What can a PNA do better because it has information from flight instruments?

A standalone PNA relies solely on GPS position and stored map data.

What does a standalone PNA do poorly without flight instrument data?

What information does a PNA obtain from flight instruments?

What does a PNA do better because it has flight instrument data? To what extent do these improvements enhance performance and/or safety? Is the improvement relevant to recreational flying, or is the degree of improvement small and only relevant to competition and record-setting?

On Monday, January 7, 2013 10:20:53 AM UTC-6, son_of_flubber wrote:
A standalone PNA relies solely on GPS position and stored map data.



What does a standalone PNA do poorly without flight instrument data?



What information does a PNA obtain from flight instruments?



What does a PNA do better because it has flight instrument data? To what extent do these improvements enhance performance and/or safety? Is the improvement relevant to recreational flying, or is the degree of improvement small and only relevant to competition and record-setting?

Flight computers can calculate wind more accurately from flight instrument data than just GPS track -- or get those better wind calculations from the instrument. This can be slightly useful in wave, ridge, or on final glides.

In competitions, it's nice to have a clear display somewhere of exactly what altitude is being recorded by the logger. Sometimes it's easier to see that on the flight computer.

That's about all I can think of

John Cochrane

You should also consider that the GPS antennas of many PNAs are of not so great quality. The antennas of the external loggers are usually better, faster and as John mentioned: they show you the position of the logger, which is useful for competitions.

If you connect a Flarm you obviously also get all the additional traffic information in form of a radar screen, that you wouldn't have with a standalone PNA/PDA.

On Monday, January 7, 2013 4:20:53 PM UTC, son_of_flubber wrote:
A standalone PNA relies solely on GPS position and stored map data.



What does a standalone PNA do poorly without flight instrument data?



What information does a PNA obtain from flight instruments?



What does a PNA do better because it has flight instrument data? To what extent do these improvements enhance performance and/or safety? Is the improvement relevant to recreational flying, or is the degree of improvement small and only relevant to competition and record-setting?

It has been mentioned that wind calculations are more accurate if the PNA receives air mass data as well as GPS data, which affects all calculations which depend on wind, including final glide and time to task completion. Most flight software nowadays also offers thermalling assistance. In my experience (mainly Winpilot Pro and SeeYou Mobile) this works quite well with connection to flight instruments but is useless without.

Connection to your external instruments may enable you to declare tasks, and to download approved ICG files.

In my opinion, if you have an instrument which can provide air mass data to your PNA you should certainly connect it. But the extra information provided over a standalone PNA with an internal GPS is fairly limited.

On Monday, January 7, 2013 1:17:00 PM UTC-5, waremark wrote:
On Monday, January 7, 2013 4:20:53 PM UTC, son_of_flubber wrote:

A standalone PNA relies solely on GPS position and stored map data.







What does a standalone PNA do poorly without flight instrument data?







What information does a PNA obtain from flight instruments?







What does a PNA do better because it has flight instrument data? To what extent do these improvements enhance performance and/or safety? Is the improvement relevant to recreational flying, or is the degree of improvement small and only relevant to competition and record-setting?



It has been mentioned that wind calculations are more accurate if the PNA receives air mass data as well as GPS data, which affects all calculations which depend on wind, including final glide and time to task completion. Most flight software nowadays also offers thermalling assistance. In my experience (mainly Winpilot Pro and SeeYou Mobile) this works quite well with connection to flight instruments but is useless without.



Connection to your external instruments may enable you to declare tasks, and to download approved ICG files.



In my opinion, if you have an instrument which can provide air mass data to your PNA you should certainly connect it. But the extra information provided over a standalone PNA with an internal GPS is fairly limited.

The thermalling assistants work better when connected to a real vario instead
of depending on the GPS altitude. At best, the GPS altitude is like an
uncompensated vario. We go to all the effort to compensate the "real" varios
in the panel: why not the PNA one too? I see this every time I use xcsoar with
Condor. When I pull up into a thermal (even just a 5kt speed change) I see
a big green streak where the pullup happened. Still, the thermalling
assistant is an advantage even with uncompensated data.

Another issue is that some PNA GPS units are optimized for travelling on roads.
They tend to project your path along a straight line. I use xcsoar on my
android phone, which fortunately doesn't do this, but YMMV.

Matt

Flight instruments provide IAS which is used to take into account kinetic energy for final glide calculations. A moder glider at 200km/h has at least 100 meters of kinetic energy stored. Now pull up and you get an instant plus of 100 meters on your final glide. With IAS this can be compensated and the final glide reading will stay stable during the pull up.

Another advantage is wind calculation. Best reading for the headwind component ist IAS vs ground speed, especially on ridge or wave where no circles are flown. Also usefull on long final glides with no circles.

Best reading for the headwind component ist IAS vs ground speed, especially on ridge or wave where no circles are flown. Also usefull on long final glides with no circles.

That is actually mathematically incorrect. You can't determine the headwind component from just the ground track and the airspeed by simply taking the difference between both...

XCSoar however uses a more advanced algorithm that gets around that limitation if you connect it to a glide computer that sends TAS/IAS to the device. It is using a Kalman filter designed by John Wharington, that works pretty well and gives you accurate wind information within a short time of flying..