Fire-Resistant Fabric for Aircraft
As the result of study carried on by the National Bureau of Standards, with the financial assistance of the National Advisory Committee for Aeronautics, a non-inflammable doped fabric has been developed for aircraft.
An airplane covering with very good resistance to ignition can be obtained by the application of 3:7 boric-acid-borax mixture to airplane cloth and subsequently doping it with cellulose acetate. This doped and fireproofed cloth, containing about five per cent of the boric-acid-borax mixture, by weight, will not burn in a horizontal or vertical position, and is not ignited by lighted matches or burning gasoline.
Investigation was also made of natural and synthetic resins and mixtures of synthetic resins with cellulose nitrate and cellulose acetate. The resins do not tighten the fabric sufficiently to be satisfactory as airplane dopes. In general a 3:1 ratio of cellulose derivative to resin is necessary to attain satisfactory tautness, and in this proportion, even the least combustible resins do not improve the fire resistance of the doped fabric. No method has been found of fireproofing airplane fabric doped with cellulose nitrate, and still maintain satisfactory tautness and weight requirements.