Availability data obtained on SNB-1 trainer-class airplanes were analyzed and results presented as flight envelopes which predict occurrences of large values of air speed and acceleration. Comparison is made with SNJ-4 trainer-class airplane data analyzed by the same method. It is concluded that flight envelopes are satisfactory; that the two types show large differences in flight loads and speeds experience; and that SNB-1 will seldom, if ever, exceed design limit load factor and restricted speed, which SNJ-4 can be expected to exceed design-limit load factor and restricted speed in a very small number of flight hours.

The effect of various vertical tail arrangements upon the stability and control characteristics of an XP-62 fighter model was investigated. Rudder-free yaw characteristics with take-off power and flaps deflected were satisfactory after dorsal fin modifications. Directional stability was obtained with all modified vertical tails. Satisfactory rudder effectiveness resulted partly because the dual-rotation propellers produced no asymmetric yawing moments. Pedal forces in sideslips were undesirably large but may be easily reduced.

Report presenting climb and high-speed tests of a Hamilton Standard No. 6507A-2 three-blade propeller, which have been made to determine the effect of blade loading on propeller efficiency. The normal and military power climb efficiencies were found to be about equal at altitudes below 16,000 feet.

Report presenting an investigation for the purpose of developing a target which can be towed satisfactorily at high speeds. Testing included drag measurements and visual observations of the stability characteristics of several full-scale and scale models of sleeve-type tow targets. The drag coefficients obtained for the currently used targets were found to be excessively high.

Report discussing the cooling characteristics of a modified 14-cylinder double-row radial air-cooled engine installed in a four-engine airplane at a pressure altitude of 7000 feet. Testing of the variable charge-air flow, variable cooling-air pressure drop, and variable fuel-air ratio was conducted. The cooling equation, temperature-limited performance, maximum engine temperatures, and other information predicted by calculations is described.

Report discussing testing on 22 inch-diameter pulse-jet engines to determine the effect on performance of a change in combustion-air temperature from approximately 80 degrees to 130 degrees. The effects on jet thrust, combustion-air flow, and engine thrust are described.

Report discussing the effects of circular-arc spoilers on the section characteristics of an NACA 66,2-216 airfoil with a 0.25-chord slotted flap. Spoilers were tested on the upper surface of the airfoil, on the lower surface, and on both simultaneously. Only the simultaneous placement of spoilers was found to provide satisfactory results as a lateral control device.