Table of contents

Preface

International Seminar on Aerospace Science and Technology (ISAST) is yearly seminar sponsored by Indonesian National Aeronautics and Space Agency (LAPAN), to publish the results of research and development the aerospace science and technology conducted mainly in Asian region. The seminar has been held since 2013, therefore in 2018 is its sixth.

The theme of this year seminar is Aeronautics and Space Technology Research and Industrial Development. The topics covers aerodynamics, astrodynamics, propulsions, light structures, propellant, energetic materials, avionics, flight dynamics, guidance & control, rocket technology, satellite technology, aircraft technology, flight sensor, and UAV applications. For such topics, eight distinguished scientists become the keynote speakers for the two-days seminar, i.e. Prof. Dr. Heri Budi from LAPAN representing Rocket Propellant Research in Indonesia, Prof. Marc Lesturgie from France representing Aerospace Testing.

From 55 papers submitted, 40 papers were selected to be presented in the seminar held in Jakarta, Indonesia, on 25-26 September 2017. The seminar participants from Indonesia came from ITB, LAPAN, and Agency for Technology Assessment and Application (BPPT). International participants came from Hongkong, Universiti Teknologi MARA and Universiti Sains Malaysia, Malaysia, Hongkong University of Science and Technology.

Bogor, October 2018

ISAST Scientific Committee

Acknowledgements

International Seminar on Aerospace Science and Technology (ISAST) 2018 was supported by Indonesian National Aeronautics and Space Agency (LAPAN).

Patron : Head of Indonesian National Institute of Aeronautics and Space (LAPAN)

Advisers : Deputy of Aeronautics and Space Technology, LAPAN

Director of Aeronautic Technology Center, LAPAN

Director of Rocket Technology Center, LAPAN

List of Steering Committee, Scientific Committee and Executive Committee are available in this PDF.

List of Conference Photographs are available in this PDF.

All papers published in this volume of Journal of Physics: Conference Series have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

Determination of UAV system configuration for oil palm harvest prediction application is an important step in plantation production maximization. The objective of this paper is to demonstrate how UAV systems can be used to produce high-resolution images that can be used to predict crops. The study is divided into two stages: UAV system configuration analysis and digital image processing to predict the crop. The UAV system configuration analysis consists of airframe, propulsion, avionic and ground control station. Airborne systems use a X-8 airframe controlled with Pixhawk avionics, electric motors, and a 20.2 Mega Pixel digital camera. The UAV system is used to produce a high-resolution digital image on a 6-year-old oil palm plantation in Labuhan Batu Utara, North Sumatra. This UAV system produces high-resolution digital image that can be used to calculate the number of plants. The number of plants in this particular area is then used as input to predict the crop. Estimated harvests of 6-year-old oil palm plantations produce an average of 50.5 tons per year per hectare. This result is bigger than the one of palm oil plantation management's estimation company which is 23 tons per year per ha.

For ensuring missions continuity in every satellite, all satellite systems are required to be active non-stop. But, for important maintenance reason, satellite system also needs reset condition when all satellite systems, except TTC unit, can be refreshed for a while every determined time. IC 4536 programmable timer circuit has main function to count every about 14 days then give signal reset for about 200 milliseconds. High level output voltage duration time can be adjusted by determining the values of capacitor and decode out, while low level output voltage duration time can be adjusted by determining resistor value. External reset system prediction time calculation shows that using capacitor C2 value 300 nF and decode out value 24 can achieve 14 day 18 hour 39 minute 31 second 172 millisecond high level output voltage duration time. Observation result shows that using resistor R3 value 2 kΩ can give 230 millisecond reset signal time. High level output voltage duration time target test shows that using capacitor C2 value 300 nF and decode out value 20 can give counting time up to 21 hours 41 minutes 59 seconds 792 milliseconds.

Control Moment Gyro (CMG) is a type Attitude Control System (ACS), a system used to change the attitude of satellite along its orbit. CMG generates required gyroscopic torque by spinning a number of rotors, and directs the torque by changing the orientation of those rotors using gimbals. CMG is capable of generating a large amount of torque with relatively low power which makes it suitable for high agility mission requiring 1-10 deg/s slew rate. A major problem encountered with the use of CMG in practice is the presence of singularity, a state in which, the CMG is unable to generate torque along certain direction. Various steering algorithms have been developed to overcome the singularity problems. In this paper, the attitude control performance of Single Gimbal Control Moment Gyro (SGCMG) system is investigated. Steering algorithm also implemented to overcome singularity problem that might be encountered. The results show that SGCMG capable of generating torque required for agile attitude maneuver in the presence of singularity.

As an experimental remote sensing microsatellite, LAPAN-A3/IPB satellite mission produces at least 10 GB payload data daily, mainly comes from multispectral imager payload with the addition of digital matrix imager, Automatic Identification System (AIS) and scientific earth magnetometer. To improve the satellite data reception capability, LAPAN had already installed dual X-band and S-band receiver on Rancabungur ground station. This research aims to analyze the performance of LAPAN-A3 payload data reception by using X-band receiver from Rancabungur ground station. The assessment consists of determining daily payload data transmission capability and realtime multispectral image acquisition performance, as well as distortion occurs on the received data caused by signal interferences. Based on the first four months of the X-band receiver operation, it is found that the receiver has similar data reception performance compare to the X-band receiver on Kongsberg ground station currently leased for LAPAN-A3 operation, i.e. receiving about 7 GB payload data in high elevation satellite pass. The X-band receiver could also receive realtime multispectral image acquisition when the satellite passes western part of Indonesia in the morning, producing up to 10 GB of multispectral image in single satellite pass. However, the data reception performance often degraded by signal interferences from ground station neighborhood, both quantitative and qualitatively. Based on these performances, a better LAPAN-A3 satellite mission planning can be developed and systematic interferences detection can be done based on the received data. This allows LAPAN-A3 satellite to produce more payload data with better quality.

LAPAN A2 is the second-generation Indonesian micro satellite which designed and developed in Indonesia. This satellite was launched in September 2015 in India as piggy-back. Orbit of this satellite is circular and near equatorial with altitude approximately 650 km. This satellite carries digital payloads such as digital space camera, Automatic Identification System (AIS) for vessel traffic, and upgrade S-Band transmitter 3 Mbps. The digital payloads of LAPAN-A2 satellite data is downloaded in Rancabungur Ground Station, which is equipped with 11 meters antenna using S-Band frequency. The data generated from the satellite is in raw format. For ensuring this missions, it needs some hardware for receiving digital payload data of LAPAN-A2 satellite. This paper describes result of design, implementation and test from the hardware for receiving digital payload data of LAPAN-A2 Satellite. The hardware uses Morph-IC FPGA using software Quartus and microcontroller ATMega128 embedded using Basic compiler-AVR, then the design and layout of printed circuit board uses Eagle Software. From the result of the hardware functionality test of hardware payload data receiver system, the hardware is capable to pass the signal from transmitter S-band around 3Mbps and forwarded to PC by using communication serial with speed 6Mbps, and is able to download digital payload of LAPAN-A2 satellite either digital space camera or AIS data. The amount of received data depends on the height of elevation and attitude of the satellite.

Glider GL-1 was especially designed for thermal updraft condition of Indonesia. The development of GL-1 is the first in Indonesia to design a glider for aero sport purpose in cooperation with FASI. This glider needs a minimum aerodynamics efficiency of 8.333 to meet design requirement derived from thermal updraft condition, which needs rate of descent little than 3 m/s at gliding angle of 2 degree. Optimum flight condition for maximum range performance has been calculated to be 25 m/s at a condition of altitude between 300 – 2000 m with Reynolds number of 1 – 1.5 million. Computational Fluid Dynamics (CFD) was employed to do numerical analyses to predict aerodynamics characteristics of the glider. CFD by using half-glider meshing results maximum lift coefficient of 1.326 at angle of attack of 8 degree, and maximum aerodynamics efficiency of 19 at angle of attack 2 degree. The result of CFD by using full-glider meshing gives maximum lift coefficient of 1.2556 at angle of attack of 10 degree and maximum aerodynamics efficiency of 16 at angle of attack of 2 degree. Both of half-glider meshing and full-glider meshing are employing k-ε turbulence model. Comparison with preliminary design result and benchmarking with similar gliders data was also done.

The design of fan blade occasionally should be optimized in order to get maximum flow capacity of the air. The result of a blade design constructs to the fan with six components blade. During the operation, the fan generated noise because of turbulence flow around the rotor dynamics system. On the process optimized fan blade, we predicted that the noise was radiated to the environment by numerical simulation. The fan during operation magnitude of Sound Power Level (SPL) has various about 74 dB to 93 dB.

In the field of wind tunnel testing, flow quality is one of considerations which determine the accuracy of data measurement. There are several aspects that affect the flow quality, such as blade design, flow conditioner application and tunnel circuit configuration (i.e. design of the corner vane, corner duct, contraction duct and etc.). Applying flow conditioner like screen or mesh and honeycomb is commonly used to improve the flow quality in the tunnel. This paper discusses about the effect of applying screen and honeycomb to the flow characteristic in a simple tunnel model. The screen was applied on the several locations at the WAD (wide angle diffuser), i.e. at the inlet, middle section, and at the outlet of the WAD. Honeycomb was applied after the last screen in the tunnel duct. In the modelization, the applied screen or mesh and honeycomb were modeled using porous media computational model and using Darcy law as a mathematical model. The CFD simulation was performed using Numeca by separating the domain into fluid domain section (for the tunnel section) and porous media domain (for the screen and honeycomb section). Unstructured mesh type, generated by Hexpress, was used on the tunnel computational domain. The results indicate the reduction of flow separation, hence more uniform flow in the tunnel, by applying screen or mesh at the WAD and by applying honeycomb in the chamber.

The bridge is the connector between two separate places. In order to manufacture the bridge, it needs to be divided into segments. Each certain distance and each segment has a cross-sectional shape in the form of a deck. Long-span bridges require aerodynamic stability due to the wind blow whose speed is varied. In order to obtain a stable design of the bridge deck, there are two complementary methods, namely the method of computation and experimentation. This paper discusses the application of computational methods and experimental for a deck of long spans bridge. The results of the simulation and experiment are in the means of aerodynamic characteristics, i.e. curve of lift, drag and moments coefficient. Aerodynamic stability can be concluded from the results of these methods.

Indonesia has two seasons in one year, the rainy season and the dry season. During those two seasons, sometimes the Indonesian people get the problem of flood and dry condition. The modification of the weather by seeding cloud is expected to be able to solve those problems. There are some technologies that have been used to do cloud seeding, i.e. air plane and rocket. This paper focuses on the development of various systems to switch the flare of TWM rocket (technology weather modification) on. The method of this development was using the GPS module, timer system, and the FTS (flight termination system) as the information for the microcontroller to switch the flare on. Based on the result of the test, all systems were able to work but which one is working, first, depends on the rocket condition in the air.

Vast maritime territory in Indonesia needs satellite technology to prevent illegal activities such as illegal fishing, fuel dumping, illegal transhipment, and trafficking/smuggling. Therefore, this research aims to design a satellite with mission for detecting illegal activities on Indonesian territorial water and ZEE. The satellite will have the capability to receive AIS signal from ships operating in Indonesian territory, and image signature for optical or radar sensor capture it by SAR. The concept of operation is that the satellite will receive/capture the ships information and send the real-time data while passing Indonesian region. Thereafter, the data received is then processed in ground segment to determine suspected ships. In this paper, the discussion focuses on the design of the satellite communication and power subsystem. In this work, LAPAN's micro-satellite design is selected as the base to determine and size components of the subsystem. Satellite communication link budget was calculated with three alternatives of antenna to determine which one has the best link performance. Afterwards, the power subsystem which consists of solar cell, as the main power generator, and battery units was designed. The result of the work is a preliminary satellite design of the subsystems, that satisfy the satellite mission requirements.

Solar UAV is an alternative technology for UAV to upgrade endurance and energy management of the UAV. PUSTEKBANG as an aeronautics institution in Indonesia also develops a project related to it. Providing research in Solar UAV field, there are some sub systems development to attain its applications, one of the most important elements is energy management system. Spesific experiments were carried out in order to improve the research development for switching process on parallel batteries. Further analysis will be conducted based of these tests related to Battery Management System (BMS) and Energy Management System (EMS). This paper presents the analysis of charging characteristics from two kinds of battery's capacity (3000mAh and 8000mAh) that have been conducted with variation of voltage inputs and two values of current inputs (2A and 1A). The result shows that when the battery is charged in 2A, time consuming for both types of batteries will increase 2 times in a row with the increasing of voltage input. Then, when the battery is charged in 1A, time consuming for both types of batteries is a little bit longer which is about 2.5 times in a row with the increasing of voltage input.

JAXA/ISAS, University of Tokyo, and Keio University have been developing an X-band compact synthetic aperture radar (SAR) system and carrying out satellite system design. Many SAR satellites are operating on orbit. Generally, weight of SAR satellites vary from three hundred to a few thousand kilograms. Compact SAR satellite has several issues. For example, high power management during mission operation, thermal management of high power amplifier, EMC related with high power consumption and target pointing with high accuracy. Considering above issues, we carried out system design of the X band compact SAR satellite and have obtained feasibility of the system. Engineering model or flight equivalent model of x band compact SAR equipment such as an antenna, a high power amplifier, a mission data recorder and a x band data transmitter have been developing and there characteristics are measured. Integration and testing of a demonstration satellite will start from the beginning of 2019 and first demonstration satellite will be launched within 2019.

After development of simulation system in laboratory tests has been completed, before implementing an autonomous flight control system directly in a high speed UAV, the system needs to be tested in a 'transitional' vehicle namely Clouds aeromodeling, to make sure all devices of the control system function well in manual mode, stability and auto pilot by way point. Compatibility of setting gain PID in the simulation test with the real flight test becomes a challenge to ensure the success of the vehicle in flying, as probability of flight failures or target missing is reduced. This research has successfully proven the compatibility of the gain PID in an auto pilot by way point flight condition.

The purpose of this research is to obtain an optimum stiffened panel geometry on wing the skin of the amphibian aircraft "WHALE" with local and global buckling criteria. Local buckling prediction was done based on ESDU while global buckling prediction was based on empirical equation which utilizes radius of gyration of the structure, so that the calculation doesn't require a high computational capability. Genetic Algorithm (GA) multi-objective optimization was performed to determine the optimum type of stiffener and the geometry of the stiffened panel which provides adequate buckling strength yet lightweight structure. A predetermined value of bending moment on the aircraft wing root was selected as a case study which result in a uniaxial compression load on the stiffened panel. The optimization results show that the more the number of stringers, the efficiency of a stiffened panel in resisting buckling will increase until a certain number of stringer. In the selected case study, integral J-stringer was the optimum type of stiffener with skin thickness of 2.45 mm, stiffener and flange thickness of 1.34 mm, stiffener height of 38.6 mm, stiffener pitch of 80 mm and 11.65 mm stiffener flange width. In comparison with the so called initial sizing method, this optimization shows a promising result of 27% weight reduction.

An approach to investigate the influence of uncertain mesoscopic parameters on the macroscopic stiffness of dry woven fabric is presented. The key input parameters that have been investigated are the yarn spacing, the yarn width, the yarn height, fabric misalignment angle and the friction coefficient between the yarns. A sensitivity analysis based on GEM-SA (Gaussian Emulation Machine for Sensitivity Analysis) is presented to determine the macroscopic stiffness and its probability density function (PDF) with respect to the given set of uncertain input parameters. The uniaxial tensile deformation of a fabric is analysed as a special case of the biaxial stretching theory and expressed in terms of frictional interactions occurring at the crimp interchange points in both warp and weft yarns. The yarn-yarn arrangement is replaced by a model in which the warp and weft yarns are straight lines with a point of inflection at the center of the overlapping yarns. The results show that the frictional component is the dominant component as compared to the adhesion component in yarn-yarn interactions. We also quantify the yarn-yarn interactions among uncertain mesoscopic parameters with respect to the macroscopic stiffness. It is found that the misalignment of yarn angle is the most influential factor followed by the friction coefficient in dry woven fabric stiffness predictions with 0.44 of first sensitivity index contribution for both methods.

This article focuses towards the newer manufacturing technique 3D Printing (3DP). The objective of this work is the mechanical characterization (flexurel properties) of materials produced by 3D printing based on fused filament fabrication with fused deposition modeling (FDM). The materials chosen are a polylactic acid (PLA). This paper described the effect of different layer thickness of PLA by 3D printing on flexural properties.Additive manufacturing, also known as 3D printing, is a common material extrusion process using (bio) polymers PLA. The study begins from manufacture the solid 3D model based on the ASTM standards for flexural properties test of the material using Three-point bending method. Three-point bending test was conducted with Tensilon Universal Testing Machine – AND RTF-2410 with a 100kN load cell, specimen shape and size according to standard size ASTM D 790. The result shown that the layer thickness had an effect on flexural strengths of PLA samples. The maximum flexural strengths from Lt = 0.4 to 0.5mm were significantly increase. Moreover, it is worth nothing that ductility decreased as layer thickness increased. According to test result that the maximum flexural strength occurred at 0.5 mm layer thickness with 59.6 MPa and the minimum flexural strength occurred at 0.1 mm layer thickness with 43.6 MPa. The higher layer thickness tended to promote higher strength. The thicker layer is the stronger layer bond in holding the load bending. In this study the thicker layer have tendend to shown a 90-degree delamination fracture and the thinner layer have tendend to shown a 45-degree delamination fracture according to the direction of printing is ± 45°.

This study about reinforced e glass fibers with processed of lycal composites resin by using hand lay-up, vacuum infusion, and vacuum bagging method. Plain-weave type woven glass fabric, commercial code: EW185 cloth, has been used as the GFRP. Experiments carried out include tensile testing to obtain tensile stress, tensile strain, and elastic modulus performed using UTM (Universal Testing Machine) tools. In addition, density, composite thickness, mass fraction and fraction of composite material volume and SEM (Scanning Electron Microscope) photographs can be determined to see the bond density between fibers and resins. Specimen preparation refers to ASTM D3039 which is the standard tensile test for composites with a polymeric matrix. Compared with hand lay-up, vacuum infusion, and vacuum bagging method, Vacuum infusion has the best ultimate tensile strength that is 346.15 MPa and average modulus elasticity is 10673.4 MPa. Failure Mode is also DAT.

In the modern days, the development of UAV's communication encourages modified antenna design to fullfil its optimum requirement in aerodynamic system. PUSTEKBANG as aeronautic institution also develop this field through designing the antenna in compact model using microstrip patch design. This paper explains simulation result of microstrip patch antenna using reflecting layer in 5.8 GHz. The result shows that antenna gain increased more than twice at 5 dBi and return loss is getting lower in -20 dB by this proposed model than its previous conventional microstrip antenna design.

The use of star sensor, which is the most accurate attitude sensor on satellites, began to penetrate into micro satellites and nano satellites. Thus the need arises to research and develop star sensor independently to meet the specific design of micro satellites and nano satellites. There are mainly three approaches in star sensor research: digital simulation, hardware in the loop simulation, and field test of star observation. In digital simulation approach, all of processes are done in a software, including star image simulation. Hence, it is necessary to develop star image simulation software which could simulate real space environment and various star sensor's configuration. This paper focuses on star image simulation results done in various parameters: resolution, defocus level, stars' magnitude limit, background noises, FOV, unexpected objects and missing stars. Those parameters are needed to test stars pattern recognition's robustness. The results show that the star image simulation is able to simulate all those parameters.

One important element in camera optical systems is the optical window because it serves as an element in the optical system to provide a clear aperture to transmit the desired radiation as well as to keep both environments separate and bear the atmospheric differences such as temperature and pressure. In designing the window there are several things to note besides the design of the optomechanical system such as window installation and structural considerations, as well as the impact of optical performance degradation due to the installation of this window. This paper discusses some important considerations for the design of optical windows with special specifications for medium wave infrared (MWIR) optical systems such as the material used, the minimum thickness associated with the pressure rating, the distance from the window to the aperture stop or the pupil as this is important when designing for degradation the wavefront is minimal and optimized to get a design whose effect on the optical degradation is very small.

Thrust Benchmarking System (TBS), a low cost and easy to manufacture instrument for electric UAV propulsion system performance measurement is being proposed. With one of its uses for determining the static thrust of a propeller based on simple empirical characterization modeling. In this paper, characteristic modeling is performed on 3 APC-Electric propellers with different pitch and diameter dimensions. As a result, there are 2 constants K₁ and K₂ which can express similar propeller characteristics with different dimensions. It costs IDR 1.6 million and took two-and-a-half months of manufacture and assembly process.

A guided missile directed toward flight direction of target must be navigated so that it would not miss the target. Many navigation methods have been published. In this paper, Proportional Navigation (PN) Method based on Line of Sight guidance feature will be evaluated by simulation only at target moving in one way parallel on Y axis. Evaluation was conducted especially regarding to the ability to handle against external disturbance during its mission. PN Method was chosen because it can be implemented in relatively simple way by using infrared (IR) sensor on board for sensing the target position and do not require transponder frequency to communicate with the ground station. To evaluate the method, simulation model was developed firstly by using MATLAB. In the simulation test, 9949 N external disturbance (-9000 N on X-axis, -3000 N on Y-axis, and -3000 N on Z-axis) represent a wind whose value is 528 m/s has been added in time range of 10 until 18 second and 10 until 24 second. It is obvious from the results that Proportional Navigation method has been able to point the missile to the target at a certain time.

Developing an autonomous flight control system for a fixed-wing unmanned aerial vehicle (UAV) requires the mathematical representation of the system dynamics which can be obtained through system identification, such as using white, grey or black box methods. In this paper, three system identification methods; white method modeling using Cook formulas which is used analytically to develop the linear-time-invariant model structure with the aerodynamic coefficients of the UAV extracted from Missile DATCOM computations at certain flight conditions, and two empirical mathematical models constructed from non-linear flight simulator defined as the Greyification of Black Box Model (B2G) and Direct Grey to White Linkage (G2W). The comparison shows that both empirical methods prove to be very instrumental to contrast and produce higher sense of engineering than the analytical one

The final objective of this paper is to make preliminary design concept of redundancy management, which applied for the automatic flight control system in LAPAN Surveillance Aircraft - 02 (LSA-02). The LSA-02 concept use a certified class I aircraft, which has a MTOW < 6000 pounds and use single reciprocating engine. Then, an automatic flight control system (AFCS) is installed in the aircraft, hence added the aircraft capability to fly autonomously. Although the pilot still onboard and act as safety pilot when the AFCS is going wrong, the design of AFCS shall be safe. The AFCS consist of components where some of them are critical and need redundancy. The identifications of component criticality are come from functional hazard analysis (FHA) where the result are list of critical and non-critical component in AFCS during the automated flight. The FHA is a systematic, comprehensive examination of basic aircraft system to identify potential minor, major, hazardous, and catastrophic conditions that may occur due to a malfunction or a function failure of AFCS. The FHA result shows the critical components of AFCS that may lead to the catastrophic conditions in case of failure are the actuator that connected to the elevator, flaperon, rudder and throttle stick, also the flight control computer. Therefore, they need redundancy and the design of redundancy explained in the redundancy management. The redundancy management suggest eight actuators needed for the critical control surface and the throttle stick. This critical actuator is configured as cold standby redundancy. For non-critical control surface (flap and air break), two actuators are needed and configured with no redundancy. The flight control computer is also a critical component and built in dual modular redundancy (DMR) configuration and one independent communication channel for each flight control computer.

The development of Flight Control Laws (FCLs) for high aspect ratio light utility aircraft have been previously accomplished by considering each control module to be independent. For the longitudinal motion, the FCLs comprise mainly the airspeed control and the flight path angle control. In addition, the altitude control and the vertical speed control have been designed based on the design of flight path angle control. Further investigation is conducted to reveal possibility to design the longitudinal control, i.e. airspeed and flight path angle control by considering the coupling behavior between both controls but still utilizing the same control design strategy that is the advanced Proportional-Integral (PI) control technique. The paper shows the concept and architecture of coupled longitudinal flight control laws, the design strategy chosen, implementation to the aircraft model and investigation of control performance. The results achieved from this research are the architecture and procedure to design longitudinal FCLs. Additionally, knowledge of coupling control behavior between the airspeed and flight path angle via aircraft simulations is acquired.

This paper contains a study on the development of propellant research in Indonesia to support the mastery of rocket technology. The objective of this study is to formulate the direction of the propellant research that must be done by Indonesia. For such purpose, 31 relevant literatures are reviewed and discussed. The discussions includes the development of propellant technology in the world, and the position of propellant research in Indonesia, which mean to support the development of sounding rocket and satellite orbiter. This study identified the challenges that must be addressed by propellant researchers in Indonesia, in order to pursue the mastery of up to date propellant technology as in the developed countries.

The development of tube-launched folding wing UAV has become current interest and accordingly static stability analysis of this UAV would be necessary. The objective of this paper is to conduct a study to evaluate static stability of tube launched tandem wing UAV at its cruise condition. Computational fluid dynamics (CFD) using ANSYS CFX is conducted to acquire forces and moments acting on the UAV at various angles of attack and sideslip angles. Furthermore, static stability parameters such as C_m, C_L, C_l, C_n, and C_Y are determined from the forces and moments obtained previously. The result indicates that the ITB tandem wing UAV complies the static stability criteria at its cruise condition.

Centrifugal compressors (impeller), sometimes termed radial compressors, are a sub-class of dynamic axisymmetric turbomachinery device. The idealized compressive dynamic turbo-machine achieves a pressure rise by adding kinetic energy/velocity to a continuous flow of fluid through the rotor or impeller. This kinetic energy is then converted to an increase in potential energy/static pressure by slowing the flow through a diffuser. Small Centrifugal compressor now is commonly used for mini turbojet engine which applications are in rapid drone among others. The usage of small centrifugal compressor in the mini turbojet has several advantages. One of them is that it can give higher pressure ratio than axial compressor (for example common single stage small centrifugal compressor can give 3-4 in pressure ratio at 80000-98000 rpm). The purpose of this paper is to assess the effect of geometry parameters, such as fillet radius, number of splitter and blades, to the pressure ratio. In this paper, typical small centrifugal compressor with diameter of 6.6 cm will be simulated using NUMECA, a CFD software and their results will be discussed to map the effect of each geometry parameter to pressure ratio hence compressor performance. Different geometry parameters are calculated and compared at several boundary conditions and flow setting to explore the trend of pressure ratio evolution with the change of those parameters. Based on the simulation result is indicated that there is similiar effect on the applying spplitter and adding blade number in the impeller configuration to increase the pressure ratio. In another case, adding fillet at the end of impeller hub wall give tendency to reduce compressor pressure ratio.

The purpose of this paper is to find the most optimal design for the PASOPATI cruise missile regarding its endurance, maneuverability, and easy manufacture process. Using pre-sizing methods to design and ANSYS Fluent to simulate the cruising condition, it is possible to find the optimal design for this iteration of the PASOPATI cruise missile. The simulations and flight test yielded several data of the design, such as the flight altitude, endurance, and cruising speed for this iteration. The final prototype design of the missile obtain has a specification as follows: 130 km/h average velocity, 13.33 minute endurance, and 280 meter flight altitude.

Tensegrity consisting pinned-jointed struts and cables is lightweight and flexible. Extensive research works on the shape change of tensegrity, especially the deployable tensegrity structures and tensegrity robots have been carried out. This paper presents the structural characteristics of a tapered three-stage tensegrity model during shape change analysis by using a shape change method. The method employed sequential quadratic programming in the optimization of forced elongation in cables, such that the model can advance to the targets. Structural characteristics of the tapered tensegrity model were examined under various displacement schemes. It was found that the tensegrity model demonstrated bending, axial and torsional deformations during the shape change analysis.

Voids analysis is useful to develop further composition and mixing technique so that the hardness of materials can be improved. In HTPB-based polyurethane, this topic is more crucial, giving impact on the propellant and the performance of rocket. Thus, the aim of this paper is to uncover the profile of voids, such as shape, size, distribution and its consequences on the hardness of bulk polyurethane. The perimeter, area, circularity and the nearest distance between voids of fifty five voids were identified by using microscope and image measurement software. Statistic methods were used to get a detailed analysis. It is concluded that polyurethane with the lower hardness, PU B, has lower standard deviation in all profiles, shorter mean distance between voids, significant difference in distribution pattern of void area data and linear correlation between area and distance. All of them suggest that void cluster can reduce the hardness of polyurethane.

This paper provides an empiric method in estimating the UAV's launched speed from the catapult. Besides its practicality, the method is applicable to validate the UAV performance in its development or configuration modification. Thus, using this method, a faster and accurate estimation of launch speed can be obtained from the catapult before launching the real UAV. Recently, the Indonesian Agency for The Assessment and Application of Technology (BPPT) has prototyped a launchable backpack UAV using the experience in the predecessors' landing-geared UAV. Such sequence was preferable, since any failure of the landing-geared take off prevented severe damage compared to the gearless UAV. Thus, after the prototypes of the backpack version of UAV were ready for first flight, the flight test crew needed to ensure that the launcher produces an adequate launch speed.

The initial idea is building a dummy prototype equipped with flight telemetry module and measuring the speed directly. But "crashing" the dummy with embedded electronic module will be risky and causing severe damage to the electronics. Another method proposed was by using a stopwatch to measure the elapsed time between the start to the release point of launching. Although preferable since it excludes electronics on board, it will suffer low accuracy.

Thus, the solution carried out by performing generalization and transformation of the problem into the energy balance case. Using the conservation of energy, the equation of catapult releasing speed can be derived by launching the dummy UAV. Thus, the method only requires practical measurement device to obtain sophisticated result. Using this prior knowledge of the catapult performance, the BPPT successfully launched the backpack UAV by 4.86% of difference between the estimated and real launch speed.

In this paper we proposed a concept of operation and developed a design requirements and objectives for a medical transport drone. The drone will be used to transport medical supplies between small islands in Indonesia. Liukang Tangaya Archipelago is chosen as study case since it represents similar archipelago in rural part of Indonesia. Limited infrastructure and man power skill are the main challenge of the operation of drone in the area. Thus, simplicity of operation and minimum support are major consideration in the requirements. A hybrid type is considered to be the best suited type for the area and mission. A hub and spoke concept is chosen with Sapuka Island as the center. A set of design requirements and objectives are defined based on the chosen drone type and mission.

Sounding rocket (or Roket Sonda in Indonesian), is a type of rocket that carries instruments to conduct some scientific experiments in suborbital altitudes. Since the use of sounding rockets is constantly increased, there has been an idea to make it reusable. The development of a reusable sounding rockets should includes at least six key technologies, which from those, the development of a proper liquid propellant engine, which thrust can be intermittently controlled, is mandatory. This paper aims to contribute in Indonesia's own reusable sounding rocket (RSR) development, by presenting an example of preliminary calculation for its liquid-propellant engine. To achieve the intended launch/flight profile to a targeted 120 km maximum altitude, and return safely to the ground, several design parameter is chosen, including the total mass of propellant for the powered ascent and descent that need to be at least 8700 kg, with the mass rate of 60 kg/s, producing 189 kN force. The force is produced by four nozzles to also provide control, where the exit area can be determined to be 0.164 m². Finally, from these values, a rough estimation of the geometry of the reusable sounding rocket can be determined.

Rain attenuation is one of the factors taken into consideration in the telecommunication system using frequencies above 10 GHz. As a tropical country, Indonesia has an annual average weather of high rainfall, causing the atmospheric conditions to contain a lot of water vapor. At frequencies above 10 GHz, the rain greatly affects the attenuation of the signal transmitted from/to telecommunication satellites. The objective of the research is to know the rain attenuation value estimation that used in link budget communication design to compensate the appropriate margin in LAPAN communication satellite. The study compared the rain attenuation estimation using ITU-R, Global Crane, and DAH modelling. The highest estimated rainfall value is found in Pare-pare using the Global Crane method. The result of the calculation with ITU-R model is the closest method for rain attenuation prediction in LAPAN communication satellite. The study recommends that the method to be used in the design of high frequency communication satellite operating in Indonesia is the ITU-R modelling.

Available GPS data in Indonesia which coincidence with large earthquake is limited and not adequate to reconstruct a well-ionospheric tomography. Large earthquake is occur in 2004 and large GPS data is only available from Sumatra GPS Array (SuGAr). This study is intended to support ionospheric tomography for limited data by checkerboard test. Tomography result is obtained by optimizing grid size, interval, a priori models, and norm damping. The dependency to a priori model is reduce by choosing alpha value parameter (α = 0.1). For case study, ionospheric tomography is implemented to preseismic analysis in Bengkulu earthquake at September 12, 2007 which expected to have long-term effects in the ionosphere. The result is validated by checkerboard test to shows the resolutions of ionospheric tomography.

The meteorological surface parameter over the Maritime Continent (MC), especially rainfall anomalies are very important to be investigated due to their impacts on the hydrometeorological hazards phenomena. Although, this region is effected by the Monsoon system, but another phenomena called as the Indian Ocean Dipole (IOD) and El Niño are suspected has a great effects in controlling the rainfall anomalies too. In this present study, we investigated the upcoming of IOD and El-Niño (represented as SST Nino 3.4) index, especially from October 2018 to February 2019. According to the prediction derived from POAMA (Predictive Ocean Atmosphere Model for Australia) model, Australia, that is issued by September 8, 2018, we found that those indexes (IOD and SST Nino 3.4) are located "near" the normal (neutral) phase condition. It means that Monsoon will become a pre-dominant peak oscillation during that period, although by assuming the Madden Julian Oscillation (MJO) also located at "near" normal condition. By using the IOD, SST Nino 3.4, and the CHIRPS (Climate Hazards Group InfraRed Precipitation with Station) monthly rainfall data for period of 37 years observation over Java Island, we found that rainy season is already started since December 2017. The transitional season (from rainy to dry season) is started from March to May 2018. The dry season itself is already started since June to August 2018. Basically, we found the second transitional season that is started from September to November 2018. Since, this study is mainly concerned to rainfall anomalies prediction when IOD and El-Nino is located "near" normal (neutral) phase position, we suspect that the early rainy season this year will be started at December 2018, and continue to rainy season at January and February 2019. Those all prediction will be working well by assuming that teleconnection between IOD and El Nino up to February 2019 still located "near" normal phase condition/position.

Bird strike case is a part of the passenger aircraft certification requirements.The numerical calculation of bird crash cases can ease the burden and time of testing to be performed.The definition of a valid bird model is often a problem in modeling bird impact cases.One of the modeling approaches that can be used is the smooth particle hydrodynamic method. In this method, birds are modeled as fluid particles that have a certain number of parameters.There are a number of geometry variations and bird model parameters that can be used, including physical properties of fluids, materials, and various other controls.The paper focuses on the building the multimaterial bird model that is more representative than tradtional bird model, but simple to make.