Ralph L. Hough

One of the components of an airborne fire extinguishing system is the spherical storage container. The container is normally half-filled with liquid agent. High-pressure gas occupies the remaining half. Discharge studies using a short line connected to a sphere indicates a discontinuity in the liquid flow during the latter portion of the discharge. Little information is available concerning the discharge process. A short research program was initiated to examine the interface during the discharge. The purpose was to determine the existence of interface distortion as the mechanism responsible for the on served discontinuity in agent discharge. A description of the test apparatus is given together with pertinent data obtained therewith. Conclusions are drawn as to possible container design changes. Suggestions are offered for future work in this field.

Lyle E. Tarbell

A full-scale test program was conducted for the purpose of evaluating the fire extinguishing system used in B-36 airplane powerplants and to assist in the design of an improved system. Certain design features of the powerplant, which affected the control of in-flight fires, also were evaluated.

Both laboratory and in-flight tests were made on the original and a number of revised extinguishing systems using an agent concentration reorder to determine the concentration and distribution of agent within the various fire zones. The quantity of agent discharged into each zone was determined from catch tests n a mocked-up system. The effectiveness of all fire control provisions ultimately was determined from laboratory tests in which actual fires were ignited in the powerplant under simulated flight conditions.

Certain firewall improvements and a fire curtain installation incorporated in B-36 aircraft by the Department of the Air Force were evaluated and found to be effective in pre venting powerplant fires from spreading forward into the wing. A revised extinguishing system, which included Zone 3 coverage, was found to be inadequate. Weaknesses in the fire seal separating Zone 1 and 3 and in the shrouding of hot surfaces in Zone 2 were indicated.

Allen V. Young

A study was made of the control of in-flight turbojet powerplant fires by conducting full-scale tests on the F-89 fire extinguishing system. The early phases of this study showed that the F-89 fire extinguishing system was ineffective in extinguishing fires of low, as well as high, intensity. Seven modifications of this system wee tested in an effort to accomplish successful extinguishment using bromochloromthane in a perforated tubing system. Considerable improvement in extinguishment of fires was accomplished but to warrant acceptance of the system.

A high-rate-discharge system then was considered as a possible means of providing effective extinguishment. A high-rate-discharge system, consisting of a manifold and distribution lines, was developed which effectively extinguished all fires ignited inside the engine bay, including those of a size which consumed all oxygen in the cooling air. Dibromodifluoromethane was found more effective than bromochloromethan as the extinguishing agent.

R.B. Jones

Utilizing principles previously established by the National Advisory Committee for Aeronautics and the Walter Kidde & Company, Inc., an aircraft crash-fire prevention system was designed, developed and flight tested. The object of the program was to demonstrate, through the use of pre-production type equipment, the feasibility of providing an airworthy and reliable aircraft crash-fire prevention system. A transport type airplane, the USAF C-119G, was used as test medium for the system. The system was designed to eliminate, in the event of a survivable type crash, the potentially dangerous crash-fire hazards usually found in an airplane. This was accomplished by providing for -'the inerting of all possible sources of ignition, as well as the shutoff of combustibles in nacelles and de-energizing of the airplane's electrical system. The system also included crash damage sensing devices coordinated by a control unit to automatically initiate the inerting and shutoff equipment in the event of crash. Circuitry for semi-automatic checkout of the system was incorporated in the control unit. The flight tests which concluded the program, demonstrated that an aircraft crash-fire prevention system can be made airworthy and reliable

Damiel Gross

Flame-spread data, as measured by the radiant panel method, have been obtained for a wide variety of materials including representative composite assemblies of interior finishes applied to common wall base materials.