Download or read book An Experimental Investigation of the Standing Thrust of Airplane Propellers written by Howard Ogier Snyder and published by . This book was released on 1920 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Investigation of the Static Thrust Characteristics for Counterrotating Propellers written by Matthew Arlington Batson (Jr.) and published by . This book was released on 1939 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Investigation of the Thrust and Torque Produced by Propellers Used as Aerodynamic Brakes written by William S. Hedrick and published by . This book was released on 1944 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents the results of a wind-tunnel investigation of propellers operating at negative thrust. Negative-thrust characteristics of two- and four-blade single propellers and four- and eight-blade duel propellers were determined. Flight conditions were simulated by installing the propellers in a powered model of a high-speed model.
Download or read book Experimental Investigation of Aircraft Propellers Exposed to Oblique Air Currents written by O. Flachsbart and published by . This book was released on 1930 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two screw propellers, a normal airplane propeller with a pitch/diameter ratio H/D = 0.5 and a helicopter propeller H/D = 0.2 were tested in the large wind tunnel of the Gottigen Aerodynamic Institute. With both propellers the angle between the propeller axis and the direction of the wind was varied from 0 to 90 degrees. In addition to the three force and the three moment components in a wind-fast coordinate system, the corresponding components in a propeller-fast coordinate system, a total of six force and six moment components, together with the propulsive efficiency, were measured or calculated from measurements. The results are given in the form of diagrams and briefly discussed. The propeller models and method of experimentation are described and the symbols are defined.
Download or read book Experimental Investigation of Flutter of a Propeller with Clark Y Section Operating at Zero Forward Velocity at Positive and Negative Blade angle Settings written by John E. Baker and published by . This book was released on 1949 with total page 686 pages. Available in PDF, EPUB and Kindle. Book excerpt: The highest flutter speeds were found in the vicinity of the angle of zero aerodynamic moment and the flutter speed increased considerably in this region with decreasing pressure. Over the rest of the pitch range, the flutter speeds were much lower and varied little with pressure.
Download or read book An Experimental Investigation of Secondary Flow in an Accelerating Rectangular Elbow with 90 Degrees of Turning written by John D. Stanitz and published by . This book was released on 1953 with total page 684 pages. Available in PDF, EPUB and Kindle. Book excerpt: The passage vortex associated with secondary flows appears to be near the suction surface and away from the plane wall of the elbow at the exit and does not have appreciable spanwise motion as it moves downstream the elbow exit. As the spoiler size increases, the boundary-layer form changes and a rather sudden difference in the secondary flow occurs, perhaps associated withthe reduced importance of viscous effects in thick boundary layers. It is suggested that the strength of the secondary vortices is small and that the energy of secondary flows is small.
Download or read book An Experimental Investigation of the Effect of Forward and Rearward Motion on the Thrust of a Shrouded Propeller written by Joe F Thompson (Jr) and published by . This book was released on 1966 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental evidence of the existence of a stagnation line between the leading and trailing edges on the outer surface of the shroud of a shrouded propeller in the static condition, in rearward motion, and in forward motion is presented. This stagnation line on the outer surface, which is a result of viscous interaction between the propeller slipstream and the external flow, causes a reduction in shroud circulation below that calculated by distributed singularities methods which assume a stagnation line at the trailing edge only. Shroud thrust decreases as the distance between this stagnation line and the trailing edge increases. It is shown that in rearward motion, such as is the case for a VTOL aircraft landing, the stagnation line moves forward from the vicinity of the trailing edge to the vicinity of the leading edge as vehicle speed increases. This forward movement of the stagnation line results in a significant loss in thrust, which can be correlated with the stagnation line location. Shroud pressure distribution, stagnation line location, and shroud thrust are presented for all three cases of motion at several propeller pitch angles, propeller rotational speeds, and vehicle linear speeds. It is shown that the flow pattern about the shroud is rather complicated in rearward motion, involving two coaxial ring-vortices surrounding the shroud. (Author).
Download or read book A Wind tunnel Investigation of Three Propellers Through an Angle of attack Range from 0 Degree to 85 Degrees written by Paul F. Yaggy and published by . This book was released on 1960 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Investigation of the Effect of Propellers Used as Aerodynamic Brakes on Stability and Control written by Victor I. Stevens and published by . This book was released on 1945 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of negative thrust were found to be significant. The longitudinal stability was increased because of the loss of wing lift and increase of the angle of attack of the tail. Directional stability and both longitudinal and directional control were decreased because of the reduced velocity at the tail. These effects are moderate for moderate braking but become pronounced with full-power braking, particularly at high values of lift coefficient.
Download or read book An Experimental Investigation of the Effect of Forward and Rearward Motion on the Thrust of a Shrouded Propeller written by Joe F. Thompson and published by . This book was released on 1966 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Two Papers Dealing with Some Tests on Model Propellers written by J. Lawrence Hodgson and published by . This book was released on 1917 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bulletin written by Stanford University and published by . This book was released on 1920 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 1921 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theoretical and Experimental Investigation of a Low Speed Propeller written by Scott William Sprehn and published by . This book was released on 1995 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Changes in Propeller Performance Due to Ground and Partial Ground Proximity written by Jielong Cai and published by . This book was released on 2020 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the increased usage of propeller-driven unmanned-aerial-vehicles (UAV) in closed spaces such as caves, buildings, pipelines, etc. for photography, surveillance, and inspection, understanding the influence of the ground and ceiling on a remote-controlled (R/C) propeller is of the utmost importance. The flying characteristics of drones changes when an object or a ground plane is in its close proximity due to changes in its propeller performance. The changes in performance are due to the changes in the flow field around the propeller that occur due to ground proximity, which is also known as ground effect. Ground effect on lifting rotor performance has been studied theoretically and experimentally for decades. Historically, most investigations focus on helicopter rotors, which have high aspect ratio, lower pitch and rarely have spanwise twist. This research focuses on smaller size rotors, in particular, the thin-electric propeller which is used widely on small UAVs. The research considers parameter variations not broadly available in the literature such as propeller pitch, diameter, solidity, and blockage. In particular, extreme ground effect is considered, where the ratio of ground plane stand-off distance to propeller diameter is 0.1 or less. Moreover, the propeller is reversed, to examine the ceiling effect. Typically, the ground effect investigation is done with a ground plane that is big enough to be considered an infinite plane. In this research, both infinite plane and circular plates of similar diameter (or less) of the propeller are used as ground planes. Various circular plates with different diameter to propeller diameter ratios are used in the research representing different 'blockage ratios'. The investigation gives insight into changes in propeller performance in proximity to fuselages of a given diameter in propeller-driven airplanes under pusher and puller configurations. All experiments were conducted on a thrust-stand built in-house at the University of Dayton Low-Speed Wind Tunnel (UD-LSWT) Laboratory. All propellers used in the experiment are from the "thin electric" APC series, with diameter ranging from 11 inches to 17 inches and pitch from 4.5 inches to 14 inches. The propeller peak Reynolds number varies from 90,000 to 190,000 in the experiment. Circular plates with diameter ratio from 0.5 to 1.0 are used in the blockage effect experiment. Force, torque and RPM propeller data are taken during the experiment from a propeller diameter normalized ground distance of -1.5 to 1.5. Results from the infinite ground experiment are separated into three major sections: thrust coefficient and power coefficient, power required at constant thrust, and effective thrust. A significant increment in the thrust coefficient and decrement in the power coefficient is found in ground proximity among the propellers with a pitch-to-diameter ratio less than 0.7. This results in a decrement of power required at constant thrust in ground effect. Almost identical changes in the power required at constant thrust in the ceiling effect is also found in most of the low pitch to diameter ratio propellers. For the blockage experiment, a less significant reduction in the power required in constant thrust for all propellers is found at lower blockage ratios as expected. Similar trends in the effect on? thrust for different propellers at the same blockage ratio are found. Results for the positive h/D region (the puller configuration), overlap regardless of the propeller pitch to diameter ratio or solidity. A phenomenological expression (an algebraic equation) for power required at constant thrust as a function of propeller parameter is established during the research to predict the changes in the propeller performance in ground effect which will benefit the operation of small UAVs in both open and confined areas.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 804 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Experimental Investigation of the Lateral Trim of a Wing propeller Combination at Angles of Attack Up to 90 Degrees with All Propellers Turning in the Same Direction written by William A. Newsom and published by . This book was released on 1958 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation has been made to study the feasibility, from considerations of lateral trim, of having all the propellers of a tilting-wing vertical-take-off-and-landing (VTOL) airplane rotate in the same direction since this is a desirable feature from practical considerations. The model was a wing with four propellers, the slipstream from which covered practically the entire span of the wing. Tests were made at angles of attack up to 90 degrees for various differential flap deflections and differential blade pitch settings on the outboard propellers.
