Order rss feed by custom field

I have posts with a custom meta field event_date. I am sorting these posts by the event date instead of the published on date using new WP_Query however the rss feed still orders the posts by the published date instead of the event date.

I have been looking for a method to sort an rss feed by a custom field like this. However I see a lot of people asking and know responses. There has to be a way to do this?