Memorandum presenting preliminary tests in order to determine the effect of forced ventilation on the hydrodynamic characteristics of a scale model of a streamline fuselage of a hypothetical transonic airplane. The forced ventilation consisted of air ejected at about 300 feet per second through small orifices distributed over the fuselage bottom in a series of patterns simulating chines or multiple steps. Results regarding resistance, effective hydrodynamic lift, trim, spray, and air flow are provided.

Report presenting an investigation of the effect of two wing sections and a tip tank on the aerodynamic characteristics of a rigid unswept wing in the high-speed tunnel over a Mach number range of 0.60 to 0.90. Results regarding the effect of original airfoil sections, effect of modifications to Section B, effect of tip tank, and characteristics of the tip tank in the presence of the wing are provided.

Report presenting an investigation of the effect of hull length-beam ratio on the hydrodynamic characteristics of flying boats that extend to a length-beam ratio of 20. The results are compared with flying boats having a length-beam ratio of 15. Results regarding longitudinal stability, spray characteristics, take-off performance, taxiing and take-off behavior in waves, landing behavior in waves, and a summary chart are provided.

Report discussing an investigation of two full-scale NACA propellers at a range of blade angles and at speeds of up to 500 miles per hour. The results are compared to previous investigations of five NACA propellers to evaluate the effects of blade-section thickness ratios on propeller characteristics.

Report presenting the results of an analytical investigation, which demonstrated that the inlet of a turbojet engine can be protected from ice accretions by bleeding hot gases from other locations within the engine to the inlet without undue loss in thrust. Results regarding the bleedback requirements, engine performance, effect of nozzle area, mixing efficiency, and seriousness of thrust losses are provided.

Report presenting an investigation of the effect of the rate of change of angle of attack on the maximum lift coefficient of a pursuit airplane equipped with a low-drag-type wing in stalls of varying abruptness over a range of Mach and Reynolds numbers. Maximum lift coefficients were found to increase linearly with increasing rate of change of angle of attack per chord length of travel up to the maximum rate attained in the tests.

"Results are presented from tank take-off tests of a dynamic model of a hypothetical high-speed airplane fitted with NACA hydro-skis and having the transverse curvature of the lower rear portion of the fuselage broken by small longitudinal chine strips. For the configuration tested, both trim and resistance were considerably reduced by the addition of the strips from the speed at which the ski emerged to the speed at which the rear of the fuselage came clear of the water. The results indicate that fuselage shape has a large effect on the take-off characteristics for a hydro-ski configuration in which the rear of the fuselage acts as a planing surface" (p. 1).

Report discussing the effect of half-span and full-span split flaps through a deflection range on the low-speed, longitudinal characteristics of a sweptback wing with a round-nose, extensible leading-edge flap. Information about the effect of split-flap deflection on lift and stalling characteristics, effect of split flaps on gliding characteristics, and effect of leading-edge roughness on longitudinal stability is presented.

Report discussing an investigation to determine the effect of sweepback on the static and rolling stability derivatives of a series of wings with a taper ratio of 0.6 and an aspect ratio of 4. The influence on the straight-flow characteristics, rolling-flow characteristics, and aileron characteristics are provided.

Report presenting an investigation to determine the effect of the primary-jet temperature on the performance of several ejector configurations. The performance of ejectors expressed in terms of the ratio of weight of secondary air flow to primary air flow was found to be affected by temperature in two ways.

Report presenting a wind-tunnel investigation to determine the effect of propeller operation on the characteristics of submerged inlets. The tests were performed with a model of a hypothetical fighter airplane powered by a turbine-propeller unit. The propeller had eight blades with thin airfoil shanks and dual rotation and the submerged inlets were placed in the fuselage behind the propeller and forward of the wing.

Report presenting an investigation of the low-speed characteristics of a wing swept back 42 degrees at the leading edge and having various high-lift and stall-control devices and fuselage and horizontal tail vertical positions. Results regarding the characteristics of the basic wing, leading-edge flap investigation, wing fuselage investigation, and horizontal tail investigation are provided.

"An additional series of high-speed wind-tunnel tests of a modified 0.17-scale model of the McDonnell XF2H-1 airplane was conducted to evaluate the effects of a reduction in the thickness-to-chord ratios of the tail planes, the displacement of the horizontal tail relative to the vertical tail, and the extension of the trailing edge of the wing. Two tail-intersection fairings designed to improve the flow at the tail were also tested. The pitching-moment characteristics of the model were improved slightly by the use of the thinner tail sections" (p. 1).

An investigation of the damping-in-roll characteristics of three wings with an aspect ratio of 4, a taper ratio of 0.6, three sweep angles at the quarter chord line, and the NACA 65A006 section as determined through a range of Mach numbers and angles of attack.

Report presenting the lift and pitching-moment characteristics of two wings of the same plan form measured over a range of Mach and Reynolds numbers using the wing-flow method. One wing had a symmetrical airfoil section and no twist, while the other was cambered and twisted to support a uniform load distribution at a lift coefficient of 0.25 at Mach number 1.5. A comparison with previous testing is also provided.

Report presenting an investigation to determine the effects of several leading-edge modifications on the maximum lift and pitching-moment characteristics on a large-scale 45 degree swept-forward wing. A full-span leading-edge flap deflected 30 degrees down tended to give the largest gain of maximum lift. Results regarding the plain leading-edge flaps and cambered nose are explored.

Report presenting an investigation in free flight of the rolling effectiveness of plain ailerons in conjunction with wings having 0 and 45 degrees sweepback with several airfoil sections. Results regarding the rolling characteristics of rectangular and sweptback-wing configurations and drag measurements are provided.

Report presenting the results of a wind-tunnel investigation of the effects of variation of trailing-edge angle and leading-edge radius on the aerodynamic characteristics of a 10-percent-chord-thick airfoil section at a range of Mach numbers.

Report presenting wind-tunnel tests up to a Mach number of 0.85 to determine the effects of wing-tip gun turrets on the aerodynamic characteristics of a typical bomber-wing model. Lift, drag, and pitching-moment data are presented for the wing alone; for the wing with the turrets in the clean condition; and for the wing and the turrets with guns and sighting equipment. The turrets had negligible effect on the lift and pitching-moment characteristics of the wing.

A lightweight instrument that utilizes resistance-wire electric strain gases to measure propeller-shaft thrust has been developed. A wind-tunnel investigation on a propeller installed, on a single-engine pursuit airplane showed that the instrument gave a reliable indication of propeller-shaft thrust to an accuracy of +/-2 percent within its calibrated range. No attempt was made to determine the relation of indicated shaft thrust to net propeller thrust.

"Investigations in the Langley 20-foot free-spinning tunnel of models of five jettisonable nose sections have shown that the airplane nose sections are inherently unstable but can be stabilized by the addition of suitable fins. An empirical criterion has been developed which indicates the fin area required for stabilizing an airplane jettisonable nose section" (p. 1).

Memorandum presenting an analysis of selected experimental pressure-distribution data at transonic speeds for the purpose of deriving an empirical method which may be used for estimating the trailing-edge loads and bending moments at the design stage. The trailing-edge normal-force and bending-moment coefficients calculated by the derived method follow the general trend of the experimental data and appear to be a guide where specifically applicable chordwise pressure-distribution data at transonic speeds are not available.

Report presenting an analysis of the estimated flying qualities of a tailless airplane with the wing quarter-chord line swept back 35 degrees in a range of Mach numbers based on tests of a model of the airplane in the 7- by 10-foot tunnel. Results regarding performance, longitudinal stability and control, and lateral stability and control are provided.

Report presenting a semiempirical method of estimating the forces on airfoil at near sonic speeds and in the presence of detached shock waves. The calculated values were found to be in good agreement with wind-tunnel testing of the forces on sharp-nose airfoils and two-dimensional wings.