Author: Vincent Michael Paglino
Publisher:
ISBN:
Category : Propellers, Aerial
Languages : en
Pages : 142
Book Description
An Experimental Investigation of the Static Performance and Transition Characteristics of a Small-scale VTOL Propeller
Author: Vincent Michael Paglino
Publisher:
ISBN:
Category : Propellers, Aerial
Languages : en
Pages : 142
Book Description
Publisher:
ISBN:
Category : Propellers, Aerial
Languages : en
Pages : 142
Book Description
Experimental Investigation of the Effects of Some Shroud Design Variables on the Static Thrust Characteristics of a Small-scale Shrouded Propeller Submerged in a Wing
Author: Robert T. Taylor
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 710
Book Description
An experimental investigation has been made to determine the effects of shroud-lip radius of curvature, shroud length, and shroud diffuser angle on the static thrust characteristics of a small-scale shrouded propeller which simulated a propeller submerged in the wing of an airplane. Also included are the effects of distance from the exit of the shroud to the ground on the thrust available take-off.
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 710
Book Description
An experimental investigation has been made to determine the effects of shroud-lip radius of curvature, shroud length, and shroud diffuser angle on the static thrust characteristics of a small-scale shrouded propeller which simulated a propeller submerged in the wing of an airplane. Also included are the effects of distance from the exit of the shroud to the ground on the thrust available take-off.
Performance and Stresses Obtained on an Isolated VTOL-type Propeller Operating in Hovering, Transitional and Axial Flight
Author: Andrew R. Trenka
Publisher:
ISBN:
Category : Propellers
Languages : en
Pages : 206
Book Description
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).
Publisher:
ISBN:
Category : Propellers
Languages : en
Pages : 206
Book Description
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).
An Experimental Investigation of VTOL Flying Qualities Requirements for Shipboard Landings
Author: Robert C. Radford
Publisher:
ISBN:
Category : Microwave landing systems
Languages : en
Pages : 526
Book Description
Publisher:
ISBN:
Category : Microwave landing systems
Languages : en
Pages : 526
Book Description
An Experimental Investigation of the Static Thrust Characteristics for Counterrotating Propellers
Author: Matthew Arlington Batson (Jr.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 54
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 54
Book Description
Measurement of Static and Dynamic Performance Characteristics of Electric Propulsion Systems
Author: Aron Jon Brezina
Publisher:
ISBN:
Category : Drone aircraft
Languages : en
Pages : 405
Book Description
Today's unmanned aerial vehicles are being utilized by numerous groups around the world for various missions. Most of the smaller vehicles that have been developed use commercially-off-the-shelf parts, and little information about the performance characteristics of the propulsion systems is available in the archival literature. In light of this, the aim of the present research was to determine the performance of various small-scale propellers in the 4.0 to 6.0 inch diameter range driven by an electric motor. An experimental test stand was designed and constructed in which the propeller/electric motor was mounted in a wind tunnel for both static and dynamic testing. Both static and dynamic results from the present experiment were compared to those from previous studies. For static testing, the coefficient of thrust, the coefficient of propeller power, and the overall efficiency, defined as the ratio of the propeller output power to the electrical input power, were plotted versus the propeller rotational speed. For dynamic testing, the rotational speed of the propeller was held constant at regular intervals while the freestream airspeed was increased from zero to the windmill state. The coefficient of thrust, the coefficient of power, the propeller efficiency and the overall efficiency were plotted versus the advance ratio for various rotational speeds. The thrust and torque were found to increase with rotational speed, propeller pitch and diameter, and decrease with airspeed. Using the present data and data from the archival and non-archival sources, it was found that the coefficient of thrust increases with propeller diameter for square propellers where D = P. The coefficient of thrust for a family of propellers (same manufacturer and application) was found to have a good correlation from static conditions to the windmill state. While the propeller efficiency was well correlated for this family of propellers, the goodness of fit parameter was improved by modifying the propeller efficiency with D/P.
Publisher:
ISBN:
Category : Drone aircraft
Languages : en
Pages : 405
Book Description
Today's unmanned aerial vehicles are being utilized by numerous groups around the world for various missions. Most of the smaller vehicles that have been developed use commercially-off-the-shelf parts, and little information about the performance characteristics of the propulsion systems is available in the archival literature. In light of this, the aim of the present research was to determine the performance of various small-scale propellers in the 4.0 to 6.0 inch diameter range driven by an electric motor. An experimental test stand was designed and constructed in which the propeller/electric motor was mounted in a wind tunnel for both static and dynamic testing. Both static and dynamic results from the present experiment were compared to those from previous studies. For static testing, the coefficient of thrust, the coefficient of propeller power, and the overall efficiency, defined as the ratio of the propeller output power to the electrical input power, were plotted versus the propeller rotational speed. For dynamic testing, the rotational speed of the propeller was held constant at regular intervals while the freestream airspeed was increased from zero to the windmill state. The coefficient of thrust, the coefficient of power, the propeller efficiency and the overall efficiency were plotted versus the advance ratio for various rotational speeds. The thrust and torque were found to increase with rotational speed, propeller pitch and diameter, and decrease with airspeed. Using the present data and data from the archival and non-archival sources, it was found that the coefficient of thrust increases with propeller diameter for square propellers where D = P. The coefficient of thrust for a family of propellers (same manufacturer and application) was found to have a good correlation from static conditions to the windmill state. While the propeller efficiency was well correlated for this family of propellers, the goodness of fit parameter was improved by modifying the propeller efficiency with D/P.
Aerodynamic Characteristics of a Powered Semispan Tilting-shrouded-propeller VTOL Model in Hovering and Transition Flight
Author: Kenneth W. Goodson
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 52
Book Description
"An investigation of the aerodynamic characteristics of a powered semispan tilting-shrouded-propeller configuration has been conducted in the 17-foot test section of the Langley 300-MPH 7- by 10-foot tunnel. The wing had an aspect ratio of 2.67 (based on wing span of 60 inches), a taper ratio of 0.67, and an NACA 2418 airfoil section with a 15-inch-diameter shrouded propeller mounted on the tip. The test results show that large nose-up pitching moments are obtained at transitional speeds of about 40 knots and duct angle of about 70°. Decelerating flight procedures further increases in the nose-up moment. Ground proximity reduces the nose-up pitching moments. The large nose-up moments can be trimmed by use of duct-exit control vanes. The results show that unloading the duct (shroud) by flying at a wing angle of attack of 15° reduces the power required by about 30 percent at 50 knots. Duct-lip stall produces large increases in power required. The results in general show that full-scale aerodynamic simulation can be made with small-scale wind-tunnel models if duct-lip separation at low Reynolds numbers is avoided."--Summary.
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 52
Book Description
"An investigation of the aerodynamic characteristics of a powered semispan tilting-shrouded-propeller configuration has been conducted in the 17-foot test section of the Langley 300-MPH 7- by 10-foot tunnel. The wing had an aspect ratio of 2.67 (based on wing span of 60 inches), a taper ratio of 0.67, and an NACA 2418 airfoil section with a 15-inch-diameter shrouded propeller mounted on the tip. The test results show that large nose-up pitching moments are obtained at transitional speeds of about 40 knots and duct angle of about 70°. Decelerating flight procedures further increases in the nose-up moment. Ground proximity reduces the nose-up pitching moments. The large nose-up moments can be trimmed by use of duct-exit control vanes. The results show that unloading the duct (shroud) by flying at a wing angle of attack of 15° reduces the power required by about 30 percent at 50 knots. Duct-lip stall produces large increases in power required. The results in general show that full-scale aerodynamic simulation can be made with small-scale wind-tunnel models if duct-lip separation at low Reynolds numbers is avoided."--Summary.
Scientific and Technical Aerospace Reports
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1282
Book Description
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.
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1282
Book Description
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.
Development of a Method for Predicting the Performance and Stresses of VTOL-type Propellers
Author: Andrew Richard Trenka
Publisher:
ISBN:
Category : Rotors (Helicopters)
Languages : en
Pages : 134
Book Description
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).
Publisher:
ISBN:
Category : Rotors (Helicopters)
Languages : en
Pages : 134
Book Description
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).
Aerospace Engineering Index
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 642
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 642
Book Description