Report presenting wind tunnel testing to investigate the possibility of reducing the hinge moments of a control surface by beveling the trailing edge. Tests were made with a 9-percent-thick airfoil with a 30-percent-chord plain flap. Results regarding the variations of lift and hinge moment, effect of shapes, and pitching moments are provided.

Report presenting an analysis of the probable aerodynamic section characteristics of a plain flap with various arrangements of internal balance. The results of the calculations previously obtained were found to be in agreement with the experiment. Some possible applications of the data to balancing tabs are also provided.

Report presenting force-test measurements in two-dimensional flow in the 4- by 6-foot vertical tunnel to determine the characteristics of an NACA 0015 airfoil equipped with a straight-contour plain flap with a chord 30 percent of the airfoil chord. Results regarding the lift, hinge moment of flap, pitching moment, and drag are provided.

Report presenting force-test measurements in two-dimensional flow in the 4- by 6-foot vertical tunnel of the characteristics of an NACA 0015 airfoil equipped with a plain flap with a chord 30 percent of the airfoil chord and a plain tab with a chord 20 percent of the flap chord. Results regarding lift, hinge moment of flap, pitching moment, drag, and tab characteristics are provided.

Report presenting force-test measurements in two-dimensional flow made in the 4- by 6-foot vertical tunnel of the characteristics of an NACA 0015 airfoil with a balanced flap with a chord 30 percent of the airfoil chord and a flap-nose overhang 35 percent of the flap chord. Results regarding lift, hinge moment of flap, pitching moment, drag, and tab characteristics are provided.

Report presenting an investigation in the 7- by 10-foot wind tunnel of an NACA 23012 airfoil equipped with a Handley Page slat and a slotted and a split flap. The purpose of the investigation was to determine the aerodynamic section characteristics of the airfoil with and without flaps as affected by the location of the Handley Page slat. A range of slat-nose locations was investigated both with and without flaps at a constant slat gap.

Report presenting an investigation in the 7- by 10-foot tunnel of various modifications to the trailing edge of a 0.155-chord plain aileron on a semispan model of the tapered wing of a fighter airplane. The stick forces and rates of roll were estimated for a fighter airplane with the plain and modified ailerons.

Report presenting lift and elevator hinge-moment characteristics of a horizontal tail with various plain and balanced elevators and mounted on a typical pursuit fuselage as measured in the 7- by 10-foot wind tunnel at attitudes simulating normal-flight and spin conditions. The lift effectiveness of the elevator was practically independent of the size of the aerodynamic balance. Results regarding the fuselage alone and fuselage interference, lift characteristics of fuselage-tail combinations, lift effectiveness of the tab, elevator hinge moments, parameters, effect of yaw on elevator hinge moments, effect of tab on elevator hinge moments, drag, and comparison with two-dimensional data are provided.

Report presenting lift and elevator hinge-moment characteristics were measured on horizontal tail provided with elevators having three different beveled trailing edges. Results regarding fuselage alone and fuselage interference, lift characteristics of fuselage-tail combination, elevator hinge-moment characteristics, drag, and comparison with data from two-dimensional-flow tests are provided.

Report presenting force tests in two-dimensional flow in the 4- by 6-foot vertical tunnel of the characteristics of an NACA 0015 airfoil with a balanced flap having a chord of 30 percent of the airfoil chord, a flap-nose overhang 50 percent of the flap chord, and a tab having a chord 20 percent of the flap chord. Results regarding the precision and presentation of data, lift, hinge moment of flap, pitching moments, drag, tab characteristics, and balancing effectiveness of various overhangs are provided.

Report presenting a summary of published information on braking friction coefficients. Analysis indicates that the magnitude of the friction coefficient available will affect the technique required for obtaining the shortest ground run only under extreme conditions.

Report presenting testing of specimens of 17S-T aluminum-alloy fittings with pressed-in steel bushings for various surface conditions. The surface conditions tested included bare surfaces, aonidcal coating and steel cadmium-plate, and one surface treated and the other bare, both without lubrication and with Gredag No. 83 as a lubricant. The calculated coefficients of friction for the various press fits for the investigation ranged from 0.33 for the unlubricated contact of bare steel and aluminum to 0.09 for the specimen with the unlubricated cadmium-plated bushing.

Porpoising characteristics were observed on V-body fitted with tail surfaces for different combinations of load, speed, moment of inertia, location of pivot, elevator setting, and tail area. A critical trim was found which was unaltered by elevator setting or tail area. Critical trim was lowered by moving pivot either forward or down or increasing radius or gyration. Increase in mass and moment of inertia increased amplitude of oscillations. Complete results are tabulated and shown graphically.

Report presenting data pertaining to forces and moments developed by V-bottom planing surfaces of different angles of dead rise in order to compute the effect of dead rise on the lower trim limit of stability on a seaplane. Increase of angle of dead rise in the range of 10 degrees to 30 degrees causes an important increase in the lower limit of stability.

Report presenting an analysis of parallel flow and contraflow single pass heat exchangers, together with charts which allow the direct evaluation of the thermal performance of the units without recourse to trail-and-error techniques. The use of equations and charts is illustrated by several examples.

Report presenting an investigation of the characteristics of air scoops in the NACA propeller-research tunnel. The investigation showed that, at inlet-velocity ratios equal to or greater than 0.3, scoops in a forward position on the fuselage gave total pressures in the inlet nearly equal to free-stream total pressure.

"Equations and necessary data for the calculation of the gaseous radiation from water vapor and carbon dioxide in an exhaust gas heat exchanger are presented. A typical calculation is included" (p. 1).

Report presenting tests in the 8-foot high-speed wind tunnel to determine the loads and the load distributions at high speeds for a number of windshields of the cockpit-canopy type. Ten windshields of various designs similar to those in general use were included in these tests. Results regarding drag, loads, and design considerations are provided.

Report presenting a report regarding the basic factors of heat transfer applied specifically to aircraft heating and to guide the experimenter in planning experiments to obtain further data.

Report presenting a description of a meter which will measure the heat flowing through surfaces. Its operation is based on the measurement of the temperature decrease through a fixed thermal resistance. Only the case of heat flow independent of time is discussed in this particular report.

Report presenting flight tests made with a modified Ryan ST airplane to determine the effect on aileron characteristics of various arrangements of balanced split flaps covering that portion of the wing span occupied by the ailerons. With the flaps fully extended, the aileron effectiveness was reduced by approximately 18 percent of the effectiveness measured with ailerons alone.

Report presenting the properties of some exhaust gases and air that are pertinent to airplane heat transfer calculations, including air, hydrogen, nitrogen, oxygen, carbon dioxide, and carbon monoxide. A bibliography related to gas properties is also provided.

Report presenting a study of two double tube cylindrical heat exchangers, in which hot exhaust gases pass through the annular space and ventilating air passes through the center tube, to determine heat transfer performance and pressure drop. Tests were performed in order to establish a simple, accurate method of predicting the performance of the double tube heat exchanger, to compare the performance of the straight and dimpled tubes, and to determine the pressure drop across the units.

Report presenting a study of two double tube, cylindrical, longitudinally finned heat exchangers in which hot exhaust gases pass through the annular space and ventilating air passes through the center tube in order to determine heat transfer and pressure drop performance.