Winds Aloft
- Thread starter PeterBain
- Start date
mmarien
Murray M.
Check page 2-17 of the installation guide for what is required for winds and where to start troubleshooting. SV subtracts the magnetic heading and airspeed from GPS ground track to calculate the winds so there are several variables. I would suggest the compass is the first culprit to check.
skydancer
RV-7 O-360 CS Prop. Dual Skyviews/AHRS. TruTrak AP
Surfboy,
Welcome to ADAHRS calibration club.
Yes, most likely you have compass calibration issue, if you have dual ADAHRS, be sure to manually select/activate each ADAHRS and compare the compass heading and find out the difference, one may be on, the other may be off.
I have dual ADAHRS in my RV-7, one of the ADAHRS compass heading is off by 30-40 degrees, Dynon hasn't come up with the solution yet.
This is what I have found......
If I calibrate with Primary ADAHRS (200) selected/activated (actually the system doesn't care which one is selected for calibration), then after the calibration, secondary ADAHRS (201) will be dead on and Primary (200) will be way off.
If I have secondary manually selected/activated, after the calibration, the Primary will be dead on and secondary will be way off.
If you have dual ADAHRS and like to discuss with me privately, call me @ 949-878-8153, I'll give you more detail information. If both of your ADAHRS agreed with each other, then don't bother to call me, you are in the right track, and you are the lucky one.
I have just talked to a friend, who has single ADAHRS in his Skyview system, his ADAHRS is also off by 30 degrees. The avionic guy who sold/installed the system for him is at the same airport, I asked him to swap with another unit for test, find out whether the problem is in his airplane or in the ADAHRS unit itself.
Even with the worest installation I have seen, the heading may gives you max 5 to 10 degree off, can't be as big as 30 degrees. try to screw up the installation and compare yourself. Anything larger than 10 degree hardly be the installation issue.
Jay
Welcome to ADAHRS calibration club.
Yes, most likely you have compass calibration issue, if you have dual ADAHRS, be sure to manually select/activate each ADAHRS and compare the compass heading and find out the difference, one may be on, the other may be off.
I have dual ADAHRS in my RV-7, one of the ADAHRS compass heading is off by 30-40 degrees, Dynon hasn't come up with the solution yet.
This is what I have found......
If I calibrate with Primary ADAHRS (200) selected/activated (actually the system doesn't care which one is selected for calibration), then after the calibration, secondary ADAHRS (201) will be dead on and Primary (200) will be way off.
If I have secondary manually selected/activated, after the calibration, the Primary will be dead on and secondary will be way off.
If you have dual ADAHRS and like to discuss with me privately, call me @ 949-878-8153, I'll give you more detail information. If both of your ADAHRS agreed with each other, then don't bother to call me, you are in the right track, and you are the lucky one.
I have just talked to a friend, who has single ADAHRS in his Skyview system, his ADAHRS is also off by 30 degrees. The avionic guy who sold/installed the system for him is at the same airport, I asked him to swap with another unit for test, find out whether the problem is in his airplane or in the ADAHRS unit itself.
Even with the worest installation I have seen, the heading may gives you max 5 to 10 degree off, can't be as big as 30 degrees. try to screw up the installation and compare yourself. Anything larger than 10 degree hardly be the installation issue.
Jay
- Joined
- Mar 23, 2005
- Messages
- 13,226
So that last statement isn't always the case. If the ADAHRS is near magnetized ferrous metal or high current devices or wires, you can see pretty huge induced heading changes from local magnetic fields.
But basically, winds issues usually are the result of magnetic heading that is isn't correct, and that's usually because of the magnetic interference issues mentioned above.
Note that Jay has experienced a different reason for magnetic heading not being right on one of two ADAHRS much of the time, but we haven't heard similar reports from other people. His issue is on our list of bugs to try to reproduce and fix if there is something in fact there, but so far, we don't think that the issue described above is widespread.
But basically, winds issues usually are the result of magnetic heading that is isn't correct, and that's usually because of the magnetic interference issues mentioned above.
Note that Jay has experienced a different reason for magnetic heading not being right on one of two ADAHRS much of the time, but we haven't heard similar reports from other people. His issue is on our list of bugs to try to reproduce and fix if there is something in fact there, but so far, we don't think that the issue described above is widespread.
mmarien
Murray M.
On the ground your compass heading should match GPS track when your ADAHRS is calibrated.
skydancer
RV-7 O-360 CS Prop. Dual Skyviews/AHRS. TruTrak AP
Be more realistic Dynon, where else in the aircraft can you get a huge amount of magnetized ferrous metal or high current devices or wires near the ADAHRS? The max I have seen was only off by 2 degree (running with one of my good ADAHRS of course).
I once put a 3 inches magnetic stone 1 foot away from the ADAHRS and hand turned the magnetic to produce different angle of the magnetic field to the ADAHRS, the max deviation I have seen was only 15 degree. That's the extreme case which is impossible to exist in the aircraft environment.
So, tell me, what could have caused the ADAHRS to be off by 30 degree or more?
What have you seen so far on your test bench? give me some numbers if you can, and describe how big the magnetic field it is and how close to the ADAHRS.
One of my ADAHRS is still broken, un-usuable, I am still suffering in every flight I make.
I once put a 3 inches magnetic stone 1 foot away from the ADAHRS and hand turned the magnetic to produce different angle of the magnetic field to the ADAHRS, the max deviation I have seen was only 15 degree. That's the extreme case which is impossible to exist in the aircraft environment.
So, tell me, what could have caused the ADAHRS to be off by 30 degree or more?
What have you seen so far on your test bench? give me some numbers if you can, and describe how big the magnetic field it is and how close to the ADAHRS.
One of my ADAHRS is still broken, un-usuable, I am still suffering in every flight I make.
johnsteichen
New Member
- Joined
- Sep 18, 2010
- Messages
- 227
Where does GPS tracking show up on the dynon display.
- Joined
- Mar 23, 2005
- Messages
- 13,226
johnS - Ground track is shown on the top of the map page in SkyView, except when the aircraft is not moving fast enough for SkyView to determine ground track. When that number is outlined in magenta, it's ground track. When outlined in white, it's mag heading.
Jay - Magnetized steel aircraft bits and fasteners close to the ADAHRS can peg the mag heading, and getting to close to high current wires can cause some pretty extreme deflections too.
Jay - Magnetized steel aircraft bits and fasteners close to the ADAHRS can peg the mag heading, and getting to close to high current wires can cause some pretty extreme deflections too.
mmarien
Murray M.
My face is magenta. So in the screens above the MAP is showing magnetic heading - same as the DG. I guess they should be close. :