TY  - JOUR
AU  - Svorcan, Jelena
AU  - Kovacević, Aleksandar
AU  - Popović, Lazar
AU  - Simonović, Aleksandar
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3718
AB  - The paper presents a starting, but necessary comparative study between two diverse designs of single-seat tandem helicopter configuration, piston-propelled vs. electrically-driven. Both possibilities have their pros and cons, and need to be considered in detail, with respect to the initial requirements. In this investigation, the primary design objectives include 100 kg of payload as well as satisfactory performances in both hover and progressive flight. The comparison is conducted through the initial sizing procedures that enabled the estimation of takeoff mass (along with its main contributors), but also characteristic speeds, flight limits and basic helicopter performances. Used models and assumptions are explained in the paper. In the beginning, some essential advantages of tandem configuration helicopters are mentioned and accentuated. Also, future trends in electric aviation are considered. After that, total mass is decomposed into several main components and rotor dimensioning is performed. By assuming sufficient available power, it is possible to estimate the basic helicopter performances in both axisymmetric and progressive flight. Obtained results are presented graphically and numerically. In the end, some conclusions and recommendations for further research are given. For the time being, piston-propelled single-seat tandem helicopter can achieve better numerical results.
PB  - Inderscience Enterprises Ltd, Geneva
T2  - International Journal of Sustainable Aviation
T1  - Comparative study of piston vs. electric single-seat tandem helicopter
EP  - 14
IS  - 1
SP  - 1
VL  - 8
DO  - 10.1504/IJSA.2022.120614
ER  - 

@article{
author = "Svorcan, Jelena and Kovacević, Aleksandar and Popović, Lazar and Simonović, Aleksandar",
year = "2022",
abstract = "The paper presents a starting, but necessary comparative study between two diverse designs of single-seat tandem helicopter configuration, piston-propelled vs. electrically-driven. Both possibilities have their pros and cons, and need to be considered in detail, with respect to the initial requirements. In this investigation, the primary design objectives include 100 kg of payload as well as satisfactory performances in both hover and progressive flight. The comparison is conducted through the initial sizing procedures that enabled the estimation of takeoff mass (along with its main contributors), but also characteristic speeds, flight limits and basic helicopter performances. Used models and assumptions are explained in the paper. In the beginning, some essential advantages of tandem configuration helicopters are mentioned and accentuated. Also, future trends in electric aviation are considered. After that, total mass is decomposed into several main components and rotor dimensioning is performed. By assuming sufficient available power, it is possible to estimate the basic helicopter performances in both axisymmetric and progressive flight. Obtained results are presented graphically and numerically. In the end, some conclusions and recommendations for further research are given. For the time being, piston-propelled single-seat tandem helicopter can achieve better numerical results.",
publisher = "Inderscience Enterprises Ltd, Geneva",
journal = "International Journal of Sustainable Aviation",
title = "Comparative study of piston vs. electric single-seat tandem helicopter",
pages = "14-1",
number = "1",
volume = "8",
doi = "10.1504/IJSA.2022.120614"
}

Svorcan, J., Kovacević, A., Popović, L.,& Simonović, A.. (2022). Comparative study of piston vs. electric single-seat tandem helicopter. in International Journal of Sustainable Aviation
Inderscience Enterprises Ltd, Geneva., 8(1), 1-14.
https://doi.org/10.1504/IJSA.2022.120614

Svorcan J, Kovacević A, Popović L, Simonović A. Comparative study of piston vs. electric single-seat tandem helicopter. in International Journal of Sustainable Aviation. 2022;8(1):1-14.
doi:10.1504/IJSA.2022.120614 .

Svorcan, Jelena, Kovacević, Aleksandar, Popović, Lazar, Simonović, Aleksandar, "Comparative study of piston vs. electric single-seat tandem helicopter" in International Journal of Sustainable Aviation, 8, no. 1 (2022):1-14,
https://doi.org/10.1504/IJSA.2022.120614 . .

TY  - JOUR
AU  - Kovacević, Aleksandar
AU  - Svorcan, Jelena
AU  - Hasan, Mohammad Sakib
AU  - Ivanov, Toni
AU  - Jovanović, Miroslav
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3503
AB  - Purpose Modern unmanned air vehicles (UAVs) are usually equipped with rotors connected to electric motors that enable them to hover and fly in all directions. The purpose of the paper is to design optimal composite rotor blades for such small UAVs and investigate their aerodynamic performances both computationally and experimentally. Design/methodology/approach Artificial intelligence method (genetic algorithm) is used to optimize the blade airfoil described by six input parameters. Furthermore, different computational methods, e.g. vortex methods and computational fluid dynamics, blade element momentum theory and finite element method, are used to predict the aerodynamic performances of the optimized airfoil and complete rotor as well the structural behaviour of the blade, respectively. Finally, composite blade is manufactured and the rotor performance is also determined experimentally by thrust and torque measurements. Findings Complete process of blade design (including geometry definition and optimization, estimation of aerodynamic performances, structural analysis and blade manufacturing) is conducted and explained in detail. The correspondence between computed and measured thrust and torque curves of the optimal rotor is satisfactory (differences mostly remain below 15%), which validates and justifies the used design approach formulated specifically for low-cost, small-scale propeller blades. Furthermore, the proposed techniques can easily be applied to any kind of rotating lifting surfaces including helicopter or wind turbine blades. Originality/value Blade design methodology is simplified, shortened and made more flexible thus enabling the fast and economic production of propeller blades optimized for specific working conditions.
PB  - Emerald Group Publishing Ltd, Bingley
T2  - Aircraft Engineering and Aerospace Technology
T1  - Optimal propeller blade design, computation, manufacturing and experimental testing
EP  - 1332
IS  - 8
SP  - 1323
VL  - 93
DO  - 10.1108/AEAT-03-2021-0091
ER  - 

@article{
author = "Kovacević, Aleksandar and Svorcan, Jelena and Hasan, Mohammad Sakib and Ivanov, Toni and Jovanović, Miroslav",
year = "2021",
abstract = "Purpose Modern unmanned air vehicles (UAVs) are usually equipped with rotors connected to electric motors that enable them to hover and fly in all directions. The purpose of the paper is to design optimal composite rotor blades for such small UAVs and investigate their aerodynamic performances both computationally and experimentally. Design/methodology/approach Artificial intelligence method (genetic algorithm) is used to optimize the blade airfoil described by six input parameters. Furthermore, different computational methods, e.g. vortex methods and computational fluid dynamics, blade element momentum theory and finite element method, are used to predict the aerodynamic performances of the optimized airfoil and complete rotor as well the structural behaviour of the blade, respectively. Finally, composite blade is manufactured and the rotor performance is also determined experimentally by thrust and torque measurements. Findings Complete process of blade design (including geometry definition and optimization, estimation of aerodynamic performances, structural analysis and blade manufacturing) is conducted and explained in detail. The correspondence between computed and measured thrust and torque curves of the optimal rotor is satisfactory (differences mostly remain below 15%), which validates and justifies the used design approach formulated specifically for low-cost, small-scale propeller blades. Furthermore, the proposed techniques can easily be applied to any kind of rotating lifting surfaces including helicopter or wind turbine blades. Originality/value Blade design methodology is simplified, shortened and made more flexible thus enabling the fast and economic production of propeller blades optimized for specific working conditions.",
publisher = "Emerald Group Publishing Ltd, Bingley",
journal = "Aircraft Engineering and Aerospace Technology",
title = "Optimal propeller blade design, computation, manufacturing and experimental testing",
pages = "1332-1323",
number = "8",
volume = "93",
doi = "10.1108/AEAT-03-2021-0091"
}

Kovacević, A., Svorcan, J., Hasan, M. S., Ivanov, T.,& Jovanović, M.. (2021). Optimal propeller blade design, computation, manufacturing and experimental testing. in Aircraft Engineering and Aerospace Technology
Emerald Group Publishing Ltd, Bingley., 93(8), 1323-1332.
https://doi.org/10.1108/AEAT-03-2021-0091

Kovacević A, Svorcan J, Hasan MS, Ivanov T, Jovanović M. Optimal propeller blade design, computation, manufacturing and experimental testing. in Aircraft Engineering and Aerospace Technology. 2021;93(8):1323-1332.
doi:10.1108/AEAT-03-2021-0091 .

Kovacević, Aleksandar, Svorcan, Jelena, Hasan, Mohammad Sakib, Ivanov, Toni, Jovanović, Miroslav, "Optimal propeller blade design, computation, manufacturing and experimental testing" in Aircraft Engineering and Aerospace Technology, 93, no. 8 (2021):1323-1332,
https://doi.org/10.1108/AEAT-03-2021-0091 . .

TY  - JOUR
AU  - Hasan, Mohammad Sakib
AU  - Ivanov, Toni
AU  - Vorkapić, Miloš
AU  - Simonović, Aleksandar
AU  - Daou, David
AU  - Kovacević, Aleksandar
AU  - Milovanović, Aleksa
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3371
AB  - Rapid innovations in 3D printing technology have allowed highly complex parts to be manufactured quickly and easily, particularly for prototyping purposes. Fused Deposition Modeling of thermoplastic materials is one of the most commonly used techniques in three-dimensional (3D) printing. The major aim of Fused Deposition Modeling (FDM) is to design and manufacture usable parts for fields such as engineering and medicine. Therefore, it is essential to investigate the mechanical properties of such FDM processed structures. One of the most commonly used materials currently on the market is Polylactic Acid (PLA). The main purpose of this paper is to investigate the effects of aging and heat treatment on the tensile properties of PLA printed test specimens. The tensile properties of parts manufactured by the 3D printer are influenced by various parameters such as extrusion temperature, infill density, building direction, layer height, etc. A total of 96 specimens were built by altering building orientation and layer height to estimate and compare the tensile properties of the printed parts. To investigate the aging effect, 30 of 96 specimens were printed 6 months before the tensile experiment. Half of both aged and new specimens were cured in an oven at 57.5 [degrees C] for 3 hours while the other half endured no heat treatment. After the performed measurement, it can be concluded that heat treatment generally improves structural strength of the printed parts, while aging decreases it. However, these effects are highly dependent on the layer thickness and printing quality. The tensile test is conducted according to the ASTM D638 standard. The fractured samples were further characterized using an electron microscope.
PB  - Revista Chimie Srl, Bucuresti
T2  - Materiale Plastice
T1  - Impact of Aging Effect and Heat Treatment on the Tensile Properties of PLA (Poly Lactic Acid) Printed Parts
EP  - 159
IS  - 3
SP  - 147
VL  - 57
DO  - 10.37358/MP.20.3.5389
ER  - 

@article{
author = "Hasan, Mohammad Sakib and Ivanov, Toni and Vorkapić, Miloš and Simonović, Aleksandar and Daou, David and Kovacević, Aleksandar and Milovanović, Aleksa",
year = "2020",
abstract = "Rapid innovations in 3D printing technology have allowed highly complex parts to be manufactured quickly and easily, particularly for prototyping purposes. Fused Deposition Modeling of thermoplastic materials is one of the most commonly used techniques in three-dimensional (3D) printing. The major aim of Fused Deposition Modeling (FDM) is to design and manufacture usable parts for fields such as engineering and medicine. Therefore, it is essential to investigate the mechanical properties of such FDM processed structures. One of the most commonly used materials currently on the market is Polylactic Acid (PLA). The main purpose of this paper is to investigate the effects of aging and heat treatment on the tensile properties of PLA printed test specimens. The tensile properties of parts manufactured by the 3D printer are influenced by various parameters such as extrusion temperature, infill density, building direction, layer height, etc. A total of 96 specimens were built by altering building orientation and layer height to estimate and compare the tensile properties of the printed parts. To investigate the aging effect, 30 of 96 specimens were printed 6 months before the tensile experiment. Half of both aged and new specimens were cured in an oven at 57.5 [degrees C] for 3 hours while the other half endured no heat treatment. After the performed measurement, it can be concluded that heat treatment generally improves structural strength of the printed parts, while aging decreases it. However, these effects are highly dependent on the layer thickness and printing quality. The tensile test is conducted according to the ASTM D638 standard. The fractured samples were further characterized using an electron microscope.",
publisher = "Revista Chimie Srl, Bucuresti",
journal = "Materiale Plastice",
title = "Impact of Aging Effect and Heat Treatment on the Tensile Properties of PLA (Poly Lactic Acid) Printed Parts",
pages = "159-147",
number = "3",
volume = "57",
doi = "10.37358/MP.20.3.5389"
}

Hasan, M. S., Ivanov, T., Vorkapić, M., Simonović, A., Daou, D., Kovacević, A.,& Milovanović, A.. (2020). Impact of Aging Effect and Heat Treatment on the Tensile Properties of PLA (Poly Lactic Acid) Printed Parts. in Materiale Plastice
Revista Chimie Srl, Bucuresti., 57(3), 147-159.
https://doi.org/10.37358/MP.20.3.5389

Hasan MS, Ivanov T, Vorkapić M, Simonović A, Daou D, Kovacević A, Milovanović A. Impact of Aging Effect and Heat Treatment on the Tensile Properties of PLA (Poly Lactic Acid) Printed Parts. in Materiale Plastice. 2020;57(3):147-159.
doi:10.37358/MP.20.3.5389 .

Hasan, Mohammad Sakib, Ivanov, Toni, Vorkapić, Miloš, Simonović, Aleksandar, Daou, David, Kovacević, Aleksandar, Milovanović, Aleksa, "Impact of Aging Effect and Heat Treatment on the Tensile Properties of PLA (Poly Lactic Acid) Printed Parts" in Materiale Plastice, 57, no. 3 (2020):147-159,
https://doi.org/10.37358/MP.20.3.5389 . .