Emergency instrumentation for cloud encounters

[[email protected]]

why not have one of these:

http://store-vllhq23n.mybigcommerce.com/turn-coordinator-in-enclosure/
http://store-vllhq23n.mybigcommerce.com/flight-feedback-systems/

This is portable and powers up in seconds in any attitude or flight condition.

Contrary to the label this is a pure yaw rate indicator, plus a slip-skid indicator. It does not behave quite like a "turn coordinator".

There are of course more comprehensive ways to go, but this is a whole lot better than nothing. I'm speaking specifically to those pilots who are currently flying with nothing. We all know that in some circles, partial-panel flying of sailplanes in clouds is, or used to be, considered a perfectly normal thing to do.

Some dual practice under the hood would be extremely beneficial of course. It's crucial to respond to the direction the ASI needle is trending, more than to the actual airspeed indication. This doesn't come intuitively.

Likewise this particular instrument has in my opinion a significant possibility of being read backwards. The fixed aircraft symbol on the front of the device has no significance and in my opinion should be covered up with a blank label, or with some design of the pilot's own creation, so the pilot is not tempted to interpret the instrument like an artificial horizon. which would be backwards. The LED's represent the wingtips of an imaginary aircraft which tips left and right to indicate turning-- not a horizon line.

But I can attest that it works.

The compass-on-a-southerly-heading trick works too, as discussed in a related thread recently. ("In wave, in blue hole at cloud level, hole closes, in IMC, then what?"). But you are utterly and thoroughly hosed if you let the compass swing out of the "sweet spot" that extends for about 45 to 60 degrees on either side of the the due magnetic "south" indication. You had better be established and stabilized on this heading before losing visibility. I'm speaking for mid-latitudes in the northern hemisphere here.

I once had an experience where I was unable to hold heading in a cumulus cloud using GPS + rudimentary turn rate indicator. I was able to keep out of a spiral dive, but not able to hold heading well enough to make good progress out of the cloud. However, I was able to keep the turn rate low enough that I could successfully "capture" a southerly heading and then I switched over to using the compass as my primary instrument, and I was able to hold heading indefinitely. On a southerly heading, the compass actually did a prompter and better job of signalling small heading deviations, than did the rudimentary turn rate indicator. It would be pretty much suicidal to try this without having the turn rate indicator to fall back on in case a spiral dive started to develop due to a strong jolt of turbulence or a wrong control input on the pilot's part.

In thermal conditions, there's no excuse for accidentally getting into clouds, and an untrained pilot is likely to be in a world of hurt. But in the (sometimes) smoother wave environment, I think there's a real case to be made for routinely carrying a turn rate indicator for emergency use. And a freshly packed parachute of course.

S

[[email protected]]

A few more thoughts after reading the other related thread:

* Have you every watched how the magnetic compass behaves in a turn? Even with a bank angle as shallow as 30 degrees, it's hopeless, especially at low airspeed. Random freeze-ups and reversals in rotation are par for the course. Nonetheless there are specific ways to use it in cloud-- by establishing a southerly heading before entering cloud, or by using another instrument to level the wings before attempting to "capture" the southerly heading via a very shallow turn. Again, these comments are for mid-to-high latitudes in the northern hemisphere.

* Is there really such a thing as an instant-on artificial horizon? Is it instant-on even in a spiral dive? Which models are these? The turn rate indicator I linked to above has an initiation time of less than 5 seconds and is not affected at all by the aircraft's orientation and flight path.

* Re the dirty vs clean question-- I'd vote strongly for "dirty". Anything that creates drag tends to dampen the pitch phugoid. Sudden changes in bank angle-- due to turbulence or wrong pilot control inputs-- pump energy into the pitch phugoid. This is a huge problem when flying "partial panel" in an aircraft with relaxed pitch stability. Drag is your friend even if the G-load at which the airframe breaks is reduced by several G's. If you are pulling more than 3 G's or so in cloud, you are unlikely to be getting the aircraft back under control anyway-- especially if it is clean.

S

[[email protected]]

Instant on artificial horizons? Yes. Two choices.
The LXNav S80.
The Butterfly Vario.
Both are functioning at all times.
Both are 100% solid state and will not tumble.

[7C]

On Monday, 20 April 2015 21:05:35 UTC+1, wrote:
> Instant on artificial horizons? Yes. Two choices.
> The LXNav S80.
> The Butterfly Vario.
> Both are functioning at all times.
> Both are 100% solid state and will not tumble.

The Vaulter - cheaper than either and both excellent and simple :)

http://wharingtonsmith.com/vaulter.html

Don't forget that none of these instruments are designed for that purpose - if you really need a AH you should buy an AH!

[[email protected]]

Thanks for the notes. Don't get me wrong, I think an artificial horizon is a very great thing to have. But, just as a point of conversation, I'd be really be surprised if these things were instant-on in the sense that I was talking about. Surely the guts of the system--the AHRS sensors and processors-- have to be up and running for at least a few tens of seconds before the artificial horizon is needed. And I doubt that those few tens of seconds can take place during a spiral dive. I'd love to be proven wrong-- it would make for a very interesting in-flight video.

Seriously, how long would it take to bring the whole system up from a cold start to accurate functioning during

a) reasonably straight-line flight
b) a spiral dive

I submit that there's some advantage offered to having a self-contained turn rate indicator unit that can be powered up quickly regardless of the glider's flight attitude, as a supplement to whatever AHRS-based artificial horizon may or may not be present.

Sure, it's all a question of how far you want to go. But maybe a vario-incorporated artificial horizon plus a stand-alone instant-on (or rapid-on) turn rate indicator with independent self-contained battery power is a reasonable alternative to a purpose-built artificial horizon instrument, at least for the purpose of strictly emergency use.

Food for thought...

S

[Dan Marotta]

I'd buy one of those turn coordinators if someone would buy my TruTrac...

On 4/20/2015 11:55 AM, wrote:
> why not have one of these:
>
> http://store-vllhq23n.mybigcommerce.com/turn-coordinator-in-enclosure/
> http://store-vllhq23n.mybigcommerce.com/flight-feedback-systems/
>
> This is portable and powers up in seconds in any attitude or flight condition.
>
> Contrary to the label this is a pure yaw rate indicator, plus a slip-skid indicator. It does not behave quite like a "turn coordinator".
>
> There are of course more comprehensive ways to go, but this is a whole lot better than nothing. I'm speaking specifically to those pilots who are currently flying with nothing. We all know that in some circles, partial-panel flying of sailplanes in clouds is, or used to be, considered a perfectly normal thing to do.
>
> Some dual practice under the hood would be extremely beneficial of course. It's crucial to respond to the direction the ASI needle is trending, more than to the actual airspeed indication. This doesn't come intuitively.
>
> Likewise this particular instrument has in my opinion a significant possibility of being read backwards. The fixed aircraft symbol on the front of the device has no significance and in my opinion should be covered up with a blank label, or with some design of the pilot's own creation, so the pilot is not tempted to interpret the instrument like an artificial horizon. which would be backwards. The LED's represent the wingtips of an imaginary aircraft which tips left and right to indicate turning-- not a horizon line.
>
> But I can attest that it works.
>
> The compass-on-a-southerly-heading trick works too, as discussed in a related thread recently. ("In wave, in blue hole at cloud level, hole closes, in IMC, then what?"). But you are utterly and thoroughly hosed if you let the compass swing out of the "sweet spot" that extends for about 45 to 60 degrees on either side of the the due magnetic "south" indication. You had better be established and stabilized on this heading before losing visibility. I'm speaking for mid-latitudes in the northern hemisphere here.
>
> I once had an experience where I was unable to hold heading in a cumulus cloud using GPS + rudimentary turn rate indicator. I was able to keep out of a spiral dive, but not able to hold heading well enough to make good progress out of the cloud. However, I was able to keep the turn rate low enough that I could successfully "capture" a southerly heading and then I switched over to using the compass as my primary instrument, and I was able to hold heading indefinitely. On a southerly heading, the compass actually did a prompter and better job of signalling small heading deviations, than did the rudimentary turn rate indicator. It would be pretty much suicidal to try this without having the turn rate indicator to fall back on in case a spiral dive started to develop due to a strong jolt of turbulence or a wrong control input on the pilot's part.
>
> In thermal conditions, there's no excuse for accidentally getting into clouds, and an untrained pilot is likely to be in a world of hurt. But in the (sometimes) smoother wave environment, I think there's a real case to be made for routinely carrying a turn rate indicator for emergency use. And a freshly packed parachute of course.
>
> S

--
Dan Marotta

[son_of_flubber]

On Monday, April 20, 2015 at 1:55:12 PM UTC-4, wrote:
> why not have one of these:
>
> http://store-vllhq23n.mybigcommerce.com/turn-coordinator-in-enclosure/
> http://store-vllhq23n.mybigcommerce.com/flight-feedback-systems/

'Wings level upright' and 'wings level inverted' gives the same reading on this instrument.

[waremark]

My LX 9000 with v9 is up within 2 or 3 seconds if I switch to a page which shows it while in a thermalling turn. I understand Dynons and other solid state horizons do the same. Why would you ever bring it up when in a spiral dive? I have no reason to doubt that it would perform correctly, but it sounds rather unlikely if equipped with an A-H to enter IMC without having switched it on.

[son_of_flubber]

On Monday, April 20, 2015 at 4:05:35 PM UTC-4, wrote:
> Instant on artificial horizons? Yes. Two choices.
> The LXNav S80.
> The Butterfly Vario.

http://www.parts4aircraft.com/Files/73374/Img/03/AV-2_Mainlarge-1.jpg
http://www.mglavionics.com/html/infinity_singles.html

[Dave Doe]

In article >,
, son_of_flubber says...
>
> On Monday, April 20, 2015 at 1:55:12 PM UTC-4, wrote:
> > why not have one of these:
> >
> > http://store-vllhq23n.mybigcommerce.com/turn-coordinator-in-enclosure/
> > http://store-vllhq23n.mybigcommerce.com/flight-feedback-systems/
>
> 'Wings level upright' and 'wings level inverted' gives the same reading on this instrument.

But a different reading on the pilot :)

--
Duncan.

[[email protected]]

On Monday, April 20, 2015 at 6:35:42 PM UTC-5, son_of_flubber wrote:
> On Monday, April 20, 2015 at 1:55:12 PM UTC-4, wrote:
> > why not have one of these:
> >
> > http://store-vllhq23n.mybigcommerce.com/turn-coordinator-in-enclosure/
> > http://store-vllhq23n.mybigcommerce.com/flight-feedback-systems/
>
> 'Wings level upright' and 'wings level inverted' gives the same reading on this instrument.

So? You'll never get wings-level-inverted if you are paying attention to the readout. How do you think Lindbergh got across the Atlantic?

S

[[email protected]]

I think our wires are a little crossed. That's still not a cold start, right? The AHRS is already on.

Anyway my main point is--

If you are flying with nothing, consider the solid state turn rate indicator that I linked to.

If you are flying with a vario-based AHRS-based artificial horizon, that's wonderful. But you might want to consider supplementing with a self-contained solid-state turn rate indicator in case the system goes belly-up or your battery dies.

Back to square one-- an experienced, highly trained, ex-military pilot blew up his sailplane in cloud in wave. I'm sure he never meant to enter the cloud. Wave cloud is squirrely. Who can argue that he would not have been much better off with some sort of turn rate indicator, than with nothing? I'm sure he had lots of partial-panel practice and experience, or at least simulated experience. If you want to argue that an artificial horizon would be better yet-- great. I agree.

S

On Monday, April 20, 2015 at 6:41:50 PM UTC-5, waremark wrote:
> My LX 9000 with v9 is up within 2 or 3 seconds if I switch to a page which shows it while in a thermalling turn. I understand Dynons and other solid state horizons do the same. Why would you ever bring it up when in a spiral dive? I have no reason to doubt that it would perform correctly, but it sounds rather unlikely if equipped with an A-H to enter IMC without having switched it on.

[bumper[_4_]]

On Monday, April 20, 2015 at 4:34:11 PM UTC-7, Dan Marotta wrote:

> I'd buy one of those turn coordinators if someone would buy my
> TruTrac...
>
> Dan Marotta

I'll keep my TruTrac. It doesn't have pitch, but with instrument training, it has what it takes with a familiar AH like display to keep wings level or to do a turn. I leave it off unless in "the vicinity" of clouds. When powered up, it "erects" in a couple of seconds, even in the middle of a steep turn. I'll add the Butterfly - redundancy.

[son_of_flubber]

On Monday, April 20, 2015 at 11:25:37 PM UTC-4, wrote:
> On Monday, April 20, 2015 at 6:35:42 PM UTC-5, son_of_flubber wrote:
> > On Monday, April 20, 2015 at 1:55:12 PM UTC-4, wrote:
> > > why not have one of these:
> > >
> > > http://store-vllhq23n.mybigcommerce.com/turn-coordinator-in-enclosure/
> > > http://store-vllhq23n.mybigcommerce.com/flight-feedback-systems/
> >
> > 'Wings level upright' and 'wings level inverted' gives the same reading on this instrument.
>
> So? You'll never get wings-level-inverted if you are paying attention to the readout.

I'd expect that it would be rather easy to get inverted in a cloud in mountain wave.

[Dave Doe]

In article >,
, son_of_flubber says...
>
> On Monday, April 20, 2015 at 11:25:37 PM UTC-4, wrote:
> > On Monday, April 20, 2015 at 6:35:42 PM UTC-5, son_of_flubber wrote:
> > > On Monday, April 20, 2015 at 1:55:12 PM UTC-4, wrote:
> > > > why not have one of these:
> > > >
> > > > http://store-vllhq23n.mybigcommerce.com/turn-coordinator-in-enclosure/
> > > > http://store-vllhq23n.mybigcommerce.com/flight-feedback-systems/
> > >
> > > 'Wings level upright' and 'wings level inverted' gives the same reading on this instrument.
> >
> > So? You'll never get wings-level-inverted if you are paying attention to the readout.
>
> I'd expect that it would be rather easy to get inverted in a cloud in mountain wave.

"C"FIT is still yer biggest problem.

--
Duncan.

[[email protected]]

WARNING: SIDETRACK--TANGENT--WAY OFF COURSE HERE

On Monday, April 20, 2015 at 6:35:42 PM UTC-5, son_of_flubber wrote:

>
> 'Wings level upright' and 'wings level inverted' gives the same reading on this instrument.

Actually it's worse than that-- the indicated turn rate (yaw rate) drops off toward zero as as the bank angle approaches 90 degrees, in which case the glider is in an extreme diving corkscrew or helix...

But again, you aren't ever going to end up there if you are watching the instrument.

In the fully inverted case, if the G-loading is still positive-- which it will be unless you are pushing the stick forward-- you won't be inverted for long. But during those few seconds that you are, if you deviate even slightly from wings-level, then if you react to the indication of the yaw rate indicator, you'll roll the aircraft toward wings-level upright. That's a good thing! Example: inverted wings-level but positively loaded, left wing drops, glider is now in a turn toward right wingtip, instrument shows right yaw, pilot gives left roll input which is indeed the shortest path toward upright. The only problem is that as the bank angle approaches 90 degrees, again the yaw rate drops toward zero...

But again, you aren't ever going to end up there if you are watching the instrument.

That's all a side-track. Let's not lose sight of the fact that the history of soaring includes many many hundreds or thousands of hours, collectively, of flying in clouds with the aid of a turn rate indicator and no artificial horizon.

S

[[email protected]]

On Monday, April 20, 2015 at 11:24:32 PM UTC-5, son_of_flubber wrote:

>
> I'd expect that it would be rather easy to get inverted in a cloud in mountain wave.

If you hit the rotor all bets are off. But I've successfully used the instrument as my primary reference in cloud in both thermal and wave lift. S

[[email protected]]

This discussion is veering awfully close to transforming into this question; "Is partial-panel flight, i.e. flight in clouds with a turn rate indicator but no artificial horizon instrument, even possible?"

I think that's been settled...

On Monday, April 20, 2015 at 11:43:17 PM UTC-5, wrote:
>Let's not lose sight of the fact that the history of soaring includes many many hundreds or thousands of hours, collectively, of flying in clouds with the aid of a turn rate indicator and no artificial horizon.
>
> S

[Dave Doe]

In article >,
, says...
>
> WARNING: SIDETRACK--TANGENT--WAY OFF COURSE HERE
>
> On Monday, April 20, 2015 at 6:35:42 PM UTC-5, son_of_flubber wrote:
>
> >
> > 'Wings level upright' and 'wings level inverted' gives the same
> > reading on this instrument.
>
> Actually it's worse than that-- the indicated turn rate (yaw rate)
> drops off toward zero as as the bank angle approaches 90 degrees, in
> which case the glider is in an extreme diving corkscrew or helix...
>
> But again, you aren't ever going to end up there if you are watching
> the instrument.
>
> In the fully inverted case, if the G-loading is still positive-- which
> it will be unless you are pushing the stick forward-- you won't be
> inverted for long. But during those few seconds that you are, if you
> deviate even slightly from wings-level, then if you react to the
> indication of the yaw rate indicator, you'll roll the aircraft toward
> wings-level upright. That's a good thing! Example: inverted
> wings-level but positively loaded, left wing drops, glider is now ina
> turn toward right wingtip, instrument shows right yaw, pilot gives
> left roll input which is indeed the shortest path toward upright. The
> only problem is that as the bank angle approaches 90 degrees, again
> the yaw rate drops toward zero...
>
> But again, you aren't ever going to end up there if you are watching
> the instrument.
>
> That's all a side-track. Let's not lose sight of the fact that the
> history of soaring includes many many hundreds or thousands of hours,
> collectively, of flying in clouds with the aid of a turn rate
> indicator and no artificial horizon.

I guess the big question is, can you recover from an unusual attitude on
limited instruments (no AH). I know I can, but it requires practice.
And it's not fantastically *easy*.

If you haven't done it, get under the hood with an instructor. And did
I say it's a lot of fun? It is, great fun. Could save ya butt one day.

--
Duncan.

[krasw]

For vfr pilot with no training I would install simple electronic AH (Dynon, Gemini etc.) for the purpose of keeping your glider right side up and getting out of imc safely. You can fly whole day with T&B only, but it requires some training.

[7C]

The interial various are really "instant display".

They record the information from the moment you turn the instrument on - which is probably when you turned the panel on. Therefore there is no concept of 'on' when switching to the A/H display. The gyros are used as part of the air model and are constantly calibrated by the external information including (in the Vaulter at least) the GPS.

In addition the one I'm familiar with has a built in magnetometer that calibrates to your installation and gives a rather nice always available compass.

Mel

[Martin Gregorie[_5_]]

On Mon, 20 Apr 2015 22:12:46 -0700, krasw wrote:

> For vfr pilot with no training I would install simple electronic AH
> (Dynon, Gemini etc.) for the purpose of keeping your glider right side
> up and getting out of imc safely. You can fly whole day with T&B only,
> but it requires some training.

I think the same definitely applies to the Dynon electronic AH and its
relations: you still need the training before trying to use it 'for
real'.

I've had some training with a Dynon (bucket over my head in an SF-25) and
find that I prefer using a partial panel, mainly because the Dynon
heading indicator is just a small box showing the heading in degrees: I
don't find it nearly as easy to scan as an analogue indicator or a ribbon
like some of the other electronic AHs provide.

Its just as well I prefer the partial panel because that is what is in my
glider and there is no space in the panel to add an AH.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[waremark]

On Tuesday, 21 April 2015 08:29:19 UTC+1, 7C wrote:
> The interial various are really "instant display".
>
> They record the information from the moment you turn the instrument on - which is probably when you turned the panel on. Therefore there is no concept of 'on' when switching to the A/H display. The gyros are used as part of the air model and are constantly calibrated by the external information including (in the Vaulter at least) the GPS.
>
> In addition the one I'm familiar with has a built in magnetometer that calibrates to your installation and gives a rather nice always available compass.
>
> Mel


Are the LX devices really running all the time? When you bring up a page showing the A-H it is not actually instant on - it takes a couple of seconds before it indicates that it is live. Presumably the sensors are alive, but there is something else which has to be on before you see the A-H display.

So many solid state A-H's have become available over a short period of time.. According to reports they all seem to work very well. Does anyone know whether the technology (both hardware and software) is common to the different manufacturers, or has each manufacturer developed their own approach? Within the LX Nav range, does anyone know whether the S80/S8 have the same sensors and software as the V9?

[waremark]

On Tuesday, 21 April 2015 12:16:13 UTC+1, Martin Gregorie wrote:
> On Mon, 20 Apr 2015 22:12:46 -0700, krasw wrote:
>
> > For vfr pilot with no training I would install simple electronic AH
> > (Dynon, Gemini etc.) for the purpose of keeping your glider right side
> > up and getting out of imc safely. You can fly whole day with T&B only,
> > but it requires some training.
>
> I think the same definitely applies to the Dynon electronic AH and its
> relations: you still need the training before trying to use it 'for
> real'.
>
> I've had some training with a Dynon (bucket over my head in an SF-25) and
> find that I prefer using a partial panel, mainly because the Dynon
> heading indicator is just a small box showing the heading in degrees: I
> don't find it nearly as easy to scan as an analogue indicator or a ribbon
> like some of the other electronic AHs provide.
>
> Its just as well I prefer the partial panel because that is what is in my
> glider and there is no space in the panel to add an AH.
>
>
> --
> martin@ | Martin Gregorie
> gregorie. | Essex, UK
> org |

Martin, I am confused. What instruments do you have in your 'partial panel' which you prefer to an electronic A-H? Surely you are not saying that you find it easier to cloud fly using a turn and slip than using an A-H? Are you referring to straightening up in the right direction when you have finished thermalling, in which case surely you would level the wings using the A-H and use your gps or your compass to exit your cloud in the right direction?

Mark Burton, London Gliding Club, UK

[[email protected]]

On Monday, April 20, 2015 at 11:43:17 PM UTC-5, wrote:
> WARNING: SIDETRACK--TANGENT--WAY OFF COURSE HERE


Whoops, I was in error. I labelled my fingers with "left" and "right" and flew it through with my hand again. Postively-loaded case, wings-level, inverted flight-- you won't be there for long, but if you try to keep the turn rate indicator needle centered, you'll give inputs that tend to roll the glider back to inverted wings-level flight after any deviation. Maybe not such a great thing. Negatively-loaded case-- if you move the stick against the direction of any indicated turn, you'll tend to roll toward a steeper bank angle. Sustained negatively-loaded flight would theoretically be possible by moving the stick in the same direction as any indicated turn-- just like one does when flying inverted visually. Obviously this is all theoretical.

For the most cases in cloud I don't think it's ending up in genuine aerobatic scenarios that the main concern. It's losing control of the pitch phugoid. A rapid increase in bank angle can put you through the redline long before the bank angle reaches sixty degrees. Likewise, a rapid decrease in bank angle during high-speed flight can pitch you up into the start of a loop if you don't react to the decreasing trend of the airspeed needle fast enough.

So yes, I absolutely agree that an artificial horizon is the best way to go.. I guess that I've had enough exposure to what is possible with just a turn rate indicator, that I have a hard time believing that an artificial horizon wouldn't give the average pilot a good fighting chance without all sorts of special training. But, that's just me. I suppose the statistics say otherwise.

I'm sure a pilot with Chukar's experience would have done very well with either an artificial horizon or a turn rate indicator.

And I still like the idea of the redundancy provided by a simple, self-contained instrument that will power up in just a few seconds regardless of the aircraft's attitude and flight path. It seems like a good thing to have if the only other other thing one has is something that is built into a vario system.

By the way, an older generation of this same instrument needed to be flown for several seconds in wings-level flight during a calibration phase immediately after the initial start-up. I think they've made a great improvement in modifying the design to eliminate this.

Thanks much for all the various comments so far. It's a topic that I find quite interesting.

S

[[email protected]]

I submit that you might be surprised at what happens if you power up the system in a steep turn. Maybe I'm wrong...

On Tuesday, April 21, 2015 at 2:29:19 AM UTC-5, 7C wrote:
> The interial various are really "instant display".
>
> They record the information from the moment you turn the instrument on - which is probably when you turned the panel on. Therefore there is no concept of 'on' when switching to the A/H display. The gyros are used as part of the air model and are constantly calibrated by the external information including (in the Vaulter at least) the GPS.
>
> In addition the one I'm familiar with has a built in magnetometer that calibrates to your installation and gives a rather nice always available compass.
>
> Mel

[Dan Marotta]

Well said.

My TruTrac is pseudo "instant on" in that, within a second or two, it
shows the turn even when switched on in the turn. It is "rate based"
whatever that means. When a gyro instrument is turned on in a turn it
will erect itself to the vertical g-loading of the aircraft unless it
has some fancy way of telling up from the load experienced. This I know
from partial panel practice whereby the front seat pilot would perform
aerobatic maneuvers while the back seat pilot, under the instrument
hood, would hold the attitude indicator caged. The AI would show level
flight regardless of attitude until the cage knob was released and, when
the aircraft was recovered from its unusual attitude, the AI would show
some strange attitude which was, of course, incorrect.

It would be very interesting to try one of these new digital gyros and
see how it erects in an unusual attitude.

On 4/20/2015 1:51 PM, wrote:
> A few more thoughts after reading the other related thread:
>
> * Have you every watched how the magnetic compass behaves in a turn? Even with a bank angle as shallow as 30 degrees, it's hopeless, especially at low airspeed. Random freeze-ups and reversals in rotation are par for the course. Nonetheless there are specific ways to use it in cloud-- by establishing a southerly heading before entering cloud, or by using another instrument to level the wings before attempting to "capture" the southerly heading via a very shallow turn. Again, these comments are for mid-to-high latitudes in the northern hemisphere.
>
> * Is there really such a thing as an instant-on artificial horizon? Is it instant-on even in a spiral dive? Which models are these? The turn rate indicator I linked to above has an initiation time of less than 5 seconds and is not affected at all by the aircraft's orientation and flight path.
>
> * Re the dirty vs clean question-- I'd vote strongly for "dirty". Anything that creates drag tends to dampen the pitch phugoid. Sudden changes in bank angle-- due to turbulence or wrong pilot control inputs-- pump energy into the pitch phugoid. This is a huge problem when flying "partial panel" in an aircraft with relaxed pitch stability. Drag is your friend even if the G-load at which the airframe breaks is reduced by several G's. If you are pulling more than 3 G's or so in cloud, you are unlikely to be getting the aircraft back under control anyway-- especially if it is clean.
>
> S

--
Dan Marotta

[[email protected]]

The TruTrac (or at least some models) is conceptually the same thing as the instrument I linked to. More bucks and a more user-friendly display. I can certainly believe that it is instant-on in any flight attitude. The main display is driven by a 1-axis turn rate gyro, not an AHRS system.

S

[[email protected]]

I mean "sensor" of course, not an actual gyro.

[Dan Marotta]

Same could be said for the untrained pilot trying to use an attitude
indicator for the first time. It's very easy under a vision restricting
device in VMC. Not so much when using it successfully makes a difference.

On 4/20/2015 11:12 PM, krasw wrote:
> For vfr pilot with no training I would install simple electronic AH (Dynon, Gemini etc.) for the purpose of keeping your glider right side up and getting out of imc safely. You can fly whole day with T&B only, but it requires some training.

--
Dan Marotta

[Dan Marotta]

I've got one of these at the airport. Had it in a box for almost 40
years and it still works! Too bad I don't have the space, battery
power, or weight allowance to mount it...

http://www.aviation-dream.com/images/Alb_inst/130621_Horizon.jpg
<http://www.aviation-dream.com/images/Alb_inst/130621_Horizon.jpg>

On 4/21/2015 7:55 AM, wrote:
> On Monday, April 20, 2015 at 11:43:17 PM UTC-5, wrote:
>> WARNING: SIDETRACK--TANGENT--WAY OFF COURSE HERE
>
> Whoops, I was in error. I labelled my fingers with "left" and "right" and flew it through with my hand again. Postively-loaded case, wings-level, inverted flight-- you won't be there for long, but if you try to keep the turn rate indicator needle centered, you'll give inputs that tend to roll the glider back to inverted wings-level flight after any deviation. Maybe not such a great thing. Negatively-loaded case-- if you move the stick against the direction of any indicated turn, you'll tend to roll toward a steeper bank angle. Sustained negatively-loaded flight would theoretically be possible by moving the stick in the same direction as any indicated turn-- just like one does when flying inverted visually. Obviously this is all theoretical.
>
> For the most cases in cloud I don't think it's ending up in genuine aerobatic scenarios that the main concern. It's losing control of the pitch phugoid. A rapid increase in bank angle can put you through the redline long before the bank angle reaches sixty degrees. Likewise, a rapid decrease in bank angle during high-speed flight can pitch you up into the start of a loop if you don't react to the decreasing trend of the airspeed needle fast enough.
>
> So yes, I absolutely agree that an artificial horizon is the best way to go. I guess that I've had enough exposure to what is possible with just a turn rate indicator, that I have a hard time believing that an artificial horizon wouldn't give the average pilot a good fighting chance without all sorts of special training. But, that's just me. I suppose the statistics say otherwise.
>
> I'm sure a pilot with Chukar's experience would have done very well with either an artificial horizon or a turn rate indicator.
>
> And I still like the idea of the redundancy provided by a simple, self-contained instrument that will power up in just a few seconds regardless of the aircraft's attitude and flight path. It seems like a good thing to have if the only other other thing one has is something that is built into a vario system.
>
> By the way, an older generation of this same instrument needed to be flown for several seconds in wings-level flight during a calibration phase immediately after the initial start-up. I think they've made a great improvement in modifying the design to eliminate this.
>
> Thanks much for all the various comments so far. It's a topic that I find quite interesting.
>
> S

--
Dan Marotta

[Martin Gregorie[_5_]]

On Tue, 21 Apr 2015 05:54:32 -0700, waremark wrote:

> On Tuesday, 21 April 2015 12:16:13 UTC+1, Martin Gregorie wrote:
>> On Mon, 20 Apr 2015 22:12:46 -0700, krasw wrote:
>>
>> > For vfr pilot with no training I would install simple electronic AH
>> > (Dynon, Gemini etc.) for the purpose of keeping your glider right
>> > side up and getting out of imc safely. You can fly whole day with T&B
>> > only,
>> > but it requires some training.
>>
>> I think the same definitely applies to the Dynon electronic AH and its
>> relations: you still need the training before trying to use it 'for
>> real'.
>>
>> I've had some training with a Dynon (bucket over my head in an SF-25)
>> and find that I prefer using a partial panel, mainly because the Dynon
>> heading indicator is just a small box showing the heading in degrees: I
>> don't find it nearly as easy to scan as an analogue indicator or a
>> ribbon like some of the other electronic AHs provide.
>>
>> Its just as well I prefer the partial panel because that is what is in
>> my glider and there is no space in the panel to add an AH.
>>
>>
>> --
>> martin@ | Martin Gregorie gregorie. | Essex, UK org |
>
> Martin, I am confused. What instruments do you have in your 'partial
> panel' which you prefer to an electronic A-H? Surely you are not saying
> that you find it easier to cloud fly using a turn and slip than using an
> A-H?
>
Yes, exactly that: I don't see all that much difference between a T&S+ASI
and an AH for flying straight or maintaining a constant rate 1 turn in
cloud.

> Are you referring to straightening up in the right direction when
> you have finished thermalling,
>
Yes. When it comes to straightening out or flying on a heading I find
that a lot easier with a 'proper' compass or LK8000's moving map than I
do trying to use the tiny 3 digit bearing box on the Dynon AH. For me
anyway this is a clear case of 'analogue display trumps digital'.

> in which case surely you would level the
> wings using the A-H and use your gps or your compass to exit your cloud
> in the right direction?
>
As I'm never far from home without a task set in LK8000, it will always
be showing the leg I need to resume travel along and I reckon that
straightening out along that is at least as easy as using an analogue
compass even after allowing for the map updating lag when turning.

A personal view, of course: ymmv.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Bill D]

On Monday, April 20, 2015 at 11:12:47 PM UTC-6, krasw wrote:
> For vfr pilot with no training I would install simple electronic AH (Dynon, Gemini etc.) for the purpose of keeping your glider right side up and getting out of imc safely. You can fly whole day with T&B only, but it requires some training.

A VFR pilot with no training will only survive a few seconds longer with a full gyro panel than without. The only "hardware solution" for a VFR pilot without extensive instrument training is an autopilot and even then survival would be in doubt without training.

[7C]

>
> Are the LX devices really running all the time? When you bring up a page showing the A-H it is not actually instant on - it takes a couple of seconds before it indicates that it is live. Presumably the sensors are alive, but there is something else which has to be on before you see the A-H display..
>

I don't know about the LX but that Vaulter is definitely instant display.

Mel

[Jonathan St. Cloud]

For those that remember the John Kennedy Jr. mishap. Current pilot with instrument familiarity (required to get SEL license) airplane with good auto pilot and hazy night, not hard IFR. Piont being the deck is stacked against most US based glider pilots. However, with yearly or bi-yearly instrument training and an AH I believe your chances have increased to maintaining control for a minute or two, enough to get you out of the soup. In climbing we always "hoped for the best, excepted the worst and brought what we could". IN other words, train and equip your glider with AH then stay out of the clouds! If you get inadvertent IFR, you have given yourself a better chance of survival.

[waremark]

People might be interested in the discussion about whether cloud flying should continue to be allowed in UK comps linked here
https://www.surveymonkey.com/r/cloudflying
You will notice that there is no reference to inadvertent loss of control. Glider pilots seem to manage to control their aircraft in cloud even though up to now there has been no formal scheme of training or qualification.

[[email protected]]

How do you guys avoid midairs when climbing in cloud? Does everyone circle left? I can't see even Flarm saving you.

[krasw]

On Tuesday, 21 April 2015 18:02:36 UTC+3, Dan Marotta wrote:
> Same could be said for the untrained pilot trying to use an attitude
> indicator for the first time.* It's very easy under a vision
> restricting device in VMC.* Not so much when using it successfully
> makes a difference.
>

That's what we all are saying here. Do not fly into clouds without proper training. If you do, you might increase your chances with proper instruments.. I bet if there is either T&B or AH to choose, untrained pilot has better chance to survive with AH. But yes, that chance is not 100%.

[krasw]

On Tuesday, 21 April 2015 21:24:09 UTC+3, Martin Gregorie wrote:
> On Tue, 21 Apr 2015 05:54:32 -0700, waremark wrote:
>
> > On Tuesday, 21 April 2015 12:16:13 UTC+1, Martin Gregorie wrote:
> >> On Mon, 20 Apr 2015 22:12:46 -0700, krasw wrote:
> >>
> >> > For vfr pilot with no training I would install simple electronic AH
> >> > (Dynon, Gemini etc.) for the purpose of keeping your glider right
> >> > side up and getting out of imc safely. You can fly whole day with T&B
> >> > only,
> >> > but it requires some training.
> >>
> >> I think the same definitely applies to the Dynon electronic AH and its
> >> relations: you still need the training before trying to use it 'for
> >> real'.
> >>
> >> I've had some training with a Dynon (bucket over my head in an SF-25)
> >> and find that I prefer using a partial panel, mainly because the Dynon
> >> heading indicator is just a small box showing the heading in degrees: I
> >> don't find it nearly as easy to scan as an analogue indicator or a
> >> ribbon like some of the other electronic AHs provide.
> >>
> >> Its just as well I prefer the partial panel because that is what is in
> >> my glider and there is no space in the panel to add an AH.
> >>
> >>
> >> --
> >> martin@ | Martin Gregorie gregorie. | Essex, UK org |
> >
> > Martin, I am confused. What instruments do you have in your 'partial
> > panel' which you prefer to an electronic A-H? Surely you are not saying
> > that you find it easier to cloud fly using a turn and slip than using an
> > A-H?
> >
> Yes, exactly that: I don't see all that much difference between a T&S+ASI
> and an AH for flying straight or maintaining a constant rate 1 turn in
> cloud.
>
> > Are you referring to straightening up in the right direction when
> > you have finished thermalling,
> >
> Yes. When it comes to straightening out or flying on a heading I find
> that a lot easier with a 'proper' compass or LK8000's moving map than I
> do trying to use the tiny 3 digit bearing box on the Dynon AH. For me
> anyway this is a clear case of 'analogue display trumps digital'.
>
> > in which case surely you would level the
> > wings using the A-H and use your gps or your compass to exit your cloud
> > in the right direction?
> >
> As I'm never far from home without a task set in LK8000, it will always
> be showing the leg I need to resume travel along and I reckon that
> straightening out along that is at least as easy as using an analogue
> compass even after allowing for the map updating lag when turning.
>
> A personal view, of course: ymmv.
>
>
> --
> martin@ | Martin Gregorie
> gregorie. | Essex, UK
> org |

I agree that AH is not a major advantage to T&B while thermalling inside cloud. GPS with map display is, compared to plain compass. I have flown most of my imc with T&B only (partial panel?), and now couple of years with AH added (national rules require T&B in any case). I've found couple of instances where AH gives added safety:

1) Straightening up after prolonged thermalling, or centering inside cloud. You just nail the correct pitch additude every single time with AH.

2) Severe turbulence, usually at the top of cloud. Flying straight and level with AH is much more accurate.

[Martin Gregorie[_5_]]

On Tue, 21 Apr 2015 22:30:16 -0700, krasw wrote:

> I agree that AH is not a major advantage to T&B while thermalling inside
> cloud. GPS with map display is, compared to plain compass. I have flown
> most of my imc with T&B only (partial panel?), and now couple of years
> with AH added (national rules require T&B in any case). I've found
> couple of instances where AH gives added safety:
>
> 1) Straightening up after prolonged thermalling, or centering inside
> cloud. You just nail the correct pitch additude every single time with
> AH.
>
> 2) Severe turbulence, usually at the top of cloud. Flying straight and
> level with AH is much more accurate.
>
Thanks for that - useful information.

One question: I haven't tried this, but my guess is that a mechanical T&B
will come up showing the correct reading if it is switched on while
turning. It will do this because what it shows is the amount a spring is
deflected by the precession force a gyro applies to it when the aircraft
yaws. Am I right in thinking this?


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Martin Gregorie[_5_]]

On Tue, 21 Apr 2015 18:55:53 -0700, mark821ac wrote:

> How do you guys avoid midairs when climbing in cloud? Does everyone
> circle left? I can't see even Flarm saving you.

1) FLARM still works in cloud, so when you're close under one with no
gliders in sight but FLARM shows a glider above you, that is a
pretty good clue.

2) You should make a radio call on the XC/cloud flying frequency[1]
giving your intentions and position. Anybody else who is nearby
should respond with their details. If FLARM shows a glider above
you in cloud, frankly you're an idiot if you don't make that call
before switching on the T&B etc.

3) Clouds are much bigger than gliders so the chances of a collision
are relatively low (the big sky theory of collision risk): its
your choice whether you take that risk or stay out of cloud.

[1] In the UK 130.4 MHz is reserved for XC message passing and cloud
flying. I don't know if other countries have similar arrangements.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[krasw]

On Wednesday, 22 April 2015 14:58:44 UTC+3, Martin Gregorie wrote:
> One question: I haven't tried this, but my guess is that a mechanical T&B
> will come up showing the correct reading if it is switched on while
> turning. It will do this because what it shows is the amount a spring is
> deflected by the precession force a gyro applies to it when the aircraft
> yaws. Am I right in thinking this?
>
>
> --
> martin@ | Martin Gregorie
> gregorie. | Essex, UK
> org |

Yes it will indicate rate of turn even if switched on during thermalling. There is always horizontal acceleration during turning, and gyro indicates only this as rate of turn. However being used to temperamental 50-something years old T&B's I might wan't to check gyro action well before entering cu-nim (got to admit that I've flown into smaller clouds switching gyro on "on the fly" just before entering cloud). I think it takes 15-30 secs to achieve stable gyro rotation, or little bit less with LiFePo4 battery as these old things seems to like little extra voltage compared to lead acid batteries.

[[email protected]]

I think the less training and/or currency in instrument flying a pilot has, the more he is going to find an artificial horizon to work better for him than some sort of turn rate indicator.

The inputs required to break a well-developed pitch phugoid without the aid of an artificial horizon, are counterintuitive.

But most important lesson that the pilot must learn is that must be prepared to utterly and completely believe the instrument, against what his senses are telling him. He must expect to be disoriented. I don't think it takes all that much training to deliver that lesson, so long as the training is truly effective. Which probably means, conducted in actual cloud!

Flying "partial panel", in my experience it's normal to be disoriented much of the time. Maybe this would no longer be the case if I had more practice at it.

S

[Jonathan St. Cloud]

With all due respect to the poster below who argues the big sky theory applies to clouds (or anywhere for that matter). While not a highest time pilot, I have multiple thousands of hours between gliders, airplanes and helicopters I have actually swapped paint once with another aircraft and have at least 10 near collisions (20 feet or less of separation). Three times were while ATC was providing separation! One time is a story in itself and only a miracle/angel kept it from being a tragedy that would have killed 110 people (this one was on take off, same controller cleared two aircraft to fly into each other). I am not a big fan of the big sky theory, I frankly think it is as out dated as Flat earth.



On Wednesday, April 22, 2015 at 5:16:31 AM UTC-7, Martin Gregorie wrote:
3) Clouds are much bigger than gliders so the chances of a collision
> are relatively low (the big sky theory of collision risk): its
> your choice whether you take that risk or stay out of cloud.
>
> [1] In the UK 130.4 MHz is reserved for XC message passing and cloud
> flying. I don't know if other countries have similar arrangements.
>
>
> --
> martin@ | Martin Gregorie
> gregorie. | Essex, UK
> org |

[Martin Gregorie[_5_]]

On Wed, 22 Apr 2015 06:21:14 -0700, krasw wrote:

> Yes it will indicate rate of turn even if switched on during
> thermalling. There is always horizontal acceleration during turning, and
> gyro indicates only this as rate of turn. However being used to
> temperamental 50-something years old T&B's I might wan't to check gyro
> action well before entering cu-nim (got to admit that I've flown into
> smaller clouds switching gyro on "on the fly" just before entering
> cloud). I think it takes 15-30 secs to achieve stable gyro rotation, or
> little bit less with LiFePo4 battery as these old things seems to like
> little extra voltage compared to lead acid batteries.

Thanks for that confirmation.

My T&B was already modified for glider use when I bought it. This meant
that its rate marks indicate a 30 second turn (nice for thermalling) and,
as it is a 28v instrument, it came with a solid state DC-DC converter so
it will run off a 12v battery. It comes up surprisingly fast: I haven't
timed it but would estimate 10-15 secs to come up to constant speed.

When first installed, it kicked up a nasty row on the radio that ferrite
cores didn't fix. What did work was installing a 500 uF electrolytic
capacitor across the 12v input to the DC converter. This is a special
capacitor designed to prevent electric motor noise from affecting other
kit on the same power rail. IIRC it is rated at 35v and 1.5 amps.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[[email protected]]

PS one instance where an artificial horizon would really win hands-down over a turn rate indicator, is if the pitot tube ices up. Has this ever happened to you (anyone?) I've had the yaw string freeze to the canopy, but don't think there was much ice elsewhere on the glider.

S

[Charlie M. (UH & 002 owner/pilot)]

I'll go back and quote.....

"I will let my superior judgement keep me from using my superior skill in a situation...."

Enough said.

After that, it's a toss-up, I would not want to place bets.

[[email protected]]

To answer all the speculation on what the characteristics of the new solid state artificial horizons, here are what the factory says about the LX Nav S80.

Question: Can you provide an explanation of the performance standards?
Answer: The internal sensors and software can respond at +/-90 degrees/sec. The internal gyro can measure up to 2000 degrees/second which is 6 revolutions/second.

Question: Any limitations on aircraft position or rate of movement?
Answer: No. There are no limitations when used in a glider.

Question: Can the unit lose orientation and "tumble" like a mechanical unit?
Answer: No. It's not like a conventional gyro. It recovers from any position.

These units are always on and always registering the aircraft orientation. Switching to the artificial horizon screen just activates the display.

[ss[_2_]]

I fully understand that the workings of the vario-associated AHRS-driven artificial horizon units are "always on". Just as a point of curiosity, I wonder how long it would take to get an accurate reading on this type of artificial horizon if you powered up the whole system from a cold start while engaged in a steep-banked turn.

No practical ramifications really, at least if the unit is for emergency use only-- system failure isn't a big concern in this context. I'm just curious.

Meanwhile, for those pilots flying with simpler instrumentation wanting something for purely emergency use, or for those pilots engaged in intentional cloud flying where there is a legitimate need for some sort of back-up system for redundancy, I still suggest-- consider the self-contained piezo-electric turn rate indicator I linked to on my first post.

S

[[email protected]]

I fully understand that the workings of the vario-associated AHRS-driven artificial horizon units are "always on". Just as a point of curiosity, I wonder how long it would take to get an accurate reading on this type of artificial horizon if you powered up the whole system from a cold start while engaged in a steep-banked turn.

No practical ramifications really, at least if the unit is for emergency use only-- system failure isn't a big concern in this context. I'm just curious.

Meanwhile, for those pilots flying with simpler instrumentation wanting something for purely emergency use, or for those pilots engaged in intentional cloud flying where there is a legitimate need for some sort of back-up system for redundancy, I still suggest-- consider the self-contained piezo-electric turn rate indicator I linked to on my first post.

S

[[email protected]]

I flew with the LX Nav S80 today.
I did loops and barrel rolls. The instrument tracked perfectly.
I then started loops and barrel rolls with the display on a different screen and turned the artificial horizon display on in the middle of the maneuver. The instrument was tracking the aircraft just fine.

Then I entered a series of spins with the display on a different screen and brought up the artificial horizon screen in the middle of a developed spin and it came up perfectly allowing me to use the instrument to correctly position the aircraft. The slip/skid indicator correctly showed a crossed control situation.

Since I fly with the vario on all the time. The instrument is always on and ready.

Finally! A complete flight instrument suite in one package.