"The high-speed photographic investigation of the mechanics of spark-ignition engine knock recorded in three previous reports has been extended with use of the NACA high-speed camera and combustion apparatus with a piezoelectric pressure pickup in the combustion chamber. The motion pictures of knocking combustion were taken at the rate of 40,000 frames per second. Existence of the preknock vibrations in the engine cylinder suggested in Technical Report no.727 has been definitely proved and the vibrations have been analyzed both in the high-speed motion pictures and the pressure traces" (p. 223).

From Summary: "The differential equation of Chaplygin's jet problem is utilized to give a systematic development of particular solutions of the hodograph flow equations, which extends the treatment of Chaplygin into the supersonic range and completes the set of particular solutions. The particular solutions serve to place on a reasonable basis the use of velocity correction formulas for the comparison of incompressible and compressible flows. It is shown that the geometric-mean type of velocity correction formula introduced in part I has significance as an over-all type of approximation in the subsonic range."

From Introduction: "The purpose of this analysis was to investigate the use of a function of intake-manifold pressure, exhaust back pressure, intake manifold temperature, and engine speed in place of a venturi as a means of measuring engine air consumption and to determine if this function is suitable for automatic mixture control."

A theoretical and experimental investigation has been made of the behavior of a cantilever beam in transverse motion when its root is suddenly brought to rest. Equations are given for determining the stresses, the deflections, and the accelerations that arise in the beam as a result of the impact. The theoretical equations, which have been confirmed experimentally, reveal that, at a given percentage of the distance from root to tip, the bending stresses for a particular mode are independent of the length of the beam, whereas the shear stresses vary inversely with the length.

From Summary: "The differential equation of Chaplygin's jet problem is utilized to give a systematic development of particular solutions of the hodograph flow equations, which extends the treatment of Chaplygin into the supersonic range and completes the set of particular solutions. The particular solutions serve to place on a reasonable basis the use of velocity correction formulas for the comparison of incompressible and compressible flows. It is shown that the geometric-mean type of velocity correction formula introduced in part I has significance as an over-all type of approximation in the subsonic range."