Epic burndown without sprints

[JaA]

Hi,

we're using epics to track our projects and each epic has multiple issues linked to it. The problem is we're not using sprints or story points in the issues. The workload is estimated via the timetracking fields.

Is there any way to calculate the original and remaining estimates of each individual issue and use the sum in combination with the due date to create a burndown chart?

I have only found a very manually solution in confluence so far.