John F. Marcy

A study was made of the burning characteristics of airplane interior materials ignited inside a 640 cubic foot cabin mockup enclosure. Test conditions were varied to investigate the effects of a number of factors on the ignition and propagation of flames within enclosures; namely, (1) flammability ratings of the materials as obtained from standard laboratory tests, (2) intensity, duration and type of the ignition source whether flaming or incandescent, (3) ventilation rate as provided by different size openings into the cabin enclosure, (4) partitioning of the cabin space by use of a fire barrier curtain and (5) discharge of bromotrifloromethane (CF3Br) into the cabin atmosphere, both at different rates and total quantities of application before and during a fire occurrence. Comparative tests conducted on flame-retardant (FR) urethane and neoprene foams showed that the flash fire hazard prevalent with the use of regular foam could be greatly reduced by replacement with these two self-extinguishing foams. A high rate discharge system employing CF2Br (1301) was shown to be effective in rapidly extinguishing the flame of a foam fire. A curtain divider placed across the ceiling was shown to be useful as a fire barrier to arrest flame propagation. Roof venting of the mockup at a location away from the fire was relatively ineffective in preventing rapid buildup of smoke and flame from a flash fire involving urethane foam.

Roger Jones

A symposium on aircraft fire detector systems held in Washington, D.C. on 16 and 17 November 1970. The purpose of the symposium was to familiarize Federal Aviation Administration Regional personnel with the characteristics, capabilities and limitations of the currently available detector systems. A number of presentations were made by representatives of leading fire detector, helicopter, and msall airplane manufacturers and by representatives of the military and the FAA National Aviation Facilities Experimental Center.

Daniel E. Sommers

Tests under simulated conditions were conducted on a small fuselage mounted turbojet engine and nacelle installation to investiaget the potential explosion and fire hazards and detection and fire control methods.

Hot surface ignition of flammables did not occur during simulated flight operating conditions until a change to the normal nacelle configuration reduced cooling airflow to the hot section of the engine (Zone I) below 0.15 pound per second.

The installed detection system did not provide for prompt detection of all fires orginated in the lower forward portion of the compressor compartment (Zone II). Both the Zone II fire detection and the Zone I overheat detection system, a portion of which travered the aft inboard section of Zone II, were sensitive to fires orginated in the inboard portion of Zone II.

The instaled extinguishing system provided rapid extinguishment of all Zone II fires until extensive accumlative damage from fires destroyed the integrity of the zone. Fireproof protection incorporated in the nacee was very effective in performing its intended function. Most susceptable to damage by fire was the aluminum portion of the nacelle, especially aluminum receptacles for camlock-type fasteners, an aluminum ventilation louver panel in the top aft portion of Zone II, and aluminum ribs, formers, and baffles inside the nacelle in the path of fire. The fire damage to the engiine and accessories was insignficant in regard to engine operation.

Robert H. Ahlers

F-86 droppable fuel tanks, fitted with reticulated polyurethane foam and filled to capacity with JP-4 fuel, were drop tested and catapulted to test the effectiveness of the foam in reducing fuel spray and leakage at impact. Also, structurally reinforced DC-7 integral wing tanks were impacted against an upright beam restrained by a steel shear pin to limit the loads. The forward spar caps were strengthened with aluminum alloy doublers and chordwise stiffeners to determine the effect of structural modifications on the crashworthiness of the structure.

It is determined that the 10 pores per inch and the 60 pores per inch polyurethane foam have little effect on the attenuation of fuel misting and spilling. The addition of a 0.040 inch thick doubler strip to the upper and lower DC-7 wing skins did not appreciably decrease the vulnerability of the intergral tank to leakage, but the front spar rails when reinforced by chordwise structural shapes did increase impact resistance.

National Aviation Facilities Experimental Center

This report is an index of all technical reports which were assigned NA numbers and published by NAFEC during the priod 1967 through 1969. Entries are arranged by NA number and include titles, authors and full abstracts. Separate sections contain indexes by subject, author, RD number, DS number, project number, contract number and AD number.