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 Potential Flow about Three dimensional Streamlined Lifting Configurations written by J. Michael Summa and published by . This book was released on 1974 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: A numerical method is developed and successfully applied which is believed capable of converging to the exact calculation of three-dimensional lifting potential flows, including cases of unsteady motion. The principal current limitation on its precision is restricted funds for computation. The exact body surface boundary conditions are enforced, and all wake surfaces are unconstrained -- allowed to move with the local velocity field. The assumptions made in the theoretical model are that the fluids is ideal (incompressible and inviscid) and that no separation may take place.

Download or read book Development and Application of a Method for Predicting Rotor Free Wake Positions and Resulting Rotor Blade Air Loads written by S. Gene Sadler and published by . This book was released on 1971 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rotor wake geometries are predicted by a process similar to the startup of a rotor in a free stream. An array of discrete trailing and shed vortices is generated with vortex strengths corresponding to stepwise radial and azimuthal blade circulations. The array of shed and trailing vortices is limited to an arbitrary number of azimuthal steps behind each blade. The remainder of the wake model of each blade is an arbitrary number of trailing vortices. Vortex element end points were allowed to be transported by the resultant velocity of the free stream and vortex-induced velocities. Wake geometry, wake flow, and wake-induced velocity influence coefficients are generated by this program for use in the blade loads portion of the calculations. Blade loads computations include the effects of nonuniform inflow due to a free wake, nonlinear airfoil characteristics, and response of flexible blades to the applied loads. Computed wake flows and blade loads are compared with experimentally measured data. Predicted blade loads, response and shears and moments are obtained for a model rotor system having two independent rotors. The effects of advance ratio, vertical separation of rotors, different blade radius ratios, and different azimuthal spacing of the blades of one rotor with respect to the other are investigated.