CH-47 Chinook Engine Pod Assembly Notes

Following are notes to aid in trimming, assembly and installation of the CH-47 engine pods. 

1. Fabricating the Engine Exhaust Pipes and Filter Washers:  The engine exhaust pipes are cut from .020" styrene or cardstock, rolled to shape and glued at the tabs.  They'll have a neater appearance if you block sand the edges at the overlapping seams to a tapered edge.  Make two .020 styrene or cardstock "washers" for mounting the cone-shaped filter housings on the front of the engine pods.  These washers should have an inside diameter of 0.92" and an outside diameter of 1.57".

2. Trimming the Engine Pods:  To mark the engine pod halves and filter housings for trimming, place each part on a flat surface and lay a pencil flat on the surface as well.  Trace around the parts to leave a pencil line 1/8" above the work surface.  Use a shim under the pencil if necessary to make the line the proper distance above the surface.  Carefully trim the parts using sharp scissors or aviation snips and lightly sand the edges.  

To assemble the pods, note that the pod halves should overlap each other by about 1/16".  Use the washers and exhaust pipes to help align the shells together and then lightly tack glue the halves.  Note that the exhaust pipes are designed to angle outward slightly as shown on the top view of the plans.  Only when you're certain of the alignment you should permanently glue the seams.

3. Final Engine Assembly:  The intake filter cones are glued over the washers to complete the engine assembly.  I recommend mounting the engine pods on the body with small rare earth magnets so that they'll pop off if they snag on something or if you have a hard landing.  To do this, I cut an oval of 1/8" balsa to fit in the base of each pod pylon and then inset rare earth magnets into this base.  The pods can be pressed up against the body and the second pair of magnets placed inside the shell to stick to their mates.  Move the pods to their proper location and then glue the magnets inside the body shell.