Auto-pilot settings RV-7A
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dlloyd
Member
Larry,
Right out of the box the factory settings work pretty good, I flew most of Phase one only changing the max torque to 50%. Dynon's directions need a couple hours on a clear calm day to do properly. Since these settings are pretty much fine tuning, what might be better for my airplane may not be best for yours. I've never seen anyone mention it but my autopilot seems to need some more adjustment with two on board, full fuel and baggage--something you should consider.
Right out of the box the factory settings work pretty good, I flew most of Phase one only changing the max torque to 50%. Dynon's directions need a couple hours on a clear calm day to do properly. Since these settings are pretty much fine tuning, what might be better for my airplane may not be best for yours. I've never seen anyone mention it but my autopilot seems to need some more adjustment with two on board, full fuel and baggage--something you should consider.
knowlesbg
Member
The only setting I had to adjust was the sensitivity
This can vary according to conditions
Bruce
This can vary according to conditions
Bruce
I have an RV6 that I started flying with Skyview last year. I suspect the the RV-7A would fly similarly. I had to reduce the Roll sensitivity to about 5 or the plane would oscillate about the roll axis.
What is the effect of setting max torque to 50%? 100% was the default setting and I never changed it.
On a bumpy day I get a lot of roll SLIP annunciations.
What is the effect of setting max torque to 50%? 100% was the default setting and I never changed it.
On a bumpy day I get a lot of roll SLIP annunciations.
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- Mar 23, 2005
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The servo will slip more, especially if turbulence is already causing slips.
Thank you for confirming the servo will slip more when max torque is reduced. I will leave it at 100%.
Is there any problem with slipping? It's not really slipping like a worn out clutch. My understanding is that the servo just can't provide enough torque to keep the axis stabilized.
Actually now I recall it is the pitch axis that slips the most and occasionally I disable the pitch axis to check the trim.
Is there any problem with slipping? It's not really slipping like a worn out clutch. My understanding is that the servo just can't provide enough torque to keep the axis stabilized.
Actually now I recall it is the pitch axis that slips the most and occasionally I disable the pitch axis to check the trim.
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When the servo is slipping, the autopilot isn't able to control the airplane because the force to control/move the control surface is exceeding the servo's output. In turbulence, this can be very momentary, but, if it's routine or for a long duration, either the servo is sized to small for the aircraft, the install isn't ideal (not using enough of the servo's rotation, assuming you can use more without getting close to going over-center), or there's something up with the servo.
In turbulent weather the slip indication can display for 3 to 5 seconds. When the slip shows longer than about 10 seconds I disconnect the pitch axis to check the plane's trim. In smoother air the AP works without exception.
I adjusted the servo arm linkage to the largest radius on the control arm without moving over-center. The servo connects to the bell crank behind the baggage wall using the recommended installation method and supplied hardware.
I adjusted the servo arm linkage to the largest radius on the control arm without moving over-center. The servo connects to the bell crank behind the baggage wall using the recommended installation method and supplied hardware.
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- Mar 23, 2005
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So are you getting those prolonged (10+ seconds, as you mentioned) slip indications when airplane isn't in turbulence? If no, then, when you disconnect, is the airplane ever near trimmed?
Put another way, if you're seeing slip indications when you're not in turbulence, and when you're not substantially out of trim (which puts the servo closer to slipping), then that might imply something is up with the servo's trim/slip sensing ability.
Put another way, if you're seeing slip indications when you're not in turbulence, and when you're not substantially out of trim (which puts the servo closer to slipping), then that might imply something is up with the servo's trim/slip sensing ability.
My apologies; the AP works fine virtually all the time. In turbulent air the AP can show the slip indication for 3 to 5 seconds and in less turbulent conditions there is no slip.
When I see the slip for longer than about 10 seconds I turn off that axis to check trim. Even with an indicating slip the AP holds the plane fairly level; within 100-200 ft max. On hot Midwest days there can be a lot of uplift and I am not surprised to see the AP working hard.
I find the airplane out of trim mostly when I engaged the pitch axis too soon after climbing and reaching level flight. I need to let the plane settle to a stable air speed after leveling off, manually trim the pitch and roll axis, and then engage the AP.
I have the roll axis sensitivity set to about 5. When I try to set the value higher (7-10) then the plane will oscillate. I seem to recall the default value was about 24 and the AP had a very pronounced roll oscillation. I don't recall the exact pitch axis sensitivity setting, but I do remember it was closer to the default.
When I see the slip for longer than about 10 seconds I turn off that axis to check trim. Even with an indicating slip the AP holds the plane fairly level; within 100-200 ft max. On hot Midwest days there can be a lot of uplift and I am not surprised to see the AP working hard.
I find the airplane out of trim mostly when I engaged the pitch axis too soon after climbing and reaching level flight. I need to let the plane settle to a stable air speed after leveling off, manually trim the pitch and roll axis, and then engage the AP.
I have the roll axis sensitivity set to about 5. When I try to set the value higher (7-10) then the plane will oscillate. I seem to recall the default value was about 24 and the AP had a very pronounced roll oscillation. I don't recall the exact pitch axis sensitivity setting, but I do remember it was closer to the default.
meljordan
Active Member
A roll sensitivity of 5 is normal for an RV. My pitch, however, is set at 18 which gives me a stable ride yet can hold my altitude pretty firmly. Are you getting "Trim Up" or " Trim Dn" indications when in level flight with the AP on? Those should be coming on if you are very far out of trim. Next time you fly, turn on the AP and gently and slowly bump in some trim until you get a trim indication then reverse until it goes out. Turn off the AP and you should be reasonably close to trimmed. Try it both directions. As you transition to level flight the AP should tell you what trim it needs.
Here in AZ we get lots of turbulence and some slips are quite normal. A bigger servo woud have less slips, but would reduce the nice light control feel of the RV. My experience is that the SV32 servo work really well in our two place RVs once you get all your settings dialed in.
Regards
Here in AZ we get lots of turbulence and some slips are quite normal. A bigger servo woud have less slips, but would reduce the nice light control feel of the RV. My experience is that the SV32 servo work really well in our two place RVs once you get all your settings dialed in.
Regards
I've played with the pitch trim when I get the AP trim up and down indications. Typically when I see the up or down trim for more than about 10 seconds I crank in some trim and the AP is happy for a while. Then a minute or less later I encounter the reverse draft and I find myself taking the trim back out. That's when I disable the axis and check the trim, and typically it is close to level. On bumpy days I have learned to check the trim occasionally but otherwise ignore the up/down and slip annunciations. I understand the AP servo is getting a workout but I don't believe it is mechanically or electrically being damaged by this condition.