Alternative magnetic compass

On Thursday, October 29, 2015 at 3:23:24 PM UTC-6, Jonathan St. Cloud wrote:
Did find a magnetic compass in the F-16. All gliders I know of do require a compass so for now I will have one. Tried to get by with a stick on compass that I bought at Auto Zone, but that did not fly (so to speak) with the examiner, so I had to install a glare shield compass.

https://www.quora.com/What-do-all-of...ets-cockpit-do

Let's see now...Hmmm....Forgetting the excellent capabilities of my LX9000, PowerFlarm, and Flarmview, does my Pathfinder watch, which really has an outstanding compass "count?" How about the compass in my Delorme inReach Explorer? It has a digital compass? Now, what year is this? Is it 1947? 1952? Geezzz...Now, please excuse me..I am trying to see if I have room in my glider for my new sextant....(available right now on the Home Shopping Network.....Stock is limited, so do not delay!).... ;-)

When you guys get finished counting up your electronics with triple redundant power supplies, keep in mind that you still have a single point of failu the GPS satellite system. I realize I'm ignoring phones that use the cell towers to triangulate your position but none of the whizzy soaring-specific gadgets have that capability, to my knowledge.

I've used a magnetic compass a LOT in nearly 3,000 hours of glider flying. Before GPS it was indispensable. I still refer to it occasionally for quick reciprocals (it's a vertical card). And it's nice to know that with it and my paper chart (yeah, how quaint), I could still get home. Of course, forget getting credit for the flight since the logger is worthless if the GPS system is taken down. Oh, well. It sits way forward on the glare shield and doesn't get in the way so that's where it will stay.

Chip Bearden
ASW 24 "JB"
U.S.A.

The *******s at China Lake like to test their GPS jammers, and test them again and again. I keep this site bookmarked:

http://www.navcen.uscg.gov/pdf/gps/g...terference.pdf

Good thing there's always "look out the window dot com".
On one of my favorite hang glider flights both the radio and vario died before launch. Super low tech.
Jim

On Thursday, October 29, 2015 at 5:32:57 PM UTC-7, wrote:
When you guys get finished counting up your electronics with triple redundant power supplies, keep in mind that you still have a single point of failu the GPS satellite system. I realize I'm ignoring phones that use the cell towers to triangulate your position but none of the whizzy soaring-specific gadgets have that capability, to my knowledge.

I've used a magnetic compass a LOT in nearly 3,000 hours of glider flying.. Before GPS it was indispensable. I still refer to it occasionally for quick reciprocals (it's a vertical card). And it's nice to know that with it and my paper chart (yeah, how quaint), I could still get home. Of course, forget getting credit for the flight since the logger is worthless if the GPS system is taken down. Oh, well. It sits way forward on the glare shield and doesn't get in the way so that's where it will stay.

Chip Bearden
ASW 24 "JB"
U.S.A.

A compass might be useful for navigation in the trackless flatlands, but out west the 12 - 13K mountains actually make better reference points even if you can't see the sun. And are pretty immune from GPS interference. Now if the Big Earthquake comes, sinking the mountains into the sea, on a cloudy day, during a GPS jamming session, maybe I'll be looking at the compass. But even then it'll be the electronic one. If the poles happen to pick that day to reverse, then we'll all be in trouble.

On Thursday, October 29, 2015 at 5:32:57 PM UTC-7, wrote:
When you guys get finished counting up your electronics with triple redundant power supplies, keep in mind that you still have a single point of failu the GPS satellite system. I realize I'm ignoring phones that use the cell towers to triangulate your position but none of the whizzy soaring-specific gadgets have that capability, to my knowledge.

I've used a magnetic compass a LOT in nearly 3,000 hours of glider flying.. Before GPS it was indispensable. I still refer to it occasionally for quick reciprocals (it's a vertical card). And it's nice to know that with it and my paper chart (yeah, how quaint), I could still get home. Of course, forget getting credit for the flight since the logger is worthless if the GPS system is taken down. Oh, well. It sits way forward on the glare shield and doesn't get in the way so that's where it will stay.

Chip Bearden
ASW 24 "JB"
U.S.A.

The GPS system isn't a single point of failure, there are currently two fully operational systems, soon to be 3 and in a while longer 4.

Plus the iPhone/iPad uses GPS and GLONASS. The current GPS systems always have multiple satellites locked in. Virtually all my flying is in the mountains and with the paper maps, I can visualize where I am by comparing the topo features with the map, thus getting primary headings.

As for reciprocals, plus 2 minus 2, or or the reciprocal works for most headings. i.e., 180 +2 - 2 is 360. Doesn't work for every heading but works for most. 270 -2 + 2 is 90. The result must make sense, but I have used this method most of my flying career.

I do agree, the vertical card compass is the most useful in aviation.


The GPS system isn't a single point of failure, there are currently two fully operational systems, soon to be 3 and in a while longer 4.

On Friday, October 30, 2015 at 8:27:44 AM UTC+3, Jonathan St. Cloud wrote:
As for reciprocals, plus 2 minus 2, or or the reciprocal works for most headings. i.e., 180 +2 - 2 is 360. Doesn't work for every heading but works for most.

Huh? It works for everything if you don't mind subtracting 360 if the answer is over 360.

Otherwise it works for *exactly* half the possible headings (0 - 180) and +20, -200 works for the rest.

On Thursday, October 29, 2015 at 8:48:58 PM UTC-6, jfitch wrote:

The GPS system isn't a single point of failure, there are currently two fully operational systems, soon to be 3 and in a while longer 4.

Magnetic compasses were a great idea for 14th century explorers - not so much for 21st Century aircraft.

We need something better.

I was having fun with my comment about counting the GPS gadgets. Agreed that the iPhone uses GPS and GLONASS. I know that's not true with all devices; does anyone know if the receivers used for our soaring-specific stuff do?

That said, I did read that one chip company conducting tests last year when the entire GLONASS system went down for 11 hours reported that one of their receivers that tracked both systems "wandered significantly in its position reports" during that outage.

As for mountain peaks, you guys need to fly in the east and midwest where, on many days in the summer, you couldn't see peaks more than a few miles away in the haze even if they did rise from the cornfields and pastures.

I don't use my vertical card compass much anymore and probably wouldn't miss it much if it were gone. But it's nice to have on those occasions when, under stress, I prefer an AOGUIRCE (Always On Graphical User Interface Reciprocal Calculator Engine).

Chip Bearden
ASW 24 "JB"
U.S.A.

On Friday, October 30, 2015 at 6:26:52 PM UTC+3, wrote:
I was having fun with my comment about counting the GPS gadgets. Agreed that the iPhone uses GPS and GLONASS. I know that's not true with all devices; does anyone know if the receivers used for our soaring-specific stuff do?

I think you'll find that all reasonably recent phones can use both GLONASS and GPS. The Russian government made GLONASS compatibility a requirement of selling in Russia, and it's not worth making some with and some without. Samsung's first was the Galaxy S II, and Apple's first was the iPhone 4s. (both released roughly northern summer 2011)

I'd expect that everything else uses GPS chips made for phones now, as phones are so much higher manufacturing volume than everything else that their chips end up the cheapest.