Backup gyros - which do you trust?

On 14-Jul-2003, "Jon Woellhaf" wrote:

Why do you think leaving it off most of the time will extend its life?

Seems to me that the two wear items in the electric AI are the brushes in
the DC motor and the gyro bearings. Also seems logical to me that both will
wear a lot less when not turning. As noted in previous post, this strategy
seems to be working for us. I would certainly entertain contrary wisdom
from anyone with more specific knowledge.

-Elliott Drucker

wrote in message
...

seems to be working for us. I would certainly entertain contrary wisdom
from anyone with more specific knowledge.


Well my understanding from the last shop which overhauled my AI was that if
an AI can be caged then it should be shipped in the caged position because
it can be damaged if transported uncaged.

Perhaps the same logic applies to flyingwith an uncaged and unpowered gyro,
but I cannot give any other source except the above.

--
Richard Kaplan, CFII

www.flyimc.com

On Sun, 13 Jul 2003 22:10:08 -0400, Roy Smith wrote:

David Megginson wrote:

Roy Smith writes:

The downside, is that I suspect I don't use the information the AI gives
me as much as I should. I tend to fly pitch by airspeed, not by the
AI.

Are you sure that using the ASI for pitch doesn't make you smoother?

Well, for example, on my initial climb, I'm looking for Vy on the ASI.
Since I'm approaching Vy from below, it means I have to just sort of
guess at the right pitch and watch the ASI to see what the airspeed
does. The "right" way is to know what pitch attitude I want, peg the AI
there, and then watch the ASI to confirm I'm getting the performance I
expected.

I guess I don't agree with the "right" way then. The pitch attitude for Vy
(or any other airspeed) will be somewhat dependent on aircraft weight,
density altitude, etc. I do exactly what you do, use the ASI as my climb
attitude reference, not the AI. Same for descents -- I peg whatever
airspeed i want, keeping the rpm's where I want them, and then make sure
that I have a reasonable descent rate using the VSI. Adust pitch as
necessary to keep everything where it should be.


I know I do it wrong, and I make a concious effort to retrain my scan,
but it's very difficult to unlearn the way you first learned to do it.

In rec.aviation.owning Roy Smith wrote:
: David Megginson wrote:
: But once you're established, do you find it easier to hold pitch using
: the ASI?

: Not really. When I'm doing partial panel work, I find I miss the DG
: much more than I miss the AI.

I totally agree with Roy here. I also don't use the AI as much as some. I too
fly pitch using the ASI, although I use the AI as a reference to set pitch
during level-offs. I too miss the DG more than the AI in partial panel
work. I do fly a fixed-gear Cherokee, though.

As an aside, I had an AI failure in IMC, on the 3rd or 4th flight after
I bought my plane. I didn't realize the AI was a little slow to align at
startup- I had only owned the plane a couple hours!
In flight, I noticed the AI leaning a couple of degrees and thought "Oh,
the AI isn't installed in the panel straight- the DG isn't turning."
About 30 seconds later, the AI started spinning in the roll axis. At
perhaps 600 degrees a second! This was pretty easy to diagnose.
The next day (VFR) the AI worked fine. It was very sensitive to temperature,
and having cold-soaked overnight at Will Rogers World, it just wasn't
happy.

PS, modern AI's won't tumble in roll, and should not tumble until
more than +/- 85 degrees of pitch. (REF the R.C. Allen install guide.)
--
Aaron Coolidge (N9376J)

Bob Gardner wrote:
You have three sources of bank information in a typical panel: the attitude
indicator, the turn coordinator, and the heading indicator.

Um, isn't this leaving out something fundamental (and pretty
reliable, if difficult to interpret)?

Sydney (Be Expert With Map and Compass)

"Roy Smith" wrote in message
...

Are you sure that using the ASI for pitch doesn't make you smoother?

Well, for example, on my initial climb, I'm looking for Vy on the ASI.
Since I'm approaching Vy from below, it means I have to just sort of
guess at the right pitch and watch the ASI to see what the airspeed
does. The "right" way is to know what pitch attitude I want, peg the AI
there, and then watch the ASI to confirm I'm getting the performance I
expected.

I think it depends on the aircraft. Flying a simple trainer on trends in
the secondary instruments is not too hard. The more slippery the aircraft,
the more difficult it becomes: by the time you've picked up the trend in the
ASI needle, your attitude is already in a mess. I noticed this
transitioning to the Mooney, and I think it's much more marked in faster
aircraft -- one of the reasons why jet pilots don't spend a great deal of
time practising partial panel but rely on multiple AIs for redundancy.

Julian Scarfe

There is one IFR flight school that gives the student the introduction to
the AI during their first briefing in the first hour...
Instructor: "See, that's the AI... See how it gives you both pitch and
bank."
Student: "Yes, that's really nice."
Plonk goes the sink stopper...
"That's the last time you will see it until your check ride, son.!"

Denny

"Aaron Coolidge" wrote in message
...
In rec.aviation.owning Roy Smith wrote:
: David Megginson wrote:
: But once you're established, do you find it easier to hold pitch using
: the ASI?

Aaron Coolidge writes:

In rec.aviation.owning Roy Smith wrote:

: David Megginson wrote:
: But once you're established, do you find it easier to hold pitch using
: the ASI?

: Not really. When I'm doing partial panel work, I find I miss the DG
: much more than I miss the AI.

I totally agree with Roy here. I also don't use the AI as much as some. I too
fly pitch using the ASI, although I use the AI as a reference to set pitch
during level-offs. I too miss the DG more than the AI in partial panel
work. I do fly a fixed-gear Cherokee, though.

Note that I wrote "ASI", not "AI", so it might be that all three of us
agree.


All the best,


David

--
David Megginson, , http://www.megginson.com/