Oudie N "TAS" "Pressure Altitude" and "IAS" with/without S100 input

[Jeff Stetson]

The general category of confusion is what data is being passed between the N, SeeYou Cloud and the S100 vario via Bluetooth.

The Oudie has nav boxes for IAS and TAS. The description states that these are calculated values, unless unless real values are available. I'm assuming that TAS comes from GPS speed & track and derived wind velocity. IAS must then come from (cabin) pressure altitude (PA) at standard temperature since no OAT is available.

I think then that these TAS & PA values from the N logged information are what's displayed by the SeeYou Cloud flight analysis program. There seems to be no way to display IAS, unfortunately.

Now, I link the N to the S100. I've only had a couple of flights experience with this. At least some part of this connection seems to work. The N display of IAS exactly matches the IAS shown on the S100 ... and my Dynon 10a EFIS. The PA also matches. The average vario sink rates do not always match. So,

Question #1: What data is getting passed from the S100 to the Oudie N? Is on only the two channels of static and pitot pressures? Or perhaps a third TE value?

(What doesn't seem to be synchronized is anything else, for example, the McReady setting, which, I think, is supposed to be. Why?)

Next, when I upload the flight to SeeYou Cloud, it's not clear to me what "extras" are included in that file. I know that "Engine Noise" is included and can be displayed. 

2) There is a display option for "TAS". Is that the value passed from the N or calculated by SeeYou?

3) The is no SeeYou display option for IAS. But during my recent test flight, I did a series of long glides holding IAS carefully at a number of different values. It was cold and I was often high so my actual TAS was higher by several knots than IAS. BUT, the SeeYou TAS box seemed very much to be showing IAS! True/False?

I very much wish to record and be able to see in SeeYou, my no-real actual IAS. That to get an accurate polar measurement for my motorglider. Glide for a couple of minutes pull the altitude lost and time, get the sink rate and the L/D = IAS / sink.

If SeeYou can't show me real IAS or it's not logged at all as promised, this expensive upgrade is quite disappointing. Anyway, some clarity in which data is moved where would be appreciated.

[moshe....@gmail.com]

A good start in unraveling these mysteries is to look at the actual NMEA sentences sent by the S100.  I don't know about the Oudie, perhaps there is a way to do it there.  But I do know that you can see, and log, the full NMEA data in Tophat (XCsoar).  (Note: Tophat will not log an NMEA stream unless it includes GPS sentences, e.g., if a FLARM is feeding into the S100 - if it's pure vario data, nothing will be logged!)  Alternatively, you can use a "terminal" app on your phone (Bluetooth or UDP etc) to see and capture the NMEA stream.

Once you look at the NMEA, you'll know what it includes (IAS, TAS, pressure or density altitude, etc) and in what format - both of which may be configurable within the S100.  There are several "standard" data protocols that varios use, e.g., Borgelt, Cambridge, XCvario, etc.  And the different protocols have slots for different data items, e.g., one may have a slot for IAS but not for density altitude.

[Kristian Roine]

Oudie N does not use following data from variometer (tested via Naviter BT dongle, and confirmed by Naviter) :

- instant TE variometer value
- wind
- mc value

What it can extract for NMEA stream :

- pressure altitude
- IAS/TAS
- Flarm data.

Oudie 2 did all of these.

[Paul Remde]

Hi,

The Oudie 2 did not use the received wind data.  Like the Oudie N, the Oudie 2 and Oudie IGC calculated the wind using the airspeed data from the vario.

Best Regards,

Paul Remde