Report presenting force-test measurements in two-dimensional flow in the 4- by 6-foot vertical tunnel to determine the characteristics of several different shaped overhang-type aerodynamic balances applied to a straight-contour flap mounted on an NACA 0015 airfoil. The flap with blunt-nose overhang was overbalanced throughout certain ranges of flap deflection. Results regarding precision, lift, flap hinge moments, pitching moment, and drag are provided.

Report presenting force-test measurements in two-dimensional flow made in the 4- by 6-foot vertical tunnel to determine the aerodynamic effects of changing the alignment of the cover plates on a sealed internally balanced flap. Manufacturing imperfections in the alignment of the cover plates with the airfoil contour may have serious effects on the resultant hinge moment of a flap with a sealed internal balance. Results regarding lift, flap hinge moments, pitching moment, and drag are provided.

Report presenting flight testing of an improved type of all-movable tail surface. The particular arrangement tested provides control-free stability and a stable variation of the control forces during maneuvers. Results regarding rudder effectiveness, directional stability, rudder-free lateral motion, and rudder-free turns are provided.

Report discusses the results of an investigation into a full-span retractable flap in combination with a full-span plain and internally balanced ailerons on a tapered wing of a typical fighter airplane.The flap was designed to improve lateral control during high lifts for landing and take-off. The effects on the maximum life coefficient, aileron effectiveness, estimated rates of roll, and stick forces are provided.

Report presenting an investigation in the 19-foot pressure tunnel of two-tapered wings with NACA 230-series airfoil sections, straight leading edges, and constant-chord center sections. Lift, drag, and pitching-moment coefficients were determined for the plain wing and for each flap arrangement for a range of Reynolds numbers. The results indicated that the wing with the square center section has greater maximum lift coefficients and increments of maximum lift due to flap deflections than the wing with the rectangular center section.

Report presenting force-test measurements in two-dimensional flow made in the 4- by 6-foot vertical tunnel to determine the aerodynamic characteristics of an NACA 66(215)-014 airfoil equipped with true-contour, straight-contour, and beveled-trailing-edge flaps with chords 30 percent of the airfoil chord. The results are presented in the form of aerodynamic section characteristics for several flap deflections and for a sealed and unsealed gap at the flap nose.

From Introduction: "The results of the load tests and some additional aerodynamic characteristics of perforated double split flaps on a rectangular NACA 23012 airfoil are given in the present report."

Report discusses the results of testing of flap position and deflection on the aerodynamic characteristics of a NACA 23012 airfoil with a double slotted flap with a chord 30 percent of the airfoil chord. The maximum lift coefficient, profile-drag coefficients, pitching-moment coefficients, lift, and drag are provided at several positions of the flap. The results were also compared to previous testing on several flap configurations.

Report summarizes the available hinge-moment data for unshielded horn-balanced control surfaces. The purpose is to correlate the available data to assist with estimating the balance characteristics for use in the design and alteration of control surfaces with horn balances. Plan forms and variation of incremental hinge-moment-coefficient slopes with balance coefficients are presented.

Report presenting a chart for the values of the coefficient in the formula for the critical shear stress at which buckling may be expected to occur in an infinitely long flat plate with parallel edges. An approximate method for the evaluation of the critical shear stress when the elastic restraints on the two parallel edges are not equal is also presented.

Report presenting measurements made of the pressures of the tail surfaces of the Republic Aviation Corporation P-47B airplane in the full-scale tunnel. Pressures were measured over the horizontal and vertical tail surfaces for several angles of attack and angles of yaw with numerous control-surface deflections to provide a check on the design loads. Results regarding the normal-force coefficients and predictions of forces on horizontal tail surfaces are provided.

Report presenting hinge-moment parameters for several typical ailerons, which were calculated from section data with the aspect-ratio correlation as usually determined from lifting-line theory. The calculations showed that the agreement between experimental and calculated results was unsatisfactory.

"The following surveys on the vibration response of the P-40 rudder and fin-rudder assembly were conducted during the fall of 1942 for the purpose of obtaining information on the flutter characteristics of high-speed airplanes of known performance. The tests on the rudder alone were made with the rudder suspended in a floating condition; the tests on the fin-rudder unit were made with the fin rigidly fastened to a concrete base" (p. 1). A variety of figures and diagrams for the assembly are provided.

Report presenting a report illustrated by photographs and vibration records on the failure of the P-47 rudder in the high-speed tunnel at a true speed of 468 miles per hour and a density corresponding to 9000 feet altitude. The fin-rudder unit was tested as being at least representative of the tail design of the P-47 airplane.

Report presenting a study of the flutter characteristics of the P-47 tail assembly, which included replacing the original fabric-covered rudder with a metal-covered rudder and reinforcing the fin. Figures are provided for different configurations and the cycles per second under the same conditions are provided.

Report presenting hinge-moment, lift, pressure difference across the balance, and pressure-distribution measurements in the two-dimensional test section of the stability tunnel on a 0.60 aileron-chord sealed internal-balance aileron on a specified NACA airfoil. The primary test objective was to determine the effect of speed on the action of the aileron.

Report presenting hinge moment, lift, and pressure-distribution measurements made on a Frise aileron on an NACA 23012 airfoil in the two-dimensional test section of the stability tunnel. Speeds up to 360 miles per hour corresponding to a Mach number of about 0.470 were used.

Report presenting tests made on an NACA 23012 airfoil fitted with a 20-percent-chord, true-contour aileron with 35-percent-chord, extreme blunt-nose balance. The primary purpose of the investigation was to determine the variation of the aerodynamic characteristics of this type of aileron with airspeed; the effect of variations of gap width and balance-nose radii was also investigated. Results regarding hinge moments, lift, and pitching-moment coefficients are provided.

Aerodynamics data are obtained for the design of linked balancing tabs and effect of varied tab span and location to produce suitable lateral control characteristics with reasonable stick pressures for high-speed aircraft. Simple and spring-linked balancing tabs may considerably reduce control pressures if aileron system is designed for low maximum aileron deflection. Spring-linked tabs also decrease variation of stick pressure with speed and impart better controlllability at low speeds.

"The variation in the necessary aileron control and in the time required to bank to 45 degrees and 90 degrees with altitude and radii of gyration for a typical fighter or a pursuit airplane have been computed and are presented herein." The lateral motions and impact pressure for several conditions of flight are provided. The report concludes that "the aileron system...should be designed for rolling-moment requirements at high altitude and the hinge-moment limitations at low altitude".

"Hinge-moment, lift, and pressure-distribution measurements were made in the two-dimensional test section of the NACA stability tunnel on a blunt-nose balance-type aileron on an NACA 66,2-216 airfoil at speeds up to 360 miles per hour corresponding to a Mach number of 0.475. The tests were made primarily to determine the effect of speed on the action of this type of aileron. The balance-nose radii of the aileron were varied from 0 to 0.02 of the airfoil chord and the gap width was varied from 0.0005 to 0.0107 of the airfoil chord. Tests were also made with the gap sealed" (p. 1).

Report presenting an investigation in the 7- by 10-foot tunnel of various modifications of the trailing-edge portion of a 0.20-chord plain aileron on a partial-span model of a tapered low-drag wing. The modifications tested included various amounts of symmetrical and unsymmetrical thickening and beveling of the aileron trailing edge. Results regarding coefficients and corrections, characteristics with ailerons neutral, characteristics with ailerons deflected, aileron trim characteristics, and estimated aileron-control characteristics are provided.

Characteristics are determined for various modifications of 0.155-chord blunt-nose aileron on semispan model of tapered fighter plane wing. Ailerons with 40 percent nose balance reduced high-speed stick forces. Increased balance chord increases effectiveness and reduces high-speed stick forces. Increased balance chord increases effectiveness and reduces adverse effects of gap at aileron hose. Increase of nose radii increased negative slope of curve hinge-movement coefficient plotted against deflection. Extended deflection range decreased aileron effectiveness for small deflections but increased it at large deflections. Peak pressures at noses of ailerons are relatively high at moderate deflections.

Report describes the standard procedure that NACA used for evaluating the aileron characteristics of airplanes. The variables measured in the testing are rolling velocity, aileron positions, aileron stick forces or tangential wheel force, indicated airspeed, altitude, free-air temperature, and rudder position. The step-by-step flight procedure is described and information regarding evaluation of the control data and general suggestions is included.