This thread was called "oxygen tank location", but perhaps this is enough of a change of subject to justify changing the title.
I have an ES and the access panel was already installed as part of the "fast build," so I left it alone. During the building process I received a bulletin that recommended changing the #6 screws to #8 in order to increase the strength and stiffness of the access port. I didn't do it, but I wonder if I should have. Of course, now there is a paint issue, but maybe the structural integrity issue would make it worthwhile changing. I could also add the large stainless washers to it and that should further increase the strength - and hurt the styling. Should I change these out? Note that the ES has a much larger horizontal stab and therefore might be
more sensitive to fuselage structure than the IV.
Gary Casey
We have a classic example in the IV-P world where some builders decided it would be nice to have the aft fuselage inspection panel hinged and latched for easier access. Turns out this panel is a part of the fuselage structure, and not mounting it with multiple screws, as specified in the plans, weakens the rear fuselage. At least two IV-P’s have developed structural cracks from the opening back to the horizontal
tail. As far as I know, we’ve not lost an airplane due to this, but on the other hand, we’ve probably been lucky… To the casual observer, this seems such a trivial mod—the opening is only about 8” x 12” or so—but the cover is designed to be a part of the fuselage structure…an important part. It can’t work that way if not secured all the way around it’s perimeter.
Hope this helps!
Bob