This paper surveys the available material and summarizes what is known to date about boundary-layer transition at supersonic speeds. Variables studied include Mach number, Reynolds number, pressure gradients, heat transfer, surface roughness, and angle of attack. The discussion is limited to bodies of revolution because similar reliable data for wings is lacking.

A limited calibration of a combined pitot-static tube and vane-type flow-angularity indicator has been made in the Langley 4- by 4-foot supersonic pressure tunnel at Mach numbers of 1.61 and 2.01. The results indicated that the angle-of-yaw indications were affected by unsymmetric shock effects at low angles of attack.

A first-order geometrical optics analysis of a facsimile camera augmented with an auxiliary lens as magnifier is presented. This concept, called quasi-microscope, bridges the gap between surface resolutions of the order of 1 to 10 mm which can be obtained directly with planetary lander cameras and resolutions of the order of 0.2 to 10 microns which can be obtained only with relatively complex microscopes. A facsimile camera was considered in the analysis; however, the analytical results can also be applied to television and film cameras. It was found that quasi-microscope resolutions in the range from 10 to 100 microns are obtainable with current state-of-the-art lander facsimile cameras. For the Viking lander camera having an angular resolution of 0.04 deg, which was considered as a specific example, the best achievable resolution would be about 20 microns. The preferred approach to increase the resolution of the quasi-microscope would be, if possible, through an increase in angular resolution of the camera. A twofold to threefold improvement in resolution could also be achieved with a special camera focus position, but this approach tends to require larger and heavier auxiliary optics.

A method is presented for the determination of the time lag in pressure measuring systems incorporating capillaries; this method is a convenient and systematic means of selecting, designing, or redesigning a pressure measuring system to meet the time requirements of a particular installation. Experimental data are shown and a step-by-step sample application is presented.

A preliminary investigation has been made of the effects of heat transfer on boundary-layer transition on a body of revolution at a Mach number of 1.61 and over a Reynolds number range of 7,000,000 to 20,000,000, based on body length. The body had a parabolic-arc profile, blunt-base, and a fineness ratio of 12.2 (NACA RM-10). The results indicated that, by cooling the model an average of about 50 degrees F, the Reynolds number for which laminar boundary-layer flow could be maintained over the entire length of the body was increased from the value of 11,500,000 without cooling to over 20,000,000, the limit of the present tests. Heatig the model an average of about 12 degrees F on the other hand decreased the transition Reynolds number from 11,500,000 to about 8,000,000. These effects of heat transfer on transition were considerably larger than previously found in similar investigations in other wind tunnels. It appears that, if the boundary-layer transition Reynolds number for zero heat transfer is large, as in the present experiments, then the sensitivity of transition to heating or cooling is high; if the zero-heat-transfer transition Reynolds number is low, then transition is relatively insensitive to heat-transfer effects.

An investigation has been made to determine the effect of heat transfer on the peak pressure rise associated with the separation of a turbulent boundary layer on a body of revolution (NACA RM-10) at a Mach number of 1.61. Tests were made over a Reynolds number range from 11.6 X 10 to the 6th to 34.8 X 10 to the 6th and with 0 to 120 degrees F of cooling, which corresponds to a ratio of model-wall temperature to stagnation temperature of 0.96 (zero heat transfer) to 0.75. The stagnation temperature was approximately 570 degrees F absolute. Boundary-layer separation was induced by means of forward-facing steps or collars at the base of the model and changes in heat transfer were obtained by cooling the model. The peak pressure rise was determined from shock angles measured from schlieren photographs.