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Garmin auto pilot in RV6

sharp308

Member
Hello, just going to instal the GSA 28 roll servo in a RV6. Drawings show it under the pax seat, right side. Is there any reason why you can’t install it on the left under pilots seat?
 
Hello, just going to instal the GSA 28 roll servo in a RV6. Drawings show it under the pax seat, right side. Is there any reason why you can’t install it on the left under pilots seat?

I put mine under the right seat but I don't see why it couldn't be put under the left seat.
 
Mine is under the left seat. The installation kit should also include a slightly longer crank arm for the servo, which is only for the -6(A). The roll installation kit for the RV-6 is called out separately and is p/n 011-02952-10.
 
Should work, but be very careful to avoid an over center condition in that location ( full control system throw to the stops).
 
Is the wing mount location preferred? Is it quite difficult in a completed plane? It had Trutrak servo’s before that we are replacing with the Garmin setup. The G3X manual only seems to show the under seat mount in the instructions.
 
Can see the old mounting bracket on the left. Just set the Garmin in on the right side to see how it would fit
 

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On my seven and a friends six the Garmin roll servo's were mounted in the wing pushing and pulling on the aileron bellcrank.
 
To those running the servo under the seat; I have heard in some instances roll can also command a slight hunt for pitch due to the angle of the servo arm to pushrod mount.
Can anyone confirm any truth to this or is it even noticeable? This is the only reason I was thinking the wing would be the better install location on my flying -6. After just being in there to run conduit I can see the seat pan being a much easier install.
 
To those running the servo under the seat; I have heard in some instances roll can also command a slight hunt for pitch due to the angle of the servo arm to pushrod mount.
Can anyone confirm any truth to this or is it even noticeable? This is the only reason I was thinking the wing would be the better install location on my flying -6. After just being in there to run conduit I can see the seat pan being a much easier install.

I have not noticed any pitch hunting but I can't say for sure because it is usually a bit turbulent where I am so I wouldn't notice any hunting anyway :)
 
To those running the servo under the seat; I have heard in some instances roll can also command a slight hunt for pitch due to the angle of the servo arm to pushrod mount.
Can anyone confirm any truth to this or is it even noticeable? This is the only reason I was thinking the wing would be the better install location on my flying -6. After just being in there to run conduit I can see the seat pan being a much easier install.

The later 7,8,9 wings had provision to bolt the servo to the spar
With the 6 wing, you probably have to make brackets to attach it to a rib making it more of an adventure to get a servo in the same general area by the bellcrank. I struggled thru one 6 this way, wont do that again.
I like the under seat location better & have done it on a few 6's since.
Left or Right doesn't really matter other than carefully check that you can get full travel on the servo lever without hitting the seat ribs. Mount the servo just aft enough so lever and linkage clears the control circuit (in all positions & directions!). The further aft you mount the servo- the greater the possibility you will get some pitch influencing. You may have to file the seat rib lightening hole bigger to clear linkage & end bearings.

I just read that this plane had TruTrak servos before. The Garmin ones should be able to mount in same brackets with a bit of modification. Why not use them??
 
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The later 7,8,9 wings had provision to bolt the servo to the spar
With the 6 wing, you probably have to make brackets to attach it to a rib making it more of an adventure to get a servo in the same general area by the bellcrank. I struggled thru one 6 this way, wont do that again.
I like the under seat location better & have done it on a few 6's since.
Left or Right doesn't really matter other than carefully check that you can get full travel on the servo lever without hitting the seat ribs. Mount the servo just aft enough so lever and linkage clears the control circuit (in all positions & directions!). The further aft you mount the servo- the greater the possibility you will get some pitch influencing. You may have to file the seat rib lightening hole bigger to clear linkage & end bearings.

I just read that this plane had TruTrak servos before. The Garmin ones should be able to mount in same brackets with a bit of modification. Why not use them??

Thanks, that answered the question I came back to ask. Under the seat it will go.
 
I'm sorry I didn't mention before that mine started out with TruTrak servos and yes, I only had to trim the mounts a little for the Garmin servos. Looking at the pushrod angle I was concerned about the skewed force vector affecting pitch but I have seen none. If I remember correctly the longer crank arm was to help eliminate any over-center danger.
 
Thank you for the confirmation. Yes we mounted the servo’s using the old trutrak brackets. Roll servo under left seat, needed the longer control arm to keep servo from over centering. Movement in all direction looks good now, although if we were to install the limit bracket on the servo, it would hit those stops before the aileron goes full travel. Have you found that as well Ralph? The old trutrak servo didn’t have a limit bracket on it either.
 
I had a Trutrak ADI II and the roll servo was mounted under the L seat. I put the GSA 28 servos in when I updated to a G3X touch system. I used the old mounting bracket and other than (I think) adding a washer between the servo body and the bracket at each mounting screw location for servo body clearance, IIRC everything else bolted right up - used the old link from servo to control linkage, etc. Garmin’s travel limiter may result in less range of motion than otherwise available - as I think someone mentioned in this thread, the old Trutrak had no such limit stop.

This is in an old slowbuild 6. Autopilot works great, was a big help in getting my IFR rating, and makes long XC work easy.

John
 
I put my AP roll servo out in the wingtip with a pushrod to the bellcrank. I started out planning to do the under seat mounting, but really did not like it. The wingtip mount has worked perfectly and doesn't cause roll/pitch coupling like the under seat version.
 
I mounted the garmin servo in the wingtip, as I had a trutrak bracket there. The pushrod goes straight to the bellcrank. Comparing the positions on my particular plane, I really preferred the wingtip as it was only applying the roll input and had no way to also apply a pitch movement.

After about 12 months flying with it there, I’m very happy with it there.
 
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