Download or read book PROPELLER BLADE VARIATION EXPERIMENTS written by S. SLUTSKY and published by . This book was released on 1961 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental program was carried out to determine the mode shapes and frequencies of a model of a typical naval propeller. The purpose of this program is to make available detailed relevant data to be used for evaluating the results of a parallel theoretical and numerical program of vibration and stress analysis of practical naval propellers. Tests carried out with both piezoelectric and capacitance probes gave practically identical results which indicated the necessity of further extension of the numerical program, and, in particular, a large increase in the number of degrees of freedom used. It was also noted that interblade coupling through the hub produces a splitting of the single blade frequencies into several frequencies (theoretically four) with a maximum separation (in air) of about 10%. (Author).
Download or read book Propeller Blade Stall Flutter Investigation Presentation of experimental data and summary of analytical work written by William Gordon Brady and published by . This book was released on 1958 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Spindle Torque and Open water Performance of Two Skewed Controllable pitch Propellers written by Robert J. Boswell and published by . This book was released on 1975 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental results are presented on the spindle torque and open-water performance of two skewed controllable-pitch propellers. Both propellers have radial distributions of skew specified so that the section midchord is forward of the spindle axis at the inner radii and aft of the spindle axis at the outer radii. One propeller has no rake and the other has substantial forward rake. The experiments were conducted at steady conditions in uniform flow in a towing basin over a range of positive and negative pitch ratios and a range of positive and negative advance coefficients so that the complete maneuvering envelope of the ship was simulated in a quasi-steady manner. The experimental open-water performance was correlated with calculated values based on a least-squares fit to previous systematic experimental data.
Download or read book Experimental Unsteady and Mean Loads on a CP Propeller Blade on a Model of the FF 1088 for Simulated Modes of Operation written by Robert J. Boswell and published by . This book was released on 1976 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments are described in which the mean and unsteady loads were measured on a single blade of a model of the controllable-pitch propeller on the FF-1088. The experiments were conducted behind a model of the FF-1088 hull under steady ahead operation, hull pitching motions, simulated crash ahead maneuvers, and simulated crash astern maneuvers. The experimental techniques are outlined and the dynamometer and data analysis system described. The results show that the circumferential variation of all measured components of blade loading is primarily a once-per-revolution variation, with maximum and minimum values occurring near the angular positions in which the spindle axis is horizontal. For sinusoidal pitching of the model hull with amplitude of 2 deg and frequency of 0.8 Hz, the peak-to-peak circumferential variation of measured forces and moments increased by a minimum of 50 percent over the values without hull pitching. For simulated operation during a crash ahead or crash astern maneuver, the circumferential variation of measured forces and moments varied approximately as the product of ship speed and propeller rotational speed, and was a function of propeller pitch. At no time during the simulated crash ahead or crash astern maneuvers were the circumferential variations of loads as large as during steady ahead operation. For steady ahead operation, circumferential variation of loading determined from the model experiments agreed fairly well with full-scale data, but was substantially larger than the theoretically calculated values. (Author).
Download or read book Marine Propellers and Propulsion written by John Carlton and published by Butterworth-Heinemann. This book was released on 2012-10-30 with total page 539 pages. Available in PDF, EPUB and Kindle. Book excerpt: The early development of the screw propeller. Propeller geometry. The propeller environment. The ship wake field, propeller performance characteristics.
Download or read book Wind tunnel Vibration Tests of a Four blade Single rotating Pusher Propeller written by Mason F. Miller and published by . This book was released on 1943 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summary: Vibration tests of a four-blade single-rotating propeller operating in a simulated pusher condition were performed because the combination of wake and downwash behind a wing was expected to provide serious excitation for reactionless vibrations of propellers with four or more blades. The tests were conducted in the LMAL 16-foot high-speed tunnel with a wing mounted at thrust-axis level ahead of the propeller; the blade sections at three-fourths the propeller radius operated at approximately twice their chords behind the trailing edge of the tapered wing at their closet position. Measurements of propeller vibratory stress were made for various airspeeds, engine speeds, and engine powers.
Download or read book Methodical Experiments with Models of Single screw Merchant Ships written by Frederick Henry Todd and published by . This book was released on 1963 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Performance and Steering Characteristics of Cycloidal Propellers written by N. L. Ficken and published by . This book was released on 1969 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report presents performance and steering characteristics of cycloidal propellers obtained from model tests for a series of cycloidal motions with various pitch ratios. Most of the results presented are for a six-bladed cycloidal propeller. Some performance characteristic curves obtained for a propeller with two and three blades are also included for comparison. (Author).
Download or read book Wind tunnel Tests of Dual rotating Propellers with Systematic Differences in Number of Blades Blade Setting and Rotational Speed of Front and Rear Propellers written by W. H. Gray and published by . This book was released on 1944 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summary: The advent of dual-rotating propellers has created a need for information concerning the effect of the number of blades of the front and rear propellers, relative rotational speeds, and small changes in the blade angles of the rear propeller. Results of aerodynamic tests of seven-blade propellers, which were considered as a possible arrangement to avoid vibration difficulties, are presented herein. Variations of relative blade angle and rotational speeds of the front and rear components of a six-blade dual-rotating propeller were also investigated. The test program was an extension of previous work on dual-rotating propellers at the NACA propeller-research tunnel; the propeller blades and test body were those used in the previous tests. The results indicated that envelope efficiencies of a seven-blade propeller with three blades in the front hub and four in the rear were form 0 to 1 1/2 percent lower than envelope efficiencies for the six-blade dual-rotating propeller; four blades in the front hub and three in the rear resulted in efficiencies 1/2 to 3 1/2 percent lower than those obtained with the six-blade propeller. This conclusion applies to blade-angle settings of the front and rear propellers to absorb equal power at peak efficiency when the rotational speeds were held equal.
Download or read book Considerations of Wake excited Vibratory Stress in a Pusher Propeller written by Blake W. Corson and published by . This book was released on 1944 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summary: An equation based on simple blade-element theory and the assumption of a fixed wake pattern is derived and fitted to available data to show the first-order relation between the parameters of propeller operation and the intensity of the wake-excited periodic force acting on the blades of a pusher propeller. The derived equation indicates that the intensity of the wake-excited periodic force is directly proportional to air density, to airspeed, to rotational speed, and to propeller-disk area. The derived equation indicates that the effect of power coefficient upon the intensity of the wake-excited periodic force is small. In normal operation the vibratory force decreases with increased power coefficient. If a pusher propeller is used as a brake, increasing the power coefficient will increase the vibratory force. For geometrically similar pusher propellers, a propeller of large diameter will, in general, experience less wake-excited vibratory stress than a propeller of smaller diameter. Limited experimental data indicate that the wake-excited vibratory stress in a propeller increases with the drag of the body producing the wake.
Download or read book Experiments on Propeller Blades written by Renaud Lage and published by . This book was released on 1903 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Air Propeller Its Strength and Correct Shape written by H. Dietsius and published by . This book was released on 1923 with total page 714 pages. Available in PDF, EPUB and Kindle. Book excerpt: Airplanes and airships, at the present day, often have engine installations totalling several hundred horsepower, the output from which must be transformed into thrust through the medium of one or more propellers; so that, not infrequently, a single propeller must transmit 250 to 500 HP. The peripheral speed of the propeller blades, in such cases, often exceeds 200 meters (656 feet) per second and the load due to centrifugal force may then amount to several tons. It is extremely desirable, therefore, that the strength of propellers should be calculated and not determined entirely by the workmen who are employed in their manufacture.
Download or read book Experimental Research on Air Propellers written by United States. National Advisory Committee for Aeronautics and published by . This book was released on 1920 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Further Measurements of Model Propeller Pressure Distributions Using a Novel Technique written by Stuart D. Jessup and published by . This book was released on 1986 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Model propeller blade pressure distributions were measured using a novel technique. A single pressure gage was installed at a radial position to measure pressures at numerous chordwise locations through pressure taps and connecting channels. The technique resulted in accurate, detailed pressure distributions along two radial positions using two pressure gages. The major advantage of this technique is the ability to make measurements in the thin parts of the blade with high potential accuracy, and no disruption to the measuring surface, except for the orifice hole. The relatively along test time required to collect the data is the disadvantage. Keywords: Marine Propeller, Propeller Research Pressure Distribution, Model Experiments.
Download or read book Propellers in Yaw written by Herbert S. Ribner and published by . This book was released on 1943 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summary: It was realized as early as 1909 that a propeller in yaw develops a side force like that of a fin. In 1917, R.G. Harris expressed this force in terms of the torque coefficient for the unyawed propeller. Of several attempts to express the side force directly in terms of the shape of the blades, however, none has been completely satisfactory. An analysis that incorporates induction effects not adequately covered in previous work and that gives good agreement with experiment over a wide range of operating conditions is presented herein. The present analysis shows that the fin analogy may be extended to the form of the side-force expression and that the effective fin area may be taken as the projected side area of the propeller. The effective aspect ratio is of the order of 8 and the appropriate dynamic pressure is roughly that at the propeller disk as augmented by the inflow. The variation of the inflow velocity, for a fixed-pitch propeller, accounts for most of the variation of side force with advance-diameter ration V/nD.
Download or read book Technical Report written by Aeronautical Research Council (Great Britain) and published by . This book was released on 1912 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: Includes its Reports, which are also issued separately.
Download or read book Aeronautics In Theory and Experiment written by W.L. Cowley and published by . This book was released on 1918 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:
