If you recall in Report No. 4, a temporary cross brace or spacer shown below was installed just in front of where the firewall will be located and I said (this one will be removed later after the crutch is completed and the firewall has been glued in place). To maintain the proper width of the motor mounts in front, a plywood jig brace was made and bolted in the two front motor mount holes as shown below. 

 

Then the temporary spacer was removed and the inside of motor mounts smoothed up as shown below.

 

Aliphatic glue was applied to the edges of the firewall and motor mounts, the firewall slipped into place on the motor mounts, and the excess glue was removed with a Q-Tip and water. The firewall was squared with the bottom of the motor mounts by placing a large steel construction block square on the bottom of the motor mounts and then clamping the firewall to the vertical face of the square as shown below.  

 

A temporary jig support was clamped in place to establish the correct height and centering location of the rear of the bottom longeron assembly as shown below. The front of the bottom longeron assembly was then glued to the firewall and the rear pinned to the jig as shown below.

 

With the bottom longeron assembly firmly in place, three of the four 3/16" sq. members that form the tapered fuselage sides were cut, fitted, and glued in place on each side as shown below. Then the temporary jig support was removed. 

 

It was when I started to glue in the fourth side member that is directly below the front of the cabin that I discovered I had made a major mistake %$#@*& ! Looking at the picture below, you can see that the 1/4" X 3/8" balsa strip laminated to the maple motor mount needs to be beveled off on the bottom by 1/16" to line up with the rear side members. This in and of itself is easy to do, however........................

 

...............the 1/16" beveling will require the lower portion of the 1/8" plywood firewall to beveled off as well as shown below, which is going to be a big deal! This causes other problems on the back side of the firewall that I won't go into right now. This situation arose when I laid out the firewall pattern. The sloping edge of the firewall should have started at the bottom of the 3/16" X 3/8" crutch strip and not at the bottom of the 1/4" X 3/8" laminated strip on the motor mount.   :O<     Sooo, I now have to come up with an acceptable way to do this unexpected beveling, which is a subject for my next report....................Tandy