Started April 21, 2007
The Cargo Doors are skinned with .032 aluminum sheet (2024 T3). The door skins must be bent or ceased slightly in a couple of locations so that when looking along the side of the airplane fuselage, the stringer shapes on the fuselage side are continued onto the cargo door. Done properly, the cargo doors blend so well that they almost disappear when closed.
I started with the aft cargo door first. The skin was rough cut slightly oversized for the door frame. To be able to locate the skin on the frame in a repeatable position, I drilled a couple of location holes through the skin and door frame so it could be clecoed in place.
The slots for the door hinges were cut so the skin could lay flat. The door frame was placed on the fuselage and reference marks were made where the crease needs to be to align with the fuselage stringers. The skin was then removed and using a brake, the creases were made. This is one of those "sneak up on it" things. Make a slight bend and then check it against the door frame. Repeat until the skin matches the shape and lays flat on the door frame.
My Father-in Law Lonnie Gibbons came by to give me a hand with the cargo
doors. Here he is drilling and clecoing the rear cargo door skin to the
frame:
Here is the aft cargo door showing the creases:
Next, all of the edges were cut to create a 1/4" overlap of the door opening
in the fuselage. The edges were smoothed and the corners rounded with
a file. Here is the aft cargo door attached to the fuselage:
As you can see, we have achieved a very nice fit.
So far so good, now its time to skin the forward cargo door. The forward cargo door has a window, but we sill start by just skinning the door with one piece of aluminum. Once the skin is properly fitted, the window opening will be cut.
Again the doorframe was placed in the fuselage and location of the creases
were marked as a reference. On the forward cargo door, the crease is
made at the aft end only. You can see it in this picture:
This partial crease was done by leaving one side of the brake up and clamping
down the other side before making the bend.
When I made the crease in in the aft end of the front cargo door, I made
it a little too sharp. This created a problem. When I closed the doors
together, I got a 1/4" gap at the point of the crease as can be seen here:
Lucky for me, I have friend who is very experienced and talented in metal
handling skills. Mickey Whittenburg used a metal shrinker to shrink
the edge slightly at the crease. Here is Mickey working on fixing my
boo-boo:
He then did a little smoothing and cleanup with a hammer and steel block:
Once Mickey had finished working his magic on the door skin, the fit was
excellent:
Click here to go to Cargo Door Skins page 2
Click here to go to the Final Assembly page
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