Report presenting tests of the low-speed lateral-control characteristics of an observation airplane with ailerons and spoilers in combination and with the spoilers disconnected and the ailerons used alone with various amounts of droop. The results indicated that in unstalled flight at low speeds and with flaps deflected, little or no aerodynamic benefit was derived by changing the lateral-control system from the aileron and spoiler combination to a normal aileron installation either with or without aileron droop.

Shock-wave equations have been evaluated for a range of Mach number in front of the shock from 1.05 to 4.0. Mach number behind the shock, pressure ratio, derivation of flow, and angle of shock are presented on charts. Values are also included for density ratio and change in entropy.

This report presents the results of a flight investigation to determine the effect on the performance of a turbosupercharged engine of an exhaust-gas-to-air heat exchanger installed between the engine-exhaust collector ring and the turbosupercharger. The background, results, and discussion of the investigation are described.

"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).

Report presenting a summary of a series of reports regarding heat exchangers, and in particular, the design of exhaust gas and air heat exchangers. The four parts included are a summary of heat transfer equations, single pass heat exchangers, heater performance in flight, and appendicies with additional aerodynamic information.

Memorandum presenting investigation on reductions of friction on wings, especially by means of boundary-layer suction. The report is broken up into several sections, including: causes of transition, laminar profiles with the transition taking place, laminar boundary-layer suction, investigation of the laminar pressure increase, investigation of the slot flow for laminar boundary-layer suction with single slots, tests about keeping a boundary layer for high Reynolds laminar with the aid of boundary-layer suction, and an investigation of a slightly-cambered laminar suction profile of 10.5-percent thickness.

Report presenting knock testing of a sensitive fuel and a relatively insensitive fuel in a full-scale air-cooled cylinder. Six engine variables were investigated: fuel-air ratio, compression ratio, inlet-air temperature, spark advance, exhaust pressure, and cylinder temperature.

Note presenting three internally cooled exhaust valves with the same external dimensions but different throat designs were investigated to determine a method of obtaining increased coolant-flow area with increasing stresses. The valves were statistically loaded to simulate stresses in the throat region caused by valve closure.

Note presenting a discussion of the integral relations for flow of the boundary-layer type. It is shown that the characteristic laws of spread of jets, wakes, and so forth, can be obtained directly for the laminar case and, with the help of dimensional reasoning, for the turbulent case as well. Measurements of the mean velocity, the intensity and scale of the turbulent fluctuations, and of the turbulent shear in a two-dimensional mixing zone are presented.

Report discussing an open box joined to a closed box subjected to torsional loading. A stiff bulkhead and a flexible bulkhead were tested at the discontinuity and the results were compared to a previously published theory. Stress distribution was found to not be sensitive to bulkhead stiffness when the stiffness is large, but the calculations became sensitive to errors in estimating when the stiffness was small.

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.

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 wind-tunnel testing in two-dimensional and three-dimensional flow to investigate the aerodynamic characteristics of spoilers on tail surfaces for low-speed flight. Test results indicated that spoilers on tail surfaces showed little possibility of replacing conventional control surfaces. Results regarding a flap alone, rear spoiler alone, forward spoiler alone, forward spoiler and flap, and a combination of forward and rear spoilers on upper and lower surfaces in both types of flow are provided.

Report discusses the results of testing on a linked differential flap system upon the effective-dihedral characteristics of an airplane scale model. The negative dihedral changes caused by power can be materially reduced or eliminated by use of a differential flap system. The static directional stability also increased with differential flap action.

Report presenting tests in a seal test chamber to determine the hinge moments contributed by the fabric seal in an internal-balance arrangement employing a thin-plate overhang. The tests were performed with various widths of fabric sealing various widths of flap-nose gap, with a horizontal, a vertical, and a circular type of wing structure forward of the balance, and with various heights of balance chamber. Results regarding seal-profile photographs, desired seal-moment characteristics, experimental seal-moment characteristics, effect of the balance configuration on the seal-moment characteristics, comparison of analytical and experimental seal-moment characteristics, computation of seal-moment characteristics by the approximate method, and application of the data are provided.

Report presenting the results of a theoretical analysis of the hinge-moment characteristics of various sealed-internal-balance arrangements for control surfaces. The results of the investigation indicated that the most nearly linear control-surface hinge-moment characteristics can probably be obtained from a flexible seal over a narrow gap, which is so installed that the motion of the seal is restricted to a region behind the point of attachment of the seal to the wing structure.

Bulletin presenting an analysis of the vertical-tail loads to be expected as a result of abrupt aileron action in accelerated flight, as in rolls from turns or pull-outs, for example. Critical tail loads may occur in rolling pull-out maneuvers, particularly on airplanes with good ailerons and low directional stability.

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 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.

Report presenting thermal and static pressure-drop performance data on three fluted-type heat exchangers. Two of the heaters used corrugated surfaces along the fluid passages and the third one was constructed with non-corrugated surfaces. Results regarding a comparison of results on the noncorrugated heater using two different air shrouds, heat transfer, isothermal static pressure drop, nonisothermal static pressure drop, and heater surface temperatures are provided.

Report presenting data on the thermal performance and the static pressure drop characteristics of two finned-type exhaust gas and air heat exchangers. One heater was constructed of copper and stainless steel while the other was constructed from aluminum alloy. The measured thermal outputs and static pressure drops are compared with predicted magnitudes.

Drag testing was conducted in the high-speed wind tunnel of 23 conditions combining six streamline shapes and three conventional cowling-fuselage bodies. All of the models were tested in combination with a wing in order to include wing-fuselage interference effects. The critical speeds of combinations tested were, in general, determined by the wing-fuselage juncture.

Report presenting force tests conducted on a model of a section of the XP-63 horizontal tail surface in the 4- by 6-foot closed-throat vertical wing tunnel. The angle-of-attack range was from the negative to the positive stall for all flap deflections.