Report presenting an investigation in two-dimensional flow to determine the effect of leakage past the aileron nose on the aerodynamic characteristics of ailerons. The effects of amount and type of leakage, aileron contour, and Mach and Reynolds number are investigated.

Report presenting wind-tunnel testing in two-dimensional flow to investigate the aerodynamic characteristics of a flap balanced by a large overhang linked to deflect more slowly than the flap. Three lengths of blunt-nose overhang were tested linked to a 0.30-airfoil-chord straight-contour flap on an NACA 66-009 airfoil. Results regarding lift, hinge moment, drag, pitching moment, and practical considerations are provided.

Report presenting wind-tunnel tests in two-dimensional flow to investigate the aerodynamic characteristics of a double flap with an internal and overhang balance. Three sizes of each type of balance were tested with three relative rates of deflection of the two flaps. Results regarding lift, hinge moment, drag, and pitching moment are provided.

Results of subject tests indicate the difficulty of obtaining closely balanced rudder surfaces for most tail assemblies with shielded horns and maintaining a near zero rate-of-change of hinge-moment coefficient without an additional balancing device. A comparison is made between shielded and unshielded horn test results. Pressure distribution and tuft tests of flow over different shaped horns showed higher critical speed for medium-taper nosed horn. The trim tab nose shape had little effect on tab test results.

Report presenting force tests in two-dimensional flow made on an NACA 66-009 airfoil with a flap having a chord 30 percent of the airfoil chord and a tab having a chord 20 percent of the flap chord. A plain flap and flaps having overhangs of 35 and 50 percent of the flap chord were tested with two gap variations: sealed and unsealed. Results regarding lift, flap hinge moments, pitching moments, drag, and tab characteristics are provided.

Report presenting lift and hinge-moment characteristics of various types of airplane control surface. The data can be used to determine curves correlating the results of many tests of the various types of aerodynamic balance.

Report presenting flight tests of an all-movable vertical tail of reduced area of the Fairchild XR2K-1 airplane. Results are in agreement with previously obtained data on a larger all-movable tail. Results regarding rudder effectiveness, directional stability, rudder-free lateral motion, rudder hinge moments, and areas of future research are provided.

Wind-tunnel tests, investigating low drag wing performance in small-scale tests, showed a large increase in minimum drag coefficient, and a decrease of maximum lift coefficient occurred with decreasing Reynolds Number above certain designated values. The lift-curve slope varied up to 6% between high and low turbulence levels. Low Reynolds Number test data are unreliable for low drag airfoils either to estimate full-scale characteristics or to determine merits of airfoils for higher Reynolds numbers.

Report presenting the effect of Reynolds number on the aerodynamic characteristics of a low-drag airfoil section tested under conditions of relatively high stream turbulence. The data are presented as curves of section angle of attack, section profile-drag coefficient, and section pitching-moment coefficient against section lift coefficient for various flap deflections.

Report presenting tests in the two-dimensional low-turbulence pressure tunnel to study the interference effects of various pusher-propeller shaft-housing combinations on a low-drag airfoil. Thirty different combinations were tested, variations being made in shaft size, shape, angle, and fillet.

Report presenting an investigation of three interchangeable sealed-gap 0.20-airfoil-chord plain ailerons of different contour on the NACA 65(sub 1)-210 airfoil section. The three aileron contours tested were the true airfoil contour, straight sides, and a beveled trailing edge. Results regarding the aileron effectiveness, aileron hinge moments, lift, pitching moment, and drag are provided.

"Recent developments in airfoil-testing methods and fundamental air-flow investigations, as applied to airfoils, are discussed. Preliminary test results, obtained under conditions relatively free from stream turbulence and other disturbances, are presented. Suitable airfoils and airfoil-design principles were developed to take advantage of the unusually extensive laminar boundary layers that may be maintained under the improved testing conditions" (p. 1).

Report presenting a series of boundary-layer surveys over the surface of an NACA 0012 airfoil at zero lift. Results regarding the pressure distribution, laminar boundary layer, transition, turbulent boundary layer, drag, and skin friction are provided.

Report presenting testing to determine the aerodynamic characteristics of an NACA 66-series 16-percent-thick low-drag tapered wing with Fowler and split flaps. The wing had a straight trialing edge and a constant-chord center section. Results regarding lift and pitching-moment characteristics and stalling characteristics are provided.

Report presenting an investigation in the 7- by 10-foot tunnel of three inset tabs and of one attached tab on the beveled aileron of a low-drag wing. The results indicated that, of the arrangements tested, an inset tab with a chord 50 percent of the aileron chord provided the most satisfactory trimming characteristics on a beveled aileron.

"An investigation has been conducted in the Langley rectangular high-speed tunnel to determine the effect of compressibility on the pressure distribution for a modified NACA 65,3-019 airfoil having a 0.20-chord flap. The investigation was made for an angle-of-attack range extending from -2 to 12 deg at .20 flap deflections from 0 to -12 deg. Test data were obtained for Mach numbers from 0.28 to approximately 0.74" (p. 1).

From Summary: "Tests were made of an 0.309-chord double-slotted flap on an NACA 65, 3-118, a equals 1.0 airfoil section to determine drag, lift, and pitching-moment characteristics for a range of flap deflections. Results indicate that combination of a low-drag airfoil and a double-slotted flap, of which the two parts moved as a single unit, gave higher maximum lift coefficients than have been obtained with plain, split, or slotted flaps on low-drag airfoils. Pitching moments were comparable to those obtained with other high-lift devices on conventional airfoils for similar lift coefficients."

Report presenting an investigation of the effects of propellers and of vibration on the extent of laminar flow on the NACA 27-212 airfoil by testing the airfoil in conjunction with a tractor and a pusher propeller and with a mechanical vibrator. The results show that neither the pusher propeller nor vibration with amplitudes up to 0.094 inch and with a frequency of 1650 cycles per minute had any consequential effect on the extent of laminar flow but that the tractor propeller had a very pronounced effect.

Report presenting problems relating to the stability and control of tailless airplanes in consideration of contemporary experience and practice. Some observations in regards to small and large airplanes are provided.

From Summary: "The results of an analytical investigation to determine the qualitative effects of elevator-fabric distortion on the stick-force characteristics of an airplane are presented. These results indicate that serious alteration of intended stick-force characteristics can be produced by elevator-fabric distortion."

Force and flight tests were performance on an all-wing model with windmilling propellers. Tests were conducted with deflected and retracted flaps, with and without auxiliary vertical tail surfaces, and with different centers of gravity and trim coefficients. Results indicate serious reduction of stick-fixed longitudinal stability because of wing-tip stalling at high lift coefficient. Directional stability without vertical tail is undesirably low. Low effective dihedral should be maintained. Elevator and rudder control system is satisfactory.

Report presenting an investigation of the power-off longitudinal stability characteristics of a tailless all-wing airplane model with various wing modifications in the free-flight tunnel. The results indicated that changes in the tip plan form or rotation of the wing tips did not appreciably reduce the instability at high lift coefficients.

Report discusses the results of an experimental investigation of two low-drag wing-nacelle units suitable for use with pusher propellers. The benefits of adding a nacelle to the wing are detailed.

Report presenting an investigation of the drag and power cost associated with the changing of the nose of a nacelle from a streamline shape to a conventional cowling shape. Full-scale propellers and nacelles were used. The results of the tests showed that the streamline afterbody drag approached that of an airship form and that the added drag due to the open-nose cowling was only a quarter of the drag increase obtained with the other afterbody.