Pre-wiring for Dynon AP servos

[rvmills]

Dynon bros,

I've ordered AP servos and an AP-74, and am finishing up a panel upgrade...almost ready to close up. In looking at other threads, I've noted that the servo install is expected to be similar (or identical) to TT servo installs (with less wires). Here are my questions:

1. I have a flying RV-6, and it looks like installing the roll servo will be much easier in the cockpit floor than in the wing. Will the servo be mountable in the removable section of the floor, just aft of the spar (as shown in the TT roll servo install .pdf for RV-6 floors)?

2. I'd like to pre-install wiring for both the roll and pitch servos, so I can run them to the panel before re-riveting the cockpit support side channel covers that I have removed to run other wires (so I can fly while waiting for the AP to begin shipping). Can I purchase a 5-wire harness from Dynon now to make that pre-wiring possible? If not, can you tell me what wire gauge to buy to make my own harness, and how many wires go to each servo, or how I need to design the harness?

Thanks very much...appreciate any feedback you are able to provide!

Cheers,
Bob

 

[dynonsupport]

The RV-6 kit locates the roll servo under the seat.

We won't be selling wiring harnesses, since wire lengths will vary so much across installs.

What you need is 5 wires:

1) +12V, at 2amps. You'll need to size this wire for your run length.

2) Ground, at 2amps. You'll need to size this wire for your run length. You can ground this locally to the airframe if you wish.

3 & 4) DSAB A & B. These can be as small as you want.

5) Disconnect. This can be as small as you want.

No special wiring needed. They can be run in a bundle.

Please note that the 2A load is for a 30in/lb servo, which I know will be used in the 6 for both servos. Other planes may need a 40 or 50 in/lb servo and thus may draw up to 3A.

 

[rvmills]

Thanks for the reply. Spoke to a Tech Support Rep this am, and I'm still trying to get this right (and thanks for bearing with a first-time AP installer!).

Understood that each servo gets 5 wires as you posted. With the Roll Servo in the floor, and the Pitch Servo behind the aft baggage wall, it sounds like I can splice the power, ground, DSAB A and DSAB B wires from each servo back under the floor, and then just run four wires (instead of 8) through the spar and up to the panel. Is that correct?

With respect to the AP disconnect, I couldn't get that quite straight on the phone. Do I splice the disconnect wires from each servo and just go straight to the stick grip(s)? Do I need to keep the disconnect wire from each servo separate? Is there any need for the AP disconnect wire to go through the spar up to the panel/AP-74?

Bottom line is that I'm just trying to figure out whether to run one or two wire bundles through the spar, and whether the bundle(s) should have 4 or 5 wires. Hope it's not too convoluted of a question!

On Servo size...my RV-6 is built like a Rocket (big motor, clipped wings, higher max GW). Would 30 in/lb servos or 40 in/lb servos be most appropriate (iow, what do you recommend for the Rockets?)

Thanks again for suffering through my questions!!

Cheers,
Bob

 

[dynonsupport]

Understood that each servo gets 5 wires as you posted. With the Roll Servo in the floor, and the Pitch Servo behind the aft baggage wall, it sounds like I can splice the power, ground, DSAB A and DSAB B wires from each servo back under the floor, and then just run four wires (instead of 8) through the spar and up to the panel. Is that correct?

Yes.

With respect to the AP disconnect, I couldn't get that quite straight on the phone. Do I splice the disconnect wires from each servo and just go straight to the stick grip(s)? Do I need to keep the disconnect wire from each servo separate? Is there any need for the AP disconnect wire to go through the spar up to the panel/AP-74?

You want your disconnect switch to affect both servo's disconnect lines. This means you can wire both of them together in the back and send a single wire to the switch.

On Servo size...my RV-6 is built like a Rocket (big motor, clipped wings, higher max GW). Would 30 in/lb servos or 40 in/lb servos be most appropriate (iow, what do you recommend for the Rockets?)

Our data on the F1 suggests that the SV32s should be enough, but obviously we couldn't say for sure yet. If you know anyone with your same aircraft that has a TT AP installed, note that our SV32 is equivalent to their B servo, and our SV42 is equivalent to their C servo.

 

[rvmills]

Thanks very much...appreciate the info! Will plan the wiring as you describe, and will ask some Rocket buds with TT which servo they use (B or C). Thanks again!

Cheers,
Bob

 

[jhgeo]

I'm am finishing up wireing and am running the wire needed for an AP now rather than later. My assumtion is that the AP disconnect goes to ground through a switch. Is this correct.

 

[Brantel]

They have confirmed this is true on another thread.

 

[Ken_Kopp]

connect both servo disconnect leads to one side of your switch and the other to ground. Works like a champ.

Ken

 

[jhgeo]

So here's another stupid question that was probably answered somewhere else. Believe me I do run searches to any question I have before asking them. My question is: Does the power to the servos run directly from your circuit protection to the servos or is there a switch installed to power up the servos independently. I noticed an amp rating for armed and disarmed servos which suggests to me that power is sent directly to the servos from the master power buss and uses the servo disconnect switch as the primary online, offline source for the servos.

 

[dynonsupport]

Power runs direct from your plane's master bus through a current protection device to the servo.

Normally, you never need to touch this. The servos can be on during engine crank and all other times. They draw almost no current when not engaged. We'd prefer to see them come on with or before your EFIS.

You control engagement via the EFIS, AP control panel, or the disconnect switch on your stick/panel. This doesn't kill power to the servo directly, but in normal operation this is a full disconnect.

We do suggest that you have a switch or circuit breaker you can pull to kill the power to the servo should anything ever fail in such a way that the servo is producing torque when you don't want it too.