Report presenting an analytical study of the influence of full-span slotted and Fowler flaps on the requirements for horizontal tail surfaces. The elevator deflection required to land at three-point attitude, elevator deflection required to stall the airplane at altitude, and permissible center-of-gravity range have been calculated for a fighter-type airplane.

Report presenting a technique of testing wind tunnel powered models developed as a result of experience gained in the investigation of the static longitudinal and lateral staiblity and control characteristics of several powered models in the 7- by 10-foot wind tunnel. A discussion of the conditions to be investigated, methods of presenting and interpreting the data, and a suggested operating technique are given.

Report presenting the results of recent spin-tunnel tests on models of seven multiengine airplanes and compared with corresponding results for representative single-engine airplanes loaded along the fuselage. Multiengine airplanes were found to give steep spins with high rates of descent and high load factors.

Report presenting testing of cooling blowers for air-cooled engine installations and an exploration of the methods used in the blower design and operating characteristics of the blowers over a range of flight speeds and altitudes. The results indicate that the blowers operate as a more efficient type of propeller cuff and in many cases provide considerably more pressure boost than using a cuff.

Report presenting an investigation of a plain aileron and a balanced aileron on a tapered wing with full-span duplex flaps, which consisted of an inboard NACA slotted flap and an outboard balanced split flap. Increments of maximum lift coefficient of 0.82 and 1.04 were obtained from the inboard flap alone and from the duplex-flap combination.

Report presenting an investigation in the 7- by 10-foot wind tunnel of several arrangements of a plug-type spoiler-slot aileron on a tapered wing model of a typical fighter airplane with a full-span slotted flap. When the aileron is deflected, the plug projects from the upper surface of the wing as a spoiler and makes a slot appear behind the spoiler.

Report presenting an investigation in the 7- by 10-foot wind tunnel to determine the aerodynamic section characteristics of several arrangements of an NACA full-span high-lift lateral-control combination. The combination consists of a full-span flap of airfoil profile that retracts ahead of a narrow-chord full-span aileron. Results regarding coefficients, precision, plain airfoil, determination of optimum aileron-flap arrangement, section aerodynamic characteristics, and lateral-control characteristics are provided.

Report presenting force tests in two-dimensional flow in the 4- by 6-foot vertical tunnel of the characteristics of an NACA 0015 airfoil with a balanced flap having a chord of 30 percent of the airfoil chord, a flap-nose overhang 50 percent of the flap chord, and a tab having a chord 20 percent of the flap chord. Results regarding the precision and presentation of data, lift, hinge moment of flap, pitching moments, drag, tab characteristics, and balancing effectiveness of various overhangs are provided.

Report presenting an analysis of the probable aerodynamic section characteristics of a plain flap with various arrangements of internal balance. The results of the calculations previously obtained were found to be in agreement with the experiment. Some possible applications of the data to balancing tabs are also provided.

Report presenting force-test measurements in two-dimensional flow made in the 4- by 6-foot vertical tunnel of the characteristics of an NACA 0015 airfoil with a balanced flap with a chord 30 percent of the airfoil chord and a flap-nose overhang 35 percent of the flap chord. Results regarding lift, hinge moment of flap, pitching moment, drag, and tab characteristics are provided.

Report presenting testing of a mock-up of a pursuit airplane in the full-scale wind tunnel and the effects of propeller operation and flap deflection on the aerodynamic characteristics of the wing-fuselage combination and of the horizontal tail. The results indicate that with the flap deflected, the propeller-operating conditions cannot be directly determined from the propeller-removed lift coefficient.