Emergency instrumentation for cloud encounters

why not have one of these:

http://store-vllhq23n.mybigcommerce....-in-enclosure/
http://store-vllhq23n.mybigcommerce....dback-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

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

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.

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!

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

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....-in-enclosure/
http://store-vllhq23n.mybigcommerce....dback-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

On Monday, April 20, 2015 at 1:55:12 PM UTC-4, wrote:
why not have one of these:

http://store-vllhq23n.mybigcommerce....-in-enclosure/
http://store-vllhq23n.mybigcommerce....dback-systems/

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

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.

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/...ainlarge-1.jpg
http://www.mglavionics.com/html/infinity_singles.html

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....-in-enclosure/
http://store-vllhq23n.mybigcommerce....dback-systems/

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

But a different reading on the pilot

--
Duncan.