An Application of Brazed Stainless Steel Honeycomb for Moderately High Temperature Structures

The C-141 airplane is powered by four Pratt & Whitney turbofan engines with the fan mounted on the compressor end. High velocity, high pressure air from the fan is ducted to the aft end of the nacelle through kidney shaped ducts. In the tailpipe area, the ducts and tailpipe utilize a common skin. During rapid engine deceleration a condition can occur that subjects the tailpipe to a collapsing pressure. A single skin tailpipe subjected to this pressure at an operating temperature of 1000 F would have been excessively heavy. Brazed stainless steel honeycomb with thin face gages and lightweight core was selected for this application with a substantial saving in weight and no loss in performance.