Al Downs Posted October 18, 2011 Report Share Posted October 18, 2011 So far I am really disappointed with the Dynon equipment. Compass reading are as much a 30 degrees off and the indicated winds aloft show at 2500 ft shows in the high 40's on calm days. Heading in one direction I may see winds coming from my left, turn 180 and they are still coming from my left. I want to recalibrate the compass readings but can't find and airport with a compass rose. Anybody no where there is one close to Racine Wisconsin. Thanks for any help you can provide. Link to comment Share on other sites More sharing options...
Tom Baker Posted October 18, 2011 Report Share Posted October 18, 2011 I've always set my Dynon compass off the GPS track, and it seems to work OK. Just taxi the airplane to get the desired track. However the numbers on the display are still going to be off. Tom Link to comment Share on other sites More sharing options...
coppercity Posted October 18, 2011 Report Share Posted October 18, 2011 If you have a wet compass in your plane you can calibrate it to that, or you can site thru a land navigation compass you get at a sporting goods store. Link to comment Share on other sites More sharing options...
S3flyer Posted October 18, 2011 Report Share Posted October 18, 2011 I used the whiskey compass to calibrate the heading and have no issues. For winds -- is your OAT correct? Link to comment Share on other sites More sharing options...
Al Downs Posted October 19, 2011 Author Report Share Posted October 19, 2011 I used the whiskey compass to calibrate the heading and have no issues. For winds -- is your OAT correct? In this case, OAT is not outside air temp, what is it? Link to comment Share on other sites More sharing options...
coppercity Posted October 19, 2011 Report Share Posted October 19, 2011 Outside air temp can effect the wind calculation as the temp is needed for the Dynon to determine accurate true airspeed. That is compared to ground speed along with ground track and heading to determine the wind direction and velocity. Link to comment Share on other sites More sharing options...
207WF Posted October 23, 2011 Report Share Posted October 23, 2011 Also, your airspeed is likely off. Most are. WF Link to comment Share on other sites More sharing options...
Al Downs Posted October 23, 2011 Author Report Share Posted October 23, 2011 Outside air temp can effect the wind calculation as the temp is needed for the Dynon to determine accurate true airspeed. That is compared to ground speed along with ground track and heading to determine the wind direction and velocity. Are the Dynon units junk? They seem so inaccurate. Can they be recalculated and maintain more accurate readings? Winds aloft are as high as 50 and seem to be from the wrong direction. Link to comment Share on other sites More sharing options...
coppercity Posted October 24, 2011 Report Share Posted October 24, 2011 Hi Al, I have been flying behind Dynons for the last 2 years and 1100hrs and find they are very reliable and accurate. There are several things that effect the wind calculations. The heading calibration has a huge impact even if it's off a few degrees. Flying uncoordinated also effects the wind calculation by changing the heading vs ground track received from the gps. I would start by going thru the heading calibration on the Dynon using your aircraft compass. After that fly straight and level for a few minutes and check the wind calculations. If it's still way out of whack record the parameters used to make the calculations and maybe we can determine where the issue is. Record the gps ground track, ground speed, Dynon heading, compass heading, indicated airspeed, true airspeed from the Dynon, and the outside air temperature. Link to comment Share on other sites More sharing options...
Al Downs Posted October 24, 2011 Author Report Share Posted October 24, 2011 Hi Al, I have been flying behind Dynons for the last 2 years and 1100hrs and find they are very reliable and accurate. There are several things that effect the wind calculations. The heading calibration has a huge impact even if it's off a few degrees. Flying uncoordinated also effects the wind calculation by changing the heading vs ground track received from the gps. I would start by going thru the heading calibration on the Dynon using your aircraft compass. After that fly straight and level for a few minutes and check the wind calculations. If it's still way out of whack record the parameters used to make the calculations and maybe we can determine where the issue is. Record the gps ground track, ground speed, Dynon heading, compass heading, indicated airspeed, true airspeed from the Dynon, and the outside air temperature. Thanks I will try calibrating. I just became aware of a compass rose nearby and can use that. I will have to go one step at a time as I am new to all of this. Link to comment Share on other sites More sharing options...
coppercity Posted October 24, 2011 Report Share Posted October 24, 2011 We will do our best to help you out! Link to comment Share on other sites More sharing options...
Al Downs Posted November 1, 2011 Author Report Share Posted November 1, 2011 We will do our best to help you out! I recalibrated the compass heading and on the ground it seems much better. Too windy Saturday and Sunday to fly and will check it next time I go up. What do I do with the OAT. Just check it against a thermometer? Anything else you can suggest at this time? Thanks Al Link to comment Share on other sites More sharing options...
Jim Posted November 1, 2011 Report Share Posted November 1, 2011 If you calibrate the Dynon on the ground, be sure the engine is running. Tried it with the engine off and got huge errors. Ran the engine and nailed the settings. Link to comment Share on other sites More sharing options...
Al Downs Posted November 1, 2011 Author Report Share Posted November 1, 2011 thanks for the tip. I did it with engine shut down but will check it and it it is off I will have the engine running next time. Link to comment Share on other sites More sharing options...
coppercity Posted November 1, 2011 Report Share Posted November 1, 2011 You can check your OAT against the AWOS at your airport if you have one or a thermometer. Link to comment Share on other sites More sharing options...
Roger Lee Posted November 1, 2011 Report Share Posted November 1, 2011 Reply #5 - Yesterday at 1:50pm Dynon Support Online Forum Administrator Dynon Employee Dynon Technical Support Posts: 7556 So winds are the difference between the ground track / speed as reported by the GPS, and the true airspeed and magnetic heading, which is determined by the Dynon. Usually, it's the magnetic heading that's not well-calibrated that causes big wind errors. GPS is almost never wrong, but, if we weren't getting an accurate GPS speed or track from a device (usually a communication problem, not an actual device problem), that could theoretically cause issues, though I don't know that I've ever heard of that happening. My money's on the heading though. Link to comment Share on other sites More sharing options...
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