Enerjet by Aerotech, Arreauxbee-Hi, Part 12, Upper Channel Tunnels

The upper channels pieces are cut to 10" long. 

Again, I cut mine a little longer to 10 1/16".

The upper end was set down 10" from the bottom of the upper tube. This left 1/16" overhanging the bottom of the tube.

The extended tunnel ends were sanded to the bottom of the upper tube as before.

This leaves a tight butt joint of the two tunnel pieces.

The tops and sides were sanded to match the sides of the lower tunnels.

 

The tunnel ends got a shot of filler/primer, directing it at the tunnel ends.

After sanding a bit, I was left with a good joint.