Milton Levy, Albert Levitt

The drive toward ever higher operating temperatures in Army weapon systems continues unabated since the thermal efficiency and effectiveness of such systems are proportional to their operating temperatures. In the case of missiles and rockets, advances in propellant technology and in system design have outstripped materials development, so that at the present time and in the foreseeable future, lack of suitable materials to resist the extremely high temperatures encountered in such systems is the primary barrier to their continued development. Two major problem areas are involved - internally in the propulsion system and externally on the nose cone and leading edges of aerodynamic control surfaces. Specific components include combustion chamber liners, nozzles, nose' cones, vanes, etc.

Paul Boris

This study was performed to provide information on the flammability of magnesium alloys. An investigation of the ignition and burning characteristics was conducted on prepared specimens of four common magnesium alloys. Standard flat specimens were of the same dimensions except for thickness. In addition, typical reciprocating engine castings were tested to determine ignition and burning characteristics under fire conditions closely representing the intensity of an aircraft power plant fire. Each casting varied in thickness from 1/4 inch to 1 inch maximum and was devoid of all internal parts and circulating fluids.

The major results of the prepared specimen test are presented as a family of curves which indicate that time to ignition did not vary significantly among the alloys tested, but varied directly with thickness of specimen and airflow over the specimen. After ignition, the airflow accelerated the alloy's burning rate. Tests on the castings revealed a minimum time to ignition of 2 minutes for the smallest (23 pounds) and 4 minutes for the largest (91 pounds).

In general, tests indicated that it would be good practice to eliminate sharp edges and protrusions from magnesium alloy casting where possible since these were observed to be more susceptible to ignition. Small magnesium components that are not an integral part of the engine could represent a substantial fire hazard in that they will ignite in a short period of time under intense fire conditions. Previous experience has shown that magnesium fires cannot be extinguished by extinguishing agents presently in use in aircraft power plants and therefore could become a source of reignition of flammables.

National Fire Protection Association

The Association campaigns to prevent needless loss of life and property by fire. Methods for fire protection and fire presentation are developed and improved. By public education, people are urged to apply known methods of preventing and controlling fires.

John F. Marcy, E.B. Nicholas, J.E. Demaree

Flammability and smoke characteristics of interior materials were determined from a selection of 109 materials representative of present usage in the aviation industry. A comparison was made of the flame-resistant characteristics exhibited by the different materials on the basis of (1) test method, (2) thickness, weight, composition and backing, (3) fire-retardant treatment, and (4) degradation from use and cleaning. By employing test methods defined in FAA Flight Standards Service Release 453 and Federal Specification CCC-T-19lb, burning characteristics were obtained in terms of burn rate, burn length, and self-extinguishing time. A Flame-Spread Index and smoke factor also were obtained by making use of the Radiant Panel Test Apparatus.

G. C. Huang

In this paper, empirical equations of local as well as average heat-transfer coefficients of single jet system were derived. Two aspects of multiple jet systems have been studied. One concerns mainly the uniform distribution of heat-transfer coefficients and economy of power consumption. The other concerns the high magnitude of heat-transfer coefficients and the interference among jets. The experiments were conducted at Reynolds number from 10 to 10 and hole size from 1/8 to ¼ in. diameter. An attempt to correlate empirical data to render practical application possible