Download or read book Wind Tunnel Tests of Thin Airfoils Oscillating Near Stall Data report written by Lewis Gray and published by . This book was released on 1969 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wind Tunnel Tests of Thin Airfoils Oscillating Near Stall Volume Ii Data Report written by Lewis Gray and published by . This book was released on 1969 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report presents the actual computer data that resulted from the two-dimensional tests of thin airfoils oscillating near stall. An introduction provides a general background, and a set of tables forms an index to specific data. More than 200 pages of computer data are included.

Download or read book Wind Tunnel Tests of Thin Airfoils Oscillating Near Stall Volume I Summary and Evaluation of Results written by Lewis Gray and published by . This book was released on 1969 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report presents the results of an experimental investigation of rotor blade dynamic stall. Forces and moments in two-dimensional flow were determined for two thin airfoil sections (NACA 0006 and Vertol 13006-.7) usually considered in advanced helicopter rotor concepts by measuring differential pressure during oscillatory pitch motions. The Mach number, Reynolds number, and angle of attack prevailing in the retreating-blade stall region were investigated up to typical first-torsion mode natural frequencies. Pitch oscillation was shown to increase the angle of attack at which stall occurred, with a corresponding increase in maximum normal force. Hysteresis effects on the pitching moment response produced regions of negative aerodynamic damping in oscillations at mean angles of attack near the steady-flow stall values for all Mach numbers from 0.2 to 0.6. It is shown that dynamic stall effects are strongly related to the reduced frequency parameter. Significant evidence of compressibility effects appears only at Mach numbers higher than 0.4. At lower Mach numbers, the data indicate that the two effects of decreased Mach number and airfoil camber are fully comparable in terms of dynamic stall patterns and increase both the usable angle of attack and the maximum normal force. (Author) 25.

Download or read book Wind Tunnel Tests of Thin Airfoils Oscillating Near Stall written by Lewis Gray and published by . This book was released on 1969 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report presents the results of an experimental investigation of rotor blade dynamic stall. Forces and moments in two-dimensional flow were determined for two thin airfoil sections (NACA 0006 and Vertol 13006-.7) usually considered in advanced helicopter rotor concepts by measuring differential pressure during oscillatory pitch motions. The Mach number, Reynolds number, and angle of attack prevailing in the retreating-blade stall region were investigated up to typical first-torsion mode natural frequencies. Pitch oscillation was shown to increase the angle of attack at which stall occurred, with a corresponding increase in maximum normal force. Hysteresis effects on the pitching moment response produced regions of negative aerodynamic damping in oscillations at mean angles of attack near the steady-flow stall values for all Mach numbers from 0.2 to 0.6. It is shown that dynamic stall effects are strongly related to the reduced frequency parameter. Significant evidence of compressibility effects appears only at Mach numbers higher than 0.4. At lower Mach numbers, the data indicate that the two effects of decreased Mach number and airfoil camber are fully comparable in terms of dynamic stall patterns and increase both the usable angle of attack and the maximum normal force.

Download or read book Two dimensional Tests of Airfoils Oscillating Near Stall Volume Ii Data Report written by Lewis Gray and published by . This book was released on 1968 with total page 491 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report presents a discussion of the test facility, models, and data gathering and reduction system used in the tests of oscillating airfoils. It also contains the actual computer data that resulted from the wind tunnel tests of the airfoils. A set of tables provides a quick cross-reference between the various test factors and the page on which the data appear. (Author).

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 1969 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Two dimensional Tests of Airfoils Oscillating Near Stall Data report written by and published by . This book was released on 1968 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wind Tunnel Investigation of Airfoils Oscillating in Reverse Flow Volume II Data Rept written by Lewis Gray and published by . This book was released on 1970 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report presents the final computer-processed data that resulted from the two-dimensional wind tunnel tests of the Vertol 23010-1.58 airfoil oscillating in reverse flow. A set of tables provides a comprehensive index to more than 250 pages of computer data. This volume also includes a series of C sub N and C sub M versus angle-of-attack and time history data plots, presenting data supplementary to Volume I. (Author).

Download or read book Design and Analytical Study of a Rotor Airfoil written by L. U. Dadone and published by . This book was released on 1978 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamic Stall of Small Wind Systems written by Richard B. Noll and published by . This book was released on 1983 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Monthly Catalog of United States Government Publications written by United States. Superintendent of Documents and published by . This book was released on 1966 with total page 1320 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Monthly Catalog of United States Government Publications Cumulative Index written by United States. Superintendent of Documents and published by . This book was released on 1970 with total page 1348 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wind Tunnel Investigation of Airfoils Oscillating in Reverse Flow written by Lewis Gray and published by . This book was released on 1970 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Annual Index written by and published by . This book was released on 1969 with total page 1008 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Two dimensional Wind Tunnel Test of an Oscillating Rotor Airfoil Volume 1 written by L. U. Dadone and published by . This book was released on 1977 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analysis of Oscillatory Pressure Data Including Dynamic Stall Effects written by Franklin O. Carta and published by . This book was released on 1974 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: The dynamic stall phenomenon was examined in detail by analyzing an existing set of unsteady pressure data obtained on an airfoil oscillating in pitch. Most of the data were for sinusoidal oscillations which penetrated the stall region in varying degrees, and here the effort was concentrated on the chordwise propagation of pressure waves associated with the dynamic stall. It was found that this phenomenon could be quantified in terms of a pressure wave velocity which is consistently much less than free-stream velocity, and which varies directly with frequency. It was also found that even when the stall region has been deeply penetrated and a substantial dynamic stall occurs during the downstroke, stall recovery near minimum incidence will occur, followed by a potential flow behavior up to stall inception.