This paper makes three contributions to research on QoS-enabled middleware for open distributed real-time embedded (DRE) systems. First, it describes the design and implementation of a dynamic scheduling framework based on the OMG Real-Time CORBA 1.2 specification (RTC1.2) that provides capabilities for (1) propagating QoS parameters and a locus of execution across endsystems via a distributable thread abstraction and (2) enforcing the scheduling of multiple distributable threads dynamically using standard CORBA middleware. Second, it examines the results of empirical studies that show how adaptive dynamic scheduling and management of distributable threads can be enforced efficiently in standard middleware for open DRE systems. Third, it presents results from case studies of multiple adaptive middleware QoS management technologies to monitor and control the quality, timeliness, and criticality of key operations adaptively in a representative DRE avionics system.