Aero Advantage closing shop.

Why spin a gyro at all? Laser ring gyros are the way to go. No moving
parts.

Sandy Mustard

Jay Masino wrote:

Jay Honeck wrote:

This whole topic drives me crazy, since the idea of a "vacuum system" is
ridiculous in the first place.
I'm stuck with one, and have replaced both of my vacuum instruments in the
last six months. Why? Because the danged electric replacements are
absurdly over-priced, and the back-up battery that would make an
all-electric system prudent (and legal) is even worse.
Personally, I think the fact that we're flying around behind vacuum
instruments in the 21st century is patently absurd.


I suspect it's a lot easier to get a gyro to spin at 10 or 15,000 RPM (or
whatever) using vanes and vaccum, than it is to design a reliable electric
motor to spin the gyro at that speed. It can obviously be done, but I
suspect the parts neccessary to do it might be a little more exotic and
expensive than vaccum gyro parts. Add to that the immense liability that
a manufacturer of such devices are taking on, you start to see why all of
these devices are expensive (even the vaccum devices, really).

Turn coordinators spin a gyro with an electric motor, but I bet the fact
that horizons have to pivot in two directons (roll and pitch) makes the
internal design way more complex.

--- Jay

Jay Honeck wrote:

Personally, I think the fact that we're flying around behind vacuum
instruments in the 21st century is patently absurd.

Fine. Then quitcherbitchin and spring the bucks for the electric system. You're only
flying behind a vacuum system because you're a cheapskate (as am I).

George Patterson
If you don't tell lies, you never have to remember what you said.

Fine. Then quitcherbitchin and spring the bucks for the electric system.
You're only
flying behind a vacuum system because you're a cheapskate (as am I).

It's amazing when spending something approaching $1500 for two lousy vacuum
instruments makes me a "cheapskate"...

Gotta love aviation!

;-)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

David Megginson wrote
Afterwards, I read the Air Safety Foundation report that everyone cites on
the danger of vacuum pump failures: it turns out that they did not find a
*single* fatal accident from 1983 to 1997 involving a vacuum-pump failure
for a fixed-gear plane flying IFR -- losing control partial panel seems to
be a retractable thing.

As a gross generalization, that makes sense to me.

IMO the really critical parameters are drag coefficient and roll
stability. Airplanes which are roll stable and draggy (Cherokees,
C-172's, and their ilk) are easy to fly partial panel and it takes a
long time for a nose low unusual attitude to develop to the point
where the airplane will redline. Airplanes that are clean and not
terribly roll stable (Bonanzas, Mooneys) are much more demanding
partial panel, and will go to redline in a heartbeat once you let a
nose-low unusual attitude develop. I suspect, though, that the new
crop of high-speed low-drag fixed gear singles from Lancair and Cirrus
are likely to behave more like the Mooneys and Bonanzas, whereas
retracts like the Arrow and Cutlass are probably not significantly
more likely to have loss of control problems when partial panel than
their fixed gear cousins.

Personally, I consider backup vacuum/gyros to be a low priority for
something like a Cherokee. I suspect that the same money spent on
regular recurrent training would have a significantly higher payoff in
safety. I would put the backup vacuum/gyro for something like a
Cherokee lower on the list than some sort of weather avoidance
capability (spherics, datalink, etc.) and lower than a good handheld
GPS with fresh batteries. Once you have those things, and you're
doing regular recurrent training, then sure - get athe backup. I'm
sure it must have some marginal safety advantage.

Michael

Michael wrote:

Personally, I consider backup vacuum/gyros to be a low priority for
something like a Cherokee. I suspect that the same money spent on
regular recurrent training would have a significantly higher payoff in
safety. I would put the backup vacuum/gyro for something like a
Cherokee lower on the list than some sort of weather avoidance
capability (spherics, datalink, etc.) and lower than a good handheld
GPS with fresh batteries.

Funny, you just listed my major purchases over the past six months: I bought
a Garmin 196 in December, and just ferried my plane back from Montreal this
afternoon with a (used but factory updated) WX-900 Stormscope installed by
an experienced shop. It was the perfect afternoon for it: solid IMC above
1,200 ft AGL, with a small risk of occasional embedded TCU and CB (normally,
I cancelled flights under those conditions).


All the best,


David

David Megginson wrote
Funny, you just listed my major purchases over the past six months: I bought
a Garmin 196 in December, and just ferried my plane back from Montreal this
afternoon with a (used but factory updated) WX-900 Stormscope installed by
an experienced shop. It was the perfect afternoon for it: solid IMC above
1,200 ft AGL, with a small risk of occasional embedded TCU and CB (normally,
I cancelled flights under those conditions).

All I can tell you is that you've made the right purchases. If you're
already taking regular recurrent training, still have money left over,
and have a burning desire to spent it to improve safety in your plane,
go ahead and get the backup vacuum or electric attitude gyro. Can't
hurt, might help.

It's all about priorities. You can keep spending money forever.

Michael

Airplanes that are clean

Aye

and not
terribly roll stable (Bonanzas, Mooneys)
are much more demanding
partial panel,

My 65 C Mooney is incredibly roll stable and extremely easy to fly
partial panel; so much so that some view it as a weakness (I dunno,
maybe in a flat scissors?). I fly partial panel approaches IMC for
practice. Later M20's are more pitch stable as well.

Richard Kaplan wrote:
At those prices, it seems a lot more practical or at least economical in a
GA airplane to simply have a conventional vacuum AI backed up by a
conventional electric AI.

I came to the same conclusion after researching all the options, the
electric AI placed in a sane location is the best overall value for a
small GA craft, IMHO. Backs up the gyro itself, always on, and has
very familiar presentation when the chips are down and you need to
decide quick.

Michael wrote:
Personally, I consider backup vacuum/gyros to be a low priority for
something like a Cherokee. I suspect that the same money spent on
regular recurrent training would have a significantly higher payoff in
safety.

I used to be of the "backup AIs are for non-proficient sissies" school
for a long time (exxagerating, I know Michael didn't say that :-),
until a recent challenging IPC at night. I held it together just fine,
but I realized how much energy it was taking me in a relaxed training
atmosphere. It suddenly hit me that things must look VERY different
when the same situation presents itself (and insidiously, at that)
after a long, tiring day, perhaps with some ice and fuel concerns
thrown in. Bad situation to be in, no doubt, but I realized it could
happen to me one day if I continue to fly weather often enough...
Besides, I am at a point in my flying career where I should
statistically see a pump failure (I have already seen an AI go, VFR).

In the end, I decided to forgo other planned upgrades in favor of the
instrument backup first. I agree its one of those low probability/high
risk scenarios (as is the single engine operation, after all), but its
really not *that* expensive in the grand scheme of things. If you have
an empty hole on the copilot side like most mid-70's spam cans (not
too far out), the electric gyro is also really easy to install, just a
pair of wires and a breaker jumpered to the bus bar. The WX info is
right behind all this, however, and it is a close call priority-wise,
I agree.

Martin


1 RC-Allen RCA26AK4 - $1600
1 P&B 3A breaker - $10
3' MIL-W-22759/20 wire - $5
Seeing both balls tilt the same direction on a dark stormy night -
......

Martin Kosina wrote:

I used to be of the "backup AIs are for non-proficient sissies" school
for a long time (exxagerating, I know Michael didn't say that :-),
until a recent challenging IPC at night.

I don't think that any of us would suggest that. It's more a matter of
statistics -- we're still looking for even one example of a fixed-gear plane
getting into a fatal accident flying IFR after a vacuum pump failure.

In the end, I decided to forgo other planned upgrades in favor of the
instrument backup first. I agree its one of those low probability/high
risk scenarios (as is the single engine operation, after all), but its
really not *that* expensive in the grand scheme of things.

That's fair -- we put a lot of money into our planes for reasons of our own.
I'm thinking of replacing my cracked old panel plastics, and those do not
affect the safety of my plane at all (unless, of course, a piece fell and
wedged under a control, I guess).


All the best,


David

(Martin Kosina) wrote:
Seeing both balls tilt the same direction on a dark stormy night -

I'll confess I've never flown with two AI's, but I would imagine that's
a very powerful argument in favor of it.

The hardest part of partial panel flying is not flying with just the TC,
but recognizing that something has gone wrong. Having two instruments
with identical presentations should make it a lot easier to recognize
that a problem exists.