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Ammonium perchlorate (AP) based solid propellant is a modern solid rocket propellant used in various applications. The combustion characteristics of AP based composite propellants were extensively studied by many research scholars to gain higher thrust. The amount of thrust and the thrust profile, which may be obtained from a specific grain design, is mainly determined by the propellant composition and the manufacturing process that produces the solid propellant. This article is intended to review and discuss several aspects of the composition and preparation of the solid rocket propellant. The analysis covers the main ingredients of AP based propellants such as the binder, oxidizer, metal fuel, and plasticizers. The main conclusions are derived from each of its components with specific methods of good manufacturing practices. In conclusion, the AP based solid propellant, like other composite propellants is highly influenced by its composition. However, the quality of the finished grain is mainly due to the manufacturing process.

Controlled degradation of deproteinized natural rubber by oxidative method using cobaltous leading to the formation of telechelic liquid natural rubber (TLNR) has been the subject of study in the current work. Hydroxyl-terminated natural rubber (HTNR) having number-average molecular weights (Mn) below 10,000 gmol-1 were synthesized at temperatures 60°C using Cobalt bis (acetyl acetonate) (Co) in the presence of ethanol and Sodium borohydride. The HTNR were characterized structurally by using Fourier Transform Infrared (FTIR), Gel Permeation Chromatography (GPC) and Nuclear Magnetic Resonance (NMR) spectroscopy. From the FTIR and GPC analysis, one hour reaction showed the lowest Mn around 6691 gmol-1 comparable to Hydroxyl terminated polybutadiene (HTPB) which were 7708 gmol-1. As the reaction time increases the Mn also increase up to 8 hours of reaction. FTIR indicated that the synthesized HTNR contained hydroxyl end groups. The study showed the optimum percentage of Cobalt bis (acetyl acetonate) is 5% which produce the lowest molecular weight. Next, the HTNR underwent crosslinking reaction with isophore diisocyanate (IPDI). Then, metal fuel (aluminium powder, Al), oxidizer (ammonium perchlorate, AP) and HTNR were mixed together and went through compression process to produce solid rocket propellant. Burning rate obtained from HTNR samples were 2.78 mms-1 which were equivalent to HTPB samples which is 2.94 mms-1.

Hydroxyl terminated epoxidized natural rubber (HTENR) was prepared by oxidative degradation of epoxidized natural rubber (ENR) with cobalt (II) acetylacetonate (co (II) aa) as a chemical agent in toluene as a solvent. Different of cobalt amount and reaction time used to study the effect on molecular weight. It was found that the number average molecular weight (Mn) and weight average molecular weight (Mw) depended on the reaction time and cobalt amount. Burning rate of solid propellant based on HTENR binder is 2.93mm/s which is approximately same with HTPB binder with 3.0mm/s. As a conclusion, HTENR binder is suitable to be used as a binder for solid rocket propellant.

The most important part to be highlighted in developing a reliable microwave absorber is the material used to fabricate the absorber. As an alternative in managing the increase of the oil palm residues throughout the country, this study is focusing on developing a microwave absorber coating using oil palm fly ash. The software uses for design and simulation of microwave absorber is CST Microwave Studio (CST MWS) which enables the fast and accurate analysis of high frequency devices. The simulation design is fabricated to a number of layers which is coated by oil palm ash as a lossy element. The measurement and performance are carried out in the high broadband frequency of 8 to 12 GHz (X-band).

There were very limited number of references published discussing the burning characteristic of aluminized propellant without any additive substance. This paper describes the performance characteristics of basic formulations of aluminized ammonium perchlorate based propellant. Four sets of propellant formulations namely by p60, p66, p74 and p80 had been formulated and manually prepared without adding any additives. The propellant consists of ammonium perchlorate (AP) as an oxidizer, aluminum (Al) as fuel and hydroxy-terminated polybutadiene (HTPB) as fuel/binder. For each mixture, HTPB binder composition was fixed at 15% per-weight. By varying AP and Al, the effect of oxidizer-fuel (O/F) ratio on the whole propellant can be determined. The propellant strands were manufactured using press-molding method and burnt in a strand burner over a range of chamber pressure from 6 atm to 31 atm. Based on theoretical evaluation using NASA CEC71 program, p66 has been selected for testing in ballistic evaluation motor (BEM) to ascertain its characteristics performance. The results from burning rate test shows that the increasing of O/F ratio and combustion pressure lead to the increase in burning rate. The highest burning rate achieved was 12mm/sec at combustion pressure of 31atm for propellant p80 which has O/F ratio of 4.0. While for the BEM, the propellant efficiency obtained for p66 was 95.44%.

In this paper, experimental investigation of pressure exponent in burning rate of composite propellant was conducted. Four sets of different propellant compositions had been prepared with the combination of Ammonium Perchlorate (AP) as an oxidizer, Aluminum (Al) as fuel and Hydroxy-Terminated Polybutadiene (HTPB) as fuel and binder. For each mixture, HTPB binder was fixed at 15% and cured with isophorone diisocyanate (IPDI). By varying AP and Al, the effect of oxidizer-fuel mixture ratio (O/F) on the whole propellant can be determined. The propellant strands were manufactured using compression molded method and burnt in a strand burner using wire technique over a range of pressure from 1atm to 31atm. The results obtained shows that the pressure exponent n, increases with increasing O/F. The highest pressure exponent achieved was 0.561 for propellant p80 which has O/F ratio of 80/20.

This paper discusses the impact of the external store on the aerodynamic performance of the light aircraft model in the subsonic region. Light aircrafts are commonly used for pilots training, survey, leisure and transportation. To date, there have been a lot of small aircrafts used for strategic purposes where an external store, either external fuel storage or armament, has been installed on its wing. Examples of such aircraft are KAI-KA1, A29 Super Tucano, and Beechcraft AT-6. Therefore, it is important to study the effect of this external store installation on the aerodynamic characteristics of a small aircraft. An available light aircraft model of UTM Low speed wind tunnel (UTM-LST) has been modified so that a generic external store can be mounted on the lower surface of the wing. Two set of experiments were carried out on the model which were; experimental with an external store followed by experimental without external store as a benchmark of tested configuration. The experiments were conducted at two different speeds of 26 and 39 m / s that correspond to Reynolds numbers 0.4 × 106 and 0.6 × 106respectively. Three measurement techniques were employed on each configuration. The first measurement was the 6 component forces and moments measurement technique. The second technique was the pressure measurement on the wing, and the final test was the tufts flow visualization. The result of steady balance indicated that the external store has no effect on the coefficient of lift at low attack angle. However, it showed that there was a reduction of lift coefficient by 2% at higher angle of attack. The data showed that the coefficient of drag increases by 4% when the external is installed. Surprisingly, the installation of the store has insignificant effects on the pitching moment coefficient. An interesting feature observed from surface pressure studies where, the results showed that the pressure coefficient increased when the external is mounted on the wing at a low angle of attack. Such changes, however, do not occur at high angle of attack.

This paper reports on the research and development activities related to the experimental solid and liquid propellant rocket in Universiti Teknologi Malaysia (UTM) from year 1992 to 2011. A total of 41 closed access academic theses and project papers from UTM library archive were exclusively selected for this review work. Some of these theses and papers originally written in Malay language were translated into English language in this paper for better understanding of the research community. This paper gives a historical insight on the apparatus and methodology designed for educational research activities related to rocket propulsion in UTM. With the available resources within UTM, a few chemical propellant using Ammonium Perchlorate, Potassium Nitrate and hydrogen peroxide as oxidizer were tested in UTM propulsion lab. Besides discussing the rocket fuel components, composite rocket body, ceramic nozzle and alternative binder using natural rubber also covered in this review work. Significant experimental results and numerical findings achieved by UTM researchers were included in this paper.

This paper reports on the discovery of unique flame structure of a composite propellant sample under hot wire ignition. The entire combustion process at atmospheric pressure condition was recorded using a high speed camera. Three hot wire orientations were chosen in this experiment for examining their effects on the propellant burning behavior. The results show that the wire orientations are crucial in propellant combustion process, as different flame patterns were observed when the hot wire orientation was altered. This paper provides an important insight into this specific ignition process that can be useful for researchers in the aerospace industry for better design and more realistic simulation results in ignition control.

This paper presents an investigation of the reflectivity performance for hollow pyramidal shape microwave absorbers. The pyramidal absorbers used in this study is constructed using four 15cm-pyramidal absorbers stacked on each other to equal the height of one single 45cm-absorber. The wave frequency ranging from 8GHz to 12 GHz was chosen for simulation and measurement of the absorber performance. The reflectivity performances of the stacked pyramidal absorbers were compared to single level pyramidal absorbers in term of their reflectivity performances. The result shows that the stacked pyramidal absorber has higher absorption level an average absorption of −24 dB for the above frequency range.

In this work, a novelty solid propellant based on Isophorone Diisocyanate (IPDI) with Hydroxyl Terminated Natural Rubber (HTNR) binder network was successfully developed. The preparation of Liquid Natural Rubber (LNR) by chemical degradation Deprotenized Natural Rubber (DPNR) using cobaltous was carried out. From the FTIR spectroscopy, a broad hydroxyl group peak at 3444cm-1 was obtained from HTNR. Rubber network depict a strong carbonyl group C=O at 1714cm-1 and amine group N-H at 3433cm-1. NMR analysis also proves that there was hydroxyl group presence in the sample where broad peak at range 1-3 ppm and 3.5 ppm peak for -HOCH2CH2CH2-. Four different mol ratio of HTNR with IPDI was carried out to find the best formulation with good properties as propellant. Flory-Rehner equation depict that only slightly increasing occur with higher IPDI mol ratio but mixing with Ammonium Perchlorate (AP) and Aluminium Powder (AL) significantly improve the crosslink density. Melting point for HTNR is near to room temperature and it increase abruptly after crosslink with IPDI up to range of 148-150 °C. For all formulation, cross section morphology showed occurrence of porosity and brittle type of failure however HTNR has good contact with AL and AP. 2 : 1 molar ratio depict the best burning rate but the combustion characteristic shows less energy and spark compared to HTPB binder.

An anechoic chamber is considered good when there is no signal reflection inside the chamber and also when there is no incoming signal from outside the chamber. The key element inside an anechoic chamber is the absorbing material. The evaluations of mini anechoic chamber fitted with coated absorbers were carried out by analyzing the absorption performance. The study includes the comparison of measurement with and without coated absorbers. The evaluations were carried out using 500 MHz, 2 GHz and 10GHz frequencies. The most significant result shows an absorption level of up to approximately 75% when the chamber was fitted with coated absorbers for 10 GHz.

This paper investigates the capability of oil palm ash paint as green-absorbing material in a way to absorb microwave radiations. The paint is coated on three different wall materials which are elephant board, plywood and cement. The absorb performance of the paint is observed using the simulation result of Computer Simulation Technology (CST) Microwave Studio software. Meanwhile, the exact performance of the absorber is carried out via the measurement of absorption performance which shows a minimum average of absorption is −4.9 dB for all materials.

Propelan pepejal untuk kegunaan roket berbahan dorong pepejal yang telah dihasilkan di Universiti Teknologi Malaysia (UTM) adalah dari kumpulan propelan komposit kalium nitrat sebagai pengoksida dan sukros sebagai bahan api. Antara kaedah fabrikasi propelan adalah teknik pembentukan (forming), penyemperitan (extrusion), tuangan (casting) dan pengacuanan mampat (compressed moulding). Semua kaedah ini telah menghasilkan pelbagai propelan dengan sifat serta gaya laku yang berbeza–beza. Bergantung kepada bagaimana ia difabrikasi, propelan ini telah menunjukkan perkaitan sifat mekanikal yang begitu ketara. Dari setiap kaedah, propelan dibentuk mengikut satu bentuk serta dimensi yang piawai. Ujian kadar pembakaran dibuat ke atas setiap jalur propelan menggunakan alat uji kaji (test rig) yang telah direka bentuk. Ujian kadar pembakaran dilakukan pada tekanan atmosfera. Melalui ujian ini, kadar pembakaran propelan telah diperolehi. Hasil uji kaji menunjukkan kadar pembakaran propelan yang menggunakan teknik pembentukan dan teknik pengacuanan mampat masing–masing adalah 1.033 cm/s dan 0.429 cm/s. Manakala kaedah penyemperitan dan kaedah tuangan didapati tidak sesuai kerana sifat propelan kalium nitrat–sukros yang likat. Hasil uji kaji menunjukkan kaedah pengacuanan mampat ialah kaedah yang paling sesuai berbanding kaedah yang lain kerana dapat menghasilkan propelan yang seragam dan stabil. Kata kunci: Propelan; komposit; pengoksida; bahan api; kadar pembakaran Solid propellant used on solid fuel rocket developed at Universiti Teknologi Malaysia (UTM) is from the composite propellant group with potassium nitrate as the oxidizer and sucrose as the fuel. Among the propellant fabrication techniques are forming, extrusion, casting and compressed moulding. All of these techniques are used to fabricate several types of propellant with different characteristics and performances. Depending upon the technique of fabrication, these propellants have shown strong relationship with their mechanical properties. With every technique, the propellants are formed according to a standard shape and dimension. Burning rate tests were performed for each propellant strand fabricated using the test rig designed. The burning rate tests were performed at atmospheric pressure. Through this test, the propellant burning rates were obtained. Experimental results show that the burning rate for propellant developed using forming and compressed moulding are 1.033 cm/s and 0.429 cm/s, respectively. Meanwhile, the extrusion and casting methods were found not suitable due to the property of potassium nitrate–sucrose that is viscous. Experimental results show that the pressed moulding method is the most suitable method compared to the other techniques since it can produce propellant that is uniform and stable. Key words: Propellant; composite; oxidizer; fuel; burning rates

An electromagnetic (EM) wave absorber is used to absorb the reflected wave that occurs on the wall of the chamber in the anechoic chamber. To date findings show that the construction of the absorber material used for the absorbers, ferrite is in the lead. A survey on materials that can be used as a carbon for the absorber is performed and the best carbon content is a mix of wood. The absorbers are made of elephant board and then coated with carbon. The absorber is measured for 10GHz frequency. The performances of the designed absorber are compared to commercial absorbers available in terms of the absorption performance.

In this work, a commonly used measurement techniques were used to define the reflection loss performance of pyramidal microwave absorbers mounted on a wall. The technique is namely, Radar Cross Section (RCS) measurement method. Six set of pyramidal microwave absorbers and flat square absorbers were installed at one side wall, in an RF shielded room in order to investigate the performance. Two types of cable losses measurement techniques were applied to compare its performance under different loss conditions. The reflection loss values resulting from this investigation were then analyzed and discussed.

Rocket propellant has been identified as a component that played an important role in the development of rockets. The ejected material in rocket propulsion is due to material called propellant. Without propellant, a rocket cannot be launched. Due to this reason, many have started to conduct research on new chemical compound of propellant with new technique if needed. The objectives of this study are to study the thermo‐chemistry aspect of the composition and to determine the burning characteristics parameters. For this reason, this dissertation presented a detail preparation of developing a solid propellant using Ammonium Perchlorate (AP) as an oxidizer, Aluminum (Al) as fuel and Hydroxyl Terminated Polybutadiene (HTPB) as the binder. To determine the propellant performance such as burning rate, testing was conducted. From testing result the propellant composition oxidizer‐fuel (76/11) at pressure 110 Psi gave the maximum burning rate. From test results the empirical constant, ‘a’ and pressure exponent ‘n’ were calculated for each different propellant compositions.

The development of rocket motor using potassium nitrate, carbon and sulphur mixture has successfully been developed by researchers and students from UTM and recently a new combination for solid propellant is being created. The new solid propellant will combine a composition of Ammonium perchlorate, NH4ClO4 with aluminium, Al and Hydroxyl Terminated Polybutadiene, HTPB as the binder. It is the aim of this research to design and fabricate a new rocket motor that will produce a thrust of 200N by using this new solid propellant. A static test is done to obtain the thrust produced by the rocket motor and analyses by observation and also calculation will be done. The experiment for the rocket motor is successful but the thrust did not achieve its required thrust.

This paper presents the absorber in which it is designed and shaped to absorb incident radio frequency (RF) radiation. The absorber is designed using composite material since the significance of the project is to find a potential solution to construct a low cost anechoic chamber. This model of mini anechoic chamber, which is consisting of the new designed absorber, is portable and small in size so that it is more user friendly. The performance of the designed absorber are compared to commercial absorber available. The absorber that has been developed is a low cost absorber with the absorption rate is 16.6% less compared to the commercial absorber.

This paper presents a method to simplify the analysis of a square patch microwave sensor built on a multi-layer substrate. The main feature of this method is the simplification of a multi-layer sensor structure into a sensor structure with a single homogeneous layer. The equivalent dieletric constant for the new single homogenous layer was discriminated using the method proposed in this paper. Effectively it eliminates the problem of mode matching between layers and thus reduces the amount of calculation and computing time. The method was compared with the experimental results and was found to give an error less than 4% in the worse case.

This paper presents a method to simplify the calculations of cavity model analysis on a multi-layer microstrip antenna. The main feature of this method is the simplification of a multi-layer antenna structure into a single homogeneous layer antenna. This in effect completely eliminate the problem of mode matching between layers and thus reduces the amount of calculation and computing time. Theoretical results obtained using this method were compared with the experimental results and were round to give an error of less than 4%.

An experimental investigation is presented on the impedance bandwidth of an electromagnetically coupled, probe-fed stacked annular-ring microstrip patch antenna. A bandwidth of 12.6% is achieved around a centre frequency of 2.38 GHz. Measurements on gain and radiation patterns are also presented. The antenna presented is suitable for use in planar and conformal arrays. It could find applications in the industrial, scientific and medical (ISM) frequency bands.

It is well-known that a strand burner is an apparatus that provides burning rate measurements of a solid propellant at an elevated pressure in order to obtain the burning characteristics of a propellant. This paper describes the facilities developed by author that was used in his studies. The burning rate characteristics of solid propellant have be evaluated over five different chamber pressures ranging from 1 atm to 31 atm using a strand burner. The strand burner has a mounting stand that allows the propellant strand to be mounted vertically. The strand was ignited electrically using hot wire, and the burning time was recorded by electronic timer. Wire technique was used to measure the burning rate. Preliminary results from these techniques are presented. This study shows that the strand burner can be used on propellant strands to obtain accurate low pressure burning rate data.

The propellant composition is one of several parameter that influencing the temperature sensitivity of composite propellant. In this paper, experimental investigation of temperature sensitivity in burning rate of composite propellant was conducted. Four sets of different propellant compositions had been prepared with the combination of ammonium perchlorate (AP) as an oxidizer, aluminum (Al) as fuel and hydroxy-terminated polybutadiene (HTPB) as fuel and binder. For each mixture, HTPB binder was fixed at 15% and cured with isophorone diisocyanate (IPDI). By varying AP and Al, the effect of oxidizer- fuel mixture ratio (O/F) on the whole propellant can be determined. The propellant strands were manufactured using compression molded method and burnt in a strand burner using wire technique over a range of pressure from 1 atm to 31 atm. The results obtained shows that the temperature sensitivity, a, increases with increasing O/F. Propellant p80 which has O/F ratio of 80/20 gives the highest value of temperature sensitivity which is 1.687. The results shows that the propellant composition has significant effect on the temperature sensitivity of composite propellant