Replacing the rear top skin
N94804 had the bigger rear windows cut out when we bought it. The Windows were flimsy, would easily pop out when someone leaned on it and we just did not like the appearance of it. The original windows are following much more the art deco lines that make this plane so good looking. So I found a mechanic that had a rear skin left over from a parts plane. One day I showed up at his place to learn how to change it.
At first, one has to drill out hundreds of rivets. Careful just drill off the rivet head and punch out the stem.
The rear top skin is riveted to the fuselage F frame on assembly and the tail cone is pushed over and then riveted in place. That leads to one rivet on the top of the frame F that one can not reach. One needs to apply significant force to bend the frame F temporarily forward so the last rivet can be removed.
The frame D is stiffened on the 415-E Models. That creates 2 lines of rivets around that frame. The skin we used for replacement did not have that extra stiffener and we had to drill all new holes around frame D after we placed the new skin where we wanted it.
Before you start riveting or even cleckoing the skin in place, double check that you are 100% satisfied with the position. We had one corner not totally aligned flush with the rest of the airframe. That needed some extra time later on to be straightened out.
After riveting the skin in place, everything felt much stronger than before. Now line up the window glass and carefully drill the holes here. And voila - job done. It took 2 Persons 1 day to finish the job.
Hartmut Beil