"Flight tests were made of a type of internally balanced sealed ailerons installed on a Ryan ST airplane. Aileron effectiveness and stick forces were measured at various airspeeds under NACA recording instruments. For comparison, the aileron characteristics were also determined without the internal balance and seals" (p. 1).

Report presenting the performance of several internally finned radiators and a comparison with more conventional honeycomb radiators. In a typical case, the new radiator can be designed with 55 percent less volume and 18 percent less power expenditure while dissipating the same amount of heat.

Report presenting a pressure-distribution investigation conducted in the 4- by 6-foot vertical wind tunnel to determine the air loads on an airfoil with a 22.1-percent-chord balanced split flap. Results regarding section pressure distribution and aerodynamic section coefficients are provided.

Report presenting an investigation of the influence of running propellers on the hydrodynamic characteristics of a model of a seaplane in the tank to evaluate the importance of power in tests of dynamically similar models. The powered propellers were found to have a large effect on the aerodynamic characteristics of the model and consequently on the hydrodynamic stability, which depends to a certain extent on these characteristics. Generally, the magnitude of the effects of a given increment of power in such tests decreases as the power is increased.

Report presenting an investigation of several modifications of 20-percent-chord plain and Frise ailerons on an NACA 23012 airfoil in the 7- by 10-foot wind tunnel. Static rolling, yawing, and hinge moments were determined for several angles of attack.

Report presenting an investigation of a spoiler-slot aileron on an NACA 23012 airfoil with a full-span 30-percent-chord Fowler flap. The static rolling, yawing, and hinge moments were determined for several angles of attack and flap deflections. The ineffective region could be eliminated by a provision in the aileron linkage that would automatically uprig the ailerons as the flap is deflected.

Report presenting testing to determine if the change of several specific variables with extreme change of humidity and test-bench temperature will have an appreciable effect on several parameters used to determine supercharger performance.

"A collection of data on the elevator deflections used in landings of several airplanes is presented in tabular form. The physical characteristics of these airplanes are also given. The elevator deflections used in landing some airplanes was found to be as much as 14.4 degrees greater than that used to stall under the same flight and loading conditions" (p. 1).

Report presenting single-cylinder tests were made with several different engines over a period of time, which have shown that a large overlap between the time of inlet valve opening and exhaust valve closing results in a considerable increase in the maximum power obtainable from a supercharged engine and reduces cylinder temperatures.

Report presenting the results obtained in compression tests of eight stiffened panels. The radius-thickness ratio of the skin between stiffeners varied from 400 to infinity.

Report presenting an investigation in the NACA 7- by 10-foot wind tunnel of several arrangements of a plug-type, spoiler-slot aileron on an NACA 23012 airfoil with a full-span slotted flap. The results indicated that a plug-type, spoiler-slot aileron probably has negligible drag in the neutral position and will provide satisfactory lateral control for airplanes equipped with full-span slotted flaps.

Aerodynamic characteristics of a tapered NACA 23012 airfoil with single and double perforated split flaps have been determined in the NACA 7- by 10-foot wind tunnel. Dynamic pressure surveys were made behind the airfoil at the approximate location of the tail in order to determine the extent and location of the wake for several of the flap arrangements. In addition, computations have been made of an application of perforated double split flaps for use as fighter brakes. The results indicated that single or double perforated split flaps may be used to obtain satisfactory dive control without undue buffeting effects and that single or double perforated split flaps may also be used as fighter brakes. The perforated split flaps had approximately the same effects on the aerodynamic and wake characteristics of the tapered airfoil as on a comparable rectangular airfoil.

Tests of 10-ft. diameter, eight-blade, single - and dual - rotating propellers were conducted in 20-ft propeller research tunnel. Propellers were mounted at front end of a streamline body in spinners that covered hubs and parts of shanks. Effect of a symmetrical wing mounted in slipstream was investigated. Blade-angle settings ranged from 20 Degrees to 65 Degrees. Results indicated that dual rotation resulted in gains of from 1 to 8 percent in efficiency over single rotation for eight-blade propellers, but presence of a wing reduced gain about one-half. Greater power absorption caused by dual rotation over flight range and higher efficiency or thrust for range of take-off and climb was indicated.

Report presenting a study of the aerodynamic factors upon which the ability to perform the maneuver depends in an attempt to obtain a better understanding of the conditions involved and, if possible, to evolve criterions that may be used during design.

"An investigation of cowlings for long-nose radial engines was made on the Curtiss XP-42 fighter in the NACA full-scale wind tunnel. The unsatisfactory aerodynamic characteristics of all the cowlings with scoop inlets tested led to the development of the annular high-velocity inlet cowlings. Tests showed that ratio of cooling-air velocity at cowling inlet to stream velocity should not be less than 0.5 for this type of cowling and that critical compressibility speed can be extended to more than 500 mph at 20,000 ft altitude" (p. 1).

Report presenting testing on elbow shapes in airplane carburetor air intake ducts with low losses and good velocity distribution without the use of turning vanes. Results regarding the flow coefficient, velocity distribution, and comparison of a variety of elbow ducts are provided.

Problem of improving thrust at low speeds is primarily one of reducing angle of attack of operation of sections to improve L/D or reducing blade helix angle. An analysis, based on recent propeller data, is presented for determining improvements in thrust or efficiency which could be obtained by increased number of blades, increased blade width, increased diameter, dual rotation, and two-speed gearing. All methods were found very effective, particularly two-speed gearing.

Report presenting a theoretical investigation of the influence of changes in vertical tail area and dihedral angle on the lateral flying characteristics of an airplane. Lateral motions were computed for nine different combinations of vertical tail area and dihedral. Results regarding the lateral motions due to applied rolling moment with different amounts of accompanying pawing moment and lateral motions due to applied yawing moment are provided.

Report presenting the section critical speeds and profile drags of the shank and hub sections of a propeller used on a current liquid-cooled-engine pursuit type of airplane. Results indicated that serious adverse compressibility effects can be expected at speeds of about 400 miles per hour. Suitable fairings for shank and hub sections were found to be necessary for maximum propulsive efficiency.

Report presenting a series of calculations made to determine the probable dynamic wing stress of two large airplanes in atmospheric gusts. The results indicate that in both isolated and repeated gusts of probable occurrence, the dynamic overstress is about 10 percent when referred to the present static design standard.

Report presenting tests made in the 4- by 6-foot vertical wind tunnel of an NACA 0009 airfoil with a 30-percent-chord flap with a medium amount of aerodynamic overhanging balance. In this investigation, the effects of the shape of the flap-nose overhang and the gap at the nose of the flap have been determined. The results indicate that, generally, the lift effectiveness of the aerodynamically balanced flap was increased slightly over that of a plain flap when a blunt or medium flap nose was used on the balanced flap.

Report presenting a discussion of the problem of establishing a rational unsymmetrical gust load criterion from available data on gust structure and it is indicated that the problem cannot be solved at the present state of knowledge without more analysis.

Report presenting tests in the 4- by 6-foot vertical wind tunnel of an NACA 0009 airfoil with a 30-percent-chord flap with a small amount of aerodynamic balance. In the investigation, the effect of balance nose shape and gap at the nose of the flap has been determined. The results indicate that, in general, the lift effectiveness of the flap was unaffected by the addition of a small amount of aerodynamic overhang, and the balance effectiveness of the flap was increased.

Report presenting testing of an NACA 0009 airfoil with a 30-percent-chord flap with a 49.5-percent flap-chord balance with various nose shapes and two gaps. The results indicated that the flap is overbalanced when deflected, regardless of nose shape. Results regarding lift, hinge moment of flap, drag, pitching moment, and effect of differential balancing tab are provided.