Search Results (4)

The presented study demonstrates that UAVs can be flown with a morphing wing to develop essential aerodynamic efficiency without a tail structure, which decides the operational cost and flight safety. The mechanical control for morphing is discussed, where the system design, simulation, and experimental realization of ±15° SDOF sweep motion for a 7 kg eVTOL wing are detailed. The methodology, developed through a mathematical modeling of the mechanism’s kinematics and dynamics, is explained using Denavit–Hartenberg (D-H) convention, Lagrangian mechanics, and Euler–Lagrangian equations. The simulation and MBD analyses were performed in MATLAB R2021 and by Altair Motion Solve, respectively. The experiment was conducted on a dedicated test rig with two wing variants fitted with IMUs and an autopilot. The results from various methods were analyzed and experimentally compared to provide an accurate insight into the system’s design, modeling, and performance of the sweep morphing wing. The theoretical calculations by the mathematical model were compared with the test results. The sweep requirement is essential for eVTOL to have long endurance and multi-mission capabilities. Therefore, the developed sweep morphing mechanism is very useful, meeting such a demand. However, the results for three-dimensional morphing, operating sweep, pitch, and roll together are also presented, for the sake of completeness. Full article

The article reviews autogiros, concentrating on their flight history, development, application, flight principle, components, and advantages over other aircraft. Firstly, the history of autogiros is presented, focusing on breakthrough inventions and clarifying their significance for overall rotorcraft development. Then, contemporary scientific research on the autogiro is reviewed in detail, and the available research gap is determined. The flight principle and technical fundamentals of autogiros are also briefly discussed, and a comparison between autogiros, helicopters, and fixed-wing aircraft is performed. Autogiros’ applications for civil, military, and mixed purposes are pointed out and schematically presented. The main part of the article comprises an overview of the different components and systems in the structure of the reviewed aircraft, including the main rotor, propeller, engine, cockpit, and others. Additionally, a comprehensive classification mostly concerning contemporary and homologated autogiros is described and schematically presented. Experimental and compound gyroplane designs are also examined and marked in the classification. The aircraft are categorized depending on the main structure type, mast availability, number of seats, number of rotors and rotor blades, rotor and mast position, propeller and tail type and position, pre-rotator type, and power source. The idea of different autogiro variants presented in the classification is enhanced with visual examples. This work is an addition to the efforts of promoting autogiros and research on them. It offers complete information regarding the aircraft and could serve as a kind of starting point for engineers in the design process of such types of flying machines. Full article

This study proposes a computational fluid dynamics and computational structure dynamics (CFD/CSD) coupled method for calculating the buffet response of a variant tail wing. The large-scale separated flow in the buffet is simulated by the detached vortex approach, vibration deformation of the tail wing is solved by the dynamic mesh generation technique, and structural modeling is based on the mode method. The aerodynamic elastic coupling is calculated through the cyclic iteration of aerodynamics and the structural solution in the time domain. We verify the correctness of the proposed method through a typical delta wing calculation case, further simulate the buffet response of a variant tail wing in maneuver state, and finally realize buffet mitigation using an active excitation method. Overall, this study can provide an important reference for the design of variant-tailed aircraft. Full article

Life on Venus Expedition (LOVE) Bugs are a proposed family of miniature, featherlight probes for exploring and sensing the Venusian atmosphere. The Bugs carry tiny ThumbSat femtosatellite buses and instruments beneath balloons or flexible parawings. They are designed to descend from 68 to 45 km altitude over several hours because this part of the atmosphere appears to be most welcoming to life as we know it, according to the Venus Life Finder Mission Study. The parawing option is the subject of this work. In order to fit in with larger probe missions, the LOVE-Bug concept is opportunistic. One anticipated opportunity is to be ejected when a “mother probe” needs to deploy a drogue chute for stabilisation through the transonic regime. This work developed an analogy for such a dramatic Venusian ejection by dropping from a high-altitude balloon in Earth’s stratosphere. By packaging the payload in a small-diameter low-drag capsule and dropping from 28 km, the vehicle accelerates to supersonic velocity at around 18 km, where the wing is ejected and deployed. A variant of the NASA ParaWing was created by incorporating a drag tail to help to stabilise the wing at extremely high and low velocities. Design, simulation, building, and testing work was carried out, and two flights were flown. The second flight demonstrated successful deployment of the wing in representative Venusian entry conditions. Both flights demonstrated that the ThumbSat performed as required in “space”-type conditions. Recommendations for future work, to qualify the LOVE-Bugs for operation on Venus, are presented. Full article