Estes Blackhawk #2053 Build, Part 5, Gluing Vent Tubes & Interior Supports

With the engine mount tube straight in the vent tube - 

I traced around the joint for glue placement.

A line of glue was placed around the pencil line and the two tubes joined.

After that dried,

Both of the cardstock central plates is set next to the engine tube. (See next picture.)

Mark both sides for the the retainer ring (or tape).

Cut a slight notch in both of the central plates.

Couldn't this have been included in the die-cuts?

This is in the instructions, to cut out an area to allow for the retainer ring.