John Seymour and I installed tank drying mechanisms in our 27B's. My ship
dumps via hoses into the fuselage and out the belly like a 20, but John's is
standard factory setup like yours.

We use a "computer" fan we got from Digi-Key (800-digi key). There are so
many fans in the catalog I can't remember which one, but anything that moves
air will work. Part number 381-1073-ND looks about right.

Get some "bilge" tubing (the white, flexible plastic stuff that looks like
trachea tube) and stick in the water dump holes on the bottom of the wing
and run it to a home-made manifold on the fan. I use a 110V to 12V cube in
the trailer to run mine, but John simply puts an old glider battery on and
runs it flat each time.

When I'm leaving a contest I hook the fan up to the trailer lights. When I'm
at home I use the 110/12 cube.

I have one of Kellerman's Kestral weather instruments which incorporates a
humidity sensor. From experience I've found that in Eastern humidity it
takes about 24 hours to clear out the residual water. Out West it would be
faster.

Obviously you want to leave the fill caps off.

Karl Striedieck

"Andy Blackburn" wrote in message
...
Anyone out there have good plans for the factory-recommended
ballast tank ventilation system? I've heard of (but
haven't seen) designs that include humidity sensors
so they know automatically when to turn off.

Thanks!

9B