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Book Effects of Winglets on the Drag of a Low Aspect Ratio Configuration

Download or read book Effects of Winglets on the Drag of a Low Aspect Ratio Configuration written by Leigh Ann Smith and published by . This book was released on 1996 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Effects of Winglets on the Drag of a Low Aspect Ratio Configuration

Download or read book Effects of Winglets on the Drag of a Low Aspect Ratio Configuration written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-06 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: A wind-tunnel investigation has been performed to determine the effect of winglets on the induced drag of a low-aspect-ratio wing configuration at Mach numbers between 0.30 and 0.85 and a nominal angle-of-attack range from -2 deg to 20 deg. Results of the tests at the cruise lift coefficient showed significant increases in lift-drag ratio for the winglet configuration relative to a wing-alone configuration designed for the same lift coefficient and Mach number. Further, even larger increases in lift-drag ratio were observed at lift coefficients above the design value at all Mach numbers tested. The addition of these winglets had a negligible effect on the static lateral-directional stability characteristics of the configuration. No tests were made to determine the effect of these winglets at supersonic Mach numbers, where increases in drag caused by winglets might be more significant. Computational analyses were also performed for the two configurations studied. Linear and small-disturbance formulations were used. The codes were found to give reasonable performance estimates sufficient for predicting changes of this magnitude. Smith, Leigh Ann and Campbell, Richard L. Langley Research Center...

Book Theoretical numerical Study of Feasibility of Use of Winglets on Low Aspect Ratio Wings at Subsonic and Transonic Mach Numbers to Reduce Drag

Download or read book Theoretical numerical Study of Feasibility of Use of Winglets on Low Aspect Ratio Wings at Subsonic and Transonic Mach Numbers to Reduce Drag written by John M. Kuhlman and published by . This book was released on 1988 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: A numerical design study was conducted to assess the drag reduction potential of winglets installed on a series of low aspect ratio wings at a design point of M=0.8, C sub L=0.3. Wing-winglet and wing-alone design geometries were obtained for wings of aspect ratios between 1.75 and 2.67, having leading edge sweep angles between 45 and 60 deg. Winglet length was fixed at 15% of wing semispan. To assess the relative performance between wing-winglet and wing-alone configurations, the PPW nonlinear extended small disturbance potential flow code was utilized. This model has proven to yield plausible transonic flow field simulations for the series of low aspect ratio configurations selected. Predicted decreases in pressure drag coefficient for the wing-winglet configurations relative to the corresponding wing-alone planform are about 15% at the design point. Predicted decreases in wing-winglet total drag coefficient are about 12%, relative to the corresponding wing-alone design. Longer winglets (25% of the wing semispan) yielded decreases in the pressure drag of up to 22% and total drag of up to 16.4%. These predicted drag coefficient reductions are comparable to reductions already demonstrated by actual winglet designs installed on higher aspect ratio transport type aircraft.

Book L D Ratio Improvement Using Dual winglets in Variable Aspect Ratio Rectangular Wings

Download or read book L D Ratio Improvement Using Dual winglets in Variable Aspect Ratio Rectangular Wings written by Tetsuya Jin and published by . This book was released on 2015 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Winglets have been used to reduce induced drag of finite aspect ratio wings. Its main role is to remove induced vortices effects from main wing. A lot of winglet models have been researched to reduce induced drag but they are not the best. It is known that induced drag increases when aspect ratio is low and lift coefficient is high. This research addresses multi winglets to improve overall lift to drag ratio. Computational fluid dynamics simulation is used to find the best winglets configuration that improve lift to drag ratio in the actual flight condition. The maximum percentage of improvement of lift to drag ratio is found to be 28% with respect to without winglets. This configuration is further subjected to different angles of attack and speeds to determine the overall performance. Scaled down model to fit to wind tunnel experiment are performed to compare the aerodynamic parameters between the computation and actual wind tunnel test. As a result, maximum improvement of lift to drag ratio is 27% and lift curve slope confirmed the experimental results. In addition, visualizing wing tip vortices by flow visualization and velocity distribution are performed to describe flow physics. It is concluded that the new winglets successfully reduced the induced vortex effects evidenced by both flow visualization and pitot static tube wake velocity distribution.

Book The Effects of Winglets on Low Aspect Ratio Wings at Supersonic Mach Numbers

Download or read book The Effects of Winglets on Low Aspect Ratio Wings at Supersonic Mach Numbers written by James A. Keenan and published by . This book was released on 1991 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Theoretical Numerical Study of Feasibility of Use of Winglets on Low Aspect Ration Wings at Subsonic and Transonic Mach Numbers to Reduce Drag

Download or read book Theoretical Numerical Study of Feasibility of Use of Winglets on Low Aspect Ration Wings at Subsonic and Transonic Mach Numbers to Reduce Drag written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-17 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: A numerical design study was conducted to assess the drag reduction potential of winglets installed on a series of low aspect ratio wings at a design point of M=0.8, C sub L=0.3. Wing-winglet and wing-alone design geometries were obtained for wings of aspect ratios between 1.75 and 2.67, having leading edge sweep angles between 45 and 60 deg. Winglet length was fixed at 15% of wing semispan. To assess the relative performance between wing-winglet and wing-alone configurations, the PPW nonlinear extended small disturbance potential flow code was utilized. This model has proven to yield plausible transonic flow field simulations for the series of low aspect ratio configurations selected. Predicted decreases in pressure drag coefficient for the wing-winglet configurations relative to the corresponding wing-alone planform are about 15% at the design point. Predicted decreases in wing-winglet total drag coefficient are about 12%, relative to the corresponding wing-alone design. Longer winglets (25% of the wing semispan) yielded decreases in the pressure drag of up to 22% and total drag of up to 16.4%. These predicted drag coefficient reductions are comparable to reductions already demonstrated by actual winglet designs installed on higher aspect ratio transport type aircraft. Kuhlman, John M. and Liaw, Paul and Cerney, Michael J. Unspecified Center...

Book Computational Study of Induced Drag Reduction Due to Winglets on Low Aspect Ratio Wings at Transonic and Supersonic Speeds

Download or read book Computational Study of Induced Drag Reduction Due to Winglets on Low Aspect Ratio Wings at Transonic and Supersonic Speeds written by Christopher Keith Brown and published by . This book was released on 1990 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book A Note on the Drag Due to Lift of Rectangular Wings of Low Aspect

Download or read book A Note on the Drag Due to Lift of Rectangular Wings of Low Aspect written by Edward C. Polhamus and published by . This book was released on 1955 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Methods of estimating the induced drag of low-aspect-ratio wings are discussed and compared with experiment. The profile drag due to lift is also discussed and a method is developed which relates the effect of aspect ratio on the profile drag due to lift to an "effective" two-dimensional lift coefficient. A simple expression for this effective two-dimensional lift coefficient in terms of the aspect ratio is derived and used to correlate experimental values of profile drag due to lift for rectangular wings in the low-aspect-ratio range. A method of utilizing two-dimensional test results, by means of this effective two-dimensional lift coefficient, to estimate the profile drag due to lift of low-aspect-ratio wings is briefly discussed.

Book Assessment of Wingtip Modifications to Increase the Fuel Efficiency of Air Force Aircraft

Download or read book Assessment of Wingtip Modifications to Increase the Fuel Efficiency of Air Force Aircraft written by National Research Council and published by National Academies Press. This book was released on 2007-08-06 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: The high cost of aviation fuel has resulted in increased attention by Congress and the Air Force on improving military aircraft fuel efficiency. One action considered is modification of the aircraft's wingtip by installing, for example, winglets to reduce drag. While common on commercial aircraft, such modifications have been less so on military aircraft. In an attempt to encourage greater Air Force use in this area, Congress, in H. Rept. 109-452, directed the Air Force to provide a report examining the feasibility of modifying its aircraft with winglets. To assist in this effort, the Air Force asked the NRC to evaluate its aircraft inventory and identify those aircraft that may be good candidates for winglet modifications. This reportâ€"which considers other wingtip modifications in addition to wingletsâ€"presents a review of wingtip modifications; an examination of previous analyses and experience with such modifications; and an assessment of wingtip modifications for various Air Force aircraft and potential investment strategies.

Book Reduction of Drag Due to Lift at Supersonic Speeds

Download or read book Reduction of Drag Due to Lift at Supersonic Speeds written by Douglas Aircraft Company and published by . This book was released on 1955 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: $EVERAL TOPICS RELATING TO THE REDUCTION OF DRAG DUE TO LIFT AT SUPERSONIC SPEEDS ARE DISCUSSED. The distribution of camber for optimial loading of diamond planform wings and some low drag geometries for rectangular wings are determined. It appears that substantial drag reduction, through the use of spanwise distribution of camber, may be achieved only for low reduced aspect ratios, M2-1 AR. The distribution of lift throughout volumes of prescribed shape is considered and some optimum distributions found for certain cases. It is shown that optimum spatial distributions of lift arc generally not unique. The possibility of using biplanes is explored and it is concluded that for non-interfering biplanes (wings acting as isolated monoplanes) there is an inherent structural advantage which is the result of a scale effect for geometrically similar structures The preacnt status of means for drag reduction is surveyed and the direction for further study indicated.

Book On the Induced Drag of Thin Plane Delta Wings

Download or read book On the Induced Drag of Thin Plane Delta Wings written by Sven-Olof Ridder and published by . This book was released on 1971 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: