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 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.

Report presenting static tests on four full-scale two-bladed propellers differing only in blade sections at blade angles from 0 to 20 degrees at the three-quarters radius. Two of the propellers were also tested as three-bladed propellers. For all of the propellers tested, the highest value of the static thrust figure of merit occurred at a tip-speed ratio between 0.7 and 0.9; the highest efficiency in flight may be expected in the same range of tip-speed ratios.

Report presenting static tests on two full-scale three-bladed propellers differing only in blade sections at blade angles from 0 to 20 degrees at the three-quarters radius.

Tests of four 10-foot propellers were made in the propeller-research tunnel for the Army Air Corps to check flight and static thrust test results made on several propellers embodying Clark Y and modified NACA 16-series sections. These propellers were identical as to diameter and activity factor and very closely identical in thickness ratio and pitch distribution. The blades embodied sections with both single- and double-cambered Clark Y, modified NACA 16-series, and a combination of Clark Y and modified NACA-16 airfoils. Tests covered a range of blade angles from 20 deg. to 70 deg., and were all made at tip speeds below 280 feet per second. Although these tests were not conclusive in themselves, owing to the conditions under which they were made, the results seem to check the flight and static tests as closely as would be expected.

"At the request of the Bureau of Aeronautics, Navy Department, tests were made in the 7- by 10-foot wind tunnel of the 1/8-scale model of the Brewster F2A airplane with full-span slotted flaps. The object of the tests was to determine the power-on static lateral and longitudinal stability of the complete model with a new wing which had a full-span slotted flap and a plain and slot-lip aileron for lateral control" (p. 1).

Report presenting information regarding the calculation of the transition point, velocity distribution in laminar and turbulent boundary layers, and thickness of the boundary layer, both laminar and turbulent, of low-drag wings.

Report presenting a discussion of the problem of establishing a rational unsymmetrical gust load criterion from available data on gust structure and it is indicated that the problem cannot be solved at the present state of knowledge without more analysis.

Report presenting testing of solid naphthalene melted and used as a fuel in a modified CFR variable-compression engine at a speed of 2000 rpm. Information regarding its knock limit, mean effective pressures, and some of its other properties are provided.

Report presenting tests of two 10-foot Hamilton Standard propellers to determine the relative merits of the Clark Y and NACA 16-series sections and to determine the negative thrust available at negative angles. Little difference was noted between propellers at peak efficiency for the low Mach numbers used in the tunnel tests.