Coleman P. Donaldson, K. Evan Gray

An extension and improvement of Warren’s momentum integral method for predicting the turbulent mixing and decay of axially symmetric, compressible, free jets o the case of the mixing of dissimilar gases is discussed. Two ideal gases having different molecular weights and specific heats are treated with the assumption that the local turbulent mixing rate at each axial location depends upon a suitably chosen local reference Mach number. This method of analysis is then compared with the results of a series of jet-mixing experiments carried out o helium, methane, nitrogen, carbon dioxide and freon jets mixing in air. Mach numbers ranging from 0.75 to 3.30 were investigated. The character and mixing rates of both properly and improperly expanded supersonic jets were studies. It is concluded from a comparison of these data with the theoretical method presented that a general relationship exists, at each axial position I the jet, between a local mixing rate parameter and the local Mach number. This general relationship is independent, within the accuracy of these experiments, of the physical properties or the thermodynamic state of the mixing gases.

Jim Brenneman

The Cleveland tests were conducted to determine if survival time in an aircraft cabin could be extended under post-crash fire conditions by using high expansion foam to completely fill the occupied portions of the cabin interior. It was hoped that the high expansion foam would hold the temperature within survivable limits while controlling smoke, toxic gases, and other products of combustion. Thus, we would provide cool, breathable atmosphere for a prolonged period of time for the occupants, pending ultimate evacuation or rescue.

As a secondary objective, we hoped to determine the exact nature of the smoke, gases, etc., that may be present in a post-crash fire in which typical modern aircraft cabin materials such as vinyl, polypropylene, polyvinyl chloride, etc, and plastics are installed and are involved in the fire.

To these ends, the tests were only to prove the concept, since the foam equipment used was “off the shelf” hardware, and not suitable for use as an installed system. It would also not be suitable for use in its present form by ground fire fighting, since it is too slow and cumbersome to put into operation.

D. Gross

Quantitative measurements of the total heat release from weight selected building materials were made during an interlaboratory study of the Potential Heat Test Method. Statistical analysis of the results indicates that a higher degree of variability existed among the nine participating laboratories than would be expected of a single laboratory performing standardized oxygen bomb calorimeter determinations of the heat of combustion. It was noted the majority of laboratories tended to rank the materials in the same order, or in an order, which could be made the same by a ranking change of a single materials

Robert F. Salmon

An airborne type thrust measuring instrument was developed and subsequently tested on both a General Electric J79-GE-8 turbojet engine mounted on a thrust stand in a laboratory altitude cell and a Pratt and Whitney JT3C-7 turbojet engine aboard a Boeing 720 aircraft. The thrust meter system using measurements of internal engine pressures, ambient altitude pressure and a total air temperature, computed engine gross thrust, net thrust and percent of maximum continuous rated thrust at the operating flight condition.

Laboratory tests indicated that : (1) the gross thrust value computed theoretically from the measured pressures were within _+2.0% of the thrust stand measured gross thrust (2) the thrust meter gross thrust values were within _+3.0% of the thrust stand measured values, (3) the net thrust values of the thrust stand measured net thrust, and (4) the thrust meter net thrust values were within _+4.2% of the thrust stand measured net thrust. The gross thrust computer module malfunctioned for a series of tests at a simulated altitude condition of 40,000 feet and Mach 1.2.

Flight test results indicated that the system functioned properly abroad the aircraft and was responsive to small changes in engine power setting. The thrust meter gross thrust and net thrust values agreed with the computed gross and net thrust of the engine within _+2.2% and _+2.8% respectively. In measuring net thrust during the flight tests, some difficulty was encountered in obtaining consistent static pressure readings at the compressor inlet station thus causing errors in the computation of ram drag.

Julius J. Gassmann

An investigation was made to determine the requirements for protecting large cargo aircraft against in-flight cargo fires. Tests were conducted within an instrumented fuselage of a large cargo aircraft using ordinary packing material as cargo. These tests demonstrated the need for suitable means, air-flow shutoff controls and adequate insulation properly installed.A procedure was developed which may be useful in conducting in-flight certification tests on smoke detection system installations. A method of generating the smoke was selected on the basis of uniformity, cleanliness and freedom from odor as a result of its use during evaluation.