novice questions about glider instruments

[son_of_flubber]

1.Why do many gliders have two variometers?

2.Assuming for a moment that you are not flying in the flatlands, how often and under what scenarios do you use your compass? What are some good exercises for developing airborne compass skills?

3.If you needed panel space for a PowerFlarm display, which existing instrument would you delete (if any)? (Assume a PDA is present.)

I've my own answers already of course, but I'd like to have the benefit of your experience/insights.

[Grider Pirate[_2_]]

On Dec 5, 7:19*am, son_of_flubber > wrote:
> 1.Why do many gliders have two variometers?

Redundancy. I want the audio of an electronic vario, but electronics
work great until they quit, then not at all. A mechanical vario
becomes very handy at that point.
>
> 2.Assuming for a moment that you are not flying in the flatlands, how often and under what scenarios do you use your compass? What are some good exercises for developing airborne compass skills?

Almost never. But almost never isn't the same as never. My compass
'clued me in' when I had rolled out of a very long climb spiral on the
wrong heading. (unfamiliar territory, complete overcast)
>
> 3.If you needed panel space for a PowerFlarm display, which existing instrument would you delete (if any)? (Assume a PDA is present.)
>
No opinion on that one. It would depend on what you had in the
panel.
> I've my own answers already of course, but I'd like to have the benefit of your experience/insights.

[Roel Baardman]

> 1.Why do many gliders have two variometers?

Sometimes its for redundancy (one comes with audio, the strictly
mechanical one doesn't), sometimes one might measure total energy
(and thus compensate for stick-lift) and the other might not.

> 2.Assuming for a moment that you are not flying in the flatlands,
how often and under what scenarios do you use your compass? What are
some good exercises for developing airborne compass skills?

Simply speaking, when orientating. Wether that is orientating to
guess on what slope the sun must be perpendicular or orientating
where I should go.

> 3.If you needed panel space for a PowerFlarm display, which
existing instrument would you delete (if any)? (Assume a PDA is
present.)

If it occupies panel space, remove the FLARM.
If not, remove any instruments which are not strictly bound to the
panel (PDAs, sometimes accelerometers) and can safely be
repositioned (do not block view towards important handles for
example).

> I've my own answers already of course, but I'd like to have the
benefit of your experience/insights.

Most of my experience is in aerobatic gliding, but I've thought
about my own (B4) panel a lot.

[Martin Gregorie[_5_]]

On Wed, 05 Dec 2012 07:50:32 -0800, Grider Pirate wrote:

> On Dec 5, 7:19Â*am, son_of_flubber > wrote:
>> 1.Why do many gliders have two variometers?
>
> Redundancy. I want the audio of an electronic vario, but electronics
> work great until they quit, then not at all. A mechanical vario becomes
> very handy at that point.
>
Yes, but be aware that you can get interference between the varios if you
hang a flow type (mechanical) and a pressure sensing (almost all modern
electronic types) vario off the same TE probe. I carry two electronics:
an SDI C4 which runs off the glider's 12 supply and a Borgelt B.40 which
also is normally on the 12v supply but also has a 9v PP3 attached to it -
it can run for over 12 hours on the latter, so is as good at 'get you
home' as a mechanical. Both varios are pressure sensors, so no chance of
interference.

There are other vario types that are designed to run off a 9v battery for
the same reasons, such as the Tasman V.1000 and the Borgelt B.400 which
will run for 7-8 hours off 4 x AA alkaline cells - it replaced the B.40.

>> 2.Assuming for a moment that you are not flying in the flatlands, how
>> often and under what scenarios do you use your compass? What are some
>> good exercises for developing airborne compass skills?
>
> Almost never. But almost never isn't the same as never. My compass
> 'clued me in' when I had rolled out of a very long climb spiral on the
> wrong heading. (unfamiliar territory, complete overcast)
>
Is it a required instrument? It is in some countries.
Mine is tucked away at the bottom of the panel. I get the same
information off my GPS. I used to use a Garmin GPS II+, which is good for
8-12 hours on its internal batteries and now use LK8000 on a Binatone PNA,
which only does 2.5-3 hours on its internal batteries

>> 3.If you needed panel space for a PowerFlarm display, which existing
>> instrument would you delete (if any)? (Assume a PDA is present.)
>>
> No opinion on that one. It would depend on what you had in the panel.
>
Agreed. I carry a RedBox FLARM which has a 30mm x 60mm display that got
squeezed in without needing to take any instruments out.

Don't forget that you can gain space by swapping 80mm instruments for
75mm equivalents, though at a cost. (cost = replacement instruments +
time & money to replace the panel).


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

[Evan Ludeman[_4_]]

Ah, an excuse to post one of my very favorite bits of off season re-reading.

This sensitive topic is covered, sort of, as a part of Philip Wills introduction to the "British Glidermanship Association". See page 6 of the linked PDF, pg 52 of the original source. Enjoy. Cracks me up, every time.

http://tinyurl.com/cfrfoez

T8

[Tony V]

> Don't forget that you can gain space by swapping 80mm instruments for
> 75mm equivalents, ...


57mm?

Tony "6N"

[Martin Gregorie[_5_]]

On Wed, 05 Dec 2012 19:08:36 -0500, Tony V wrote:

>> Don't forget that you can gain space by swapping 80mm instruments for
>> 75mm equivalents, ...
>
>
> 57mm?
>
Correct, Sir.

And I thought I'd proof read it too!


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

[kirk.stant]

On Wednesday, December 5, 2012 4:19:23 PM UTC+1, son_of_flubber wrote:
> 1.Why do many gliders have two variometers?
> 2.Assuming for a moment that you are not flying in the flatlands, how often and under what scenarios do you use your compass? What are some good exercises for developing airborne compass skills?
> 3.If you needed panel space for a PowerFlarm display, which existing instrument would you delete (if any)? (Assume a PDA is present.)

1. Backup "get home" vario. Unlike the other posters so far, I don't bother with a mechanical, instead have two electrics with audio, with two completely independent battery systems. Has worked as designed so far for the past 12 years. Oddly, it was the pitot static system that killed my main vario once, when a bug clogged the pitot tube and resulted in incorrect readings of the primary flight computer/vario. Backup worked fine - and I really like having two varios to crosscheck and strongly dislike not having audio.

2. I have never used my compass in anger, either in the mountains or flatlands. It's only in the panel because it's required. Note that I'm a retired AF navigator, so know a little about compasses and navigation. I think a whiskey compass in a glider is basically useless unless you do the preflight planning to use compass headings and a marked up chart. Yeah right...get a backup GPS if you don't have a redundant system.

3. I would pitch the compass without hesitation. As it is, my Flarm display is going to hide my backup vario, and my Oudie will hide my compass, but both are on RAM mounts and can be moved if needed (but with audio, I don't really need to see my backup vario).

Kirk
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