The aerodynamic performance of Non-planar hex-rotors aircraft subjected the horizontal wind disturbanceLei yao1,2* Ma Chensong1 Feng Zhicheng1

The non-planar hex-rotor aircraft mentioned in this article can change its flight status by simply changing the tilt angle of the rotor. In this paper, mainly studied the best aerodynamic performance of a non-planar hex-rotor aircraft under the influence of horizontal wind (0m/s, 2.5m/s and 4m/s). Firstly, the rotation speed of the rotor is a fixed value (2200r/min) in the low-speed wind tunnel test, the horizontal wind speed and the tilt angle of the rotor are variable values, the thrust, power consumption and power loading(PL) values of the aircraft are obtained. Secondly, the computational fluid dynamics(CFD) method is used to simulate the aerodynamic performance of a non-planar hex-rotors aircraft when subjected to a horizontal wind to obtain the simulation results. Finally, comparing the experimental values and the simulation values, it is found that the horizontal speed has a greater impact on the thrust and power consumption of the non-planar hex-rotor aircraft. From the change of PL values, it is concluded that the horizontal wind speed is 0m/s, 2.5m/s, 4m/s, the best inclination angle is 10°, 30°and 50°, and the strongest anti-wind performance.

Stress Evaluation in the Blank Critical Region During Extrusion of the Pipe Blank into the Hole

The study assessed the stress state of the pipe blank in the process of extrusion into the hole. A finite element formulation of the research problem with the setting of boundary conditions in displacements and surface loading conditions is presented. The calculation of the workpiece was carried out in an elastic formulation using the Nastran engineering analysis application. The assessment of the stress state in the critical region is presented in two approximations with a thickening of the grid in the stress focus area. Based on the results of the distribution of equivalent stresses, an assessment of the unevenness of the stressed state of the workpiece was carried out. The presented study is important because it allows us to predict the appearance of defects in the process of forming a pipe billet during extrusion into a hole, to evaluate the power loading mode.

Underwater noise of commercial vessels in Nusakambangan Strait and the relationship with distance

The existence of shipping activities can produce noise with certain characteristics as a main source of noise pollution in the waters. This research aimed to study the sound characteristics (frequency and sound pressure levels) of various type of commercial vessels crossing the Nusakambangan Strait, its relationship to the distance, and their potential impact to the marine biota. Noise frequency and sound pressure level were determined by spectral and envelope analysis from sound recording by hydrophone, while the type of vessel that produces noise and the distance from receiver were analyzed based on video recording. Relationship between frequency and sound pressure level to the distance were analyzed using simple linear regression. Results showed that frequency of noise is varied more clearly compared to the sound pressure level (1,7 – 20 kHz and 93.8 -117.8 dB re 1 μPa respectively) for each type of vessel (ro-ro ferry, small fishing boat, small ferry, tug boat and pilot boat) based on the size of the ship, engines type and power, loading capacity and vessels speed. Sound characteristics changed based on distance, where the frequency of sound increases (0.04 – 34.28 Hz.m-1) and different things for sound pressure level (0.04 – 0.11 dB dB re 1 μPa m-1). Estimated source level also differ from one ship to another (105 – 128 dB dB re 1 μPa). The existence of ship noise has the potential impacts on the presence of marine biota in these waters.

A design methodology for rotors of small multirotor vehicles

A model is presented for the aerodynamic performance prediction of fixed-pitch rotors for small unmanned aerial vehicles. The method uses a blade element momentum theory based approach that is formulated specifically for small rotors operating in hover and edgewise flight. In order to validate the model, a rotor test stand is used to measure the performance of a commercially available rotor for several inflow angles and advance ratios. The predictions agree with measurements for operating conditions excluding conditions with suspected vortex ring state. The model is incorporated into a numerical optimization scheme to demonstrate its potential as a design tool. Designs are presented that minimize the power loading for single- and multi-point operating conditions. The optimized designs have hyperbolic twist distributions, higher solidities, and operate at lower tip-speeds than existing designs. A potential flow based model is also presented to predict the wake interactions between multiple rotors in configuration.

A design methodology for rotors of small multirotor vehicles

A model is presented for the aerodynamic performance prediction of fixed-pitch rotors for small unmanned aerial vehicles. The method uses a blade element momentum theory based approach that is formulated specifically for small rotors operating in hover and edgewise flight. In order to validate the model, a rotor test stand is used to measure the performance of a commercially available rotor for several inflow angles and advance ratios. The predictions agree with measurements for operating conditions excluding conditions with suspected vortex ring state. The model is incorporated into a numerical optimization scheme to demonstrate its potential as a design tool. Designs are presented that minimize the power loading for single- and multi-point operating conditions. The optimized designs have hyperbolic twist distributions, higher solidities, and operate at lower tip-speeds than existing designs. A potential flow based model is also presented to predict the wake interactions between multiple rotors in configuration.

Design and Analysis of a Rocket-Deployed Flying-Wing UAV

This undergraduate paper demonstrates the design, analysis, and manufacturing of a rocket deployable electric powered experimental unmanned aerial vehicle. The design process begins with defining the volume and dimensions of the allocated payload space for the UAV in the rocket. These dimensions are given by the aerostructures sub team in the Ryerson Rocketry Club. The dimensions given were used to determine the best configuration for the mission. The wing loading, power loading and endurance of the UAV are obtained from the constrained payload volume in the rocket and the avionics system of the of the UAV. The wing area, UAV weight and power requirements were calculated based on the previously determined values. The power requirement determines the motor size and propeller configuration. Aerodynamics, stability, and control were based the selected airfoil and obtained wing area. After completing the design, foam, additive manufacturing, and composite layups were used to create prototypes of the UAV. These prototypes were used to iterate the aircraft and address any immediate changes. The chosen design is a foldable flying wing, once deployed from the rocket has a wingspan of 70 inches, an aspect ratio of 13.35 and a surface area of 367 in2 . A prototype was created to prove the design feasibility of the UAV. The prototype proved to function as planned, capable of gliding, powered flight, and takeoff.

Design and Analysis of a Rocket-Deployed Flying-Wing UAV

This undergraduate paper demonstrates the design, analysis, and manufacturing of a rocket deployable electric powered experimental unmanned aerial vehicle. The design process begins with defining the volume and dimensions of the allocated payload space for the UAV in the rocket. These dimensions are given by the aerostructures sub team in the Ryerson Rocketry Club. The dimensions given were used to determine the best configuration for the mission. The wing loading, power loading and endurance of the UAV are obtained from the constrained payload volume in the rocket and the avionics system of the of the UAV. The wing area, UAV weight and power requirements were calculated based on the previously determined values. The power requirement determines the motor size and propeller configuration. Aerodynamics, stability, and control were based the selected airfoil and obtained wing area. After completing the design, foam, additive manufacturing, and composite layups were used to create prototypes of the UAV. These prototypes were used to iterate the aircraft and address any immediate changes. The chosen design is a foldable flying wing, once deployed from the rocket has a wingspan of 70 inches, an aspect ratio of 13.35 and a surface area of 367 in2 . A prototype was created to prove the design feasibility of the UAV. The prototype proved to function as planned, capable of gliding, powered flight, and takeoff.