The RadChart doesn't expose an event that notifies when the chart is rendered. However, if you tell us why you need to use such event we might be able to assist you further with your implementation.
Note that we have a new charting suite, RadChartView
, that resolves many known issues and limitation in the old RadChart control. The new components have better implementation and improved performance. You can read about the differences between the controls in the RadChart vs RadChartView
Check out Telerik Analytics, the service which allows developers to discover app usage patterns, analyze user data, log exceptions, solve problems and profile application performance at run time. Watch the videos
and start improving your app based on facts, not hunches.