A/C Install photos
First and foremost, this being my first time working on an airstream, there is likely better and easier ways of doing it, I just didn't find them before installing! I wanted to make sure it was structurally secure and electrically safe (and of course water tight).
It all became clearer once the install got underway. I cut the small hole last night to find the wires, and spent the time tracking down where wires were supposed to go. I was confused until I cut the hole bigger and could see where the wires were running between the skins.
After making sure all wires were clear I carefully drilled a 3/8 hole in each corner of my marked 14" square on the ceiling, the followed up with tin snips and carefully cut the opening. Once clear I again drilled, this time through the skin the four corners, then climbed the ladder and connected the dots and again cut the skin.
I used 2" aluminum "C" channel to add support. I had to scribe the ends and taper them down a bit so the ends didn't press into the outer skin, then attached both new cross members to the ribs, then boxed to the new cross members to complete all 4 sides. Each connection was made with 2 1" L brackets from the hardware store. A 1 1/2 in hole saw was used to cut a hole on the drivers side for the wiring, and wires passed through with a 1 1/2 rubber grommet.
Once that was done, I had to shim with some of the cut-out scrap to maintain the exact outer skin curve, then secured top and bottom sheet metal to the c channel with 3/16 aluminum pop rivets. Had a friend over for about 10 minutes to get the unit out of the house and on the roof. We use 2 3 legged orchard style step ladders which could be placed parallel at a 45 degree angle next to the trailer (so we never had to climb up there, and didn't have to lean anything on the trailer).
Unit fit great, but noticed the profile in the ceiling trim wouldn't allow for the unit to fit without being distorted. I cut 3 pieces of 1x3 poplar with a 35 degree miter to match the profile. That will later get caulked and painted to match the ceiling (which already had 2 different colors of paint on it when we purchased it).
Torqued unit down until the gasket looked just over half size, and wet the trailer down to check for leaks, none! Trim on for now until painting time. It was 90 degrees today, and the unit had the trailer down to a cool 72 degrees pretty fast while on the low setting.
Hope the pictures help anyone else that was nervous like me. Thanks Andy for the measurements and assistance with location in the ceiling.