilized in many engineering applications for circulation control, is here reviewed for the design of Coandă Micro-Air-Vehicles (MAVs). Based on the review, a basic spherical configuration is analyzed to obtain the relationship between relevant parameters to the lift that can be produced based on fundamental principles. The results can be used for preliminary design purposes and are discussed in view of existing literature.
Authors: Mehdi Nadji, Afshin Banazadeh
Abstract: Matching diagram is a key part of the conceptual design process to determine the wing area and the required power. However, it requires drag polar estimation and the assumption of maximum lift coefficient. In case of conventional manned aircraft, early estimation techniques are based on statistical data that are not suitable for hand-launched aircraft. In this study, it has been attempted to present the performance calculations and a proper conceptual design model by acquiring sound values for the aerodynamic coefficients in low Reynolds number, using statistical wetted area as well as a raw design of fuselage, wing and tails. The process is applied to a sample scenario and the results are evaluated.
Authors: Navanitha Marimuthu, Ermira Junita Abdullah, Dayang L.A. Majid, Fairuz I. Romli
Abstract: Micro Air Vehicle (MAV) has the capability to fly autonomously in complex environments which enables human to conduct surveillance in areas which are deemed too dangerous or in confined spaces that does not allow human entry. Research and development of MAVs aim to reduce their size further, thus novel techniques need to be explored in order to achieve this objective while still maintaining the MAVs’ current performance. In this paper, a conceptual design of an MAV with a main drive system using shape memory alloy (SMA) actuator to provide the flapping motion is proposed. SMA is considered superior to other smart materials due to its efficiency and large energy storage capacity. By incorporating SMA in the flapping wing MAV, it will provide users the flexibility to add more payloads by reducing bulky cables or reduce operating cost by using less fuel. However, there are some drawbacks in using SMAs such as nonlinear response of the strain to input current and hysteresis characteristic as a result of which their control is inaccurate and complicated.
Authors: Wai Chee Mun, Ahmad Rivai, Omar Bapokutty
Abstract: The use of composite materials in aircraft structures have been increasing for the past decade. The anisotropic and heterogeneous nature of composites remains a major challenge to the design and analysis of composite aircraft structures. Composite structures require a different design approach compared to the design of metallic structures. This paper aims to provide a step by step definitive guide to design and analyze composite structures using finite element approach. A simplified design model for the composite structural design was used to analyze an aircraft composite hinge bracket. The composite hinge bracket which is made of IM7/8552 laminated composite plates was successfully designed with a margin of safety of 0.216 and a weight savings of 43.77 percent was estimated.
Authors: Martin T. Burston, Roberto Sabatini, Reece Clothier, Alessandro Gardi, Subramanian Ramasamy
Abstract: A method for deriving the parameters of a six-degree-of-freedom (6-DoF) aircraft dynamics model by adopting reverse engineering techniques is presented. The novelty of the paper is the adaption of the 6-DoF Aircraft Dynamics Model (ADM) as a virtual sensor integrated in a low-cost navigation and guidance system designed for small Unmanned Aircraft (UA). The mass and aerodynamic properties of the JAVELIN UA are determined with the aid of an accurate 3D scanning and CAD processing. For qualitatively assessing the calculated ADM, a trajectory with high dynamics is simulated for the JAVELIN UA and compared with that of a published 6-DoF model of the AEROSONDE UA. Additionally, to confirm the validity of the approach, reverse engineering procedures are applied to a published CAD model of the AEROSONDE UA aiding to the calculation of the associated 6-DoF model parameters. A spiral descent trajectory is generated using both the published and calculated parameters of the AEROSONDE UA and a comparative analysis is performed that validates the methodology. The accurate knowledge of the ADM is then utilized in the development of a virtual sensor to augment the UA navigation and guidance system in case of primary navigation sensor outages.
Authors: Hudyjaya Siswoyo Jo, Mark Tee Kit Tsun, Carmella Sim Lee Yoong
Abstract: This paper presents the development of a semi-automated blimp platform for aerial photography. The blimp can be tele-operated from a ground station and is capable of autonomously holding its heading and altitude when the pilot releases control. The blimp consists of a helium-filled envelope to achieve the buoyancy and a pair of propellers to drive the blimp in the desired direction. A basic control algorithm and sensing system are also proposed to control and maintain the heading and altitude of the blimp.
Authors: Amir Rasydan Mat, Liew Mun How, Omar Kassim Ariff, M. Amzari M. Zhahir, Ramly Mohd Ajir
Abstract: This paper covers exploratory efforts that attempt to address limitations and restrictions in the operating envelope of UAVs, and proposes a conceptual solution to the problem. UAVs, like aircraft, can be categorized into two main types: fixed wing and rotary wing. A fixed wing UAV flies using wings that generate lift caused by the vehicle’s forward airspeed and the shape of the wings. The greatest advantage of fixed wing UAVs obtained from utilizing aerodynamic lift is its long range and high endurance performance. However, this primary advantage comes from the fact that most fixed wing UAVs have wings that are of a high aspect ratio, which becomes a liability in confined operating conditions. An autonomous aerial hard docking system is proposed as a system that manages to enable different UAV platforms to have operational envelopes which far exceed the operational envelopes of the constituent UAV platforms. The paper outlines necessary subsystems that need to exist for autonomous aerial hard docking capability. It presents practical requirements of the various constituent subsystems, namely the guidance and navigation subsystem, the grasping subsystem and the damping subsystem. For each of the subsystems, the challenges which have to be overcome to ensure the effectiveness of the complete system are examined. It further elaborates the testing, investigation and development steps that need to be implemented to realize this capability. It ends by elaborating on the work already underway and future development plans. Note that this paper presents a conceptual logical and architectural solution, and as such detailed analysis findings are inappropriate and premature.
Authors: Tan Kai Jun, Mohammad Yazdi Harmin, Fairuz I. Romli
Abstract: Bee Colony Optimisation (BCO) method is used to optimise the fibre orientation of a simple rectangular composite wing with respect to maximising flutter/divergence speed. A modified implementation is proposed to provide a suitable version of BCO algorithm for solving the multi-variable optimisation problem. 50 test cases are performed and the statistical investigation is made in order to investigate the effectiveness and robustness of the proposed algorithm. Consideration is also made in terms of the best weightage of the minimum confident parameter. The overall results indicate that the modified BCO algorithm offers outstanding performance in terms of both accuracy and computational time.
Authors: Izzuddin Bin Zaman, Muhammad Mohamed Salleh, Bukhari Manshoor, Amir Khalid, Sherif Araby
Abstract: A current challenge for researchers is the design and implementation of an effective vibration control method that reduces vibration transmission from vehicle structures such as aircraft. This challenge has arisen due to the modern trend of utilizing lightweight thin panels in aircraft structural design, which have the potential to contribute towards significant vibration in the structures. In order to reduce structural vibration, one of the common approaches is considering vibration neutralizer system attached to the structure. In this study, a vibration neutralizer is developed in a small scale size. The effectiveness of attached vibration neutralizers on a thin plate are investigated through experimental study. Prior to the experiment, a finite element analysis of Solidworks® and analytical modelling of Matlab® are produced in order to determine the structural dynamic response of the thin plate such as the natural frequency and mode shapes. The preliminary results of finite element analysis demonstrate that the first four natural frequency of clamped plate are 48Hz, 121Hz, 194Hz and 242Hz, and these results are in agreement with the plate’s analytical equations. However, there are slight discrepancies in the experiment result due to noise and error occurred during the set up. In the later stage, the experimental works of thin plate are performed with attached vibration neutralizer. Result shows that the attachment of vibration neutralizer produces better outcome, which is about 41% vibration reduction. It is expected that by adding more vibration neutralizer to the structure, the vibration attenuation of thin plate can be significant.

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