Repairing the Big Waco SRE (2)

The first job was to clean away everything that was left of that 1/8″ ply plate. As it turns out, that plate was designed with several tabs that fit into corresponding slots in the formers (or bulkheads) ahead of and behind it. Neither of those formers was damaged. It would have been impossible to get a new ply plate with tabs into the fuselage structure without cutting into those formers. I chose not to do that, and decided to find another way to reinforce mounting the plate.

I used a micro saw to cut out the remains of the plate flush with each former.

A small broken section stayed attached to the front former. You can see the original assembly slot just to the left. TAKE NOTE: The original ply plate fell cleanly out of the former during the crash...there was no glue holding it in place. This is not an unusual thing to discover in working on ARF models.

I cut away all of the remaining broken plywood. The flat plate further down inside the airplane is the bottom of the motor battery mounting tray, which was not involved in the damage.

This is where I messed up and lost a photo image I wanted you to see. The new plywood plate won’t have tabs to fit those slots, so I added a strip of 3/8″ square spruce to both the front and rear formers right along the line where the inside surface of the old plate was atached, using lots of slow curing epoxy for a solid bond. The assembly you see next then rests directly against those strips.

It was easy to reassemble to broken parts of the landing gear strut fairing and use thin CYA to stick it all back together. I then cut an entirely new 1/8" ply plate using the opening in the fuselage for dimensions and epoxied the new plate againt the inside surface of the old landing gear mount.

I drilled out the new plate to fit the old 8-32 blind nuts and bolted the landing gear in place from what will become the bottom/outside of the airplane.

Using more slow curing epoxy I reassembled the repaired landing gear assembly into the fuselage tight against those 3/8" square rails (which you can't see now because they're "inside" the assembly). I also straightened the aluminum auxiliary struts and let them rest inside the original openings in the belly.

The auxiliary struts mount to 4-40 blind nuts set into 1" square ply plates inside the fuselage. Both of these were knocked loose in the crash leaving a hole like this on each side.

Look down inside the fuselage, at the right center. With the aluminum auxiliary struts held in place by the main landing gear assembly, I inserted the 4-40 retaining screws from the outside through the blind nuts. and epoxied each of the plywood mounting plates in place using a C-clamp to hold it in place.

This is where the trouble started. I have bushed the old steel wire axle with a piece of 5/16″ diameter brass tubing to fit the inside of the new wheel, and then ground a flat exactly where the set screw of a DuBro wheel collar will rest.

When I pull the spacer out, the wheel is attached securely with just the right clearance to rotate freely.

The next step is refinishing of the belly of the airplane where it got scraped up, and reassembly, ready for pre-flight check-out. But…while this part of the job was going on, I discovered that the motor shaft had gotten bent in that “landing”. The motor is now being repaired, and when I get it back we’ll finish putting the airplane back together.