Wind Tunnel Test of A R.A.F.28 Aerofoil with Thurston Rotors

1934 ◽  
Vol 38 (278) ◽  
pp. 141-161
Author(s):  
A. S. Hartshorn ◽  
C. Callen
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Leading Edge ◽  
Lateral Stability ◽  
Primary Object ◽  
Wing Tips ◽  
Wing Tip

The suggestion has been put forward by Dr. A. P. Thurston that the characteristics of a wing can be considerably improved by adding self-starting rotors at or near the wing tips. It is claimed that by placing these on each wing near the leading edge improvements analogous to those of a slotted wing tip can be obtained together with slow landing characteristics. Previous experiments (1) have shown that rotors can give about the same degree of lateral stability as tip slots. The primary object of these experiments was to test the second assertion, and the criterion by which this should be judged was that the gliding angle should be as steep as possible for a given rate of descent.

An experimental parametric study on planar sheared wings tip devices for low-to-moderate aspect ratio wings

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Lourelay Moreira dos Santos ◽  
Guilherme Ferreira Gomes ◽  
Rogerio F. Coimbra
Keyword(s):  
Wind Tunnel ◽  
Aspect Ratio ◽  
Parametric Study ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Sweep Angle ◽  
Wind Tunnel Tests ◽  
Content Type ◽  
Wing Tips ◽  
Wing Tip

Purpose The purpose of this study is to investigate the aerodynamic characteristics of a low-to-moderate-aspect-ratio, tapered, untwisted, unswept wing, equipped of sheared wing tips. Design/methodology/approach In this work, wind tunnel tests were made to study the influence in aerodynamic characteristics over a typical low-to-moderate-aspect-ratio wing of a general aviation aircraft, equipped with sheared – swept and tapered planar – wing tips. An experimental parametric study of different wing tips was tested. Variations in its leading and trailing edge sweep angle as well as variations in wing tip taper ratio were considered. Sheared wing tips modify the flow pattern in the outboard region of the wing producing a vortex flow at the wing tip leading edge, enhancing lift at high angles of attack. Findings The induced drag is responsible for nearly 50% of aircraft total drag and can be reduced through modifications to the wing tip. Some wing tip models present complex geometries and many of them present benefits in particular flight conditions. Results have demonstrated that sweeping the wing tip leading edge between 60 and 65 degrees offers an increment in wing aerodynamic efficiency, especially at high lift conditions. However, results have demonstrated that moderate wing tip taper ratio (0.50) has better aerodynamic benefits than highly tapered wing tips (from 0.25 to 0.15), even with little less wing tip leading edge sweep angle (from 57 to 62 degrees). The moderate wing tip taper ratio (0.50) offers more wing area and wing span than the wings with highly tapered wing tips, for the same aspect ratio wing. Originality/value Although many studies have been reported on the aerodynamics of wing tips, most of them presented complex non-planar geometries and were developed for cruise flight in high subsonic regime (low lift coefficient). In this work, an exploration and parametric study through wind tunnel tests were made, to evaluate the influence in aerodynamic characteristics of a low-to-moderate-aspect-ratio, tapered, untwisted, unswept wing, equipped of sheared wing tips (wing tips highly swept and tapered).

Exploration on application of dredging thermal protection in the leading edge of the wing

2020 ◽  
Vol 34 (14n16) ◽  
pp. 2040105
Author(s):  
Xiao-Jun Zhu ◽  
Feng Li
Keyword(s):  
High Temperature ◽  
Wind Tunnel ◽  
Heat Pipe ◽  
Thermal Protection ◽  
Wind Tunnel Test ◽  
Leading Edge ◽  
Temperature Zone ◽  
Temperature Heat ◽  
Thermal Protection Structure ◽  
High Temperature Heat Pipe

Aiming at the severe aerodynamic heating problem in the leading edge of the hypersonic vehicle, in order to ensure the sharp shape of the leading edge of the wing, a dredging thermal protection structure is proposed, and the built-in high-temperature heat pipe structure is used to provide thermal protection for the leading edge of the wing. By means of numerical simulation and arc wind tunnel test, the dredging thermal protection structure of the leading edge of the wing is analyzed, and the thermal protection effect of the built-in high-temperature heat pipe is obtained. The numerical results show that under certain thermal conditions, the temperature at the leading edge of the wing decreases by 304 K, and the minimum temperature of the tail increases by 130 K. The heat flow is dredged from the high-temperature zone to the low-temperature zone, and the thermal load of the leading edge of the wing is weakened. The same result can be obtained by the arc wind tunnel test, which verifies the accuracy of the numerical method and the feasibility of the dredging thermal protection structure with high-temperature heat pipe embedded in the leading edge of the wing.

scholarly journals Wind Tunnel Test of the S814 Thick Root Airfoil

1996 ◽  
Vol 118 (4) ◽  
pp. 217-221 ◽  
Author(s):  
D. M. Somers ◽  
J. L. Tangler
Keyword(s):  
Wind Tunnel ◽  
Lift Coefficient ◽  
Wind Tunnel Test ◽  
Leading Edge ◽  
Reynolds Numbers ◽  
Rotor Blades ◽  
Roughness Effects ◽  
Root Region ◽  
University Of Technology ◽  
Thick Airfoil

The objective of this wind-tunnel test was to verify the predictions of the Eppler Airfoil Design and Analysis Code for a very thick airfoil having a high maximum lift coefficient designed to be largely insensitive to leading-edge roughness effects. The 24 percent thick S814 airfoil was designed with these characteristics to accommodate aerodynamic and structural considerations for the root region of a wind-turbine blade. In addition, the airfoil’s maximum lift-to-drag ratio was designed to occur at a high lift coefficient. To accomplish the objective, a two-dimensional wind tunnel test of the S814 thick root airfoil was conducted in January 1994 in the low-turbulence wind tunnel of the Delft University of Technology Low Speed Laboratory, The Netherlands. Data were obtained with transition free and transition fixed for Reynolds numbers of 0.7, 1.0, 1.5, 2.0, and 3.0 × 106. For the design Reynolds number of 1.5 × 106, the maximum lift coefficient with transition free is 1.32, which satisfies the design specification. However, this value is significantly lower than the predicted maximum lift coefficient of almost 1.6. With transition fixed at the leading edge, the maximum lift coefficient is 1.22. The small difference in maximum lift coefficient between the transition-free and transition-fixed conditions demonstrates the airfoil’s minimal sensitivity to roughness effects. The S814 root airfoil was designed to complement existing NREL low maximum-lift-coefficient tip-region airfoils for rotor blades 10 to 15 meters in length.

scholarly journals Experimental and Computational Analysis of Model–Support Interference in Low-Speed Wind-Tunnel Testing of Fuselage-Boundary-Layer Ingestion

2019 ◽  
Vol 304 ◽  
pp. 02020
Author(s):  
Biagio Della Corte ◽  
André A.V. Perpignan ◽  
Martijn van Sluis ◽  
Arvind Gangoli Rao
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Leading Edge ◽  
Horseshoe Vortex ◽  
Junction Flow ◽  
Tunnel Model ◽  
Aerodynamic Interaction ◽  
Support Interference ◽  
Model Support

Junction flow caused by the aerodynamic interaction between a wind-tunnel model and the support structure can largely influence the flowfield and hence the experimental results. This paper discusses a combined numerical and experimental study which was carried out to mitigate the model–support interference in a wind-tunnel test setup for the study of fuselage boundary-layer ingestion. The setup featured an axisymmetric fuselage mounted through a support beam, covered by a wing-shaped fairing. The junction flow appearing at the fuselage–fairing connection produced undesired flow distortions at the fuselage aft section, due to the formation of an horseshoe vortex structure at the fairing leading edge. Numerical and experimental analysis were performed with the aim of reducing the distortion intensity by improving the fairing design. Results show that modifying the leading-edge shape of the fairing effectively decreased the flowfield distortions. Moreover, the addition of a dummy fairing diametrically opposed to the first one was found to be beneficial due to the enhancement of the configuration symmetry.

scholarly journals The Effect of Rigging Angle on Longitudinal Direction Motion of Parafoil-Type Vehicle: Basic Stability Analysis and Wind Tunnel Test

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Takahiro Moriyoshi ◽  
Kazuhiko Yamada ◽  
Hiroyuki Nishida
Keyword(s):  
Stability Analysis ◽  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Leading Edge ◽  
Longitudinal Direction ◽  
Aerodynamic Characteristics ◽  
Vehicle Stability ◽  
Flexible Wings ◽  
Allowable Range ◽  
Analytical Approaches

The paraglider, a flexible flying vehicle, consists of a parafoil with flexible wings, suspension lines, and a suspended payload. At this time, the suspension lines have several parameters to be designed. Above all, a parameter called Rigging Angle (RA) is sensitive to the aerodynamic characteristics of a paraglider during flight. In this study, the effect of RA is clarified using the two-dimensional stability analysis and a wind tunnel test. The mechanisms about the parafoil-type vehicle stability are clarified through the experimental and analytical approaches as follows. The RA has an allowable range for a stable flight. When the RA is set out of the range, the parafoil cannot fly stably. Furthermore, the behavior of the parafoil wing in the case of lower RA than the allowable range is different from the case of higher RA. The parafoil collapses from the leading edge of the canopy and cannot glide in the case of lower RA.

scholarly journals GPC-Based Gust Response Alleviation for Aircraft Model Adapting to Various Flow Velocities in the Wind Tunnel

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Yuting Dai ◽  
Chao Yang
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Open Loop ◽  
Ar Model ◽  
Aircraft Model ◽  
Input Amplitude ◽  
Aeroelastic Model ◽  
Wing Tip ◽  
Gust Response ◽  
Flow Velocities

A unified autoregressive (AR) model is identified, based on the wind tunnel test data of open-loop gust response for an aircraft model. The identified AR model can be adapted to various flow velocities in the wind tunnel test. Due to the lack of discrete gust input measurement, a second-order polynomial function is used to approximate the gust input amplitude by flow velocity. Afterwards, with the identified online aeroelastic model, the modified generalized predictive control (GPC) theory is applied to alleviate wing tip acceleration induced by sinusoidal gust. Finally, the alleviation effects of gust response at different flow velocities are estimated based on the comparison of simulated closed-loop acceleration with experimental open-loop one. The comparison indicates that, after gust response alleviation, the wing tip acceleration can be reduced up to 20% at the tested velocities ranging from 12 m/s to 24 m/s. Demonstratively, the unified control law can be adapted to varying wind tunnel velocities and gust frequencies. It does not need to be altered at different test conditions, which will save the idle time.

scholarly journals Design, Manufacturing, and Testing of a New Concept for a Morphing Leading Edge using a Subsonic Blow Down Wind Tunnel

Biomimetics ◽  
2019 ◽  
Vol 4 (4) ◽  
pp. 76
Author(s):  
David Communier ◽  
Franck Le Besnerais ◽  
Ruxandra Mihaela Botez ◽  
Tony Wong
Keyword(s):  
Wind Tunnel ◽  
Lift Coefficient ◽  
Wind Tunnel Test ◽  
Leading Edge ◽  
Test Results ◽  
Deformation Method ◽  
Blow Down ◽  
Aerial Vehicle ◽  
Compliance Mechanism ◽  
Stall Angle

This paper presents the design and wind tunnel test results of a wing including a morphing leading edge for a medium unmanned aerial vehicle with a maximum wingspan of 5 m. The design of the morphing leading edge system is part of research on the design of a morphing camber system. The concept presented here has the advantage of being simple to manufacture (wooden construction) and light for the structure of the wing (compliance mechanism). The morphing leading edge prototype demonstrates the possibility of modifying the stall angle of the wing. In addition, the modification of the stall angle is performed without affecting the slope of the lift coefficient. This prototype is designed to validate the functionality of the deformation method applied to the leading edge of the wing. The mechanism can be further optimized in terms of shape and material to obtain a greater deformation of the leading edge, and, thus, to have a higher impact on the increase of the stall angle than the first prototype of the morphing leading edge presented in this paper.

scholarly journals Application of the HPCMP CREATETM-AV Kestrel to an Integrated Propeller Prediction

Aerospace ◽  
2020 ◽  
Vol 7 (12) ◽  
pp. 177
Author(s):  
Pooneh Aref ◽  
Mehdi Ghoreyshi ◽  
Adam Jirasek ◽  
Jürgen Seidel
Keyword(s):  
Experimental Data ◽  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Test Case ◽  
Simulation Tools ◽  
Electric Aircraft ◽  
Computational Resources ◽  
Adaptive Cartesian Grid ◽  
Low Speed Wind Tunnel ◽  
Wing Tip

This article presents the results of a computational investigation of an integrated propeller test case using the HPCMP CREATETM-AV Kestrel simulation tools. There is a renewed interest in propeller-driven aircraft for unmanned aerial vehicles, electric aircraft, and flying taxies. Computational resources can significantly accelerate the generation of aerodynamic models for these vehicles and reduce the development cost if the prediction tools can accurately predict the aircraft/propeller aerodynamic interactions. Unfortunately, limited propeller experimental data are available to validate computational methods. An American Institute of Aeronautics and Astronautics (AIAA) workshop was therefore established to address this problem. The objective of this workshop was to generate an open access-powered wind tunnel test database for computational validation of propeller effects on the wing aerodynamics, specifically for wing-tip-mounted propellers. The propeller selected for the workshop has four blades and a diameter of 16.2 in. The wing has a root and tip chord of 11.6 and 8.6 in, respectively. Two different simulation approaches were used: one using a single grid including wind tunnel walls and the second using a subset grid overset to an adaptive Cartesian grid that fills the space between the near-body grid and wind tunnel walls. The predictions of both approaches have been compared with available experimental data from the Lockheed Martin low-speed wind tunnel to investigate the grid resolution required for accurate prediction of flowfield data. The results show a good agreement for all tested conditions. The measured and predicted data show that wing aerodynamic performance is improved by the spinning tip-mounted propeller.

Wind Tunnel Test of Effect of Sound-Absorbing Material on Lift of Two-Element Airfoil

2013 ◽  
Vol 830 ◽  
pp. 17-23
Author(s):  
Yong Wei Gao ◽  
Qi Liang Zhu ◽  
Long Wang
Keyword(s):  
Wind Tunnel ◽  
High Frequency ◽  
Lift Coefficient ◽  
Wind Tunnel Test ◽  
Low Frequency ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Fluctuating Pressure ◽  
Flow Parameters ◽  
Absorbing Material

The flow parameters of fluctuating pressure and fluctuating velocity in the gap can be changed by the porous absorption material on the leading edge of upper surface of the flap of multi-element airfoil (GAW-1),and the aerodynamic characteristics is also altered. Experiment was conducted in the NF-3 wind tunnel. It turns out that porous absorption material has a significant effect on fluctuating velocity (i.e. turbulent kinetic energy), and the lift coefficient drops when fluctuating velocity increases ; but the influence on RMS of fluctuating pressure on upper surface is not obvious; the average speed in gap is reduced. The PSD of fluctuating pressure and fluctuating velocity show that low-frequency signal has a more obvious influence on lift of multi-element airfoils than high-frequency.

Four Prop Tilt Wing with Leading Edge BLC: Results of Semi-Span Wind Tunnel Test

1970 ◽  
Author(s):  
Charles E. Kolesar ◽  
George Kassianides ◽  
Joyce Andrews
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Leading Edge
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