Rotary Wing Aircraft Research Articles

On the Growth of Small Cracks in 2024‐T3 and Boeing Space, Intelligence and Weapon Systems AM LPBF Scalmalloy®

ABSTRACTThe desire to use additively manufactured (AM) parts to ensure the availability of military aircraft, and to build limited‐life unmanned aerial vehicles (drones), coupled with the United States Air Force (USAF) approach to the airworthiness certification of AM parts has focused attention on durability analysis/assessment, and hence on the growth of small cracks in AM parts. Previous studies have shown that laser powder fusion built (LPBF) Scalmalloy® has: i) A yield stress and an ultimate strength that are greater than that of AA2024‐T3 and comparable to that of AA7075‐T6; ii) A resistance to crack growth that is better than that of AA7075‐T6 and comparable to that of AA2024‐T3. However, since the ability to predict the durability of a part is essential for its airworthiness certification, the present paper illustrates how to perform a linear elastic fracture mechanics (LEFM)‐based durability assessment of Boeing Space, Intelligence and Weapon System (BSIWS) LPBF Scalmalloy®. The durability study includes specimens with both machined surfaces and surfaces left in the as‐built condition. As a result, it would appear that BISWS AM LPBF Scalmalloy® is an ideal candidate for building limited‐life AM replacement parts for fixed and rotary wing aircraft and drones.

Statistical Analysis of Airfoil Usage in Aircraft

The study aims to answer how frequently airfoils are used in fixed and rotary wing aerial vehicles produced both individually and based on airfoil families. Frequency distribution analysis of airfoil utilization in fixed-wing and rotary-wing aircraft helps in understanding design preferences and performance needs and constraints. The literature study provides the history of airfoils, the subjects mostly studied regarding airfoils and mentions the current state of the field. The study investigates the airfoil families to which the wing profiles of approximately 6,000 fixed-wing and approximately 450 rotary-wing aircraft belong through frequency distribution. The results indicate that in fixed-wing aircraft, NACA airfoils are used in 52.2%, Clark-Y airfoils in 8.2%, Goettingen airfoils in 5.9%, Wortman airfoils in 4.8%, and TsAGI airfoils in 3.1%. When considered as singular airfoil use rather than airfoil families, Clark-Y is the most widely used airfoil, followed by the NACA 23XXX series. In rotary-wing aircraft, NACA 0012 and NACA 0015 airfoils, both symmetrical profiles developed by NACA, are the most widely used. The study is valuable as it provides statistical data on the use of both airfoil families and singular airfoil design in fixed and rotary-wing aircraft. However, it is important to note that the airfoil data is incomplete, and the study aims to provide a general impression of the findings.

Maximization of Flight Performance of Eight-Rotor Multirotor with Differentiated Hub Angle

The aim of this article is to design a rotary wing aircraft autopilot system that improves flight performance by changing the body shape during flight. The method is to obtain values that stabilize the longitudinal and lateral flight of the aircraft, where the amount of metamorphosis and Proportional-Integral-Derivative (PID) coefficients are determined using the simultaneous perturbation stochastic approximation (SPSA) optimization algorithm. The rotary wing aircraft has a deformable structure with eight rotors. Shape-changing rotary-wing aircraft are aircraft that can fly with the lift generated by propellers. Aerial platform; It consists of arms and trunk. The angle between mechanism A and the arm to which the rotors are connected can be changed with the horizontal plane and different configurations are obtained. When the angle between the arms is 45°, the octo configuration turns into a stable structure, while when the angle between the arms is 0°, the X8 configuration provides high maneuverability and increased controllability. Metamorphosis, its effect on longitudinal and lateral flight stability and improvement studies were carried out in a simulation environment and the results are presented in this study. As a result of the shape change, longitudinal and lateral narrowing occurred by 26.8° percent. Simulation tests were modeled in a closed environment, free from atmospheric effects. The obtained flight performance values are presented in Tables.

Hypothermia and the Global War on Terror: 18 Years of Minimal Progress.

The association between hypothermia, coagulopathy, and acidosis in trauma is well described. Hypothermia mitigation starts in the prehospital setting; however, it is often a secondary focus after other life-saving interventions. The deployed environment further compounds the problem due to prolonged evacuation times in rotary wing aircraft, resource limitations, and competing priorities. This analysis evaluates hypothermia in combat casualties and the relationship to resuscitation strategy with blood products. Using the data from the Department of Defense Joint Trauma Registry from 2003 to 2021, a retrospective analysis was conducted on adult trauma patients. Inclusion criteria was arrival at the first military treatment facility (MTF) hypothermic (<95ºF). Study variables included: mortality, year, demographics, battle vs non-battle injury, mechanism, theater of operation, vitals, and labs. Subgroup analysis was performed on severely injured (15 < ISS < 75) hypothermic trauma patients resuscitated with whole blood (WB) vs only component therapy. Of the 69,364 patients included, 908 (1.3%) arrived hypothermic; the vast majority of whom (N = 847, 93.3%) arrived mildly hypothermic (90-94.9°F). Overall mortality rate was 14.8%. Rates of hypothermia varied by year from 0.7% in 2003 to 3.9% in 2014 (P <0.005). On subgroup analysis, mortality rates were similar between patients resuscitated with WB vs only component therapy; though base deficit values were higher in the WB cohort (-10 vs -6, P < 0.001). Despite nearly 20 years of combat operations, hypothermia continues to be a challenge in military trauma and is associated with a high mortality rate. Mortality was similar between hypothermic trauma patients resuscitated with WB vs component therapy, despite greater physiologic derangements on arrival in patients who received WB. As the military has the potential to conduct missions in environments where the risk of hypothermia is high, further research into hypothermia mitigation techniques and resuscitation strategies in the deployed setting is warranted.

Inter hospital transfers in rotor wing aircraft. Patterns and challenges. Protocol for a scoping review.

Inter-hospital transfer is necessary for the transport of patients to specialized treatment. Rotor-wing aircraft may be used in lieu of ambulances in time-critical conditions over long distances and when specialist team skills are called for. The purpose of the review is to assess the current scientific literature that describes the scenario to develop a national guideline for inter-hospital transfers using rotor-wing aircraft. The aim is to describe the patterns and challenges. The authors will conduct a scoping review as per Joanna Briggs Institute guideline. The protocol for the scoping review will adhere to the Open Science Framework guideline for scoping reviews and we will report the findings of the scoping review as per PRISMA-ScR guideline. We have developed the search strategy with the help of a research librarian and will conduct search in relevant electronic databases and include gray literature as well, using the PRESS and PRISMA-S guidelines. Two authors will independently screen titles and abstracts for inclusion as per eligibility criteria and conflicts will be resolved by a third reviewer. Full text retrieval will be conducted accordingly. We will analyze the extracted data using validated statistical methods. According to Danish law, scoping reviews are exempt from ethics committee approval. The findings of this scoping review will provide the scientific foundation for a national guideline on rotor-wing aircraft conveyed inter-hospital transfers in Denmark. Furthermore, we will publish the results of the scoping review in a relevant scientific journal.

Particle Image Velocimetry Investigation Of The Aerodynamic Interaction Between Helicopter And An Aircraft Carrier

Helicopters greatly expand operational capabilities during military missions at the sea. The aircraft carriers are capable of accommodating fixed-wing and rotary-wing aircraft operations. They not only have one runway for take-off, but also have different spots for helicopter operations. As they are spread over the deck of the aircraft carrier, the non-aerodynamic geometries of the take-off ramp and the island can generate complex flows, with high velocity gradients and turbulence intensities that can make complex the helicopter landing and take-off maneuvers for pilots. This study analyses the interaction between the aerodynamic patterns generated by the warship and those generated during the operation of the helicopter. Two wind conditions are simulated: headwind and crosswind. The results are provided by a Particle Image Velocimetry (PIV) system installed at the wind tunnel test section of a low-speed wind tunnel. The model of aircraft carrier and helicopter are tested in a reduced scale of 1:100. And the helicopter rotor rotates at sufficient speed to ensure the similarity of the thrust coefficient with the real case. Finally, during the wind tunnel tests, using an automatic positioning system, the helicopter is placed in different positions above the aircraft carrier flight deck in order to obtain PIV images and extract non-dimensional velocity contours with and without the helicopter effect. The results have shown important effects of the aerodynamics generated by the bow, the hull and the aircraft carrier island, with velocity differences up to 70 % depending on the landing spot analyzed.

Direct Combat-related U.S. Army Aviation Injuries 2003-2014.

The U.S. Army Aeromedical Research Laboratory (USAARL), a partner in the Joint Trauma Analysis for the Prevention of Injury in Combat (JTAPIC) partnership, conducted a series of retrospective reviews to investigate injuries sustained by occupants of U.S. Army rotary-wing aircraft involved in combat damage incidents. The reviews were conducted to provide occupant survivability information to the Aviation Survivability Development and Tactics team, an agency within the U.S. Army Aviation Center of Excellence. For these reviews, combat damage incidents that produced casualties were separated into direct events (i.e., events in which an enemy weapon system directly injured occupants) and indirect events (i.e., incidents in which occupants were injured as a result of a crash caused by the enemy weapon system). The previous USAARL reviews provided an overview of injuries sustained during direct and indirect events. The objective of this review was to conduct a detailed analysis of injuries occurring during direct events. A descriptive retrospective review was conducted on injuries sustained by occupants of U.S. Army rotary-wing aircraft involved in combat damage incidents between 2003 and 2014. All Black Hawk, Apache, and Chinook combat aviation damage incidents for the study period were reviewed. Personnel casualty information from the Defense Casualty Information Processing System (DCIPS) was linked to combat damage incident information by matching the aircraft platform, incident date, and circumstantial information found in incident narratives. Injury information for personnel identified in DCIPS as being wounded in action was obtained from the JTAPIC partnership; injury data for personnel killed in action were retrieved from the Armed Forces Medical Examiner System. All injuries were coded using the Abbreviated Injury Scale (AIS). Descriptive statistics were used to describe the frequency and distribution of injuries to personnel involved in direct events. Overall, the extremities were the most commonly injured body regions, with lower extremities suffering more injuries than upper extremities. Penetrating injuries were identified as the primary injury mechanism for all body regions. Injuries to each AIS body region were predominantly of minor (AIS 1) and moderate (AIS 2) severity. Although injury severities were generally low (AIS 1 or AIS 2), the results of this effort indicate which body regions may benefit from additional protection during rotary-wing operations in hostile environments. The influence of occupant position within the aircraft and the use and effectiveness of personal protective equipment could not be effectively analyzed due to a lack of information.

Aircraft Designed for Cargo Transportation and Investigation of its Benefits

In this study, an Octorotor UAV capable of carrying 10 desi/2 kg cargo was designed. It is an eight-rotor rotary wing aircraft and its body consists of eight arms connected to each other by two moving mechanisms. When requested in emergency situations, the fastest intervention can be provided by aircrafts. The auxiliary battery and generator system carried by the aircraft is to provide enough energy to reach the nearest electric charging station for the stranded vehicles. In cases such as disasters, the rapid delivery of health supplies can also be provided by this method. The aircraft designed for this purpose has a rotary wing and a feature that can change its body structure according to different load and weather conditions. The shape change improves its performance compared to conventional aircraft and increases its ability to fulfil its mission. For this purpose, the design of a shape-changing aircraft was realized.

PI-Filter compensator for LQG controller aimed to fixed-wings aircrafts

Fixed-wing aircraft use their wings to generate lift and propulsion, relying on forward motion for airflow rather than rotating blades like helicopters. They offer advantages such as extended range, higher speeds, stability in turbulent weather, and lower operational costs compared to rotary-wing aircraft. A study introduces a method to improve control smoothness for fixed-wing aircraft using LQG control and PI filter compensation. Flight simulators like FlightGear are used for testing control algorithms before real-world experiments, offering realistic flight dynamics and versatile options for various aircraft types. This approach provides a cost-effective and efficient way to develop and test controllers for challenging flight scenarios.

Investigation and validation of the TEG6s during rotary wing aeromedical flight.

To improve rural and austere trauma care, hospital-based testing performed at the point of injury may shorten the time lapsed from injury to intervention. This study aimed to evaluate the use of the TEG6s device (Haemonetics(R), Clinton, PA) in a rotary wing aircraft. Prior attempts suffered from limitation related to lack of vibration mitigation. This was an investigator-initiated, industry-supported study. Haemonetics provided a TEG6s analyzer. The device underwent a standard validation. It was secured in place on the aircraft using shipping foam for vibration mitigation. Donors provided two tubes of sample blood in one sitting. Paired studies were performed on the aircraft during level flight and in the hospital, using the Global Hemostasis with Lysis Cartridge(Haemonetics (R), Clinton, PA). Both normal and presumed pathologic samples were tested in separate phases. Paired t tests were performed. For normal donors, the mean R for laboratory compared with the aircraft was 6.2 minutes versus 7.2 minutes ( p = 0.025). The mean ± SD Citrated Rapid TEG Maximum Amplitude (CRT MA) was 59.3 ± 5.6 mm and 55.9 ± 7.3 mm ( p < 0.001) for laboratory and aircraft ( p < 0.001). Among normal donors, R was within normal range for 17 of 18 laboratory tests and 18 of 18 aircraft tests ( p > 0.99). During the testing of pathologic samples, the mean R time was 14.8 minutes for laboratory samples and 12.6 minutes for aircraft ( p = 0.02). Aircraft samples were classified as abnormal in 78% of samples; this was not significantly different than laboratory samples ( p = 0.5). The use of the TEG6s for inflight viscoelastic testing appears promising. While statistically significant differences are seen in some results, these values are not considered clinically significant. Classifying samples as normal or abnormal demonstrated a higher correlation. Future studies should focus on longer flight times to evaluate for LY30, takeoff, and landing effects. Overall, this study suggests that TEG6s can be used in a prehospital environment, and further study is warranted. Diagnostic Tests or Criteria; Level III.

Preliminary Design and Optimization of Primary Structures for a Tilt-Duct UAV

Tilt-duct Unmanned Aerial Vehicles (UAV) combine the high-speed efficiency of fixed-wing aircrafts with vertical takeoff and landing (VTOL) and the hover capabilities of rotary-wing aircrafts while maximizing the advantages of ducted fans in terms of noise reduction, efficiency, and safety, making it a pivotal direction for the future of aviation such as urban air mobility. This paper concentrates on the design and optimization of the primary structures of a laboratory-designed reference tilt-duct UAV. Firstly, the general data of the reference tilt-duct UAV are presented. According to the load conditions, the overall structural layout design for the wing, fuselage, and empennage is carried out, where special attention has been paid to account for the requirements of VTOL/hover and cruise flight modes. Based on the structural layout, finite element models (FEM) are established and static analyses are performed. The results indicate that the design can fulfill the structural requirements during a flight mission. Furthermore, based on the Method of Feasible Directions (MFD) algorithm, we have carried out the optimization of the composite wing box that incorporates manufacturing constraints. Via optimization, the total mass of the wing box is reduced by 38.6%, i.e., from 3.73 kg to 2.29 kg. The results indicate that the combination of composite materials with a tilt-duct configuration holds significant potential for future high-efficiency and environmentally friendly aviation.

Development of a solar powered multirotor micro aerial vehicle

Rotary-wing aerial vehicles offer manoeuvrability and vertical take-off and landing (VTOL) advantages over fixed-wing systems. Rotary-wing systems do however have comparatively higher energy demands and consequently shorter flight times and therefore a greater energy dependence over their fixed-wing counterparts. Advances in photovoltaic technologies have resulted in significant increases in the specific power (power-to-weight-ratio) of solar cells enabling the design of solar-powered rotary-wing aircraft, and now micro-sized variants. The micro aerial vehicle (MAV) presented, the Micro Solarcopter, is a 0.15 m ×\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ imes$$\\end{document} 0.15 m ×\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ imes$$\\end{document} 0.02 m solar-rechargeable radio-controlled aircraft. The 0.071 kg aircraft can fly for an average time of 3.5 min, recharge in approximately 68 min under 1000 W/m2 irradiance at 25 °C and can hibernate for 38 days without sunlight. The paper explores the use of commercially available photovoltaic cells for the purpose of increasing the energy autonomy of multi-rotor MAVs, by enabling them to stay out in the field without returning to base for charging. A working prototype has been presented which incorporates a battery management system, automatic power on and off, low-power sleep mode, and first-person-view (FPV) camera.

Incidence of cervical and lumbar spine injuries in Brazilian air force helicopter pilots

This paper is a brief analysis of the incidence of pain and discomfort caused by flying rotary-wing aircraft. This is due to the excessive vibration exerted by the rotors on the pilot's seat, which is absorbed by the pilot's spine, and the posture adopted by the pilot during the flight due to the layout of the controls. Air forces from various countries such as Israel, Sweden, England, among others, have considered low back pain to be a primary health problem in airmen and admit that this type of problem is detrimental to flight safety, given that the pain acts throughout the flight and can appear at a level that distracts the pilot. The aim of this study was to clarify the incidence of pain and discomfort among rotary-wing pilots in the Brazilian Air Force. To help carry out the study, an online questionnaire with multiple-choice, scale and full answer questions was used, answered by 124 aviation officers belonging to the Brazilian Air Force. Corroborating previous research in this area, we identified that the main discomforts are related to the position of piloting the aircraft, mainly located in the region of the spine. Most of this discomfort lasts from a few minutes to a few hours. The main preventative methods used by helicopter pilots are related to strength training. Thus, we can infer the awareness of pilots and authorities of the importance of physical exercise, thus inferring an important preventive measure.

Cervical Disc Displacement in Military Pilots.

Cervical disc displacement (CDD) may disqualify pilots from flying and have a profound impact on military unit capability. The objective of this retrospective database review is to characterize the incidence and demographic predictors of symptomatic cervical spine disc displacement in pilots of fixed- and rotary-wing aircraft and ground-based controls. The Defense Military Epidemiology Database was queried for first-occurrence ICD-9 code 722.0: CDD cases from 2007 to 2015. Injury count rates among aircraft groups and overall incidence per 1,000 person-years were calculated and standardized for age, gender, and military rank, and 95% confidence intervals (CIs) were compared to determine significance. There were 934 new cases of CDD among active duty U.S. Military pilots during the study period. The overall incidence of CDD in all pilots during this time frame was 2.715 per 1,000 person-years (95% CI, 2.603-2.830). Helicopter pilots had a significantly higher incidence compared to all other aircraft pilots and crew at 3.79 per 1,000 person-years (95% CI, 3.48-4.13). This finding remained statistically significant after standardizing for age, gender, and rank. Among all military officers, increasing age was a risk factor for CDD. The U.S. Military helicopter pilots have an increased risk compared to fixed-wing pilots and non-pilot controls. CDD remains a rare, though career-threatening, condition. Increased education and awareness training are warranted for both helicopter pilots and flight physicians to recognize signs and symptoms of cervical pathology. Continued investigations into preventive measures to minimize injury and time unfit for flight are warranted.

Morphing concepts in the field of rotorcraft

Drawing inspiration from avian creatures, aeronautical engineers strive to create an ideal wing design that can seamlessly perform in various flight conditions. Avian creatures, as well as bats and other flying organisms, exhibit a striking aptitude to adjust the lift produced by their wings, displaying the capacity to repeatedly tailor their wing configurations to match specific environmental conditions. An example of this is when their wings are tightly tucked during dives for hunting, or fully extended during gliding to conserve energy. Moreover, these organisms can manipulate the curvature and twist of their wings to maintain precise control over their aerial maneuvers. In contrast, engineers in the aircraft industry continue to rely on the standard, robust and structured “one-point design” approach, which remains the most practical and feasible method to apply. Nonetheless, advancements in technology have emerged to address long-standing challenges in wing manufacturing that were previously deemed insurmountable. This convergence of different technologies has given significant momentum and recognition to the field of “morphing discipline”. When considering an aircraft, shape changes primarily relate to the wing of a fixed-wing aircraft or the blade of a rotorcraft. The concept of achieving a "smooth" shape change stems from the crucial need for drag reduction and improved flow quality, resulting in improved overall performance. The state-of-the-art morphing concepts applied to rotorcrafts comprise a wide range of investigations aimed at improving performance. Looking ahead, the primary challenge for morphing technology will be to persuade the industry of its tangible benefits. This encompasses enhanced aerodynamic efficiency, minimized installation footprint when contrasted with conventional control surface mechanisms, reduced overall weight, and an equivalent standard of safety. This research provides an overview of the current development of different control devices and explores the impact of previous and continuous research endeavors in this field. Numerous ideas for managing airflow have been explored with the aim of enhancing the performance abilities of rotary-wing aircraft. These include active morphing in rotorcraft such as leading edge slats, trailing edge flaps, and passive morphing in rotorcraft such as variable rpm rotorcraft. The aim of these blade modifications is to achieve various desired effects such as increasing the maximum lift coefficient, reducing drag, and minimizing vibratory loads. Convincing the industry of these advantages will play a crucial role in shaping the future of morphing technology.

Design and analysis of an electric tiltrotor unmanned aerial vehicle

The concept of tiltrotor aircraft has been around for over seventy years, but it was not until the last decade that the advancement in Unmanned Aerial Vehicle (UAV) technology has made them a viable option. Although the design requirements of such UAV are complex and require careful consideration, the potential benefits are significant. Motivated by their potential capabilities, this paper aims to present a complete procedure for designing an electric tiltrotor UAV that incorporates the attributes of both fixed and rotary wing aircraft, including all necessary mathematical formulations. The paper explores the diverse aspects of the design and analysis of tiltrotor UAVs, from conceptual, preliminary, and detail design to aerodynamics, performance, and stability analysis. The detailed weight analysis is performed using six different methods from different references to assess their applicability for use with electric tiltrotor UAV. After designing and selecting the UAV components, an iteration process is performed to check and resize the estimated design parameters.

Microstructure Image-Based Finite Element Methodology to Design Abradable Coatings for Aero Engines

Upgrading abradable or wearable coatings in the high-temperature zone of aero engines is advised to increase the efficiency and high-density power in gas turbine engines for military or commercial fixed-wing and rotary-wing aircraft. The development of these coated materials is also motivated by minimization of the number of failures in the blade, as well as increasing their resistance to wear and erosion. It is suggested that abradable coatings or seals be used to accomplish this goal. The space between the rotor and the shroud is minimized thanks to an abradable seal at the blade’s tip. Coatings that can withstand abrasion are often multiphase materials sprayed through thermal spray methods, and which consist of a metal matAzmeerix, oxide particles, and void space. The maintenance of an ideal blend of qualities, such as erosion resistance and hardness, during production determines a seal’s effectiveness. The objective of this research is to develop microstructure-based modelling methodology which will mimic the coating wear process and subsequently help in designing the abradable coating composition. Microstructure modelling, meshing, and wear analysis using many tools such as Fusion360, Hyper Mesh, and LS-Dyna, have been employed to develop an abradable coating model and perform wear analysis using a simulated rub rig test. The relation between percentage composition and morphology variations of metal, oxide, and voids to the output parameters such as hardness, abradability, and other mechanical properties is explored using simulated finite analysis models of real micrographic images of abradable coatings.

Prediction of Noise-Power-Distance Data for Urban Air Mobility Vehicles

In contrast to most commercial air traffic today, vehicles serving the urban air mobility (UAM) market are anticipated to operate within communities and be close to the public at large. The approved model for assessing environmental impact of air traffic actions in the United States, the Federal Aviation Administration Aviation Environmental Design Tool (AEDT), does not directly support analysis of such operations due to a combined lack of UAM aircraft flight performance model data and aircraft noise data. This paper addresses the latter by offering two prediction-based approaches for generation of noise–power–distance data for use within AEDT. One utilizes the AEDT fixed-wing aircraft modeling approach, and the other utilizes the AEDT rotary-wing aircraft modeling approach.

The Evolution of Air Threats in Future Conflicts

Currently, there is an observable trend towards continuous and comprehensive development in both fixed-wing and rotary-wing aircraft design. Furthermore, a dynamic progression has been also witnessed in the evolution of unmanned aerial vehicles, loitering munitions, lethal autonomous weapons systems, ballistic missiles, cruise missiles, hypersonic cruise missiles, lighter-than-air sensor platforms, high altitude pseudo satellites and any others. The development of modern technologies and the acquisition of new materials create opportunities for the modernization of existing air threats as well as the development of novel types. Additionally, the potential of artificial intelligence in unmanned systems is a significant factor that should not be overlooked. The aforementioned circumstances have prompted the author of the article to conduct a thorough examination of contemporary military air threats and to make a forecast regarding the evolution of air threats in future conflicts.

Vertical take-off and hover to cruise transition for a hybrid UAV using model predictive controller and MPC allocation

PurposeDual-thrust hybrid unmanned aerial vehicle (UAV) technology offers a highly robust and efficient system that incorporates the take-off and landing capabilities of rotary-wing aircraft with the endurance capacities of fixed-wing aircraft. The purpose of this study is to model and control a hybrid UAV in three distinct flight modes: rotary-wing, fixed-wing and over-actuated model.Design/methodology/approachModel predictive control (MPC) along with linear models are applied to design controllers for the rotary-wing or vertical take-off and transition to the fixed-wing flight. The MPC algorithm is implemented with two approaches, first in its usual form and then in a new form with the help of tracking error variables as state variables.FindingsBecause the tracking error variables are more compatible with the cost function used in MPC, the results improve significantly. This is especially important for a safe and stable transition from rotary-wing to fixed-wing flight, which should be done quickly. The authors also propose a control allocation strategy with MPC algorithm to exploit the thrust and control inputs of both rotary-wing and fixed-wing systems for the transition phase. As the control system is over-actuated, the proposed algorithm distributes the control signal among the actuators better than the MPC alone. The numerical results show that the flight trajectory is also improved.Originality/valueThe research background is reviewed in the introduction section. The other sections are originally developed in this paper to the best of the authors’ knowledge.