Asrel Aerospace Research Letters Latest Issue

In this study, the design of a photovoltaic solar power plant with an installed capacity of 1 MW was carried out in Konya, one of the leading provinces in Turkey in terms of solar energy potential. The performance of the plant was thoroughly evaluated through comprehensive simulation analyses. During the feasibility phase, two widely used simulation software programs in the solar energy sector, PVsyst and PVSOL, were employed. Using these tools, the plant's annual energy production capacity was calculated in detail based on long-term solar radiation data specific to the region. The simulation process focused not only on estimating energy production but also took into account several technical and environmental parameters, such as panel layout, inverter selection, cabling and conversion losses, geographical location, environmental effects, and meteorological conditions. By considering these factors, the plant was modeled in a way that closely reflects real operating conditions. To assess the accuracy of the simulation results, the data obtained were compared with actual production data from an existing solar power plant in the Konya region with similar technical characteristics for the years 2022 and 2023. The comparative analysis revealed that PVsyst showed a deviation of 5.43% in 2022 and 13.44% in 2023. In contrast, PVSOL demonstrated lower error margins, with deviations of 1.83% and 9.58% for the same years, respectively. Consequently, the use of PVSOL-based analyses in investment planning could offer more reliable projections for investors, contributing to increased system efficiency, more accurate calculation of return on investment, and overall cost optimization. The study aims to shed light on the key criteria for selecting software tools in solar energy investments, thereby contributing to the development of the sector.

This paper presents a validation study of a Computational Fluid Dynamics (CFD) solver based on the inviscid Euler equations. The aim is to assess the accuracy and applicability of a fast and efficient numerical method that can be employed in the conceptual design phase of a coaxial drone, developed by an undergraduate research group. For this purpose, the Caradonna-Tung rotor experiment—widely used as a benchmark in rotorcraft aerodynamics—is selected as the reference case for comparison. The rotor geometry consists of two straight blades with a constant chord, modeled using a symmetrical NACA 0012 airfoil. The rotor has a diameter of 1.143 meters and a chord length of 0.1905 meters. Numerical simulations were conducted at 1750 RPM with a collective pitch angle of 8°, under steady-state flow conditions. Euler equations were solved without including viscous effects or boundary layer modeling. A refined mesh was generated around the rotor to increase solution accuracy near the blade surfaces, particularly to better resolve pressure gradients. The computed pressure coefficient distributions were obtained for five spanwise locations (r/R = 0.5, 0.68, 0.8, 0.89, 0.96) and compared with experimental data. A generally high level of agreement was observed, particularly in the outboard blade sections (r/R ≥ 0.8), where the flow tends to behave more two-dimensionally. Minor discrepancies were noted near the leading edge and suction peaks, likely due to the lack of viscosity modeling in the Euler approach. Overall, the results suggest that Euler-based CFD methods can offer a low-cost and reliable alternative for early-stage rotor analysis. The validated model provides a solid foundation for future optimization studies and system-level performance assessments in coaxial UAV configurations.

This study includes the design and investigation stability of aircraft. The designed unnamed air vehicle (UAV) mission is conducting observation and gather intelligence without being detected by enemy radars. The designed UAV has fixed wing, mass of 10 kg and cruising speed of 30 m/s. The most important characteristic of UAV is use stealth technology.To select using stealth technology for UAV because the detection of UAVs using stealth technology is more difficult than that of conventional UAVs. When design, the initially selected wings profile analyzed use XFLR5 software. After choose S1210 airfoil profile among the other airfoils. Because S1210 airfoil profile has the best lift coefficient and minimum drag coefficient. The tail airfoil profile uses symmetric airfoil NACA 0010 because appropriate of aircraft design. Then selected profile, configuration selection phase exists. At this phase configuration selection for wing, fuselage, tail and landing gear. Mid-wing and T-tail configurations are used because they provide the aircraft with better balance and stability. Conventional fuselage and articulated landing gear configurations are used because they provide the aircraft minimum parasite drag and undetected by enemy radars. Then selected configuration, designed aerodynamic and control surface with specific dimensions and after the aircraft has been drafted using CAD software. Payload consists of T-Motor MN4014 brushless motor, compatible 40A ESC, 4S 5000mAh Li-Po battery, and Teledyne FLIR Hadron 640 imaging system for day and night reconnaissance missions. Then design phase, state-space matrices has been created because aircraft designed to investigate longitudinal stability. In the matrix parameters used to XFLR5 software derived from the stability of analysis and elevator deflection is OpenVSP software derived from the analysis. The finally, PID controller used for investigation stability and the best system’s response was derived.

In search and rescue operations following natural disasters, the effective use of unmanned aerial vehicle imagery is crucial for rapid and accurate damage assessment. This study presents a real-time multi-class object and damage detection approach developed using the YOLOv8n and YOLOv11n base models for use in post-earthquake search, rescue, and damage assessment processes. A real-time, video-based domain-generalized YOLO framework is proposed for response to unmanned aerial vehicle-monitored disasters. It combines multi-dataset fusion with adverse condition augmentation and lightweight temporal integration to maintain detection speed. In this paper, a hybrid dataset consisting of 8,754 images is generated from datasets obtained by collecting online earthquake imagery from VisDrone2019, VisDrone-Adverse Weather, DAWN, UAVDT, RescuNet, and other sources. It is also augmented with images from low-visibility conditions such as fog, smoke, darkness, rain, and dust using various data augmentation methods. During the data augmentation process, geometric transformations were applied: rotation, horizontal and vertical translation, and scaling; color space manipulations were adjusted for brightness, contrast, and HSV; environmental conditions were simulated using fog, smoke, darkness, rain, and dust; and Gaussian noise was added and random pixel manipulations were applied. Furthermore, models were trained on this dataset to perform real-time video processing and object detection, aiming to ensure rapid adaptation to dynamic conditions in disaster areas. The YOLOv11 model demonstrates the highest performance compared to YOLOv8 with a mAP value of 92.1% and an F1 score of 0.89, achieving an average of 15% more robust results in challenging environmental conditions. This study directly works on unmanned aerial vehicle video streams and provides temporal consistency through instantaneous adaptation in dynamic disaster scenes. The proposed method is comprehensively evaluated for its real-time object detection performance and damage classification accuracy. The results demonstrate that the model can be effectively used in disaster management processes.

Transitioning to cleaner energy alternatives is necessary due to the increasing demand for energy and the dominance of fossil fuels. Nuclear power plants, on the other hand, garner attention due to their consistent base load and low greenhouse gas emissions. Small modular reactor (SMR) technologies have been prioritized in non-electrical applications. This study comprehensively analyzes the economic impact of green hydrogen production by using SMRs on the decarbonization of the aviation sector. A literature review examined the technological and economic characteristics of SMRs, their correlation with hydrogen production, and their potential integration into the aviation sector. The cost-effectiveness of hydrogen production using SMRs for aerospace was evaluated. Furthermore, the levelized cost of electricity (LCOE) and levelized cost of hydrogen (LCOH) were calculated, considering key parameters and potential price fluctuations. Sensitivity analysis was performed specifically for ACP100, NuScale (VOYGR-4), BWRX-300 and i-SMR designs, and as a result, it was seen that the effect of operating life and reduction rate on LCOH remained below 1%. The most effective parameter has been determined as the lower calorific value (LHV) of hydrogen, which has an effect of approximately 8-9%. Notably, no significant technology-specific differences were observed. Although it was obtained that the LCOH did not fall below $6/kg even when all parameters were at their lowest, it was concluded that with a 10% change in the parameters, the cost of hydrogen could potentially reach $10/kg per kilogram. For competitiveness with jet fuel, the LCOH needs to fall below $4/kg. Within this, it was concluded that when all parameters decrease by 10%, the LCOE value should decrease to $42/MWh for the scenario and $33/MWh for the reference scenario. In addition, the main suggestions and points to be considered to guide other researchers working on nuclear energy, hydrogen and aviation are presented in the conclusion section.

As aircraft grew in size and speed, operating landing gear solely through manual lever force became increasingly difficult, necessitating the development of dedicated hydraulic power systems. The hydraulically assisted automatic landing gear mechanism was first implemented in the legendary Douglas DC-1, DC-2, and DC-3 models, marking a significant technological milestone in aviation history. In parallel with advancements in aircraft design, it was decided that the landing gear originally located at the tail would be repositioned to the front of the aircraft. This modification improved takeoff and landing performance while reducing pilot workload. In tailwheel aircraft, the pilot had to push the control stick forward during takeoff to raise the tail and, during landing, either touch down both main wheels simultaneously at slightly higher speed or achieve a highly precise and level touchdown. The introduction of nose landing gear eliminated these challenges, providing pilots with more controlled and safer takeoff and landing operations, and consequently becoming the standard configuration in modern aviation. Today’s aircraft typically employ a nose landing gear along with two main landing gears located under the wings. This study focuses on the design of fixed hydraulic landing gear systems commonly used in general aviation aircraft. The primary objective of the design is to develop a high-strength, high-durability, and cost-effective hydraulic landing gear concept for ultra-light aircraft used in various operational fields, and to present simulation analyses demonstrating the performance of the developed system.

This study encompasses the engineering analysis of Airstream, a flying vehicle developed within the framework of Urban Air Mobility as an alternative transportation solution, equipped with a hydrogen fuel cell and dual-mode mobility capability, and possessing high maneuverability. Airstream is equipped with a hybrid propulsion system that offers near-zero emission values, based on a sustainability-focused transportation approach. For ground mode, an electric motor with a power of 178 kW is used, while for vertical takeoff and flight mode, eight independent electric motors with a power of 40 kW each are utilized. The hydrogen fuel cell, which forms the basis of the hybrid system, provides high efficiency throughout the mission profile thanks to battery-supported energy sharing. In the design, biomimicry and symmetrical layout principles have been adopted, and especially through the integration of steerable propellers into the wheel hubs, an effective vertical takeoff/landing performance has been achieved even in confined spaces. The vehicle can respond dynamically during land-air transitions thanks to its jump-assisted active suspension system; flight stability is maintained through gyroscopic stabilization and autonomous orientation control systems. The carbon fiber composite body and titanium alloy wheels used in the structural system both increase the load capacity and contribute to overall energy efficiency by reducing the system's weight. Flight control is provided in an integrated manner with multi-layered navigation systems such as GNSS, VOR/DME, ILS, and TCAS through a central flight computer developed by ASELSAN. Additionally, safety elements such as fire detection and suppression modules, parachute-assisted emergency landing systems, and electromagnetic protection ensure the integrity of the system. Airstream offers a concrete engineering solution for the smart and sustainable transportation systems of the future with its high performance, eco-friendly structure, safety-focused system design, and technological components. Prototyping and flight tests will guide the integration of this concept into commercial applications.

This article presents a Fault Tolerant Control (FTC) scheme for an octoplane UAV, a fixed-wing unmanned aerial vehicle (UAV) equipped with eight vertical rotors, using sliding mode control (SMC) allocation. The proposed approach requires the design of only a single baseline controller that is effective under fault-free and fault/failure scenarios. The octoplane, a hybrid dual-system UAV (a fixed-wing aircraft with vertical takeoff and landing (VTOL) capabilities), presents unique challenges and opportunities due to its actuator redundancy. The scheme fully exploits the octoplane’s redundant vertical rotors and additional control surfaces, including the elevator, rudder, and independently operated ailerons, to manage total actuator faults/failures during cruise flight. The approach utilises sliding mode control with a control allocation (CA) strategy to redistribute control signals in the case of actuator failure. Simulation results based on a nonlinear model of the octoplane are presented at the end of the article to demonstrate the effectiveness of the proposed scheme. The paper commences with an introduction that includes a general review of the SMC Method and dual-system UAVs, specifically an octoplane configuration, highlighting the significance of FTC in improving UAV stability and the benefits of including extra actuator redundancy in the FTC design. The paper then presents an analysis of the equations of motion for an octoplane UAV, setting the foundation for examining the FTC of cruise mode. Subsequently, it introduces the SMC design process and explains its implementation of FTC. In cruise mode, the proposed SMC-CA method exhibits no performance degradation in the event of fault/failure compared to fault-free cases. The scheme demonstrates the effective combination of CA and SMC methods to an octoplane UAV during cruise flight.

This study presents the dynamic analysis of the NREL/MIT tension leg platform (TLP) supporting the NREL 5-MW wind turbine using OpenFAST. The simulations represent environmental conditions specific to the Kıyıköy region in the western Black Sea. Selected Design Load Cases (DLCs) cover both response characterization and extreme sea states defined by IEC guidelines. The platform hydrodynamics are modeled using first-order potential-flow theory to capture primary motions and tendon tensions efficiently. Viscous and second-order effects are excluded to emphasize computational performance. Simulation durations are selected to allow consistent comparison. A computational cost assessment is also conducted. Results show that OpenFAST produces stable and realistic platform responses across all conditions while maintaining low computational demand. The study confirms the capability of time-efficient modeling for preliminary assessments of floating wind turbines in regional environments such as Kıyıköy.