RV-6 Roll Servo Fuselage Insall Question
 

I am installing a TruTrak roll servo per their RV6 fuselage installation plan except I really don't like the reinforcement plate messing up the nice and smooth under side of my fuselage. I know it is the bottom and only visible when looking under, but I prefer leaving the exterior of my plane clean and undisturbed if possible.

I see the Dynon servo installation instruction mentioned fixing the servo mount to seat ribs instead of the bottom skin, but offered no plan or other details. Does anyone have a picture or two to show how this is done?

I am also considering installing per TruTrak plan without the plate but with more screws to distribute the load. Do you see any problem with this?

Any feedback or comments are appreciated.

On a different brand, but similar servo, I installed angle horizontally on each rib and bolted the servo to that. You would need to insure mounting it off the floor still allows adequate clearance for the push rod to clear the control weldment throughout its range of motion.
I would not bolt the servo to the floor without a doubler.

I can't imagine that an .063" plate with a tapered edge could do much to your performance. Far better to focus your attention on the fuel drains and fuel vents. They are far more visible, ugly and drag inducing. However, if it bothers you, look for alternatives. I will caution you to find a mounting approach that provide very good stability. Unless reinforced properly, the ribs can flex. You do not want ANY movement in a servo. It must be firmly mounted to establish equal and linear actuation of the controls.

Let us know what you come up with. I mounted mine according to the proven instructions, as I thought it was a good compromise approach. I put a nice taper on the forward edge of the exterior support plate to help with drag reduction.

I also would not recommend installing the servo on the fuselage without a doubler.

Larry

Dynon servo, but similar problem.

I just made a plate to fit from 0.025 alum. with flanges on all four sides.

The sides are riveted in, pull rivets to the seat support frame and hard rivets to the outer skin/frame. No rivets through the belly skin and the lower flange is about 1/8 inch above the skin. The full flanges make it a stiff assembly.

The location dimensions came from the Dynon installation drawing.

Gill,

I like your approach here. I wish I had thought of it before I made my bracket.

Larry

I had similar concerns when I went to install mine 5 or so years ago. Ultimately, I got over those concerns and installed it with the external plate. Funny enough, nobody has ever mentioned the plate, probably because it is relatively small, and not many people see the belly of the plane up close.

You might think about installing the plate per plans. The plate mounting is easy, and besides, nobody other than you will know it is there.

Skin
 

I trimmed and mounted the doubler skin on the inside between the ribs. Only thing on the outside is the rivets. Also made a doubler for my comm antenna. iA friend suggested it because he sees the antennas on production airplanes start a tear there.