I am about to install my D100 and have it wired up on my bench. With the unit turned on and the pitot line connected, the AOA line plugged and the static port open, if I blow in the pitot line to get about 100 mph indicated, the dynon shows a nose dive of about 40 degrees. If I plug the line to hold 100 mph indicated, the nose slowly comes up to the horizon after about 20 seconds. Also, the roll is off about 5 degrees and takes longer to straighten than the pitch. This unit is about 6 months old and has original software/firmware. Is there somthing I am doing wrong? Thanks. Michael
D100 attitude change as airspeed increases
- Thread starter mikey1ten
- Start date
Hello,
Can you explain this a little further? Why couldn't it calculate airspeed by itself? You mean to say if you were sitting on the runway, not moving, with a 60 mph headwind that the efis would be showing a 40 degree nosedive along with the 60 mph airspeed indication? What other data does it need to know? Thanks. Michael
Can you explain this a little further? Why couldn't it calculate airspeed by itself? You mean to say if you were sitting on the runway, not moving, with a 60 mph headwind that the efis would be showing a 40 degree nosedive along with the 60 mph airspeed indication? What other data does it need to know? Thanks. Michael
khorton
New Member
When the EFIS is stationary, the accelerometers can sense the direction of the earth's gravity, and that tells it which way is up. That will work in steady flight too. But, if you accelerate or decelerate, the unit senses the wrong direction for the gravity. You can visualize this by imagining a pendulum. It hangs straight down, as it is pulled that way by gravity. But, if you had the pendulum in a car, and you accelerated, the bottom of the pendulum would move aft.
So, if we accelerate, the accelerometers send a false signal that would make the unit think that you had pitched up. The clever Dynon engineers use the airspeed data to correct for this. If the airspeed is increasing, they calculate a pitch down correction for the sensed attitude, to cancel out the effect of the false gravity reading. This works just fine when the unit is installed in an airplane. But, if you have the unit sitting on the bench, and blow in the pitot line, without actually accelerating the unit forward, that airspeed correction algorithm does its magic by sending the pitch down correction.
It sounds like your unit is working just the way it should.
So, if we accelerate, the accelerometers send a false signal that would make the unit think that you had pitched up. The clever Dynon engineers use the airspeed data to correct for this. If the airspeed is increasing, they calculate a pitch down correction for the sensed attitude, to cancel out the effect of the false gravity reading. This works just fine when the unit is installed in an airplane. But, if you have the unit sitting on the bench, and blow in the pitot line, without actually accelerating the unit forward, that airspeed correction algorithm does its magic by sending the pitch down correction.
It sounds like your unit is working just the way it should.
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- Mar 23, 2005
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Kevin's got it right. Airspeed is used to create an attitude solution that most of our customers find is basically the best performing out there.
Some additional information:
Airspeed and Altitude are determined solely by pitot and static pressure.
Heading is ultimately determined referenced to the magnetic sensors in the EFIS or remote magnetometer (depending on your product and configuration), but we use rate and other information from the attitude solution so that heading is dead on from the moment you roll in to a turn to the time you complete it, in any pitch attitude. Think of it as a slaved DG that never drifts, leads, or lags.
Some additional information:
Airspeed and Altitude are determined solely by pitot and static pressure.
Heading is ultimately determined referenced to the magnetic sensors in the EFIS or remote magnetometer (depending on your product and configuration), but we use rate and other information from the attitude solution so that heading is dead on from the moment you roll in to a turn to the time you complete it, in any pitch attitude. Think of it as a slaved DG that never drifts, leads, or lags.
One last note. I sure wish Dynon would create a a small, round faced DG for the screen. Makes it easier to line up with runways at unfamiliar airports. The one I use on my EKP IV doesn't keep up as fast on the heading changes as the Dynon appears to. Future? Michael
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- Mar 23, 2005
- Messages
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Michael,
Look at the firmware updates next week - you'll like what you see!
Look at the firmware updates next week - you'll like what you see!
Gee Whiz, i didn't know it was that easy! Okay, it sure would be nice if Dynon would come out with an autopilot setup for my plane...........Hmm. i don't see any smoke coming out of this lamp, yet? Ha. Thanks. Can't wait to see the firmware update. Michael.