On Monday, 19 September 2016 03:42:36 UTC+3, Sean wrote:
I thought accurate straight line glide computer wind accuracy required a fixed compass (aka LXNAv) for the best not thermaling wind detection sensitivity. My S10 is going to have a compass module shortly. But I really can't imagine a need that that much wind accuracy. The wind where you are now isn't the problem. It's accurate anticipation of what the wind is 1, 5 10 and 20 miles ahead, just like sailing, but much less critical.

Am I right or wrong on the compass module?

I believe the butterfly an fixed compass built in, and this is the reason that it is more energetic on updates? Correct?

There are ways to calculate wind vector on straight flight without compass module, Oudie claims to do it by comparing track/gs to different straight paths (did not get it to work, though), so it is possible at least theoretically.

But bottom line is: you either have full inertial platform with 3D acceleration, rate gyros and compass data, or you don't. Former gives you instant airmass data in all directions instantly, if implemented correctly. That's big IF.

It is not enough to throw in electric compass if the system is not up to it.. Many variometer systems have compass option that manufacturers do not use for any meaningful data. Representative of one company told me of pilot who was very happy after installing optional compass module. He didn't have the heart to tell pilot that variometer firmware version couldn't use compass data at all. I always take pilot reports with a grain of salt.

And no, we do not *need* anything, you can fly perfectly well with seat-of-pants feeling. It just nice to have all that data.