Engineering topics
Publications and source records attributed to Lawrence, D. L..
Clementine spectral reflectance and compositional data and Lunar Prospector gamma-ray data are used to map individual basalt flows in the western Procellarum and to investigate whether Th was inherent to the basalts or the result of surface contamination. Additional information is contained in the original extended abstract.
It is pointed out that the effective cooling of aircraft reciprocating engines is still a problem area for the general aviation industry. Miley et al. (1981) have reported the results of an investigation of problems associated with cooling and installation aerodynamics. A description is given of a flight test procedure which was developed in connection with the considered investigation. It is shown that the test procedure provides valid cooling requirements data for a particular installation. The data are in terms of easily measurable parameters. The employment of the test procedure, which is based on the NACA cooling correlation method, can lead to more effective cooling installations and the solution of existing cooling problems.
A flight-test based research program was performed to investigate the aerodynamics and cooling of a horizontally-opposed engine installation. Specific areas investigated were the internal aerodynamics and cooling mechanics of the installation, inlet aerodynamics, and exit aerodynamics. The applicable theory and current state of the art are discussed for each area. Flight-test and ground-test techniques for the development of the cooling installation and the solution of cooling problems are presented. The results show that much of the internal aerodynamics and cooling technology developed for radial engines are applicable to horizontally opposed engines. Correlation is established between engine manufacturer's cooling design data and flight measurements of the particular installation. Also, a flight-test method for the development of cooling requirements in terms of easily measurable parameters is presented. The impact of inlet and exit design on cooling and cooling drag is shown to be of major significance.
The goal of cooling installation design is to provide adequate cooling air flow to the engine with a minimum drag penalty. To achieve this goal, attention must be given to certain aerodynamic factors involved in the design problem. In the present paper, the factors which influence the aerodynamic design of horizontally-opposed engine cooling installations are discussed with particular reference to the performance of the aircraft in terms of the dynamic pressure generated for the power output of the engine, the gains or losses through the propeller, proper inlet design, altitude effects on the orifice characteristics of the engine, and exit area sizing. Results of a flight research program showed that the inlet design has a significant influence on cooling effectiveness and drag; the inlet should be designed for low velocity ratios and should avoid small radii of curvature in its geometry. The influence of the propeller on the inlet appears to cause the stagnation point on the lip to move toward the inside.