Sunday, September 23, 2012

Trim Servo Wiring Run & Static Air Ports

Work on the RV-12 was done in short bursts today in between running errands but nevertheless, progress was made. Yesterday, the left skin was hung on the tail cone assembly but not fully clecoed in place so today the left skin was fully clecoed onto the tail cone assembly. Next the right skin was put in place and clecoed in place.
                                           Installing Clecoes to hold the right skin onto the tail cone assembly.

The plans call for a string to be run through the fuselage frames then through holes in the aft bulkhead for the running of control cables later in the building process. Next is the running of the trim servo cable which is placed in one of the J stiffener channels on the left skin and runs the length of the tail cone. Holes are already in the J stiffener channel for using wire ties to secure the cable tightly in the “J”.
       Fishing the trim servo cable along the lower left skin’s J stiffener between the fuselage frames and outer skin.
                                                     Trim servo cable in place and held in place by wire ties.

The wire ties forward of the F-1208 front fuselage frame are not to be tightened down because the static air tubing and another wire will be added later. I was not happy with the way the trim servo wire transitioned from the J channel to the wire grommet in the aft bulkhead. Basically the wire is just bent over the edge of the J stiffener so I thought it best to place the wire in a short piece of vinyl tubing.
                 Trim servo wire placed in a vinyl tube … note how far away from the aft end the wire tie is located.

Not being happy with the way the tube/wire was lifting up out of the J stiffener, I added another hole in the J stiffener closer to the rear edge for an additional wire tie.
                   The wire tie on the right is the additional wire tie and it held down the tube/wire quite nicely.

Work for the day ended with the instillation of the special rivets that will become the static air ports. I decided to not pop the rivets in place without sealing them first with some sensor-safe silicone gasket maker.

To prevent any silicone from getting onto the outside skin where finish paint will be sprayed, I used the static air rivet as a template to cut a hole into a piece of masking tape. The metal around the hole was cleaned and the masking tape was then placed over the unset rivet so it could be centered.

                          Tape centered over the hole before setting the rivet so no silicone gets on the outer skin.
After the tape was in place, a light coating of sensor-safe silicon gasket maker was applied to the backside of the rivet then the rivet was set and the small amount of excess silicone was cleaned up before pealing the masking tape off.
The set static port rivet then needed to have the broken mandrel and ball removed to make the static port hollow. Removed the broken mandrel/ball inside the rivet by drilling a hole into a block of wood. Jan placed the block over the backside of the rivet and kept it tight to the skin to prevent denting as I pounded a mandrel into the rivet hole from the front side and pounded the broken mandrel/ball out the backside.
                   Right side static air port rivet with mandrel and ball pounded out. Yep, you can see light through it.