Vector Compass on fixed wing

Andy Sayle · September 06, 2016, 12:40:34 AM

Hi folks.

I was just wondering if anyone uses the Vector compass on fixed wing setups? I had a situation the other day where I was flying on a reasonably stable heading according to my video feed, but the GPS "direction to home" arrow was all over the place, because my ground speed was very low, due to a head wind.

I'm wondering if enabling the compass on the vector will eliminate the home arrow flying around wildly in that situation?

Andy

luvbus · September 06, 2016, 08:50:35 AM

I have the compass turned on and have not experienced the issue you describe.

Curious as to why you wouldn't have it turned on?

Andy Sayle · September 06, 2016, 08:54:30 AM

I think it was mainly down to the warnings about critical alignment and stuff in the manual, and I'm sure I read somewhere it wasn't required on an fixed wing installation.

I'll give it a shot over the weekend though, and see if it helps....

Cheers
Andy

BlueFlyer · September 06, 2016, 09:25:53 AM

Eagle tree actually recommend you DONT use the compass on fixed wing applications.

Reasons I don't use it...

1. I was fed up of having to do the calibration dance with a 1.8m wingspan plane, awkward to say the least and it usually took 3 or 4 attempts

2. I was fed up of having the OSD shouting at me to calibrate the compass mid flight, even though I'd just wasted 30 minutes doing just that

3. As stated above... Eagle tree recommend not to enable it for fixed wing. With a plane constantly moving forward (apart from the extreme circumstances when flying into a strong headwind) the GPS data is perfectly capable of telling you which direction your going, if not then there's a problem and relying in a temperamental compass is just masking that issue.

dp106 · September 06, 2016, 09:56:00 AM

I have never enabled it due to the manual stating its not needed on a fixed wing. Can't say I've ever experienced that issue, don't fly so slow :D

BlueFlyer · September 06, 2016, 10:00:45 AM

Quote from: luvbus on September 06, 2016, 08:50:35 AM
Curious as to why you wouldn't have it turned on?

If your compass is not 100% perfectly lined up with the forward direction of your plane, then the GPS data and compass readings will be conflicted, in a multicopter they tend to hover in one spot more often than planes lol so the compass would be the only data providing a direction indication.

Loopdreams · September 06, 2016, 10:05:52 AM

If you have a pitot tube then the air speed and ground speed will often be at odds with each other, but this is a good thing, you can use this to determine the wind speed.

So I'm not sure why it can't be programmed to use all the data available as appropriate but there we are. If Eagle Tree say to turn it off for fixed wing then personally that's what I'd do.

BlueFlyer · September 06, 2016, 10:09:51 AM

You can choose which data is displayed, ground speed or airspeed or both. Also, the speed of the aircraft isn't important for knowing which way to fly to get home.

The direction of travel isn't selectable anywhere in the GUI other than to disable or enable the mag compass.

dp106 · September 06, 2016, 10:16:04 AM

Quote from: BlueFlyer on September 06, 2016, 10:09:51 AM
You can choose which data is displayed, ground speed or airspeed or both. Also, the speed of the aircraft isn't important for knowing which way to fly to get home.

The direction of travel isn't selectable anywhere in the GUI other than to disable or enable the mag compass.

You can't have them both displayed on the speed ladder though can you? I was looking for an option the other day but couldn't find one.

Sent from my Nexus 5 using Tapatalk

Loopdreams · September 06, 2016, 10:19:11 AM

Quote from: BlueFlyer on September 06, 2016, 10:09:51 AM
You can choose which data is displayed, ground speed or airspeed or both. Also, the speed of the aircraft isn't important for knowing which way to fly to get home.

The direction of travel isn't selectable anywhere in the GUI other than to disable or enable the mag compass.

Yeah, I was just saying that it seems like a bit of a shortcoming of the flight controller firmware that you need to actually disable one of the sensors in order for RTH to work properly (which is the problem which Eagle Tree seem to acknowledge). Sometimes planes do end up flying slowly so surely it could use the compass to give you an always accurate visual home arrow but use GPS track to fly the plane in an RTH or waypoint scenario.

BlueFlyer · September 06, 2016, 10:23:51 AM

Yeah even put an option in there to choose which method is used to display direction.

No, speed ladder is one or the other, but you can have the other displayed elsewhere on the screen

dp106 · September 06, 2016, 10:28:10 AM

Quote from: BlueFlyer on September 06, 2016, 10:23:51 AM
Yeah even put an option in there to choose which method is used to display direction.

No, speed ladder is one or the other, but you can have the other displayed elsewhere on the screen

Yeah thats what I've done, would just have liked to have it on the speed ladder to easily glance at the two

BlueFlyer · September 06, 2016, 10:37:38 AM

Mfd ap is good as it actually shows both values on the ladder once airspeed sensor is detected

luvbus · September 06, 2016, 09:13:15 PM

Oh well, been doing it wrong so far.....
The only time I have had to calibrate the compass was when I initially set up the FC not had to do it since. Although to be fair I haven't done that many flights with the Vector.

I just give it a cursory glance to check it is reading roughly the correct direction and that is it. Not had a request to recalibrate when in flight.

Is everyone using the V2 GPS?

BlueFlyer · September 06, 2016, 09:26:18 PM

V1 here, sold my V2 to pk surfing