Aft Autopilot Servo Brackets Installed

Rather than sit around and wait for the replacement F-1236 step attach angles to arrive decided to forge ahead and complete as many tasks as possible that are not dependent on the F-1236 attach angles being installed.

The four F-1251 nutplate brackets receive one 1/4” nutplate each and will eventually be match drilled and riveted onto the F-1236 step angles.  Decided there was no reason the nutplates couldn’t be attached at this time, so they were riveted onto the F-1251 brackets.

Riveting nutplates onto one of the four F-1251 nutplate brackets.

Looking for more to do, the F-1213-L&R step floors required having 4 nutplates riveted onto each floor panel. All the nutplates required dimpling and once that was accomplished, the nutplates were riveted in place onto the F-1213 step floors.

Using the pneumatic squeezer to rivet nutplates onto the F-1213-L step floor.

The last two components worked on during today’s shop session was the F-1207B baggage bulkhead and the autopilot servo brackets. The F-1207B bulkhead receives four nutplates which must also be dimpled prior to instillation onto it.

Using the pneumatic squeezer to rivet nutplates onto the F-1207B baggage bulkhead.

Before riveting the F-1207B baggage bulkhead in place, the plans have the builder take a diversion to section 39 if the auto pilot option is being installed, as it is in my case. In section 39, the F-1286A-L&R servo brackets and F-1286B-L&R servo angles which make up the autopilot servo mounting and are riveted onto the F-1207B baggage bulkhead and F-1206 baggage ribs.

Securing the F-1286A-R autopilot servo bracket onto the F-1207B baggage bulkhead with Clecos.

Access was good for using the pneumatic squeezer through the lightening holes, so all the rivets used to install the servo brackets onto the F-1207B bulkhead were AN470AD4-4.5 solid rivets in place of LP4-3 pop rivets. An AN470AD4-4 rivet was used on the one remaining bottom F-1207B bulkhead rivet.

Riveting the F-1286A-L autopilot servo bracket onto the F-1207B baggage bulkhead with AN470AD4-4.5 solid rivets in place of LP4-3 pop rivets.

The access was also good for riveting the F-1286B servo angles onto the F-1286A brackets using AN470AD4-4 rivets.

Riveting the F-1286B servo angles onto the F-1286A servo brackets using AN470AD4-4 solid rivets in place of LP4-3 pop rivets.

Completed autopilot servo bracket instillation onto the F-1207B baggage bulkhead and F-1206 baggage ribs using all solid rivets in place of LP4-3 pop rivets.

Oops – Read Twice, Cut Once

Well, for the second time during the RV-12 construction, a replacement part is needed due to a faux pas on my part.  During the hasty push to move forward and prep all the fuselage parts for primer and paint before the long talons of winter gripped DOG Aviation, a mistake was made cutting the F-1236 step angles.

The four F-1236 step angles come as one long piece of angle and require being separated into four parts … two of which become F-1236A and two become F-1236B after trimming one of the edges back. The instructions call for trimming TWO of the angles to make the side with no holes 1”wide. The trimming is ONLY done to two of the angles NOT four as I apparently had done in my haste to beat the winter weather. Fortunately, the error was caught before riveting the parts in place.

Error of my ways highlighted in yellow …. read twice, cut once. The undrilled side should be at least 1/8" or so wider Duh!

The angles are used to help distribute the load created when stepping up on the steps that extend out from the side of the fuselage. The angles create a bridge between the bulkhead and step ribs for support and are a mounting point for 1/4 inch nutplates used to mount the fuselage steps onto the fuselage.  There is quite a bit of match drilling to be done so moving on with assembly would not be a good idea. Van’s is not open until the Monday after the Thanksgiving weekend so will have to wait until the later part of next week before the fuselage can grow more. Fortunately, it is a small part and only $10 to replace. In the mean while, there are still things that can be done while waiting for the replacement part, quite a few parts require platenuts installed, the autopilot servo brackets on the aft end of the baggage bulkhead could be installed (even the servo motors for that matter) and perhaps some of the tubing for the fuel system.

Riveting Of Fuselage Bottom Skin Completed

Due to Hoiday preparations and getting the snow blower ready for the season’s first major snow storm, the last couple of work sessions in the DOG Aviation production facility have been abbreviated. The riveting of the RV-12’s F-1276 fuselage bottom skin continued as planned. All the rivet holes aligned nicely … so apparently having the fuselage on its side as opposed to being upside down on saw horses did not create any adverse issues.

Continuing with the riveting of the F-1276 bottom skin onto the fuselage skeleton.

 

For being a relatively small structure, there sure are a whole lot of rivets set into the F-1276 fuselage skin. Every rivet set into the bottom skin was a flush pop rivet as opposed to the low profile dome shaped LP4-3 pop rivets.

Setting a flush pop rivet into the F-1276 fuselage bottom skin with the pneumatic rivet puller … only a few more rivets to set and the bottom skin riveting will be completed.

Because of the way the fuselage was on its side, decided it best to first rivet the majority of the bottom skin in place prior to riveting the F-1274L corner skin. Prior to setting rivets in the rivet holes common to both the F-1276 bottom skin and F-1274L corner skin, the alignment was rechecked and then the parts were riveted together. After that, the rivets common to the F-1274L corner skin and the tabs on the F-1275A skin were riveted together. Because the fuselage was on its side, to gain access to the F-1274R corner skin’s rivet holes, the forward portion of the fuselage was slid over the edge of the bench and the same procedure was followed for the F-1274R corner skin that was used on the left corner skin.

To casual observers of the Blog, the following two photos may look like ones posted last week … and they are, but now the fuselage assembly has a bottom skin attached.

Aft view of the fuselage assembly with bottom skin riveted in place.

Forward view of the fuselage assembly with newly attached bottom skin riveted in place.

Fuselage Bottom Skin Riveting Begins

Only had time again for another abbreviated work session yesterday, so went to work on knocking out the center section riveting. Riveting of the F-1276 fuselage bottom skin, F-1268 doublers and F-1204Z stiffeners began after checking and rechecking the plans to identify rivet holes not to be riveted at this time.

The game plan for riveting the F-1276 fuselage bottom skin is to start at the midway point of the center channel forward and aft bulkheads and begin riveting the F-1276 skin onto the fuselage skeleton. Riveting alternated between the center channel’s forward and aft bulkheads … while also alternately working towards the outer edges of the F-1276 fuselage bottom skin. All of the rivets that will be set into the bottom skin will be the flush pop rivets being used on the RV-12 project as opposed to LP4-3 dome head rivets.

Using the pneumatic rivet puller to set the first flush rivet into the F-1276 bottom skin. Riveting began at the center section bulkheads starting at a midway point on the center channel.

Setting the last rivet of the work session into the F-1268D doubler using the pneumatic rivet puller.

Suspect the remaining riveting of the bottom skin will go much quicker because the rivets are spaced out much more than they are in the center section area. During the next riveting session plan on continuing the same approach … riveting from the center towards the outer edges.

F-1204Z Stiffeners & F-1268E Doublers Added

Yesterday’s session in the shop was brief, but fruitful. With the F-1276 fuselage bottom skin now attached onto the fuselage’s skeleton, a few more parts needed to be added prior to beginning riveting of the bottom skin. There are six L shaped F-1204Z stiffeners that bridge between the forward and aft center channel bulkheads … they are attached onto the F-1276 fuselage bottom skin from inside the fuselage by reaching through the inspection holes to position the stiffeners.

A small portion of one of the six L shaped F-1204Z Stiffeners can be seen by looking through the inspection holes.  The line of six Clecos below the inspection hole secures the F-1204Z stiffener in position for riveting.

The ten F-1268 A thru E doublers are somewhat thick metal plates attached onto the outside of the F-1276 fuselage bottom skin. They tie the fuselage’s ribs, center channel bulkheads and bottom skin together. The rivet holes in the F-1268 doublers were previously machine countersunk for the flush rivets being used on the RV-12 project. Subsequently, the underlying rivet holes were not dimpled in the F-1276 skin, center channel bulkheads, baggage or fuselage’s ribs. Of course, this took a little bit of time to figure out a few months ago … but the parts fit together perfectly without a screwup on my part, so all the advanced planning paid off.

 Placing Clecos into one of the F-1268 doublers.

Because the fuselage assembly is lying on its side, as opposed to upside down, decided it would be a good idea to spot check the parts alignment and after a few minor tweaks, all the rivet holes in every bulkhead received a Cleco ensuring the F-1276 bottom skin is in good alignment with the main structural components of the fuselage. In addition, the left and right F-1274 fuselage corner skins were placed in position and secured with Clecos for riveting.

W-1276 fuselage bottom skin in position along with F-1268 doublers, F-1204Z stiffeners and F-1274 corner skins ... all ready for riveting. Clecos were placed in all the bulkhead rivet holes to ensure good alignment.

Quite a few holes are to remain unriveted at this point in time, so they will be identified and marked during the next shop session and then the riveting of the bottom of the fuselage can begin.

F-1276 Bottom Skin Ready For Riveting

Horizontal space in the shop is at a premium … so to facilitate the removal of the blue protective film from the bottom skin’s rivet lines, the bottom skin was temporally hung from the fuselage while it was on its side.

Removing the blue film from the rivet lines on the F-1276 fuselage bottom skin.

There are six corner skins per side which require being riveted onto the fuselage prior to installing the bottom skin. Van’s suggests the builder turn the fuselage upside down on a pair of saw horses to install the side skins and fuselage bottom skin. Frankly, there is no room in the shop for two saw horses and the temps outside are in the high teens, so moving the fuselage outside is NOT happening.

Because the fuselage seemingly balances fairly well on its side, decided to move forward and see if the riveting of the corner skins and bottom skin could be done while the fuselage was on its side. After all, the holes are all predrilled … and now dimpled, so the parts will either align well … or not. Mike suggested a contingency plan that seemingly would work well too. Mike’s suggestion was placing four 5 gallon buckets on the workbench, cover them with padding or towels and turn the fuselage upside down and rest it on the buckets if need be. Being fearful of the possibility of marring the interior paint … ultimately opted to first try keeping the fuselage on its side and see if that would work.

The twelve F-1275 corner skins are lettered A thru F and come in both a left and right version. The corner skins create the transition between the side skins and the fuselage’s bottom skin.  After being secured with Clecos the corner skins are only riveted to each other, the F-1204P and F-1203B attach flanges. The edges where the bottom skin and side skin attach are not riveted at this time.

Right side’s F-1275A-F corner skins Clecoed and ready to be riveted to one another. Doing a last minute blue film removal from the F-1275A corner skin’s rivet line.

Riveting the fuselage’s right side F-1275A-F corner skins to one another.

After the fuselage’s right corner skins were riveted onto each other, the fuselage assembly was turned around and placed on its opposite side so the left side’s F-1275A-F corner skins could be installed in similar fashion.

Just finished with the riveting of the left side F-1275A-F corner skins to one another. Mike’s small platform ladder proved to be a great help performing this task.

Before attempting to mate the F-1276 fuselage bottom skin onto the fuselage’s skeleton, the edges of the bottom skin adjacent to where the blue film was removed were smoothed with a few strokes of a 3M foam sanding pad. While I was dimpling the 40 nutplate rivet holes around the five inspection ports with the pneumatic squeezer, Mike jumped in and tested and dimpled the 20 K1000-08 nutplates that needed to be riveted onto the inspection ports on the bottom skin. The 20 nutplates were then riveted in place onto the F-1276 bottom skin.

The bottom skin was now ready for mating with the fuselage’s skeleton. An initial worry about obtaining proper rivet hole alignment because the fuselage was on its side quickly faded after a hand full of Clecos were installed at strategic locations and the fuselage skeleton began aligning perfectly with the rivet holes in the bottom skin.

Placing Clecos into the F-1276 fuselage bottom skin securing it onto the fuselage’s skeleton for final riveting.

A nail set was used to ensure good alignment … the taper is such that with the skin and ribs being dimpled, if the nail set was held centered in a rivet hole, the adjacent rivet hole was almost assuredly aligned for Cleco placement.

The F-1276 fuselage bottom is now ready to receive a few stiffeners and doubler plates but decided to call it quits for the evening and will attach the stiffeners and doubler plates during the next work session along with adding more Clecos to the structure.

The New WD-1210 Control Column Installed

Yesterday was a Pro-Seal day. Those of you in the know are familiar with the ramifications of that statement. Fortunately, having helped Pete work with Pro-Seal on his RV9A proved very useful … in that, I knew what to expect and how to make the process go smoother. For those of you not familiar with Pro-Seal, the product is used to seal fuel tanks and is used on aircraft much the same as silicone would be used to fill gaps or make a gasket. It is an epoxy type of product that has a catalyst agent mixed into it to set off the curing process. Pro-Seal is thick … gooey … goopy … sticky … stringy … and tenacious. Get one drop of it on your gloves and it will quickly spread to every tool you touch in the immediate work area. Get it on your clothes and it will be there ten years later. Paper towels shred when trying to wipe it up … suggest shop towels or rags for easier cleanup.

Sadly, I did not take any photos of using Pro-Seal … frankly, I did not want my camera in the same room with it. I’m making it sound far worse than it really is … but the point is, Pro-Seal is messy, very messy. But if you want to make a flexible seal on an aircraft, there is no better product than Pro-Seal … and unlike silicone, it is paintable.

Mike had the morning free and offered to lend assistance, so before the Pro-Seal was mixed, we cleared off the work area, got tools ready and laid down paper to protect adjacent surfaces. Mike scuffed the upper flange of the F-1201C firewall and the bottom of the F-1201B firewall shelf with a Scotch-Brite pad and cleaned the parts with Acetone. The Pro-Seal was then mixed and a thin layer was spread on the upper flange of the F-1201C firewall and the bottom edge of the F-1201B firewall shelf that will be riveted onto the F-1201C bottom firewall. After the spreading of a thin coat on both surfaces was completed, the pieces were mated and secured with Clecos. The Pro-Seal coated parts were then riveted together. There are two rivet holes which need to be left open at this time which can be seen in the photo below with blue tape on the Clecos closest to me.

After the Pro-Seal cleanup, the finishing touches to the F-1201B firewall shelf consisted of riveting it onto the top flanges of the F-1217A tunnel ribs. The two Clecos with blue tape closest to me are to be left open for the oil tank mounting bracket - later in the build.

Once the F-1201B&C firewall parts were riveted together and the Pro-Seal cleaned up, the FF-1204D firewall stiffener was Clecoed in place and riveted onto the right side of the F-1201C firewall.

Mike using the pneumatic rivet puller to install the FF-1204D firewall stiffener onto the F-1201C firewall.

The last item in section 22 that could be worked on at this point in time is the VA-188 Flo-Scan mounting bracket. This is a bracket that will hold a device that measures the RV-12’s fuel flow and reports the results to the Skyview for display on the screen. The mounting plate has two sets of nutplate mounting holes … the model of the Flo-Scan shipped with the kit dictates which pair of holes will receive the nutplates.

Riveting nutplates onto the VA-188 Flo-Scan bracket.

Because the VA-188 Flo-Scan bracket installs onto the bottom of the fuselage, the bracket was dimpled earlier prior to priming for the flush rivets being used on the RV-12 project. The VA-188 bracket was secured in place with Clecos and then riveted with flush 120 degree pop rivets in place of LP4-3 pop rivets.

VA-188 Flo-Scan bracket secured with Clecos on the F-1272 forward fuselage floor.

Riveting the VA-188 Flo-Scan bracket in place using flush pop rivets in place of LP4-3 pop rivets.

The next instruction in section 22 of the plans instructs the builder to mate the forward firewall assembly with the main fuselage assembly which can’t be done at this point in time because of the assembly diversion created by the WD-1210-PC’s miss aligned holes and subsequent wait for the replacement part.

Fortunately, the replacement WD-1210-PC control column has been received from Van’s so work can resume on the fuselage assembly. The powder coating was removed from inside the bolt holes and must say, the replacement unit looks far better than the old unit. The bolt holes align much better. I took a photo and one can easily see the bolt holes align far better than the holes did on the original unit. This one is far superior … the welds look much better as well.

Compared to the photo posted last week, the holes in this WD-1210-PC control column are aligned much more to my satisfaction.

The WD-1210-PC control column was fished into position and secured with the AN3 mounting hardware. Rather than fight gravity, I left the fuselage assembly on its side and the inner washers that go between the mounting tabs on the control column and the bearing were a piece of cake to install that way. Took 7 minutes tops to install the hardware … never dropped a single washer.  Builders usually have quite a fight installing the washers.

WD-1210-PC control column in position and ready for the instillation of four washers - two spacer washers to be placed above and two below the control mount bearing. Having the fuselage in its side made this task a piece of cake.

The typical torque range for AN3 hardware is 20 to 25 inch pounds. However, if the nut is a platenut or stop nut they offer a resistance which must be compensated for to acheive the desired torque. The nylon stop nuts used offered approximately 7 inch pounds of resistance. I desired a final mid range torque value of 23 inch pounds so set the torque wrench to 30 inch pounds and tightened the hardware until the torque wrench clicked. After the torquing of the mounting hardware was completed, yellow torque seal was placed onto the nuts to aid in spotting movement during subsequent inspections.

Using a torque wrench to tighten the AN3 mounting hardware to 30 inch pounds … 23 lbs desired plus 7 lbs for the internal resistance of the stop nut.

Finished WD-1210-PC control column instillation … note the yellow torque seal on stop nuts.

Now that the WD-1210-PC control column installation has been completed, work can now resume on completing section 21 of the plans.
 

 

Firewall Shelf Readied For Install

A fair amount was accomplished yesterday beginning with riveting the F1288 cooler stiffener onto the F-1201C firewall. Access was good for the pneumatic squeezer so the stiffener and three associated nutplates were riveted in place using solid rivets as opposed to pop rivets.

Riveting the F-1288 cooler stiffener onto the F-1201C firewall using AN470 and AN426 rivets in place of pop rivets.

The forward fuselage assembly receives quite a few nutplates … seven are riveted onto the forward flange of the firewall and an additional six nutplates are riveted through the F-1272 forward fuselage skin which will become part of the nose gear mounting.

Using the pneumatic squeezer to attach nutplates onto the forward flange of the F-1201C firewall.

Using the hand rivet puller to rivet nutplates using the #40 flush rivets Van’s supplies.

After all the nutplates were riveted in place, the F-12118 cowl attach plates and F-1201U spacers were match drilled to the forward flange of the F-1201C firewall. Before drilling, a centerline is drawn on the spacers so they can be centered on the holes in the F-1201C firewall’s forward flange. The F-1201U spacers are then sandwiched between the firewall’s flanges and the W-12118 cowl attach plates. The assembly was match drilled, deburred, dimpled and then riveted onto the firewall’s forward flange. AN426 flush solid rivets were used in place of the AN470 dome headed rivets normally used here. After riveting is completed, two nutplates are attached to both cowl mounting tabs.

Match drilling the F-12118 cowl attach plates and F-1201U spacers (hidden) to the existing rivet holes on the forward flange of the F-1201C firewall.

Mike helping to hold the forward lower fuselage assembly while I use the pneumatic squeezer to set AN426AD4 flush solid rivets into the F-12118 cowl attach plates. This location would normally be receiving a dome headed AN470AD4 rivet.

Nutplates and F-12118 cowl attach plates riveted in place on the forward flange of the F-1201C firewall.

Next, preparations began on the F-1201B firewall shelf so it can be added to the forward lower fuselage assembly. The shelf was deburred then dimpled for nutplates. The F-1201B shelf receives four F-1257 rudder pedal support channels and a ten nutplates of assorted sizes.

Securing the F-1257 support channels onto the F-1201B firewall shelf with Clecos.

Riveting one of the various sized nutplates onto the F-1201B shelf with the pneumatic squeezer.

The finished firewall shelf assembly requires a coating of Pro-Seal just prior to riveting. The Pro-Seal is used to make a permanent seal on the firewall parts and creates a seal between the engine compartment and cockpit. Figured that was a good stoping point for this shop session.

Finished F-1201B shelf assembly ready for Pro-Seal and riveting onto the forward lower fuselage assembly.

Forward Lower Fuselage Assembly Riveted

Today was one of those days where nothing went as planned … a late start in the shop coupled with one step forward, two steps back progress all afternoon equated to not much progress.

Yesterday, the forward lower fuselage assembly was secured with Clecos and ready for riveting … or so it was thought. Today, that all changed. For some reason, felt hesitant about riveting the parts together … something didn’t feel right. The plans were looked at a couple of times and finally discovered the small issue that was subconsciously bothering me. There are two tabs of metal that will be riveted onto the bottom of the firewall for the cowling to attach onto. The plans call for AN470 (domed heads) rivets … I want the rivets to be flush, so want to use AN426 (flat head) rivets. So the rivet holes in all the parts at those locations needed dimpling … and the dimples needed to be 100 degrees and not the 120 degrees used for the flush pop rivets.

The three holes marked in red are riveted later (same applies to the right side) when the cowling mounts are installed … but since I’m going with flush solid rivets here, they were dimpled with a #30 100 degree dimple dies. Looking closely at the photo one can see the difference in the angle compared to adjacent 120 degree dimples.

All the Clecos holding the whole assembly together needed to be removed so the six rivet holes in all the parts could be dimpled to the correct angle for the solid flush rivets. After dimpling the six holes and reassembling the parts with Clecos, it was discovered the blue film was left on along the rivet lines. So once again the fuselage side skins were removed from the assembly and a soldering was used to remove the blue film from long the rivet lines. The parts were Clecoed back together … but then discovered I forgot to deburr  the edges where the blue film was removed  … so the Clecos were removed YET AGAIN and the edges were smoothed with one of the foam 3M sanding blocks. Note: When parts are deburred with the 3M ScotchBrite wheel and the blue protective film is left on during deburring, the part will tend to get a rough edge adjacent to the blue film. After the film is pealed away, a quick swipe or two with the 3M foam sanding pad smoothes the part quickly.

Placing Clecos in the F-1271-R fuselage corner skin for the third time today!

Using the pneumatic rivet puller to rivet the F-1201C firewall onto the F-1217A-R tunnel rib.

Riveting the F-1271-L corner skin onto the F-1201C firewall.

Forward lower fuselage assembly riveted together ... finally!