Compass overhaul

I think I’ve finished the compass overhaul. The rebuild kit arrived from ACS yesterday. After carefully cleaning the glass with denatured alcohol, I installed the new gasket and the glass. With everything reassembled, I filled it with compass fluid. I had about half a pint from a rebuild kit I had bought several years ago, when I came across an old Airpath compass that ultimately turned out to be an oddball military model for which there are no replacement parts or gaskets. It was leaky around the glass, and I eventually figured out that the cork gasket was slightly oversized. From what I can tell, it’s supposed to apply pressure around the edges of the glass to seal it against the inner black rubber gasket. It was getting squeezed between the case and face plate. After trimming about a millimeter or so from the outside, I finally got it to seal up.

Normally you would submerge the compass in a container of fluid to work out all the bubbles. In fact, the Airpath manual specifies submerging it and pulling a vacuum for a few hours to ensure there is no trapped or dissolved air. I didn’t go to those lengths. I was able to work all the bubbles out and get the fill (or drain) plug in, and so far there’s no sign of leakage.

The new LED lamp works great. In a dark room there’s a nice red light that makes the compass quite readable. I’m happy with it.

I’ll let it sit on the bench for a few more days to ensure there’s no leak and no bubbles develop. If I do see any air, I’ll submerge it in a container and do it their way. I figure it won’t be getting mounted in a panel for at least a year or two, maybe longer, so I’ll have plenty of time to validate the quality of the rebuild. For a total investment of less than $71 I’ve got a completely rebuilt, well lighted Airpath compass. That total includes an extra nine little LED lamps that I’ll use elsewhere; if you don’t count those it’s under $65 total. Not bad considering I see dried-out junkers going for more than that on Fleabay.

Score!

I haven’t been doing much on the biplane recently, but I did manage to score an altimeter for it.  I’ve been watching the for sale ads on line for decent deals.  Someone offered an altimeter that worked, but failed an IFR certification due to out of tolerance leakage at 15,000′.  Well…  if I ever do finish the bipe and fly it, it certainly won’t be at anything over 10K, let alone 15K.  So for fifty bucks it was a no-brainer.  It’s a pretty nice altimeter, not one of the super cheap imported junkers that’s being sold now.  It’s really more altimeter than I need… 

My “new” used Shinko Electric altimeter

So…  I have an altimeter, and a quad oil temp / oil pressure / CHT / EGT gauge for monitoring the engine.  I will still need an airspeed indicator.  Most that I see for sale have speed ranges not appropriate for the Celebrity — I really don’t need or want a 200 knot ASI.  Then I’ll need a compass, of course; a slip/skid ball; a tachometer.  Whether I need a fuel gauge or not depends on what I decide to do for fuel tanks.  I’m thinking no electrical fuel gauges, all float or sight type.

I could just ditch all of it and go with a single instrument from Dynon or Garmin, but I just think such a thing would look out of place in a classic biplane.  I’m not sure what I’ll do for the front cockpit, though.  It would be nice to at least have airspeed and altitude there for passengers, but I’m not sure I’ll be able to score a deal like this again.  There’s always UMA