Mechanical tach failure?

"Stealth Pilot" wrote in message
...

my airspeed indicator is ww2 vintage and is still calibrated within 1
knot of what it should read.
my black and white AH is out of a dead cessna.
in fact none of the instruments is younger than the airframe. they
were all selected as old trusted mechanisms.
no need to change the approach Rich.
it works the world over.

Phew! One flame avoided. . .

Rich S.

On Fri, 5 Nov 2004 08:22:51 -0800, "Rich S."
wrote:

"Stealth Pilot" wrote in message
.. .

my airspeed indicator is ww2 vintage and is still calibrated within 1
knot of what it should read.
my black and white AH is out of a dead cessna.
in fact none of the instruments is younger than the airframe. they
were all selected as old trusted mechanisms.
no need to change the approach Rich.
it works the world over.

Phew! One flame avoided. . .

Rich S.


had a tacho fault in a cessna once. would periodically read zero in
flight. on the next flight it would be ok. needless to say it would
always work perfectly when the maint guy disassembled it and looked it
over. then it would fail and read zero again.

one day when it failed I took it apart. (there IS a fault here it is
just a matter of looking long enough at it)
the end of the tacho drive shaft (coiled wire inner gubbins) ends in a
ferrule at one end. the gubbins bit had come loose within the ferrule
and worn itself into a conical shape within the ferrule. occasionally
it would lock together like two parts of a morse taper and drive away
perfectly. other times it would work apart.
maint guy looked it over,pulled it apart, pushed it back together,
played with it a while then said "F*** Me, thats nifty, you ought to
patent it :-) "

Stealth Pilot

"Stealth Pilot" wrote in message
...

had a tacho fault in a cessna once. would periodically read zero in
flight. on the next flight it would be ok. needless to say it would
always work perfectly when the maint guy disassembled it and looked it
over. then it would fail and read zero again.

I *hate* intermittent faults. The mechanic always looks at you like you're
nutso.

Rich S.