Skyview Autopilot and Loss of Trim Servos

[lynnb]

I'm working through a panel layout using the skyview autopilot. I'm told the autopilot powers the trim servos so the trim servos are not on there own circuit breaker, but are on the A/P circuit breaker. So my question is, if I have a short circuit on a trim motor, will it blow the A/P circuit breaker and prevent me from using the A/P? If the trim motors fail, would the A/P still work anyway? I guess I'm trying to be comfortable with not being able to pull a CB for the trim if I was to have runaway trim or to loose my A/P if I was to have a trim motor fail or short circuit.

Thanks,
Lynn Buchanan

 

[Dynon]

Strictly speaking, "The Autopilot" is the servos.

The "autopilot" (IE servos) do not power the trim servos. There is a feature within the AP control panel that allows it to be your trim controller, but it's electrically independent from the AP itself. Think of one of the AP control panel's features as being the same as an external trim controller or relay deck. IE, they aren't required to use the same power source as the higher current autopilot servos unless you choose to wire up your system that way.

Put another way: If you wire your autopilot servos to and trim servo motors to the same breaker/fuse, yes, tripping that circuit would take out both. But you can still breaker/fuse your AP servos and trim servos completely separately, as most people do, and have power independence between these systems.

 

[MikeAg03]

I'm fairly certain the answer is no...
See this and section 18
http://dynonavionics.com/public_html/yabbfiles/Attachments/SkyView_System_Installation_Guide-Rev_W_v14_0.pdf

So the Autopilot control panel gets power thru Skyview DB9 connectors but can also get power thru the connection going to this that is used to power the trim servos. Trim servo can be on it's own breaker from autopilot to power this trim servo.
I imagine if you remove power to the autopilot panel, it will revert to using skyview power and continue to function. Regardless if the controls get disabled, they're just secondary controls and not the actual autopilot (as it's an optional control panel - unless you have electric trim).
Based upon that, you should have Skyview, autopilot, and trim all on separate circuit breakers imho.

I could be wrong, so I'll wait for someone from Dynon to confirm.

 

[lynnb]

Strictly speaking, "The Autopilot" is the servos.

The "autopilot" (IE servos) do not power the trim servos. There is a feature within the AP control panel that allows it to be your trim controller, but it's electrically independent from the AP itself. Think of one of the AP control panel's features as being the same as an external trim controller or relay deck. IE, they aren't required to use the same power source as the higher current autopilot servos unless you choose to wire up your system that way.

Put another way: If you wire your autopilot servos to and trim servo motors to the same breaker/fuse, yes, tripping that circuit would take out both. But you can still breaker/fuse your AP servos and trim servos completely separately, as most people do, and have power independence between these systems.

Ok, so I'm working with Stein on my panel design and they are saying the AP is on one circuit breaker and the A/P servos are on a separate one, but that the AP deck powers the trim servos. This is there quote:
"Dynon network architecture uses the autopilot power to power the trim. You could provide a separate power source but you would lose the autopilot automatic trim feature. Dynon has been doing this for a long time and we haven't had any feedback about it from customers who are flying completed airplanes."

I would think trim servos would have there own power and circuit breaker and doing this wouldn't limit the functionality of the A/P in any way, is this correct?

Thanks for the quick response by the way.

Lynn

 

[Dynon]

The autopilot power does not power the trim.

Think of the SV-AP-PANEL as two products in one.

One product is a set of buttons for the AP. That's powered by SkyView via the SkyView Network.

The other product is a trim controller, with a few smart features. The SkyView-driven smarts - the Autopilot auto-trim and IAS-based speed scheduling - are indeed passed along to the trim controller half from SkyView, but the trim controller circuitry is fundamentally self-powered by the power input on the D15. So even if somehow SkyView completely failed, or let's say your D9 SkyView Network cable came off the back of the SV-AP-PANEL, you still have trim control, albeit without speed scheduling or autopilot auto-trim.

Note that on page 18-4 the manual says "integrated trim controller is wired to a D15 connector that can be connected to Aircraft power (12V only),..." . It doesn't say anything about using the autopilot circuit. It needs ship's power, period. And for the reasons outlined above, you probably don't want to gang together the AP and trim servos on the same circuit. Also note the wiring diagram and table on the same page, which shows that you need to be able to sink 12V@4A, which comes from ship's power (nominally via a separate circuit for trim). Similarly, the AP servos get their own ship's power source (again, nominally via their own separate circuit)

Put another way: SkyView Network is used to pass data signals along to the both the AP servos and the SV-AP-PANEL. But both of the power that is used to drive the actual motor functions in each of these cases is coming from ship's power.

Now that I think about it, I think some competitors may have the trim controller in the AP servo itself. We didn't do it that way keep AP servo failure independent of your trim system, even when you use our trim controller solution.

 

[kellym]

Ok, so I'm working with Stein on my panel design and they are saying the AP is on one circuit breaker and the A/P servos are on a separate one, but that the AP deck powers the trim servos.  This is there quote:
"Dynon network architecture uses the autopilot power to power the trim. You could provide a separate power source but you would lose the autopilot automatic trim feature. Dynon has been doing this for a long time and we haven't had any feedback about it from customers who are flying completed airplanes."

I would think trim servos would have there own power and circuit breaker and doing this wouldn't limit the functionality of the A/P in any way, is this correct? 

Thanks for the quick response by the way.

Lynn
[/quote]
I don't know if Stein does theirs differently. My trim is powered separately, but controlled by the AP Panel. Before I installed the AP panel the trim was powered and controlled by my VPX. I can turn off power to my AP servos, and I still have pitch trim. I chose not to install aileron or rudder active trim. They just are not needed on the RV-10. A small wedge takes care of rudder trim, and the stick forces are light enough that even if you let fuel get significantly out of balance, you hardly notice the force needed for wings level, unless you let go of stick. The roll servo has no problem managing any out of balance condition.

 

[Raymo]

Lynn,

The AP Button panel optionally controls your trim servos, which also means it powers them. The voltage sent on either of the white wires to the trim servos is what causes it to move one direction or the other.

This is completely separate from the auto pilot servos and power.

 

[lynnb]

Ok, I got it worked out. I think the confusion came in the way the CB's were being labeled on my panel layout going back and fourth with Stein. I was not trying to wire the Trim Servos to the AP servos, but there were two circuit breakers being called out, one for AP servos and one just labeled Auto Pilot. Well the one labeled Auto Pilot was to the Auto Pilot panel, which is the power for the trim motors, nothing more.

Thanks for all the feedback,
Lynn