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.

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.

Successful Installation Of Tosten CS-8 Grips Onto W-1212 Control Sticks

Yes ... It can be done!!!

What’s all the fuss about installing a multi-wire control grip onto the RV-12’s goose neck W-1212 control stick? Just slide the wires through the top of the tubing, pull them out the bottom and move on … right? WRONG!! For starters, the Tosten CS-8 soft touch grips purchased by the DOG Aviation procurement department have a total of ten 22 gauge wires that need to be routed through the control stick. Ultimately, this is akin to stuffing 10 pounds of crap in a 9 pound bag because the RV-12 control stick is not a hollow tube for its entire length … it is segmented twice and has a 90 degree bend at one of the segments. Pictured below is a close-up of the RV-12’s W-1212 control stick. On the left, the viewer can see where the lower portion of the goose neck makes a 90 degree bend … at this location the viewer can also see the outer edges of a metal gusset plate that dissects the control stick, creating two inner chambers. To the right, the 90 degree transition is immediately followed by a tubular weldment which also dissects the W-1212 control stick creating two more chambers (small ones) … this tubular weldment becomes the mounting and pivot point for the control stick. It is at this location where the inside clearances are at a minimum … there is just barely enough room for five 22 gauge wires to slip by on either side of the tubular weldment.

Close-up of the RV-12’s W-1212 control stick … both the weldments being pointed to dissect the tubing … thus creating two chambers inside the control stick at each weldment location which the Tosten CS-8 grip wires must be routed through.

The chambers created inside the RV-12 control stick by the internal gusset and tubular pivot point weldment, coupled with the 90 degree bend, creates quite a challenge for installing wires. As mentioned in a previous post, planning ahead, the DOG Aviation procurement department asked Kevin at Tosten to create two custom CS-8 soft touch grips for the DOG Aviation RV-12. Both grips are provisioned with much longer wires … 3 1/2 foot long (and frankly feel that is still six inches too short but will work nonetheless) and Kevin grouped the wires into two bundles of 5 wires each. One bundle contains the four way hat switch wires, the other is for the remaining switches on the grip. A special request was made of Kevin to also include a 6' + piece of wire sleeve … which Kevin kindly provided as well.

The plan: Use the wire sleeve as a sort of “Chinese finger” to pull the two bundles of wire through the inner chambers of the W-1212 control stick.  Below is a detailed synopsis of the steps utilized to successfully route all the wires through the W-1212 control stick.  The following worked well for me – YMMV.

First, having access to Mike’s fiber optic camera, thought it prudent to have a look inside the control stick for weld goobers and sharp burrs. The camera showed no evidence of anything that would impede pulling wires through the stick other than the total lack of room at the tubular weldment. Thanks Mike.

The multi-step process began by feeding in a thin waxed cord from the bottom of the W-1212 control stick to the 90 degree bend … (making quite sure it did not cross chambers). Then a vacuum cleaner was used to suck the cord the rest of the way through the control stick. The waxed cord (purchased from an arts and crafts shop) is a smaller diameter version of the old style cable lashing waxed cord used before wire ties. The waxed cord was tied off taut with electrical tape to reduce the likelihood of the second cord becoming entangled with it. The process was repeated for passing another waxed cord through the remaining chambers on the opposite side of the control stick.

My apologies for the poor quality of most of the following photos ... forgot to bring the good camera home from the hangar.

Using a portable vacuum cleaner to suck the waxed cord through the W-1212 control stick.

Waxed cord after being pulled through chambers inside the W-1212 control stick .. one down one to go.

Next the waxed cords were tied onto the ends of the extra wire sleeve I requested Kevin at Tosten send me. The ends of the wire sleeves were pulled into the W-1212 control stick from the bottom forming a U. (Felt it was easier to leave the sleeve as one long 6 foot + piece rather than cutting it up).

The ends of the long wire sleeve successfully pulled up through the W-1212 control stick using the waxed cords.

Unfortunately, the heat shrink that Kevin placed over the end of each bundle of five wires to dress out the wire sleeve seemingly make the bundle too thick to pass through the close quarters created by the tubular thru weldment … so the heat shrink was removed and replaced with a VERY TIGHT single wrap of electrical tape … you need to keep it as thin as possible here. This also aids the bundle of five wires with the wire sleve covering to easily slide inside the extra wire sleeve being used as a sort of combination “Chinese finger”/pull rope without fraying or bunching up while being inserted into the second wire sleeve. The wire bundles were inserted about 5 or 6 inches into the “Chinese finger”/pull rope. Of note: After removing the heat shrink on the end of each wire bundle the wires were worked as flat as possible with my fingers and then the existing wire sleeve covering the wire bundle was pulled down as tight as possible over the wires then secured with a very tight wrap of electrical tape.

The heat shrink seen here on the ends of the two wire bundles needs to be removed and temporarily replaced with a very tight wrap of electrical tape after the length of the wire bundles are worked as tight and flat as possible with the fingers and the wire sleeve pulled down as tight as possible.

To aid in pushing the wires into the control stick later, the Tosten provided bushing was slid up the wires and onto the shaft coming out of the CS-8 grip and the distance from the stick bushing to the gusset at the 90 degree bend was measured. The wires were then wrapped with electrical tape from the grip to just about an inch or so shy of where the internal gusset is welded inside the stick (this is where the wire bundles need to split into separate chambers then immediately make the 90 degree bend).

The Tosten provided bushing was slid up the wires onto the shaft of the CS-8 grip and the assembly was placed over the W-1212 control stick so measurements could be made from the point the wires come out of the grip to the internal gusset my finger is pointing to. The wires between these two points were wrapped in electrical tape to stiffen the wires a little so they can be pushed into the tubing easier.

The first bundle of five wires was slid into the “Chinese finger”/pull rope sleeve for about 5 inches or so … the “Chinese finger”/pull rope sleeve was then pulled down tightly over the wire bundle and secured with a VERY TIGHT wrap of electrical tape to the wire bundle.

The “Chinese finger”/pull rope sleeve slid over the bundle of five wires for about 5 inches or so and now ready to have the end wrapped with a VERY TIGHT thin wrap of electrical tape.

Next, while feeding the bundle of five wires into the top of the W-1212 control stick, the additional wire sleeve Kevin at Tosten provided was used as a sort of “Chinese finger”/pull rope to guide the wires through the inner chambers of the W-1212 control stick and out through the bottom. I stopped pulling as first bundle of wires were even with the bottom of the control stick. This should occur prior to the outer piece of electrical tape reaching the tight spot.

First bundle of 5 wires successfully pulled through the W-1212 control stick.

Close-up of where the wires were initially pulled to before moving on to the second bundle of wires.

The process was then repeated for the remaining bundle of five wires. After both of the wire bundles were successfully pulled through the control stick, the remaining length of wire from the grip was then worked down into the control stick while pulling on the ends coming out the bottom of the control stick. It is really a tight fit but the wires will pull through. The outer wrap of electrical tape will snag but the wires should already be through the control stick at this point … so just keep simultaneously pushing from the top and pulling from the bottom. Luckily, after binding a bit, both pieces of electrical tape eventually came out for me with the wire bundles. But if they don’t, it is not a big deal  …. at least the wires will be through the control stick.

The wires for the Tosten CS-8 grips almost completely pulled into place through the W-1212 control stick.

First W-1212 control stick now outfitted with a Tosten CS-8 soft touch grip.

Gee, this was just so much fun … let’s do it all over again for the second W-1212 control stick!

Completed instillation of Tosten CS-8 soft touch grips on both of the RV-12’s W-1212 control sticks.

The Tosten CS-8 soft grips are coated with the same soft coating used on some cell phones and other hand held electronic devices. The coating provides a nice feel to an already very hand friendly and truly comfortable grip.

Thanks again to Kevin at Tosten for the willingness to modify his CS-8 soft touch grips for the DOG Aviation RV-12 and also for providing the extra wire sleeve which proved to be instrumental getting all 10 wires routed through the RV-12’s control stick. I’ll say it again Kevin provides wonderful customer service!

Adapting The RV-12’s Control Sticks For Tosten Grips

I was hopeful the temporary bounce in temperature a couple of days ago would offer a good day for priming all the brackets that came in the avionics kit. In recent days, all the parts were totally deburred and readied for a final quick scuffing with Scotch-Brite and Acetone cleaning. Unfortunately, the warm weather was accompanied by 30 MPH plus winds making airbrushing the parts totally out of the question … so attention was diverted back to the control sticks.

Based on the test fit of the Tosten CS-8 grips while sitting in “The Perch” last week, 2 1/4" was cut off each W-1212 control stick using a hack saw. Fellow builders be forewarned … doing this will require quite a bit of filing to custom fit the Tosten CS-8 bushings to the control stick. This is because the bushings are being inserted into the beginning of the transition of the goose neck bend … felt it desirable to get the Tosten grips as low as possible which still leaves them about an inch or so higher than the standard bicycle grip would be. As such, the tubing is no longer perfectly round at this point, so the bushings require a lot of tweaking to get them to fit correctly.  Basically, the Scotch-Brite wheel was used until the lower half of the bushing could be inserted into the control stick. From there on, a nut, bolt and washers were used so the bushing could be removed after pushing it into the tubing enough to put score marks onto the soft aluminum of the bushing. Then the areas of the bushings that showed scuffing were filed a little with a jewelers file … then the process repeated until the bushing went all the way into the control stick.

W-1212 control stick on left after cutting 2 1/4" off to accommodate the Tosten CS-8 stick grips. A bolt, nut and washers made it easy to remove the bushing during many trial fittings.

Saving the fingers during one of the many – many - many insertions and removals by popping the bushing out of the control stick using a clothes pin to pull up on the washer.

Once the bushings were fitting nicely in the W-1212 control sticks, the sticks and bushings were marked so they stay as a matched set. Next a #12 hole for the locking screw needed to be drilled into the forward side of the control stick. The #12 hole is centered 1/2" below the shoulder on the bushing. I used an interesting method to drill the bushing as can be seen on the following photo … don’t recommend this, but it did work.

Progressively drilling the W-1212 control stick to a final size of #12 for the set screw that locks the Tosten CS-8 grips onto the control stick.

Both W-1212 control sticks cut shorter and bushings fitted … now ready for the Tosten CS-8 stick grips.

Checking Out The View From “The Perch”

Every builder has the moment … sitting in the cockpit for the first time, the control stick firmly ensconced in hand, hearing yourself involuntarily making airplane noises. It is a momentous moment … somewhat a right of passage.  Prior to climbing into the cockpit for the first time, the Flightline Interiors box was opened and a seat bottom and back were removed and taken to the hangar to pad “The Perch” for a trial fit.

Checking out the view from “The Perch” for the first time … have to say, the seat in the eagle seems plenty comfy.

The main reason for getting into the cockpit was to get a feel for the position of the Tosten grips purchased at Oshkosh. Because the Tosten grips do not slip down over the control stick, the height of the stick needs to be cut shorter. Because of the unique gooseneck design of the RV-12’s control stick (compared to other RV models) the stick can only be shortened to just above where the bend begins. This is because there is a collar that inserts into the stick to secure the Tosten grip to the control stick. Unfortunately, it will leave the stick a least an inch or so higher than would be ideal for me, but it should be just fine. These grips are really comfortable and designed so either hand can grip them … so even though they will not end up quite as low as I feel ideal, their overall comfort should win out. They simply feel good in the hand.

After purchasing the grips at Oshkosh from Kevin (the owner of Tosten), it was quickly realized that the length of wiring coming out of the grips was not what I would consider long enough for the RV-12. A call to Kevin was made requesting that the wires be made longer. Kevin said he was planning on making the wires longer in future production runs because there are now quite a few gooseneck stick designs these days. In addition, I requested Kevin split the bundle of wires after they leave the stick into two separate bundles of five wires … as opposed to all ten wires in one large bundle. One bundle is for the four way hat switch and the other bundle is for the stick’s other four switches. Each grouping of switches has a common ground wire which is why there are a total of ten wires. The grips were sent back to Tostin in California and Kevin returned a pair of grips with longer wires and the wires were split into two bundles as requested for no additional charge.  I offered to pay for time and materials, but there was no charge … great customer service. Thanks Kevin.

The modified Tosten CS-8 grip with longer wires and two separate wire bundles.

Looking at the above photo, the viewer can easily see the challenge and possibly dilemma of trying to get all those wires fished down through the gooseneck, then make the radical 90 degree and then past either side of the tube weldment dissecting the center of the tubing (which is the pivot point for the control stick). The wires will need to take two paths on either side of the weldment because there just is not enough room otherwise … and still may not be.  I think I have figured out a way to get this done without drilling an exit hole, but will work on it over the next couple of weeks.

Preparing Avionics Kit Parts For Primer

The RV-12’s avionics kit has a handful of parts which require either being separated on the band saw or have areas on the part which require being removed. Yesterday afternoon decided to get at it and separate the parts on the band saw and remove material from the areas requiring trimming.

Using the band saw to separate the F-00045B-L&R mounting brackets.

Noticed there were a few pieces in the avionics kit that were duplicates of pieces included with the fuselage kit such as the protective pieces used to cover the wire run in the center channel, along with parts for under the flap handle and flaperon mixer assemblies. Van’s must be including them now with the avionics kit … which makes sense because they are not needed until the all the wiring is completed. Also included was the ADAHRS stiffener rib modification released by Van’s earlier in the year which goes in the tail cone … I purchased this modification when it was first released by Van’s not knowing they were planning on including it in the avionics kit. So it looks like I have an extra ADAHRS stiffener rib to pass onto a builder who’s completed assembling the RV-12 prior to the ADAHRS stiffener rib being available.

The avionics kit pieces which required either separating or had areas where material needed to be trimmed away.

Having the band saw work out of the way, all of the metal pieces that will be primed were then hand filed to remove the big burrs and smooth out the nooks & crannies. The Scotch-Brite wheel will add the finishing touches to smooth the edges of the pieces.

It is forecasted to get into the 40’s for a couple of days after we get through this entire week of cold ... so hoping the weather cooperates and a priming session can take place outside and the painted parts can be moved inside into the heated drying box to cure.

Avionics Kit Brings Pain - In The Form Of Redo

Having the RV-12’s avionics kit inventory out of the way, decided it would be a good strategy to work on the handful of metal brackets and mounting plates now. These parts need to be primed at some point and in a couple of cases, sprayed with the JetFlex interior paint. That being the case, feel it best to take those parts out of the box and up to the hangar to  deburr the edges of the parts.  The strategy being … if the temperatures bump up at some point in the next few weeks, the parts will be ready for a quick priming session with the airbrush.

The assorted small brackets and mounting plates in the avionics kit which need to be deburred and primed.

After looking at the new parts, it became very apparent there has been a change to the way the instrument panel components are attached. Four of the mounting brackets looked much the same as the four brackets already riveted onto the instrument panel base. The four new parts consist of the F-1200054-L&R  stack angles and the F-1200055-L&R comm supports … these parts apparently replace the already installed F-00026-L&R instrument stack angles and F-00027-L&R comm supports.

The avionics kit’s new F-1200054-L&R instrument stack angles and F-1200055-L&R comm supports.

So it appears some pop rivets need to be drilled out and old parts removed so the new pieces can be installed. I have not read forward in the plans yet, but the part numbers are not the same for the parts in question ... therefore, at this point, I’m inclined to think the new pieces must replace the parts currently installed. If this not the case, I will return from the future and edit this post accordingly.

Photo of the primed F-00026-L&R instrument stack angles and F-00027-L&R comm supports that will require having their mounting rivets drilled out so they can be removed.

Another discovery which truly sucks is the mounting location of the F-1205G ELT antenna mounting bracket. Van’s has the builder mount this bracket on the already riveted in place F-1205 A&C mid fuselage brace components. Here again this will require drilling out 3 rivets so the mounting bracket can be installed. Unfortunately, this is a painted part so a lot of extra care will be needed to keep the paint in good shape. I went back and looked at section 23-3 step 4 in the plans and there is no mention of leaving the three rivet holes associated with the ELT mounting bracket open. RV-12 builders note: When riveting the F-1205A&C parts together which make up the mid fuselage brace, do yourself a favor and leave the three rivet holes open that are adjacent to the holes in the ELT antenna mounting bracket pictured below.

Mounting location for the F-1205G ELT antenna mounting bracket … the mid fuselage brace rivets adjacent to the holes in the mounting bracket will need to be drilled out.

Fortunately, all the rivets that need to be drilled out are pop rivets and not solid rivets so it should not be that bad of a job ... but a pain nonetheless.