Glyn,
This data is from the factory database. The distance on the ceiling centerline
from the front rib to the centerline of the air conditioner shaft for the 18'
1969 Caravel is 67".
The old original Armstrong "Bay Breeze" unit weighed collectively at least 100
lbs. Current production units from Duo Therm, Coleman, and Carrier weight in
around 75 lbs.
On the Armstrong unit the "adapter/drain pan" was part of the ac unit its self.
The Armstrong's were only every used by Airstream and thus custom built.
Once the change was made to first a Coleman and then to the Duo Therm's of today
it was necessary to create an "adapter/drain pan" that would adapt for the two
different contours and consolidate drainage to the built in drain tube.
Airstream has only every made two adapter/drain pans. The first for a Coleman ac
available in the 80's. It was much longer than any current Coleman model. As
much as they would like to get rid of them Airstream still has a number of them.
The current production pan was developed specifically for the Duo Therm ac
units. It is available through any Airstream dealer.
You will find when it comes time to install the AC unit that the bottom gasket
seal does not mate to the pan. It is necessary to at least notch the gasket or
as the factory does remove it in its entirety and use either Vulkem or SikaFlex
sealant.
Charlie