Small Problem - Static Air Line Placement Causes Interference

This will be the last post for at least a week because of the Rotax engine classes that I’ll be attending in Virginia this coming week.  This is good timing because the DOG Aviation purchasing department just placed the order for the RV-12 powerplant kit which is the final kit to complete the DOG Aviation RV-12.

During the instillation of the left F-1265 flaperon pushrod it was discovered my chosen location for attaching the static air line alongside the seat rib has created interference with the left F-1265 pushrod. At the time this location was chosen for the static air line, it did not seem likely the left F-1265 pushrod would get close enough to the static air line to touch it … but it does. It just barely touches … however any contact is unacceptable.

After installing the left F-1265 flaperon pushrod, it was discovered there are combinations of stick and flap handle positions that create contact with the static air line. My finger is pointing to the area of contact.

If the lightening holes in the seat rib did not have flanges, doubt there would be any interference. The solution is not going to be a big deal … it will just require pulling back the static air line and routing it on the backside of the rib using the exact same routing. The static air line will need to pass through the lightening hole near the flap handle block, follow the same path on the backside of the seat rib it is on and get tied down using the same holes for the wire ties. At the forward end of the seat rib it will need to pass through the large lightening hole and through the wire grommet it is currently in.

Moving the static air line behind the rib will solve the clearance issue and as can be seen in this photo, there will be no issues bringing the static air line back through the large lightening hole in the seat rib and forward through the wire grommet.

Left F-1265 Flaperon Pushrod & WD-1215 Flaperon Torque Arm Installed

Continuing on where work stopped yesterday, progress was made installing the left F-1265 flaperon pushrod. The forward end of the pushrod was attached onto the flaperon mixer bellcrank. The right WD-1215 flaperon torque arm was installed next.

About to install the left WD-1215 torque arm onto the F-1206D bearing bracket.

The aft end of the F-1265 flaperon pushrod was installed onto the left WD-1215 torque arm. Because these last two assemblies need to be removed after match drilling the flaperon torque tubes, these parts were just tightened down snug but did not waste the time torquing the bolts since all this gets disassembled after the match drilling process.

Installing the bolt that secures the aft end of the left F-1265 flaperon pushrod onto the left WD-1215 flaperon torque tube.

Completed instillation of the left and right F-1265 flaperon pushrods and the left and right WD-1215 torque arms.

The center bolt in the flaperon mixer bellcrank assembly was tightened then torqued to specifications along with the hardware for all the attachments to the flaperon mixer bellcrank assembly.

Tightening the hardware for the F-1264 control stick pushrod.

Completed flaperon mixer bellcrank assembly with all four pushrods connected.

Before any more work can be done on the flight controls the wings need to be attached so the flaperon torque tubes can be installed and match drilled to the WD-1215 flaperon torque arms. This will have to wait for at least a week because of Rotax engine classes I will be leaving town to attend.

F-1265 Flaperon Pushrods Assembled - One Installed

Now that the primer on the guard I made to keep the static tube secured to the top of the flap handle block has dried, it was bolted down onto the left flap handle block and the bolts for both blocks were tightened.

The guard that was made for keeping the additional static tube secured on top of the flap handle block is now bolted in place.

With the guard for the static line now installed on the left flap handle block, the instillation of the F-1265 flaperon pushrods could begin. But first the flaperon pushrods need to be assembled. Months ago the threaded rod ends were placed in the pushrod tubes and four rivet holes were drilled. To insure the parts went back together correctly, each rod end and tube received tags with matching numbers. Each tag was placed through the matching rivet hole for that set.

Flaperon pushrod tube and threaded rod end with matching rivet holes marked with numbered tags to insure a correct fit during reassembly.

Frequent readers of the DOG Aviation Blog may recall I had center punched the rivet hole locations prior to drilling without the threaded rod end inserted … which apparently slightly deformed the tube enough to make getting the threaded rod end in and out a tough chore.  During reassembly, a thin film of Corrosion X was placed on the parts to add a little slick factor along with offering some long term protection. The rod ends needed to be tapped back into the tube. Not wanting the damage the rod ends a washer with tape was slid onto the threaded rod end and a deep socket was used to tap the rod end into the tube after eyeballing for perfect alignment. To verify rivet hole alignment after the pieces were mated, a 1/8" center punch pin was placed into the rivet holes. I got lucky and did not have to fuss with any of the rod ends, they all aligned perfectly.

Setup for tapping the threaded rod end into the flaperon pushrod tube.

Using a 1/8" center punch pin to test the rivet hole alignment.

After the rod ends were fully seated in the pushrod tubes, they were riveted in place using MSP-42 pop rivets.

Riveting the threaded rod ends and pushrod tube together with MSP-42 pop rivets.

Both completed F-1265 flaperon pushrods.

The plans call for screwing on F3514 rod end bearings on both ends of each pushrod and adjusting the length from center to center of the eyelets to 38 3/4". I started with screwing the rod end bearings onto the threaded rod end 9 1/2 turns this turned out to be within half a turn or so from being correct. The rod end bearings are offset from each other by 90 degrees … so to aid in getting the measurement right, two pieces of tape were marked at 38 3/4" and an AN3 bolt was slid into the eyelet of one of the rod end bearings and clamped onto one of the marks on the tape.

An AN3 bolt is centered and clamped over the line. This holds position as adjustments are made to obtain the correct length of 38 3/4".

Other end of the rod end bearing centered over the 38 3/4" mark.

Completed F-1265 flaperon pushrod assemblies 38 3/4" long from the centers of the holes in the bearings. Note the two bearing assemblies at each end of the pushrod are orientated 90 degrees from each other.

Because the auto pilot servo is already installed, I found it best to install the right F-1265 pushrod first by passing it along the left side of the servo motor and then bringing it forward through the holes in the center channel bulkheads on the right side. Installing the mounting hardware at the flaperon bellcrank assembly was challenging … trying to do it with your fingers is really tough because there is little room coupled with bad angles. I used the age old trick of using a box end wrench with tape closing off one end of the box so the nut would not fall through and then secured the washer to the wrench with a little more blue masking tape. This method worked out quite well.

Torquing the right F-1265 flaperon pushrod assembly onto the flaperon bellcrank assembly.

The right F-1215 flaperon torque arm was installed onto the right F-1206D bearing bracket and then the right F-1265 pushrod assembly was bolted onto the F-1215 torque arm. At this time the mounting hardware for these pieces will just be made snug. Sadly, it all needs to be removed after the wings are attached and the flaperon torque tube is match drilled to the F-1215 flaperon torque arm. Builders will want to make sure all the bolt holes in the F-1215 flaperon torque arm are clear of powder coating prior to installing so the AN3 bolts slide through the holes nicely. Mine were so full of powder coat material I could not even get any of the threads of the bolt into the holes. Sure glad I checked this prior to installing.

Right F-1215 flaperon torque arm with the right F-1265 flaperon pushrod assembly attached … ready for the instillation of the flaperon torque tube and subsequent match drilling process.

Did not have time to completely install the left F-1265 flaperon pushrod assembly so completing that will be the task for the next work session.

Flaperon Bellcrank Assembly Installed

The first order of business today was to clean the lower cowl parts along with a few other items requiring priming with acetone, do a little scrubbing with Scotch-Brite and re-clean the parts with acetone. Mixed up a 1 oz batch of primer and broke out the airbrush.  One thing that amazes me is it takes just about as long to spray a couple of small parts with the airbrush as it does to use the large spray gun to spray a bunch of large parts. When one takes into consideration the prepping for spraying, getting the compressor hose outside, adjusting the air flow, mixing the paint, waiting for the induction time (30 minutes), cleaning the measuring ladles, breaking out the respirator and goggles, straining the paint, spraying the parts, walking back and forth to hang the parts for drying, then tearing down the airbrush for cleaning with acetone followed by reassembly. Anyways, the lower cowl hinge components were primed as well as a few other miscellaneous items.

After the spray painting equipment was put away, started going through the plans and finishing up on small things here and there not worthy of photos. Because of the large amount of skipping around through the plans that has taken place, one practice that has been incorporated is to mark steps in the plans which have temporarily skipped with a colored vinyl flag that has an adhesive similar to a post –it-note. During the last few days have been able to remove quite a few of the flags. One such item that had a flag was the instillation of a grommet in the center section where the wires come up. Van’s instructs the builder early on to slice the grommet so it can be spread to fit over all the wires coming up through the hole in the center section.  Rather than taking the grommet in and out as wires were added, I just left it out untill now. Installing the grommet should be an easy task, but I was finding it a little difficult to spread the grommet open with one finger while sliding the wires through it. I came up with an idea that made the instillation a snap … fellow builders may want to remember the following trick. I used a pair of snap ring removing pliers to hold the grommet open so the wires could be easily slid inside of it.

 Wires coming up through the hole in the center channel. This hole is to receive a wire grommet that has been split.

Using snap ring removal pliers to spread open the wire grommet. Doing this made installing the wire grommet in the center channel a total snap.

Moving onto section 32 - installing the flight controls, work resumed where it had left off a few weeks ago. The parts for the flaperon mixer bellcrank were rounded up and discovered yet another challenge … a washer needs to go UNDER the F-1263B flaperon bellcrank, then the flaperon push tube is sandwiched between the F-1263A&B flaperon mixer bellcrank pieces. All of this slides in between the F-1212A&B flaperon mixer arms and is bolted together. This was not an easy task … and trying to get all the pieces aligned without losing the bottom washer seemed darn near impossible. After a couple of unsuccessful tries, came up with the idea to tape the washer in place … this is the way to go.

F-1263A&B flaperon bellcranks and mounting hardware.

Builder tip: Cut a couple of long pieces of blue painters masking tape with scissors so there is a nice straight edge. Center the washer over the bolt hole on the lower portion of the F-1263B flaperon bellcrank and tape the edges of the washer down onto the bellcrank making sure no tape covers the bolt hole. (The masking tape needs to extend beyond the sides of the bellcrank so it can be grabbed and pulled off later). Position the F-1263B bellcrank over the bolt hole in the F-1219A mixer arm. Place the bolt through the center of the bellcrank to verify it is aligned with the mounting holes in the mixer arm, then remove the bolt while keeping steady downward pressure on the bellcrank to hold positioning. Add the flap handle pushrod and again add downward pressure on the pushrod to hold positioning while the upper F-1263A bellcrank is added … then drop in the bolt and hand tighten. Do not final tighten the bolt yet. Verify that the washer did not fall off by using an inspection mirror while lifting up on the assembly to gain viewing clearance. If the washer is still in place, continue lifting the assembly and pull the masking tape down and away from the washer. Look closely at the ends of the masking tape … if it still has the perfectly straight edge from the scissors cut, you know no tape was left behind on the washer and you are good to go.

F-1263A&B flaperon mixer bellcranks and flap handle push tube mounted on the F-1219A&B mixer arms. Note the two pieces of blue tape that were used to keep the bottom washer held in place during assembly of the parts.

Next the F-1264 control stick pushrod assemblies were attached to the F-1263A&B flaperon mixer bellcranks.

Did not tighten any of the hardware yet because want to also install the flaperon pushrods so everything can be tightened at one time. The flaperon pushrods have already been cut and primed but still require assembly and riveting during the next work session.