Download or read book Development of a Method for Predicting the Performance and Stresses of VTOL type Propellers written by Andrew Richard Trenka and published by . This book was released on 1966 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report presents a theoretical method which allows the prediction of performance and stress characteristics of a single VTOL-type of propeller-wing-nacelle combination operating in various flight conditions from hovering through transition and into axial flight. The method includes (1) the effects of a distorted wake, i. e., the effects of contraction and radial and axial velocity variations; (2) the effects of hovering close to the ground; (3) the interference effects from a nacelle and wing buried in the propeller slipstream. Also presented are experimental thrust and torque data. However, because of the insufficient accuracy of the experimental data collected, no definite evaluation of the model is made. (Author).

Download or read book Performance and Stresses Obtained on an Isolated VTOL type Propeller Operating in Hovering Transitional and Axial Flight written by Andrew R. Trenka and published by . This book was released on 1967 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental performance and blade stresses measured on a three-bladed VTOL-type propeller tested in free air are presented. The isolated propeller was tested over ranges of prop speed, forward velocity, blade angle setting, and thrust axis to free-stream angle. Correlation with a theoretical method of predicting propeller performance and blade stresses was made. It was found that when the propeller was operating in a flight condition for which the theory was developed, correlation between theory and experiment was good. When the propeller was operating in a flight condition where very small positive or negative effective angles of attack were encountered, correlation between theory and experiment was poor. (Author).

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1976 with total page 978 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Technical Abstract Bulletin written by and published by . This book was released on 1967 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government wide Index to Federal Research Development Reports written by and published by . This book was released on 1966-09 with total page 732 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Predictive Methods for the Dynamic Response of a Quad Tilt duct V STOL Aircraft in Transition written by Irving Carl Statler and published by . This book was released on 1970 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wakes of Lifting Propellers rotors in Ground Effect written by F. A. DuWaldt and published by . This book was released on 1966 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report presents the development of a wake model for a lifting propeller (rotor) in ground effect and the computational procedure used to determine the spacial distribution of wake vorticity and the induced velocity field accompanying that vorticity distribution. Sample calculations for a two-bladed rotor were carried out on an IBM 7044 computer. Locations of wake vortical elements and the associated induced velocities at selected field points are presented for advance ratios of 0, 0.02, 0.05, and 0.10 for an H/R (ratio of rotor height above ground to rotor radius) of 1.0. Also, a few results for a hovering case with H/R = 0.5 are presented. A calculated root-mean-square velocity map is compared with measured hovering data (time averaged) and good agreement is obtained in the outer half of the slipstream. The implications of computed results with respect to the flow field at a horizontal stabilizer or tail rotor are noted as examples of the use of the model. The wake vortex model used for these calculations is a distorted continuous helix emanating from each blade tip. (Author).

Download or read book U S Government Research Development Reports written by and published by . This book was released on 1969-05 with total page 928 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 1982 with total page 1018 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The National Union Catalogs 1963 written by and published by . This book was released on 1964 with total page 812 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book National Union Catalog written by and published by . This book was released on 1968 with total page 810 pages. Available in PDF, EPUB and Kindle. Book excerpt: Includes entries for maps and atlases.

Download or read book Government Reports Announcements written by and published by . This book was released on 1974-01-11 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book U S Government Research and Development Reports written by and published by . This book was released on 1969-04 with total page 1338 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bibliography of Scientific and Industrial Reports written by and published by . This book was released on 1971 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1981 with total page 1102 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Practical Methods for Predicting Periodic Propeller Loads written by Robert J. Boswell and published by . This book was released on 1983 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Improved Panel Method for the Prediction of Performance of Ducted Propellers written by Hongyang Fan and published by . This book was released on 2015 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: An improved perturbation potential based lower order panel method is applied to the three dimensional problems of flow around ducts and ducted propellers. One significant development of this method is the application of full wake alignment scheme in which the trailing vortex wake sheets of the blades are aligned with the local flow velocity by also considering the effects of duct and duct wake. A process of repaneling the duct is simultaneously introduced to improve the accuracy of evaluation of the method. The results from the improved wake model are compared with those from a simplified wake alignment scheme (PSF-2 type scheme). At the same time, full-blown RANS simulations of the three dimensional problem are conducted. The forces, i.e. thrust and torque on the propeller predicted by the present panel method under the improved wake alignment model show good agreement both with experimental measurements, a hybrid method developed by the Ocean Engineering Group of UT Austin, and the full blown RANS simulations. Moreover, detailed pressure distribution on the blades and duct are compared among the various methods. The interactive method which couples the lower order panel method with a two dimensional boundary layer solver through a wall transpiration model is also introduced. An assumption of two dimensional flow is made on the individual stations of a three dimensional geometries and the coupling is applied in a stripwise manner by including the interaction effects from other strips. The interactive method is then validated through the cases of bare ducts and ducted propellers. An important improvement is also made on the extension scheme for hydrofoils and propeller blades with blunt trailing edge. A more physical criterion has been established for determining the location of cut planes or the starting points of the extension. The extension scheme is applied to both axisymmetric problems and fully three dimensional problems. Correlations of results with experimental measurements and RANS simulations are presented.