One more time on Univolts, and then I'll try to talk about other things for awhile.

Sometimes the good folks at Airstream did things with which I find myself at odds at the onset. The Univolt installation in my SS is a case in point. It sucks. Well, it used to more than it does . . .

Since I built my first crystal set just after W.W.II, I have accrued a fair amount of formal education and hands-on experience with, among other things, electronic equipment. One of the things I think I know about the stuff is: As a general rule, it doesn't like excessive heat.

One hot September day in Fresno (are there ever any other kind of days in Fresno in September?) I had occasion to get into the storage compartment in the SS that also contains the Univolt. It came to me, as I reached in for whatever I was getting, that it was just hotter than--well, it was really warm in there. And the Univolt . . . it seemed to me that the phrase "excessive heat" applied. I resolved therewith to "do something" about that.

My Univolt is tucked into its own little sheet metal compartment, measuring about 9 X 10 X 16. The fuse panel end faces "front" so that you can change the things when necessary.

Being in a mostly closed-in box, the Univolt was essentially stewing it its own juice inside its own little box inside a closed-up compartment. To use an Orwellian expression, "double-plus ungood."

If you have a similar situation in your SS, perhaps you will find what follows of interest . . .

The mod:

My objective was to get some air moving past the Univolt. I initially considered punching a hole in the rear end of the sheet metal box and put a "whisper" fan there, facing the Univolt. This looked like the slickest way of doing things, but I needed arms that let my knuckles drag the ground to get to it with enough "oomph" to do something. Scratch that.

Something like the ventilation fan/hose assemblies such as one finds in boats to keep dangerous fumes out of the engine compartment looked possible, but those that I've seen used brush-type "universal" motors. Usually noisy, mechanically and electronically. Besides, the ones I've priced were thought very highly of by the store that was selling them. Also scratch that.

Then I observed that, in my SS, the sheet metal compartment is actually wider (something like two or three inches) and deeper (maybe three inches or so) than it really needs to be to hold the Univolt.

It seemed to me that a piece of 1/4" or 3/8" (or whatever's sitting around) plywood, with a hole, etc., suitable for a whisper fan could be mounted a couple of inches forward of the rear end of the box. Size the plywood for a snug top-to-bottom fit and about 2" less wide than the sheet metal box (hereafter: SMB) is wide. This piece will abutt the side of the SMB furthest from the side of the SS. Position the whisper fan hole so that the fan will blow at the back end of the Univolt.

Time out: A "whisper fan" is one like you find cooling the power supply in practically every PC you'll ever see. Common as dirt and cheap, quiet, work fine and last a long time.

Time in: Using another chunk of whatever you have, (I used a piece of flashing aluminum) attach a "wall" to the "fan" chunk such that, when everything is in place with the "fan" chunk, a plenum is formed about 2" wide from the inner skin of the trailer to the "fan" chunk of whatever--inside the SMB. Extend the plenum to the front end of the SMB from the "fan" chunk.

Hook the fan up so that it comes on when the SS is running on ground power.

Crude and inefficient, you say? Maybe even ugly as sin?

Alas, (sigh) so true . . . I'll try for more elegance on another project.

It works. It makes ME feel better--quite apart from any benefits that may accrue to the Univolt.

Clark
WA7GGV
27''70