Hovering and Low-Speed Performance and Control Characteristics of the Kaman Helicopter Rotor System as Determined on the Langley Helicopter Tower. TED No. NACA DE 205

An investigation has been conducted with the Langley helicopter tower to obtain basic performance and control characteristics of the Raman rotor system. Blade-pitch control is obtained in this configuration by utilizing an auxiliary flap to twist the blades. Rotor thrust and power required were measured for the hovering condition and over a range of wind velocities from 0 to 30 miles per hour. The control characteristics and the transient response of the rotor to various control movements were also measured. The hovering-performance data are presented as a survey of the wake velocities and the variation of torque coefficient with thrust coefficient. The power required for the test rotor to hover at a thrust of 1350 pounds and a rotor speed of 240 rpm is approximately 6.5 percent greater than that estimated for a conventional rotor of the same diameter and solidity. It is believed that most of this difference is caused by th e flap servomechanism. The reduction in total power required for sustentation of the single-rotor configuration tested at various wind velocities and at the normal operating rotor thrust was found to be similar to the theoretical and experimental results for ro tors with conventionally actuated pitch. The control effectiveness was determined as a function of rotor speed. Sufficient control was available to give a thrust range of 0 to 1500 pounds and a rotor tilt of plus or minus 7 degrees. The time lag between flap motion and blade-pitch response is approximately 0.02 to 0.03 second. The response of the rotor following the blade-pitch response is similar to that of a rotor with conventionally actuated pitch changes. The over-all characteristics of the rotor investigated indicate that satisfactory performance and control characteristics were obtained

NACA Research Memorandums

From Summary: "An investigation has been conducted with the Langley helicopter tower to obtain basic performance and control characteristics of the Raman rotor system. Blade-pitch control is obtained in this configuration by utilizing an auxiliary flap to twist the blades. Rotor thrust and power required were measured for the hovering condition and over a range of wind velocities from 0 to 30 miles per hour. The control characteristics and the transient response of the rotor to various control movements were also measured.

NACA Technical Notes

Report presenting an investigation of the flutter of a small one-blade wooden propeller with a Clark Y section. The highest flutter speeds were found in the vicinity of the angle of zero aerodynamic moment, with flutter speed increasing in this region with decreasing pressure

NACA Technical Notes

Report presenting an investigation to obtain basic performance and control characteristics of an aerodynamic-servocontrolled rotor system. Results regarding the hovering performance, low-speed flight performance, control effectiveness, transient response to collective pitch, and transient response to cyclic pitch are provided

cm I em P I=Q NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS TECHNICAL NOTE 2086 . . HOVERING AND LOW-SPEED PERFORMANCE AND CONTROL CHARACTERISTICS OF AN AERODYNAMIC-SERVOCONTROLIED HELICOPTER ROTOR SYSTEM ASÕ N TH

SUMMARY An investigation has been conducted with tower to obtain basic performance and control TOWER S. Paulnock the Langley helicopter characteristics of an aerodynamic-servocontrolledrotor system. Blade-pitch control is obtained in this configuration by utilizing sn auxiliary flap to twist the blades. Rotor thrust and power required were measured for the hovering condition and over a rauge of'wind velocities from O to 30 miles per hour. The control chsxacteristics end the transient response of the rotor to various control movements were also measured. The hovering-performance data sre presented as a survey of the wake velocities and the variation of torque coefficient with thrust coefficient. The power required for the test rotor to hover at a thrust of 1350 pounds and a rotor speed of 240 rpm is approximately 6.5percent greater tham that estimated for a conventional rotor of the same dismeter and solidity. It is believed that most of this difference is causedby . the flap servomechanism. The reduction in total power required for sustentation of the configuration tested at various wind velocities and at the normal operating rotor thrust was found to be similar to the theoretical and experimental results for rotors with conventionally actuated pitch. The control effectiveness was determined as a function of rotor speed. Sufficient control was available to give a thrust range of O to 1500 pounds ad a rotor tilt of &7°. me time lag between flap motion and blade-pitch response is approximately 0.02 to 0.03 second. The response of the rotor following the blade-pitch response is similar to that of a rotor with conventionally actuated pitch chsnges. The over-all that satisfactory characteristics of the rotor investigated indicate performance and control characteristic& were obtained