Red River Rocketry Starliner DST, Part 3 Engine Mount

The 20/50 rings needed some inside notches to fit over the engine hook.

A Kevlar line was knotted and the loop slipped under the top bend of the engine hook, Semroc style. I didn't go with the supplied tri-fold mount.
A 20/55 flat centering ring goes against the side of the lower 20/50 ring.
This is the rear form support for the conical shroud.
A 3/16" square notch is cut for the launch lug to slide through.

Here's how the engine mount sits in the rear of the BT-50 mainframe tube.
The long launch lug will fit in the notch after the shroud is glued in place.
(The lug is just held in place for the picture.)