The requirements on real-time systems are changing. Traditionally, reliability and predictability of hard, real-time systems in particular were the main requirements. This lead to systems that were stand-alone, embedded and static. Future real-time systems, but even current systems, still require reliability and predictability, but also distribution of the real-time system, integration with non real-time systems and the ability to change dynamically the components of the system at run-time. Traditional approaches to real-time system development have difficulty in addressing these additional requirements. New ways of constructing real-time systems must therefore be explored. In this article, we develop a real-time object-oriented model that facilitates the requirements of flexibility without sacrificing the predictability, integration and dynamicity aspects.