Craig,
I put in two Dynon servos in my bought-flying 6, having not built an RV. It was part of my panel upgrade, so Paul's caveat on mission creep is a good one. That creep can be very good, since you get stuff done (and learn a lot), but it can be time consuming, so just plan your down time and leave some room on the back so you don't get rushed...been there!
From all I've read, the various mfgr servo installs are similar, and I went with the Dynon recommended RV-6 roll servo location, under the seat (and either seat is OK). Its interesting to hear the mechanical advantage issues of the wing install, but it makes sense in thinking about it. However, being my first install, and being an early adopter of the Dynon AP, I went with the recommended method (they had pictures for me to follow by doing so!
)
Couple thoughts from the new-to-this perspective that I had during the project:
The pitch servo was straight-forward, just took a little study on the diagrams to figure out where to drill the bellcrank, and a little finesse (and hucky-pucky) to get the washers to stay in place as the bolts were placed through the bellcrank.
I was hesitant to drill out the 3 fuselage rivets to mount the pitch servo bracket, so I tried riveting it only through the side part of the brace. It was not secure enough at all, so I had to remove the bracket, which ruined it, so had to copy and re-fab the bracket, and then I riveted it both on the bottom (through the fuse) and on through the side of the bracket. Worked well, just took longer because I tried a "shortcut". So don't let drilling out rivets put you off, it turned out to be easy.
Safety wiring the three bolts on the pitch servo bracket was a bit tricky for this neophyte, and I did it partially backwards the first time. A three-fer safety wire job took me a little throught to get right, but it worked out, and was an interesting learning event.
I put the roll servo in the outer bay below the left seat. Worked well, but also entailed some drilling through the fuselage for the bracket. A bit tight in there, but pretty workable. You do want to make sure to use the correct placement, per the instructions, so you have the proper clearance from the aileron push tube throughout the full range of control stick movement.
The wiring for the pitch servo has to move from behind the baggage wall, under the cargo floor, under the seat floor, then past the spar to the panel. I had my cargo floor up for the panel upgrade (mission creep), so that part of the wiring was easy. Some builders put in a conduit and pull strings in there to make that easy...mine did not.
To get past the spar, I took both the pitch servo and roll servo wires up the inside of the side brace above the spar. That meant drilling out a few rivets and pulling off the cover of that side brace, but it was actually pretty easy.
If you go with a wing-mount for your roll servo, you can still take the wires from the wing root, under the seat, and up that side brace channel as well. If your builder put in wing conduits with pull strings, it'll make getting the wires to the wing root and cockpit easier.
One other issue that popped up for me having used the under-seat location was the impact on my belly whip antenna locations. For ease of install, I placed one whip in the next bay inboard from the roll servo, and the other in the mirror location. Turns out they may be a bit close together, so my Comm 2 or my APRS make some noise on my comm 1. So take a look at you antenna locations or future locations, as it may impact you rdecision to go with the floor bay or the wing.
The more experienced guys will likely have some more detailed thoughts and good methodology, but those are just some things I remember about the project, which was pretty fun and gratifying. And my experience was strictly Dynon gear. Other mfgrs will have other requirements and gotchas.
Sounds like a lot, but it was not too bad. I was more along the couple week timeframe, as I'm still learning all the building/tinkering techniques that Paul was talking about, and I just took little bites out of the elephant as I went along (and got help from builders whenever I could). If you give yourself time to do it with no pressure, it'll be enjoyable.
Depending on your choice of equipment, if you want to see pics of any parts of my project, happy to send them along, if it'll help.
Have fun!!
Cheers,
Bob
