Embodiments of the disclosure are directed to methods and devices for communicating fluid into or out of a blade cavity.
Aircraft blades, such as propeller blades, may include an internal cavity that is plugged to prevent hub oil from migrating into the blade during operation. The plug may be installed during manufacture of the blade and, thus, ambient pressure may be locked within the cavity when the blade plug is installed. During manufacturing, ambient air pressure trapped within the blade cavity may be ambient air pressure at ground level. Then, during operation of the blade, i.e., during flight, a differential pressure may exist between the air locked within the blade cavity and the ambient air at altitude. Specifically, the ambient air at altitude may be significantly lower than the air pressure locked or trapped within the blade cavity. This differential pressure may result in stresses imposed on the blade that are added to the normal operating stresses that result from aerodynamic loading on the blade.
USPTO Backgrounds
USPTO Backgrounds