JBinSV

This is a NASA image taken when the door was being installed. You may have seen this online. The door has a partial inner skin which makes a box frame around the perimeter. Views of the door on the assembly fixture. This is in the hanger at NASA Ames where the ER-2 aircraft used to operate. The forward end of the door and the extra structure to withstand the stress and strain around the opening. The aft end of the door.

Zebra, I just joined Britmodeller to comment on your SOFIA model. I occasionally look around for anything related to the SOFIA program and found your post here. I have a personal interest as I was the lead structural design engineer for the Upper Rigid Door taking it from loft-lines to the solid model used to make the production drawings. I left the program just as the drafter was starting to work on the drawings. I happened to go back for a visit when they had a roll-out ceremony when the door assembly was completed. It was sitting on the assembly tool and I crawled under and took detail photos. Kind of a walk-around of the door. I still have a copy of the cad file with some of the 747SP fuselage dimensions near the door. Anyway, I just wanted to say that I am very impressed by your 3d print model. It looks very much like the original. I never did get a copy of the final drawings. I would like to have studied them but oh-well. Some interesting notes. The 747 fuselage tapers from constant section to the tail, however the taper starts at different stations. The bottom of the fuselage has to be shaped to clear the ground for aircraft rotation. The sides of the fuselage maintain full width a little further aft because that allows for about two more rows of seats. The top of the fuselage starts to taper about in the middle of the door. So the front of the door is integrated with the round upper shell of the fuselage but the back of the door integrates with a fuselage that has a taper that is continuously changing. That is part of the reason why the fairing aft of the door has that step in it which you correctly modeled. When they did the fight test the goal was to have access to the full flight envelope. One of the last of the flight test parameters was a high speed dive. So yes, this door has been exposed to Mach 0.9 and passed the test.