Looks like thrust pipe failure. Would have melted through the elevator servo leads fairly quickly. Sorry for the loss but happened safely. Good piloting in all aspects.
I spent 3 years building a Ray Hayes Oly III 3 meter sailplane, it was flawless. On my second outing, I flew it into a steel power pole and it looked like someone threw 10 deck of cards in the air. I was sick for months. I feel for this dude.