Aerotech Mega Initiator #89541, Part 10, Final Fin Fill & Dry Fits

The fins on the flight version were left square.

That inside leading edge angle still wouldn't match up. I added some CWF for a better flow.

Here's the same fill after sanding. Some 400 grit was wrapped around a pencil to sand the angle.

Another dry fit of the fins showed the ring slots were too tight.

The sides were shaved down, widening the slots.

Here's how far the engine mount is recessed, the ring face is just under 7/8" from the end of the tube.

With the fins in the slots set the placement depth of the  engine mount.