Geek's STi Build

[efwd]

wait wait. Are you saying, the only wiring is from the pitch servo to the yaw damper? Nothing to the panel?! Oh Lord, Do I Want to Know the answer?$

[Geek]

wait wait. Are you saying, the only wiring is from the pitch servo to the yaw damper? Nothing to the panel?! Oh Lord, Do I Want to Know the answer?$

Yup. Nothing to the panel. All the wiring I need to tie into in order to add the yaw servo is at the pitch servo. CANBUS, 12V, Ground, Autopilot disconnect is all there. Right now my pitch servo is at the end of my CANBUS run so I need to clip the jumper that I have on that connector that sets the BUS termination. The CANBUS gets extended to the yaw dampener
(just like you hooked all your components together on the system as a whole) and the termination jumper gets put on the yaw connector. No runs required to the panel - the beauty of the BUS.

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[Jez]

Nice, something to consider thanks.

[MFleming]

So while I am waiting on the FAA, I decided to add in the yaw dampener to my autopilot. Talked to Brandon about this and he compares having it in the plane to having heated seats in your car; once you have them, you don't not want to have them. I bought the kit sans servo to get things set up and tied into my aircraft wiring. Built up the mounting plate by installing the plate nuts and built up the cable that will run from my pitch servo to the yaw servo. Will actually do the wiring install after my inspection and buy the servo then.

Attachment 33326Attachment 33327Attachment 33328Attachment 33329

Very interesting. Looks like the wiring is straight forward. What about how the servo operates the rudder? Is that included in the install kit?

[Geek]

Very interesting. Looks like the wiring is straight forward. What about how the servo operates the rudder? Is that included in the install kit?

I think Brandon did a great job on building up this kit and the design. I snaked a pic from Dustin (Dual STi Build Log) on the parts that connect to the rudder (since I don't have the servo yet.) Take a look at his build log (last few posts - easy to find). He did a great job of writing up his experience in doing the install

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IMG_3382.jpg

[rv9ralph]

Ok, Geek (Gary). Quick question. The buss takes care of the signal, so you don't have to wire that to the panel. What about power? Will you make a run back to your power buss? Or, tap into something else towards the back?

Your build is looking good. Hope to see you in June.

[Geek]

Ok, Geek (Gary). Quick question. The buss takes care of the signal, so you don't have to wire that to the panel. What about power? Will you make a run back to your power buss? Or, tap into something else towards the back?

Your build is looking good. Hope to see you in June.

Thanks Ralph. Good to hear from you and look forward to seeing you in June. Same power run from the VPX that currently runs/goes to the pitch and roll servos. With the VPX controlling the current, I set the autopilot circuit at 6A which should be fine if I read the current requirements in the manual correctly AND I could never think of anytime that all three servos would pull max current at the same time. (Spec for the servos is 0.36A typical and 1.8A Maximum so all three at max would be 5.4A). If it does, I think I probably should not be flying with the autopilot on anyway.

Geek

[rv9ralph]

Thanks, on review of our wiring, we have 20 ga wire to each servo from the VPX on their own dedicated circuit. If we decide on installing a yaw damper, we will have to either increase the size of one power or run a dedicated circuit. You made it sound so easy. We knew it was too good to be true.

[Shadowrider]

Ralph I had a dedicated circuit with 20 gauge to each servo. (Roll and pitch) Mil spec 20 Gauge is good to about 8-9 amps. I just pulled power from the roll servo at the roll servo. Also tied into the canbus there. Solider sleeved it and ran wire back to the pitch servo. I went back an changed the VPX labeling so Roll is now Roll/Yaw Servos. With the autopilot on and trying to overpower the servos I saw just over 1 amp. Its less than that during flight. Doing it again I would of put all 3 servos on one circuit. GSa-28 has an average .4 amp draw. If you have your servos wired to the 5amp circuit that is plenty. I have quite a few hours on the yaw dam setup now and it working great with absolutely no regrets of doing. I agree with Brandon, don't think I could fly without it now!

[Geek]

What Dustin said. Even at the specified max current draw of 1.8A, two servos trying to draw the max at the same time would only be 3.6A. The 20 gauge would be more than enough for that and I like I said, if two or three of those servos are trying to pull max current for a longer period of time (greater than something in the millisecond range) then I should be flying the plane and not the autopilot. I think with two servos on one circuit you are MORE than covered. I've got three servos on one circuit and think that's good to go. I'll hawk the current draw once I start flying but taking Dustin's observations, where he pushed the servos into trying to overcome his control inputs, you should be golden with splicing into one of your existing servos.

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