"The pitching and the yawing moments of a vee-type and a conventional type of tail surface were measured. The tests were made in the presence of a fuselage and a wing-fuselage combination in such a way as to determine the moments contributed by the tail surfaces" (p. 1).

"Span load distributions of swept-back wings have been calculated. The method used was to replace the wing with a bound vortex at the quarter-chord line and to calculate the downwash due to the system of bound and trailing vortices to conform at the three-quarter-chord line to the slope of the flat-plate wing surface. Results are given for constant-chord and 5:1 tapered plan forms, for sweep-back angles of 0 degrees, 30 degrees, and 45 degrees, and for aspect ratios of 3, 6, and 9" (p. 1).

"The effects of power on the stability and the control characteristics of an airplane are discussed and methods of analysis are given for evaluating certain dynamic characteristics of the airplane that are not directly discernible from wind-tunnel tests alone. Data are presented to show how the characteristics of a model tested in a wind tunnel are affected by power. The response of an airplane to a rolling and a yawing disturbance is discussed, particularly in regard to changes in wing dihedral and fin area" (p. 1).

"This analysis deals with the indirect regulator, wherefrom the behavior of the direct regulator is deduced as a limiting case. The prime mover is looked upon as "independent of the load": a change in the adjusting power (to be applied) for the control link (as, for example, in relation to the adjusting path (eta) with pressure valves or the rudder of vessels) does not modify the actions of the prime mover. Mass forces and friction are discounted; "clearance" also is discounted in the transmission links of the regulator" (p. 1).

Note presenting computations made to determine the effects of some airplane design trends on the fin area and the dihedral angle required for lateral stability. The specific factors studied were wing loading, moments of inertia in roll and yaw, wing chord, and tail length. The results of the computations are presented in the form of diagrams of variations of fin area with dihedral angle for neutral stability.

Report presenting an examination of the design of exhaust-stack nozzles for individual cylinder exhaust-gas jet propulsion and the results of tests on the effect of nozzle area on jet thrust and engine power. A satisfactory method of correlatig the test data for various engine-operating conditions is developed.

Note presenting testing performed on scale models of a modern low-wing monoplane in the 15-foot free-spinning wind tunnel. Results are presented in the form of charts that afford a direct comparison between the spins of the two models for a number of different conditions. The results indicate that, within the range of Reynolds numbers used in the present investigation, such factors as difficulty of ballasting and testing are more important in determining proper model size than the changes in scale effect likely to result from the use of different sizes of models.

"Pressure-distribution measurements were made at the request of the Materiel Division, U.S. Army Air Corps, on a 24-inch-chord wooden model equipped with a slotted flap and submitted by the Curtiss-Wright Corporation. The tests were made in the Langley two-dimensional tunnel at a Reynolds number of about 5,600,000" (p. 1).

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 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 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.

From Summary: "Tests have been made to determine the effect of a gap at the flap nose upon the aerodynamic section characteristics of an NACA 0009 airfoil with a plain flap and tab. The results are presented in the form of airfoil and flap section characteristics for several flap deflections, tab deflections, and for four sizes of gap."

Report presenting an investigation in the 7- by 10-foot wind tunnel of an NACA 23012 airfoil with a 30 percent-chord Maxwell leading-edge slat and a slotted and a split flap. The main purpose was to determine the optimum slot cap of the Maxwell slat for, and the aerodynamic section characteristics of, the airfoil with several deflections for both types of flaps. Curves of lift, drag, and pitching-moment characteristics for optimum arrangements are provided.

Report presenting an investigation in the 7- by 10-foot wind tunnel of a large-chord NACA 23021 airfoil with a 15-percent-chord and a 25-percent-chord balanced split flap of Clark Y profile, to determine the aerodynamic section characteristics of the airfoil-flap combinations as affected by the size, nose location, and deflection of the flaps.

"At the request of the Bureau of Aeronautics, Navy Department, tests were made in the variable-density wind tunnel of a tapered wing of 3-10-18 plan form and based on the NACA 4400R series sections. The wing was also tested with 0.2 chord split flaps, deflected 60 degrees, in the center of the wing and having flat span to wing span ratios of 0.3, 0.5, 0.7, and 1.0, respectively" (p. 1).

Report presenting an investigation of the aerodynamic characteristics of a rectangular NACA 23012 airfoil with single and double perforated split flaps in the NACA 7- by 10-foot wind tunnel. A large range of flap spans and deflections and a large range of spanwise and chordwise locations of the flaps were investigated. Results regarding the double split flaps, single split flaps, diving speed, and aileron control are provided.

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.

Report presenting an investigation in the 7- by 10-foot wind tunnel of an NACA 23012 airfoil with an 18.05-percent-chord Maxwell leading-edge slat and with a slotted and a split flap. The main purpose of the investigation was to determine the optimum slot gap of the Maxwell slat for, and the aerodynamic section characteristics of, the airfoil with several deflections of both types of flap.

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.

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 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 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.

From Introduction: "As a part of this investigation, a study is being made of test results obtained during the development of devices designed primarily for other purposes, such as high lift or lateral control, but which may also be used for dive control. These results have been reanalyzed and are herein presented in a form that should make them convenient for design purposes."

Report presenting an investigation of a slot-lip aileron and a plain aileron, singly and in combination, on an NACA 23012 wing with a full-span flap. The characteristics of these lateral-control devices were essentially the same as those of similar devices on the wing with full-span NACA slotted flaps as tested in a previous investigation.