Maintenance Questions

wrote

acid free white kerosene
fill compass/ get A&P to replace tubing

I'm curious, for those that know sailboat and airplane compasses, why the
difference in fluids?

In sailboats, I was told the reason for using mineral oil was to dampen the
movements, with the more viscous fluid doing that function.

I would think that airplanes would need the same characteristics of the
dampened movement, but yet, people are saying that the thinner kerosene is
the fluid of choice to use in the compass.

Anyone got any insights to this?
--
Jim in NC

Yeah, I did this whole "what fluid to use" thing about four years ago on
this same newsgroup. No, kerosene isn't the optimum choice, but that's what
Lindy had to use going across the Big Pond, and the FAA has proceeded little
from that point.

Mineral oil freezes at a fairly high temperature. Damned few sailboats out
on the water when it freezes, so that isn't a problem for them. It is for
us.

The viscous fluid of choice for compasses is copy machine fuser oil. Good
from boiling to freezing and well past. Thick enough not to ooze past
slightly dried out seals. Not to be used except in experimental aircraft
and aviation quality (ahem) "boat" compasses.

Jim

--
"Life is not a journey to the grave with the intention of arriving safely in
a pretty and well preserved body, but rather to skid in broadside,
thoroughly used up, totally worn out, with chocolate in one hand and wine in
the other, loudly proclaiming 'WOO HOO What a Ride!'"
--Unknown


"Morgans" wrote in message
...


In sailboats, I was told the reason for using mineral oil was to dampen
the movements, with the more viscous fluid doing that function.

I would think that airplanes would need the same characteristics of the
dampened movement, but yet, people are saying that the thinner kerosene is
the fluid of choice to use in the compass.

"RST Engineering" wrote in message

Yeah, I did this whole "what fluid to use" thing about four years ago on
this same newsgroup. No, kerosene isn't the optimum choice, but that's
what Lindy had to use going across the Big Pond, and the FAA has proceeded
little from that point.

Mineral oil freezes at a fairly high temperature. Damned few sailboats
out on the water when it freezes, so that isn't a problem for them. It is
for us.

The viscous fluid of choice for compasses is copy machine fuser oil. Good
from boiling to freezing and well past. Thick enough not to ooze past
slightly dried out seals. Not to be used except in experimental aircraft
and aviation quality (ahem) "boat" compasses.

Interesting.

Is that "fuser oil" the stuff that was used in the old purple letter
mimeograph copy machines, or something in newer machines that I know
absolutely nothing about?

I always used to love that smell, of freshly run copies. So if I smelled
that wonderful smell in flight, I know my compass just sprung a leak!

What do the new compasses (those that still have magnets in them) use for
fluid?
--
Jim in NC

Morgans wrote:
"RST Engineering" wrote in message

Yeah, I did this whole "what fluid to use" thing about four years ago on
this same newsgroup. No, kerosene isn't the optimum choice, but that's
what Lindy had to use going across the Big Pond, and the FAA has proceeded
little from that point.

Mineral oil freezes at a fairly high temperature. Damned few sailboats
out on the water when it freezes, so that isn't a problem for them. It is
for us.

The viscous fluid of choice for compasses is copy machine fuser oil. Good
from boiling to freezing and well past. Thick enough not to ooze past
slightly dried out seals. Not to be used except in experimental aircraft
and aviation quality (ahem) "boat" compasses.

Interesting.

Is that "fuser oil" the stuff that was used in the old purple letter
mimeograph copy machines, or something in newer machines that I know
absolutely nothing about?

No, it's not that.

Fuser oil was used in older copy machines.
It's a clear, probably silicon-based oil
that kept the fuser rolls soft and pliable.

Haven't seen it for years.

The SIRS compasses are using a silicon fluid. The claim is that the
"thicker" fluid reduces turning and acceleration errors.

personally, I really like the big numerals on the dial!

Yes, I can actually see the numbers on my SIRS compass. I think there were
numbers on the old original one. They may even have been somewhat visible
when it was new.

"Blanche" wrote in message
...
The SIRS compasses are using a silicon fluid. The claim is that the
"thicker" fluid reduces turning and acceleration errors.

personally, I really like the big numerals on the dial!