MGL Avionics User Forum

Hi Rainier,
On the Flight 3 millibar readout, why does it show 867mB when all the weather stations around me show 1018mb?
I thought that the manual says this is the true pressure at the moment.
Marvelous little gadget this.

I wanted to add a picture of the screen showing the millibar readout, but cannot find a way to do that.
Is it possible to add photos?

If your local "Altimeter Setting" is 1018mb and the F3 is showing 867mb, you need to turn the knob on the front of the F3 until it shows 1018.
Don't push it in, just turn it.

The Barometer would display ~867 on a standard day if you were at ~3900ft above seal level.

The Altimeter setting is the pressure you would measure if you dug a hole down to sea level. It does not change with altitude.
The Baro pressure is the actual local ambient pressure. It changes with altitude.

by Bill Hertzel » Sun Sep 13, 2020 6:19 am
If your local "Altimeter Setting" is 1018mb and the F3 is showing 867mb, you need to turn the knob on the front of the F3 until it shows 1018.
Don't push it in, just turn it.

The Barometer would display ~867 on a standard day if you were at ~3900ft above seal level.

The Altimeter setting is the pressure you would measure if you dug a hole down to sea level. It does not change with altitude.
The Baro pressure is the actual local ambient pressure. It changes with altitude.

Hi Bill. Thanks for the response.
The BAR number changes from day to day I'm a bit confused!
What is the purpose of giving us this info?

It is a barometer. It is quite useful if you fly an unpressurized aircraft as it effectively shows you how much oxygen you are getting relative to sea level. Judging by your reading you are somewhere between 4000 or 5000ft altitude. So already down.
It's a more useful tool for this than the altimeter as pressure systems have a good effect at altitude - in particular around 10-20.000 ft were oxygen becomes an issue.

Of course it also makes a good monitor for weather fronts - it's traditional use.
We included this from out very first instrument (The original Flight done in about 2000). It's free - you are not paying for it - we measure the pressure anyway for the altimeter. So why not give you that information.

Rainier

OK. Thanks Rainier.
That explains it very nicely.
Got it!
Can I ask a new question?
If I add a little GPS module to the F3, how can I tell if it's getting the data it needs, while on the test bench.?

This might help...

From Page 6 of the instructions.
<<<
FE: (Fuel Endurance) Fuel endurance is only shown if fuel level and fuel flow is enabled.
The fuel endurance will alternate with the GPS NMEA speed value if enabled.
The text color will turn magenta if receiving valid NMEA GPS data.
>>>

That's great, Bill!
Thanks very much for the info. I'll try that out
Best,
Stalky