Sunday, December 21, 2014

Left WD-1212 Control Stick Instillation Completed

Not being completely happy with the fit of the left WD-1212 control stick assembly because it still had a little more endplay than desired … the left control stick was unbolted from the F-1210 control column and the brass bushing was removed for tweaking. The whole stick assembly does not need to be removed … just unbolted and moved to the side so the bushing can be removed from the WD-1212 control stick. The Lubriplate grease was cleaned off the bushing so metal fragments would not contaminate the grease and the bushing was chucked into the drill press and filed down a little.
Using the drill press to file down the left control stick’s bushing. Removing material from the bushing this way is easy and insures a square end.

After removing a little material from the bushing, it was deburred and reinstalled. To get the desired fit it took two attempts. I could have removed just a little more from the bushing, but overall the fit is just great and the stick moves quite freely without a hint of drag. By the way, I feel it is much easier to tweak the length of the bushing than try to file the control stick … so if the control stick is filed a little too much, filing down the bushing a little using the drill press is really easy and all the hardware is easily accessible.

The two wire bundles for the switches on the Tosten CS-8 grips were rerouted up along the outside of each F-1212 control stick and wire tied in place. Now the two wire bundles clear the moving parts nicely.
Completed instillation of both W-1212 control sticks and finalized routing of the wire bundles for the Tosten CS-8 grips.

Thursday, December 18, 2014

Left WD-1212 Control Stick Installed - Almost

Yesterday, work resumed on installing the WD-1212 control sticks. The hardware for the right stick was tightened and a sweet spot was found where there is no endplay and no drag on the stick. Moving on, began preparation of the left control stick for instillation. This time I remembered to take a photo of the rod end and spacers.

Builder tip: Fellow builders follow the tip from Joe in Florida and install the F-1264 pushrods onto the control stick prior to installing. It is tricky to do with the parts right in front of you yet alone trying to install the parts from underneath the stick after it has been installed.
Photo of the F-1264 push rod assembly being installed onto the left control stick prior to installing the control stick. The two tiny spacers are the problem… it is a really tight fit. The spacer on the right is not yet fully in place.

At first appearance, it does not appear as though the WD-1212 control stick with the F-1264 push rod assembly attached will be able to get fished into place … but it will fit with a little finagling.
Installing the WD-1212 control stick with attached F-1264 push rod assembly on the pilot side. It is a tight fit installing the entire assembly this way, but it IS the way to go.

When tightening the hardware for the left control stick I could not find the sweet spot as I did on the right stick. The slots in the castle nut either allowed too much endplay or no endplay but some drag on the stick. So a little filing on the brass spacer will be necessary during the next work session to hopefully improve the fit.

I think the .025" that was filed off the left stick was a little too much … so will attempt to trim the bushing down a little to compensate. If doing it over again, would only have trimmed the control sticks down .008" shorter than the bushings … but either way looks like there is a little custom massaging necessary to get to the point of little endplay with a smooth feel and the yoke clearance seemingly come into play here.

Of note: There is a difference between the left and right mounting yokes for the sticks on my WD-1210 control column. The mounting yoke on the right side is a little wider than the 2” brass spacer and the mounting yoke on the left side just barely accepts the brass spacer. As such, when the right side is tightened it creates a slight taper which helped close up the endplay gap. The left side however is tight to begin with so the endplay gap does not close much.
Both sticks installed but the brass bushing on the left stick will require a little filing to obtain the perfect feel.

Tuesday, December 16, 2014

Control Stick Instillation & Bad Paint Resolved

Although not having posted in a while, have made some small progress on the DOG Aviation RV-12 … however the nature of most of the work was not worthy of generating any posts.

One issue that needed resolved was the finish on the firewall forward parts that were sprayed with VHT high temperature paint. Originally I was planning to powder coat these parts … then figured I could get by using high temperature paint. Frequent readers of the Blog may recall during the summer I painted a bunch of parts and was not happy with the result so sanded them down and re-sprayed them recently.  The second spraying turned out much better than the first but there was still an issue with the way the paint dried resulting in a really rough finish. Decided to throw in the towel and just powder coat the parts. Unfortunately, I forgot to take photos of the bad finish to share with others.

Mike has a friend that owns a powder coating business so we boxed up the pieces and went to seek professional help. I was told all the paint and primer would have to be blasted off the parts and that I could use his bead blasting chamber to clean up the parts … which took all of an afternoon to accomplish. (As a side note, there was a customer there who was a professional painter and he said he has seen paint that had become frozen outgas like mine did. I know the VHT paint did not become frozen on my watch, so it was either frozen during shipping to the auto parts store or it reacted to the Akzo primer ... the latter most likely the main issue).  I can tell you the VHT paint blasted off the parts in moments … however getting all the Akzo primer off the parts required a lot of work … Akzo primer really grips well.

Prior to attaching the tail cone to the fuselage, have decided to install some of the flight controls so I can install the roll autopilot servo prior while access is good. The instillation of the flight controls begins with installing the WD-1212 control sticks. Prior to installing the control sticks there is a brass bushing that gets inserted into the pivot point on the control stick that needs to be drilled out to 1/4". The hole in the bushing is just slightly under sized, so not much material is removed by the drill bit.
A control stick bushing clamped in the vice between two V blocks being drilled out to 1/4".

The plans instruct the builder to file down the pivot point tube on WD-1212 control stick so the previously drilled brass bushing sticks out just past the control stick on both sides. Van’s does not give an exact measurement here so I used the digital caliper. The bushings measured 2” so I filed the control stick down to .025" smaller. This will give about .012" clearance on each end … perhaps a little less as the bushing sinks into the powder coating on the control column so it should be a good starting point.
Return from the future: filing down the control stick to .025" smaller than the bushing may have been a little too aggressive. So if doing it again, would suggest starting at .008" smaller. See the next newest posting for more details.
Filing the pivot point on the WD-1212 control stick so the brass bushing will protrude by .025" further.
Looking closely, notice the brass bushing that is inside the WD-1212 control stick’s mounting tube protrudes slightly on either side. Looking at the digital caliper, one can see the tube has been filed down to .025" less than the 2" brass bushing.
Prior to mounting the WD-1212 control stick, the wires were covered with heat shrink at the point of the 180 degree bend and then wire tied in place.

Based on a suggestion from Joe (a builder in Florida) the plan is to attach the fabricated F-1264 pushrod assembly onto the control stick prior to installing it. This makes perfect sense to me because there are two tiny spacers to install … installing the push rods after installing the control stick will significantly add to the difficulty because of working in very tight quarters. This can be totally alleviated by attaching the pushrods now prior to installation while it is so much easier to do so. The rod end bearings or heim joints as they are called are to be installed 9 5/16" from center to center on the fittings. As it turned out, my blue line paper measured that perfectly from the first line to the bottom line. It worked out that each heim joint was screwed in 20 turns to get the measurements correct.
Rod ends attached onto each end of the F-1264 push rods adjusted to a length of 9 5/16" from center to center per the plans.

Although the plans don’t call for it, I placed a little blue Loctite on the last three threads going into the pushrods and also placed some on the lock nuts. Hoping the spacing given in the plans is an exact measurement that will not require tweaking later.
Using a torque wrench to torque the rod end hardware onto the F-1212 control stick.
Finished control stick with F-1264 pushrod assembly attached and ready for instillation.
Installing the WD-1212 control stick with attached F-1264 pushrod assembly onto the WD-1210 control column.

One side down one side to go … I also took the flap handle in for powder coating so hope that that gets finished in the near future because it will be needed very soon to continue on with the instillation of the flight controls.

Monday, December 8, 2014

Instrument Stack Angle & Comm Support Replaced

Sometimes to make forward progress it is necessary to take a step or two backwards. As mentioned in an earlier posting the avionics kit brought both joy and heartache … the F-00054-L&R instrument stack angles and F-00055-L&R comm. support brackets being components of the headache.

Van’s wise decision to switch from the Garmin SL40 radio over to the new Garmin GTR200 radio necessitates installing the new mounting brackets. Unfortunately, the previously riveted in place F-00026-L&R instrument stack angle brackets and F-00027-L&R comm. support brackets needed to have their mounting rivets drilled out so they can be removed. A few days back, Bernie offered a helping  hand by supporting the instrument panel with a block of wood in the area of the rivets while the rivet mandrels were pounded out from below … so that was already done.
Drilling out the mounting rivets for the F-00026-R instrument stack angle.

Once the F-00026 and F-00027 brackets were removed, the new replacement F-00054-L&R instrument stack angles were prepared for instillation. The instructions have the builder machine countersink all the rivet holes that secure the 7 nutplates that attach onto each of the stack angles. After machine countersinking all the nutplate mounting holes, the nutplates were all tested by running a screw lubed with Boelube through them, then riveted onto the F-00054-L&R instrument stack angles.
Using the pneumatic squeezer to rivet nutplates onto the F-00054-L instrument stack angle.

The photo below is a comparison of the new F-00054-L&R stack angles on the bottom left and the removed stack angles are on the bottom right. The new and taller F-00055-L&R comm. support brackets are on the top left and the removed comm. support brackets are on the top right. Also note the much larger lower grommet holes in the new comm. support brackets.
The new brackets for mounting the Garmin GTR200 radio are on the left half of the photo and the removed brackets for the Garmin SL40 mounting are on the right half of the photo.

Installing the four new mounting brackets was uneventful … fortunately the rivets were still easy to get to because the side skins are not on yet ... which allowed for easy access.
Securing the new F-00055-L comm. support bracket in place with Clecos.
Both F-00055-L&R comm. support brackets in the background are now riveted in place and about to rivet the F-00054 –R instrument stack angles onto the instrument panel base.
Both pairs of brackets now riveted in place onto the RV-12’s instrument panel base.

Of note … looking closely at the above photo one can see the lower grommet holes in the F-00055-L&R comm. support brackets are huge compared to the previous brackets.

The other small task that was finished as preparation for the ADS-B antenna install in the tail cone was the drilling of three #30 holes in the lower right side of F-1208 fuselage frame. The holes were drilled 1/4" below the flange of the frame per the instructions. These three holes will be used to secure the ADS-B antenna cable onto the F-1208 fuselage frame with wire ties.

Wednesday, December 3, 2014

Prepping Tail Cone For Mating With Fuselage

In preparation for mating the RV-12’s tail cone onto the fuselage, the two units were moved a little closer so the wires for the ADAHRS would be pulled into position enough to allow the wires to be installed into the DB-9 connector that will plug into the back of the Dynon SV-ADAHRS-200 unit.
Installing the ADAHRS wires into the DB-9 connector that will attach onto the Dynon SV-ADAHRS-200 unit that gets mounted inside the RV-12’s tail cone.

I was about ready to install the plastic shell halves onto the DB-9 connector when it occurred to me the screws and nuts used for mounting are made of steel.  I’m sure it is not a big deal because there are hundreds of flying RV-12’s that have steel screws securing the plastic connector shell onto the ADAHRS unit … but in keeping with the long honored DOG Aviation tradition of making the easy just a little more difficult, decided to replace the steel mounting hardware with brass components. This will even further reduce the amount of steel in the vicinity of the magnetometer inside the ADAHRS unit … which is a good thing.
Steel hardware included with the DB9 connector’s plastic back shell kit.

A trip to the local big box aviation supply store was made and four #4-40 1/2" brass screws were purchased that have a head cut for both a straight screwdriver blade and a Philips screwdriver (I feel the Philips will be much easier to use in this application after the ADAHRS is installed … the original screws only have a straight slot). I discovered the heads on the brass screws were a larger diameter so spent a fair amount of time dressing all the screw heads down on the Scotch-Brite wheel. The heads for the two screws that mount the connector to the ADAHRS unit require more material removed than the two screws securing the back shell halves together. Of course, it was quickly discovered the nuts were also larger … so they needed to be dressed down on the Scotch-Brite wheel as well before they would fit into the molded recesses in the back shell halves.
On the left the replacement brass hardware after being dressed down on the Scotch-Brite wheel for a custom fit to the DB9 connector’s plastic back shell … on the right the original supplied hardware.

While perusing forward through the plans it was realized that holes needed to be drilled into the bottom skin of the tail cone for the ADS-B antenna’s F-00020 antenna doubler plate. The area that needed to be drilled was sitting on top of the workbench so I asked Bernie to swing by the hangar to give me a hand with moving the workbench back about a foot as I held the tail cone in position. After we repositioned the workbench the F-00020 antenna doubler plate was set in position and the holes match drilled into the bottom skin of the tail cone.
Match drilling the F-00020 ADS-B antenna doubler plate into the bottom skin of the RV-12’s tail cone.

After the four corner holes of the F-00020 antenna doubler were drilled and secured with Clecos, the two screw holes for the antenna mounting were drilled to #12. Next the center of the large hole was determined and the bottom skin was drilled out to 9/16" using a step drill.
Completed drilling of the F-00020 ADS-B antenna doubler plate to the bottom skin of the RV-12’s tail cone.

After the drilling was completed the parts were disassembled for deburring. Because the DOG Aviation RV-12 project is utilizing flush rivets in the place of LP4-3 rivets, another extra step of dimpling the four corner holes in the F-00020 ADS-B antenna doubler plate is required. So the four rivet holes in the F-00020 doubler were dimpled to 120 degrees using the pneumatic rivet squeezer. In order to dimple the bottom skin of the tail cone, the 120 degree dimple die set that has a hole in the center for a nail to be used with a hand rivet puller was utilized.  Once again, this was a two person job so Bernie fed the nail holding the male die up from the bottom and I slid the female die in place from inside the tail cone and formed the dimples in the tail cone’s bottom skin with the hand rivet puller.

While Bernie was at the hangar thought it best to also get his assistance in the removal of the four brackets in the instrument panel. Frequent readers of the Blog may remember me being a little miffed that the avionics kit contained two new F-00054-L&R instrument stack angles and two F-00055-L&R comm support brackets which will replace the four brackets already riveted onto the instrument panel base. The new brackets support the radio changeover Van’s has made from the Garmin SL40 to the new Garmin GTR200 radio.

A total of 10 rivets need to be removed … but prior to drilling the rivets out, the rivet mandrels need to be driven out. This step was bothering me because I know you have to pound quite hard to drive a mandrel out of a rivet. The idea of pounding on the panel base while unsupported troubled me … so while Bernie was at the hangar, enlisted his services once again to press down with a block of wood along the edge of the rivets while I drove the mandrels up from below using a hammer and scrap mandrel that had been dressed to a rounded point on the Scotch-Brite wheel.
Bernie pressing down with a block of wood while I’m pounding out the rivet’s mandrel from below.

Now that the rivet mandrels have been removed, the rivets securing the brackets can be drilled out at my leisure in the near future. The new replacement parts have already been primed, so will get them changed out soon so I can move on and have one less thing to worry about.