POLYURETHANE FOAM INSERT FOR OVEREXPANDED ROCKET ENGINE NOZZLES TO PREVENT START TRANSIENT SIDELOADS

摘要

A polyurethane foam insert is adhesively secured within the nozzle of a regenerative cooled rocket engine. The insert has a central bore which reduces the engine throat to nozzle exit area ratio so as to prevent dangerous sideloads during normal or extended engine start transient periods at sea level conditions, but quickly erodes in a few seconds to permit normal engine operating conditions which follows the start transient period.