YAGQ (Yet Another Gyro Query)

[[email protected]]

It looks like the AI on my Cherokee finally bought the farm. My
friend who just flew it on a cross-country said it laid over and died on
the way.

So, the question is, used, overhauled, or new? Any thoughts on
this? Brands to get/not get? I'm leaning away from overhauling the gyro,
since I don't know how long it's been alive. I'm pretty sure it's old and
hasn't been touched in over 20 years.

Just wondering what folks think. I'm currently finishing my
instrument training and plan to use it for some light IFR cross-country
trips later on.

-Cory

--
************************************************** ***********************
* The prime directive of Linux: *
* - learn what you don't know, *
* - teach what you do. *
* (Just my 20 USm$) *
************************************************** ***********************

[Maule Driver]

My AI failed at 300 hours. Had it overhauled and it's running strong at
900. No recommendations here though. Just don't know enough.

> wrote in message
...
> It looks like the AI on my Cherokee finally bought the farm. My
> friend who just flew it on a cross-country said it laid over and died on
> the way.
>
> So, the question is, used, overhauled, or new? Any thoughts on
> this? Brands to get/not get? I'm leaning away from overhauling the gyro,
> since I don't know how long it's been alive. I'm pretty sure it's old and
> hasn't been touched in over 20 years.
>
> Just wondering what folks think. I'm currently finishing my
> instrument training and plan to use it for some light IFR cross-country
> trips later on.
>
> -Cory
>
> --
> ************************************************** ***********************
> * The prime directive of Linux: *
> * - learn what you don't know, *
> * - teach what you do. *
> * (Just my 20 USm$) *
> ************************************************** ***********************
>

[Steve]

Light IFR cross country can turn into hard IFR cross country. Consider the
importance of the instrument and then decide whether it would be better to
buy a new one or overhaul a 20 year old AI. I think you already know what
you should do.

> It looks like the AI on my Cherokee finally bought the farm. My
> friend who just flew it on a cross-country said it laid over and died on
> the way.
>
> So, the question is, used, overhauled, or new? Any thoughts on
> this? Brands to get/not get? I'm leaning away from overhauling the gyro,
> since I don't know how long it's been alive. I'm pretty sure it's old and
> hasn't been touched in over 20 years.
>
> Just wondering what folks think. I'm currently finishing my
> instrument training and plan to use it for some light IFR cross-country
> trips later on.
>
> -Cory
>
> --
> ************************************************** ***********************
> * The prime directive of Linux: *
> * - learn what you don't know, *
> * - teach what you do. *
> * (Just my 20 USm$) *
> ************************************************** ***********************
>

[[email protected]]

Steve > wrote:
: Light IFR cross country can turn into hard IFR cross country. Consider the
: importance of the instrument and then decide whether it would be better to
: buy a new one or overhaul a 20 year old AI. I think you already know what
: you should do.

Well, that's why I'm leaning towards a new one. I'm really not
considering overhauling the one I've got, but possibly purchasing a used
overhauled unit. Most likely not, though... 'tis a rather important
instrument... :)

-Cory


--
************************************************** ***********************
* The prime directive of Linux: *
* - learn what you don't know, *
* - teach what you do. *
* (Just my 20 USm$) *
************************************************** ***********************

[Aaron Coolidge]

wrote:
: Steve > wrote:
: : Light IFR cross country can turn into hard IFR cross country. Consider the
: : importance of the instrument and then decide whether it would be better to
: : buy a new one or overhaul a 20 year old AI. I think you already know what
: : you should do.

: Well, that's why I'm leaning towards a new one. I'm really not
: considering overhauling the one I've got, but possibly purchasing a used
: overhauled unit. Most likely not, though... 'tis a rather important
: instrument... :)

: -Cory

Cory, I would really recommend NEW. Costs twice as much, lasts four times as
long - in my experience. I prefer R.C. Allen - get the one with the lo-vac
flag.

--
Aaron Coolidge (N9376J)

[David Levy]

I had a new one fail at 160 hours. Wanna buy it for overhaul?

> wrote in message
...
> Steve > wrote:
> : Light IFR cross country can turn into hard IFR cross country. Consider
the
> : importance of the instrument and then decide whether it would be better
to
> : buy a new one or overhaul a 20 year old AI. I think you already know
what
> : you should do.
>
> Well, that's why I'm leaning towards a new one. I'm really not
> considering overhauling the one I've got, but possibly purchasing a used
> overhauled unit. Most likely not, though... 'tis a rather important
> instrument... :)
>
> -Cory
>
>
> --
> ************************************************** ***********************
> * The prime directive of Linux: *
> * - learn what you don't know, *
> * - teach what you do. *
> * (Just my 20 USm$) *
> ************************************************** ***********************
>

[Dennis O'Connor]

I'm as frugal as anyone (c h e a p is the word my bride uses) but, cutting
corners on something that will kill you is not good.. I do not overhaul or
buy a used primary gyro, altimeter, or compass... The savings aren't more
than pocket change, and the downside can be a long ways down...
Now having said that, when it comes to upholstery, radios, gadgets, etc.,
cheap is good!
Denny

> wrote in message
...
> Steve > wrote:
> : Light IFR cross country can turn into hard IFR cross country. Consider
the
> : importance of the instrument and then decide whether it would be better
to
> : buy a new one or overhaul a 20 year old AI. I think you already know
what
> : you should do.
>
> Well, that's why I'm leaning towards a new one. I'm really not
> considering overhauling the one I've got, but possibly purchasing a used
> overhauled unit. Most likely not, though... 'tis a rather important
> instrument... :)
>
> -Cory
>
>
> --
> ************************************************** ***********************
> * The prime directive of Linux: *
> * - learn what you don't know, *
> * - teach what you do. *
> * (Just my 20 USm$) *
> ************************************************** ***********************
>

[Ben Jackson]

In article >,
> wrote:
> So, the question is, used, overhauled, or new?

Whatever you do, get a heading bug. And if you think you'll ever put
an autopilot in it, consider getting one with bootstrap heading output.

--
Ben Jackson
>
http://www.ben.com/

[Thomas Pappano]

wrote:
> It looks like the AI on my Cherokee finally bought the farm. My
> friend who just flew it on a cross-country said it laid over and died on
> the way.
>
> So, the question is, used, overhauled, or new? Any thoughts on
> this? Brands to get/not get? I'm leaning away from overhauling the gyro,
> since I don't know how long it's been alive. I'm pretty sure it's old and
> hasn't been touched in over 20 years.
>
> Just wondering what folks think. I'm currently finishing my
> instrument training and plan to use it for some light IFR cross-country
> trips later on.
>
> -Cory
>

Back in nineteen and sixty nine, I worked in an avionics & instrument
shop. I would watch George, who was also a watchmaker, overhaul
gyros. The most interesting part was resurfacing and polishing
the tiny rotor journals, and replacing the ball bearings and races.
He would then spin them up, listening closely to an almost imperceptible
ticking sound as each ball would roll up over the top of the journal
then fall down upon the descending ball below! The sound had to
be just-so, or he was not happy. Anyway, I would think a unit properly
overhauled would be as good or better than new. We did lots of
overhauls, but I don't recall ever installing a new one.

Tom Pappano, PP-ASEL-IA

[Jim Weir]

I'd think twice about a new one. There was an intermediate period in the gyro
world where we gave up on the old AN style gyro but still hadn't migrated to the
plastic and potmetal crap that passes inspection for new today. It sounds to me
like you've got one of those good, solid instruments (after all, it ran for
twenty years, didn't it?) and I'd probably opt for getting a good overhaul with
first quality bearings on the old unit.

Jim




wrote:
->> It looks like the AI on my Cherokee finally bought the farm. My
->> friend who just flew it on a cross-country said it laid over and died on
->> the way.
->>
->> So, the question is, used, overhauled, or new? Any thoughts on
->> this? Brands to get/not get? I'm leaning away from overhauling the gyro,
->> since I don't know how long it's been alive. I'm pretty sure it's old and
->> hasn't been touched in over 20 years.


Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

[Snowbird]

"Steve" > wrote in message >...
> Light IFR cross country can turn into hard IFR cross country. Consider the
> importance of the instrument and then decide whether it would be better to
> buy a new one or overhaul a 20 year old AI. I think you already know what
> you should do.


Well, gosh, what should he do?

When our DG failed, we figured the AI was the same (unknown) age
and bought a new instrument with a vacuum failure flag.

The new AI failed less than 50 hrs later.

It was replaced under warranty, of course, and has been OK since.

I have friends with overhauled AIs which work perfectly for hundreds
of hours

So tell us, what should Cory already know that he should do, because
having gone through 2 instrument and 1 vac pump failure in 1000 hrs
of flying time it's not so clear to us?

FWIW Cory if you don't have a vacuum guage in your primary scan
I'd consider a new instrument with a vacuum flag on the face.
But, it's just not clear to me that new is necessarily superior
to a good O/H. A lot of people seem to like Kelley Instruments
these days.

Cheers,
Sydney

[[email protected]]

Snowbird > wrote:
: FWIW Cory if you don't have a vacuum guage in your primary scan
: I'd consider a new instrument with a vacuum flag on the face.
: But, it's just not clear to me that new is necessarily superior
: to a good O/H. A lot of people seem to like Kelley Instruments
: these days.

While I agree that when toddling around in the soup, you don't
need anymore challenges, I'm thinking that the additional $150 overhead
for adding a flag needs to be reconsidered. I've got the vacuum gauge,
albeit on the far side of the panel. At some point, however, one needs to
say, "enough is enough. I won't get raped any longer on aviation price
gouging." Having the flag doesn't make the gyro work when it breaks, just
potentially alerts you sooner.

Dunno... need to think about it a bit more. Don't even get me
started on the $150 price overhead for getting a lighted one....

-Cory

--
************************************************** ***********************
* The prime directive of Linux: *
* - learn what you don't know, *
* - teach what you do. *
* (Just my 20 USm$) *
************************************************** ***********************

[[email protected]]

In a related note, anyone have reason to believe foul-play for the
regulator if it reads a solid "4.25" in operation? I don't suspect a weak
pump, since it'll stay at 4.25 once RPM is about 800 or so. I just find
it weird that it would be off that far without intentional mis-setting.
Do the regulator springs really get weak over time and drift?

-Cory

--
************************************************** ***********************
* The prime directive of Linux: *
* - learn what you don't know, *
* - teach what you do. *
* (Just my 20 USm$) *
************************************************** ***********************