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Propellers in yaw

Description: 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. 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.
Date: January 1, 1945
Creator: Ribner, Herbert S
Partner: UNT Libraries Government Documents Department

Formulas for propellers in yaw and charts of the side-force derivative

Description: General formulas are given for propellers for the rate of change of side-force coefficient with angle of yaw and for the rate of change of pitching-moment coefficient with angle of yaw. Charts of the side-force derivative are given for two propellers of different plan form. The charts cover solidities of two to six blades and single and dual rotation. The blade angle ranges from 15 degrees or 20 degrees to 60 degrees.
Date: January 1, 1945
Creator: Ribner, Herbert S
Partner: UNT Libraries Government Documents Department

Field of Flow About a Jet and Effect of Jets on Stability of Jet-Propelled Airplanes

Description: A theoretical investigation was conducted on jet-induced flow deviation. Analysis is given of flow inclination induced outside cold and hot jets and jet deflection caused by angle of attack. Applications to computation of effects of jet on longitudinal stability and trim are explained. Effect of jet temperature on flow inclination was found small when thrust coefficient is used as criterion for similitude. The average jet-induced downwash over tail plane was obtained geometrically.
Date: April 1, 1946
Creator: Ribner, Herbert S.
Partner: UNT Libraries Government Documents Department

Proposal for a propeller side-force factor

Description: Report discusses a proposal for propeller manufacturers to consider the side-force factor with the activity factor as a fundamental parameter for all blade designs and for the side-force factor to be included in all reports of powered models in wind tunnels. The proposal includes a method for calculating the side-force factor and how it can be used in propeller development. It is shown to be a good index of the relative effectiveness per blade of a yawed propeller in developing side force.
Date: December 1943
Creator: Ribner, Herbert S.
Partner: UNT Libraries Government Documents Department

Attainment of a straight-line trajectory for a preset guided missile with special reference to effect of wind or target motion

Description: Report discusses the results of a study "of the requirements for the attainment of a straight-line trajectory for a preset guided missile in the presence of wind or target motion" (from Summary). Information about the straight-line trajectory, position of the launching airplane, straight-line collision course, and arrangement of the autopilot in the missile is provided. Recommendations are also made about the creation of a bombsight mounting for the pilot of the launching airplane in order to attain the desired straight-line collision course.
Date: August 1945
Creator: Ribner, Herbert S.
Partner: UNT Libraries Government Documents Department

A Remote Indicating Hinge-Moment Balance, Special Report

Description: This report describes an electrical hinge-moment balance for use with wind-tunnel models of aircraft. A brief description of the principle of operation and operating experience with the balance is given in part I. Part II gives constructional details and part III gives theoretical considerations. Extensive constructional information is given to enable the reproduction of the equipment.
Date: August 1941
Creator: Stoller, Morton J. & Ribner, Herbert S.
Partner: UNT Libraries Government Documents Department

Theoretical lift and damping in roll at supersonic speeds of thin sweptback tapered wings with streamwise tips, subsonic leading edges, and supersonic trailing edges

Description: On the basis of linearized supersonic-flow theory, generalized equations were derived and calculations made for the lift and damping in roll of a limited series of thin sweptback tapered wings. Results are applicable to wings with streamwise tips and for a range of supersonic speeds for which the wing is wholly contained between the Mach cones springing from the wing apex and from the trailing edge of the root section. A further limitation is that the tip Mach lines may not intersect on the wing. For the portion of the wing external to the Mach cones springing from the leading edge of the wing tips, the pressure distributions for lift and roll previously obtained for the triangular wing are valid. For the portion of the wing contained within the wing-tip Mach cones a satisfactory approximation to the exact pressure distribution was obtained by application of a point-source-distribution method developed in NACA-TN-1382. A series of design curves are presented which permit rapid estimation of the lift-curve slope and damping-in-roll derivative for given values of aspect ratio, taper ratio, Mach number, and leading-edge sweep. (author).
Date: January 1, 1950
Creator: Malvestuto, Frank S , Jr; Margolis, Kenneth & Ribner, Herbert S
Partner: UNT Libraries Government Documents Department

Stability derivatives of triangular wings at supersonic speeds

Description: The analysis of the stability derivatives of low-aspect-ratio triangular wings at subsonic and supersonic speeds, given in NACA TN no. 1423, is extended to apply to triangular wings having large vertex angles and traveling at supersonic speeds. The lift, rolling moment due to sideslip, and damping in roll and pitch for this more general case have been treated elsewhere on the basis of the theory of small disturbances. The surface potentials for angle of attack and rolling taken therefrom are used to obtain the several side-force and yawing-moment derivatives that depend on leading-edge suction, and a tentative value for the rolling moment due to yawing. The lift and moment due to downward acceleration are obtained on the basis of an unpublished unsteady-flow solution. All the known stability derivatives of the triangular wing at supersonic speeds, regardless of source, are summarized for convenience and presented with respect to both body axes and stability axes. The results are limited to Mach numbers for which the triangular wing is contained within the Mach cone for its vertex. The spanwise variation of Mach number in the case of yawing is neglected, although the effect must be of importance.
Date: January 1, 1948
Creator: Ribner, Herbert S & Malvestuto, Frank S , Jr
Partner: UNT Libraries Government Documents Department