Ying-Jie Guan and Yong-Ping Li
To solve the shortcomings of existed search and rescue drones, search and rescue the trapped people trapped in earthquake ruins, underwater and avalanches quickly and accurately…
Abstract
Purpose
To solve the shortcomings of existed search and rescue drones, search and rescue the trapped people trapped in earthquake ruins, underwater and avalanches quickly and accurately, this paper aims to propose a four-axis eight-rotor rescue unmanned aerial vehicle (UAV) which can carry a radar life detector. As the design of propeller is the key to the design of UAV, this paper mainly designs the propeller of the UAV at the present stage.
Design/methodology/approach
Based on the actual working conditions of UAVs, this paper preliminarily estimated the load of UAVs and the diameters of propellers and designed the main parameters of propellers according to the leaf element theory and momentum theory. Based on the low Reynolds number airfoil, this paper selected the airfoil with high lift drag ratio from the commonly used low Reynolds number airfoils. The chord length and twist angle of propeller blades were calculated according to the Wilson method and the maximum wind energy utilization coefficient and were optimized by the Asymptotic exponential function. The aerodynamic characteristics of the designed single propeller and coaxial propeller under different installation pitch angles and different installation distances were analyzed.
Findings
The results showed that the design of coaxial twin propellers can increase the load capacity by about 1.5 times without increasing the propeller diameter. When the installation distance between the two propellers was 8 cm and the tilt angle was 15° counterclockwise, the aerodynamic characteristics of the coaxial propeller were optimal.
Originality/value
The novelty of this work came from the conceptual design of the new rescue UAV and its numerical optimization using the Wilson method combined with the maximum wind energy utilization factor and the exponential function. The aerodynamic characteristics of the common shaft propeller were analyzed under different mounting angles and different mounting distances.
Details
Keywords
Ying-Jie Guan, Yong-Ping Li and Peng Zeng
To solve the problems of short battery life and low transportation safety of logistics drones, this paper aims to propose a design of logistics unmanned aerial vehicles (UAV) wing…
Abstract
Purpose
To solve the problems of short battery life and low transportation safety of logistics drones, this paper aims to propose a design of logistics unmanned aerial vehicles (UAV) wing with a composite ducted rotor, which combines fixed wing and rotary-wing.
Design/methodology/approach
This UAV adopts tiltable ducted rotor combined with fixed wing, which has the characteristics of fast flight speed, large carrying capacity and long endurance. At the same time, it has the hovering and vertical take-off and landing capabilities of the rotary-wing UAV. In addition, aerodynamic simulation analysis of the composite model with a fixed wing and a ducted rotor was carried out, and the aerodynamic influence of the composite model on the UAV was analyzed under different speeds, fixed wing angles of attack and ducted rotor speeds.
Findings
The results were as follows: when the speed of the ducted rotor is 2,500 rpm, CL and K both reach maximum values. But when the speed exceeds 3,000 rpm, the lift will decrease; when the angle of attack of the fixed wing is 10° and the rotational speed of the ducted rotor is about 3,000 rpm, the aerodynamic characteristics of the wing are better.
Originality/value
The novelty of this work comes from a composite wing design of a fixed wing combined with a tiltable ducted rotor applied to the logistics UAVs, and the aerodynamic characteristics of the design wing are analyzed.
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Keywords
Jie Ying Chua, Ryan Foo, Kim Hock Tan and Kum Fai Yuen
This study aims to study the resilience of the maritime industry by analyzing the impacts of COVID-19 on the maritime industry, in particular, on the shipping management aspect…
Abstract
Purpose
This study aims to study the resilience of the maritime industry by analyzing the impacts of COVID-19 on the maritime industry, in particular, on the shipping management aspect and offshore sector, investigate the effectiveness of current solutions and recommend future solutions for the industry to reduce or mitigate the negative impacts.
Design/methodology/approach
In order to better appreciate resilience in the maritime industry, the study conducted secondary research and semi-structured online interviews to (1) identify the impacts of COVID-19 on the shipping management and offshore sector, (2) analyze the effectiveness of current solutions and (3) provide some strategies to enhance the effectiveness of the current measures.
Findings
he results are congruent with existing literature which indicate that the pandemic has negatively affected the global economy, changed the global trade network and contributed to the sharp decline in demand for oil. In response to the pandemic, governments have implemented safety and health-related measures such as lockdown, safe-distancing and travel restrictions. Often, measures differ from countries to countries and these non-standardized and changing regulations further increase the challenges faced by the industry. From the shipping management perspective, the industry experienced issues such as crew changing, trade contraction and the expiration of shipping certificates, which supported and validated current research. Meanwhile, the offshore industry is challenged by the increasing market volatility and uncertainty, increasing need to source for alternative fuels and the declining oil exploration activities. Current strategies adopted by shipping management companies include crew change management, capacity management and the extension of ship certificates, whereas offshore industry chose to collaborate with oil majors.
Research limitations/implications
By identifying the impacts and challenges and studying the effectiveness of solutions adopted by the maritime industry, this paper allows maritime industry stakeholders and policymakers to develop strategies to mitigate the effects of the global health crisis and strengthen the resilience of the industry. However, as the pandemic continues to develop and evolve, strategies need to be reviewed continuously in response to the changing situations.
Originality/value
This research analyses the impacts and solutions in response to the COVID-19 pandemic, which contributes to the development and formulation of strategies to strengthen the resilience of maritime transport.