Instillation Of Throttle And Choke Cables Begins

Van’s instructs the builder to install the Mc Farlane Vernier-Assist  throttle cables first, feeding them through the grommet on the firewall and then through an Adel clamp installed on the engine mount. For both the throttle and choke cable pair’s one cable is longer than the other … the longer of the two is routed over to the right carburetor.  I quickly discovered the wires for the GPS 2020 antenna previously installed were somewhat in the way. There was not enough slack firewall forward to move the wires underneath the big Adel clamp mounted to the engine mount and the wires would have ended up wedged between the throttle and choke cable bundle and the big Adel clamp … this was not to my liking. Fortunately, when the Dynon GPS 2020 antenna was installed, the wires were cut so a little extra length was available behind the instrument panel. The down side is that the upper forward fuselage skin needed to be removed to gain access to the slack. So another minor setback was incurred and the upper forward fuselage skin was removed so the instrument panel is now opened up again. Actually, that is not a bad thing because I have an EAA tech inspection scheduled for next weekend … so they will now be able to have a look at the instrument wiring. After pulling enough slack forward to route the GPS 2020 wires under the large Adel clamp and out of harm’s way, the instillation of the throttle cables resumed.

Feeding the Mc Farlane Vernier-Assist throttle control’s two cable ends through the lock washer and locknut for the throttle control as it is being inserted into the panel hole.


With the throttle cables fished through the firewall grommet and into the engine compartment with the longest cable of the two closest to the right carburetor, the locknut for the throttle was tightened. This is a 1" nut and I quickly realized I did not have a wrench that size, so took a look in Mike’s hangar and fortunately there was a 1” wrench sitting on the table waiting for me to borrow it for a few minutes … thanks Mike. At this point, I realized it would be in my best interest if the autopilot disconnect switch were installed now because it would be easier to get a wrench onto the locknut without the choke control in the way … so it was rounded up and installed along with the associated Molex connector the wires slip into.


With the autopilot disconnect switch now installed, the choke control was installed next. The choke cable routing is through the grommet in the firewall and UNDER the throttle cables with the longest cable positioned closest to the right carburetor. The handle on the choke control locks in a closed position, so the cable is to be installed with the handle locked so it is in a vertical position.

Tightening the locknut on the choke cable assembly … the handle needs to be in the locked “off” position and vertical when the choke control is secured to the panel. The red autopilot disconnect switch and associated Molex connector can also be seen.


With the throttle and choke controls now tightened down, attention was given to the Adel clamp the four cables need to pass through. Unfortunately, in order to get all the cables through the clamp it was necessary to remove the bolt. This created a small problem of trying to get the screw installed again while fighting two clamps. The solution was to use a piece of safety wire around the Adel clamp attached to the engine mount and twist it tight enough to bring the ends of the clamp together so the bolt could be inserted through the smaller Adel clamp and slipped into the hole in the other clamp without a fight.

The mounting screw for the Adel clamps was left lose so once the four cables are connected to the carburetors, the angle of the clamps can be adjusted to prevent the cables from rubbing on the engine mount they are sitting on now. The grey and orange wires with the do not remove label on them are the GPS 2020 antenna wires which were routed so they now pass below both Adel clamps.


The next step will be installing the throttle and choke cables to the Rotax 912's carburetors ... which will hopefully be accomplished during the next work session.

T-1211 Fuel Filler Neck Assembly & Fuel Tank Venting Installed

To complete the fuel system the only steps remaining was installing the T-1211 fuel filler neck assembly and the new T-1219C vent pipe which was installed and the fitting tightened. The holes and nutplates were installed on the T-1211 long ago and the mating area on the turtle deck around the filler neck was masked off to minimize the fuel tank sealant mess. All that was required now to complete the job was mixing up a small batch of fuel tank sealant and slather it in onto the flange on the fuel filler neck then mate the assembly to the turtle deck.


Van’s plans suggests using car wax as a release agent so the filler neck assembly can be easily separated from the turtle deck ... which will be necessary for fuel tank removal. I elected to slather Vaseline on the turtle deck skin as the release agent. The assembly went fast, prior to mixing the tank sealant, the T-1212 rubber fuel neck collar was slipped up on the fuel filler neck and two band clamps were placed on the fuel tank. After the tank sealant was mixed, the flange on the fuel filler neck was given a liberal slathering of sealant and the fuel filler neck was carefully mated to the turtle deck with six screws. The screws are tightened until the tank sealant begins to ooze out evenly around the filler and turtle deck junction. The screws are not to be tightened fully because the idea here is to make a gasket that becomes part of the flange on the T-1211 fuel filler neck and is reusable.

Tightening the band clamps for the T-1212 rubber fuel neck collar.

Completed instillation of the fuel tank filler neck and new fuel tank venting system. The RV-12’s fuel system is now 100% completed.

Propeller Re-pitched - Correctly This Time

A few days ago after completing the oil purge process, the propeller was pitched to 71.4 degrees and photos of the setup were posted on the DOG Aviation Blog and fortunately caught the eye of a fellow builder. One of the perks of sharing the building process of the Van’s RV-12 via the DOG Aviation Blog is there are many eyes watching the build, producing feedback from around the world. After posting the photo covering the process of using a digital level to set the pitch of the propeller, I received an Email from Nick, a fellow RV-12 builder in Colorado, saying one of us pitched the propeller wrong and would be saying “crap” …. Well, that would be me …. Crap!


Nick referenced a photo on a page 47-07 in the latest version of the plans, which is not in my plans. I had viewed the new page online and the use of the digital level seemed simple enough … but I managed to mess it up by rotating the prop blades the wrong way to obtain the required 71.4 degrees … DUH! The DOG Aviation RV-12 would have had the first RV-12 in the fleet that could back into a hangar under its own power. Many thanks Nick for the sharp eyes and taking the time to write and get me pointed “pitched” in the right direction so to speak.

This photo is incorrect … the photo was posted a few days earlier on the Blog covering use of a digital level to set the initial pitch to 71.4 degrees. What Nick spotted as being incorrect is the level is leaning in the wrong direction … good eyes Nick! The level should be leaning to the left or aft and NOT forward as it is here.


One unfortunate aspect of pitching the propeller blades the other way is the gap seals were shaped when the blades were in the opposite position, so it required many hours of filing with a jeweler’s files to get the shape acceptable. I did not want to remove the blades by myself or bother friends, yet again, for the same task. So with only a very tiny gap to work with, blue masking tape was placed on the prop for protection and the gap seals were slowly reshaped using lots of careful filing until there was approximately 1/16" gap between the gap seal and propeller when the blades were positioned correctly … an allowance was made in case the blades need to be pitched shallower because the 71.4 degrees is just a starting point. Builders will adjust the pitch to best fit their needs based on many factors such as field elevation, runway length and type of flying they mostly do.

Carefully filing one of the gap seals using a jeweler’s file to obtain the necessary clearance between the gap seal and the prop blade when the propeller blade is positioned correctly.


After filing both gap seals, the propeller blades were adjusted to 71.4 degrees (correctly this time) and the bolts were tightened one flat at a time and the angle rechecked and tweaked if necessary. After a couple of cycles of tightening the blades by one flat on the bolt, the blades were pretty much locked in position. At this point the propeller bolts were tightened in four stages of torqueing checking the blade angles after each stage ... 75 inch pounds, followed by 10 ft. lb., 14 ft. lb. and final torque of 19 foot pounds. The final blade angles ended up at 71.4 degrees and 71.35 degrees. Time to put the spinner back on and move on.

This is the correct orientation of the digital level when using the TOOL-00002 pitch tool with a digital level to set the propeller blade pitch to 71.4 degrees. The level should be leaning aft as it is in this photo.

The final result after torqueing the bolts to 19 foot pounds.

Checking Hydraulic Valve Tappets After Oil Purge Procedure

After performing the purging of the oil system, the hydraulic valve tappets need to be checked to make sure they have pumped up with oil. The hydraulic valve tappet is built into the lower portion of the valve rocker arm. To perform the check, the lower spark plugs are removed and the valve cover for the cylinder being tested is removed. The valve cover is held onto the cylinder head by one M6 screw that is removed with a 5 mm hex wrench. A little bit of caution needs to be exercised when removing the valve cover to insure the rubber O ring on the screw comes off with the valve cover. The larger O ring around the perimeter of the valve cover will typically stay in place on the valve cover but sometimes the tiny O ring around the bolt can stick to the cylinder head and later fall off ... so it is important to verify that it is still on the bolt when the valve cover is removed.

The valve cover has a large gasket around the perimeter of the cover and a much smaller O ring on the M6 bolt as can be seen in the photo.


The test consists of pushing on the LOWER portion of the rocker arm to make sure it feels solid and there is only approximately a .020  gap between the rocker arm and valve stem. A hard plastic dead blow hammer was used to push on the lower portion of the rocker arm. Because the purge was done the day prior the first cylinder tested did not pass the test. I figured this was likely because the oil had time to drain away overnight so the valve cover was reinstalled and the propeller was rotated vigorously for a minute … then the valve cover was removed and the test was repeated, this time with success. Pushing on the lower portion of the rocker arm with the dead blow hammer handle just rocked the fuselage and the valve tappets did not collapse.

Using the handle of a plastic dead blow hammer to press on the LOWER portion of the rocker arm to verify the built in lifter is pumped up and can hold pressure.


The same procedure was used on the remaining cylinders and there were no valve tappets that failed the test. After the testing was completed, the hex nuts on the valve covers were torqued to 90 inch pounds.

Torqueing the M6 bolt on the rocker arm cover to 90 inch pounds.

At this point the oil system is ready for an engine start.

Performing Oil Purge Process On The Rotax 912ULS Engine

Prior to starting the Rotax 912ULS engine for the first time or anytime the supply oil line is removed between the oil tank, oil cooler or Rotax 912ULS engine an oil purging procedure MUST to be followed to remove air from the oil system.


The procedure is not complicated, but does require help. In a nut shell, the goal is to pressurize the oil tank to between 6 and 14 psi of pressure and with the sparkplugs removed from the cylinders, spin the propeller as fast as possible by hand for a minute or two allowing the hoses, oil cooler, and internal oil galleries to completely fill with oil until a steady oil pressure is built up.


The setup: To perform the oil purge, the oil return line from the engine is removed from the In port on the oil tank ... and the In port on the oil tank is capped off. The oil return line is to be placed into a container to capture oil … I elected to just use a vinyl hose directly off the fitting on the crankcase to collect the return oil. The oil tank is pressurized via removing the air vent hose and connecting an air hose to the air vent fitting on the oil tank. I made up a small manifold so an air gun could be connected to a pressure gauge via 1/4" tubing. From the manifold to the oil tank 3/8" ID tubing is used.

An air gun connected to a manifold with an air gauge is used to control the amount of pressure applied to the oil tank. A 1/4" ID hose connects the air gun to the manifold and a 3/8" ID hose connects the manifold to the air vent pipe on the oil tank.

As mentioned previously, I elected to connect a vinyl hose directly to the oil return fitting on the bottom of the crankcase instead of dealing with collecting oil dripping out of a hose on the top of the engine. The vinyl hose created a small issue in that it wanted to kink because the muffler is so close to the return oil fitting on the crankcase the vinyl hose needed to make an abrupt bend. To solve that issue, a piece of stiff safety wire was curled up and inserted into the hose to prevent it from kinking.

To collect the oil that will run out of the oil return port on the bottom of the engine during the oil purging process, a vinyl hose was slipped over the fitting. A piece of safety wire was curled up and slid inside the soft vinyl hose to prevent it from kinking at the bend.


With all systems a go, the manifold assembly was connected to the air vent on the oil tank and the regulator on the air compressor was backed down a bit so Mike K. could easily control the air flow to keep a steady 10 psi of pressure applied to the oil tank. Because the oil pressure sending unit was moved from the engine and mounted on the firewall, figured it would be a good idea to first make sure the hose was full of oil … so the fitting was removed from the oil sending unit (I had never tightened it knowing it would be removed for the purge) and while Bernie held the oil sender  line in a rag, the prop was vigorously turned until oil flowed from the hose. This took a little while because there is a restrictor on this oil line at the engine. Once the line was full of oil it was connected to the oil pressure sending unit and the official purge process began. (Note: Builders who do not move the oil pressure sender to the firewall would not need to fuss with this first step).

Mike K. the “pressure man” controlled the air pressure being applied to the oil tank's vent fitting, keeping it around 10 psi during the purging process. During the oil purge process, the oil return hose is removed from the oil tank and the In port on the oil tank is capped off ... which can be seen in this photo as a blue cap on the In port on the oil tank.

Oil running out of the oil return fitting on the bottom of the crankcase was collected in a clean container and poured back into the oil tank through a paint strainer when the purging was completed.


By the time oil began coming out of the oil pressure sender line I was getting a little tired but after connecting the oil line back on the sender unit continued to spin the propeller until oil began flowing out of the oil return port on the bottom of the crankcase. This is when we switched roles and I turned on the Skyview to monitor the oil pressure, Mike began turning the propeller, and Bernie controlled the air pressure applied to the oil tank. After a few moments the oil pressure came right up and Mike had it holding steady at 78 PSI and the pressure would vary depending on how fast or slow Mike turned the propeller. With the oil purge complete. there is one more step that is required before an engine start is attempted and that is involves removing the rocker arm covers and verifying all the hydraulic valve lifters are pumped up … this will be covered in the next post.


This concludes the oil purging process … we return to normal programing.

S-1201 Spinner Instillation Completed

Conceding to the harsh reality the propeller needs to be removed to complete the S-1201 spinner instillation, Bernie was asked to lend me a hand removing the propeller blades so the S-1202 spinner plate and S-1203-1 spinner bulkhead could be removed to install nutplates. Once the parts were removed the nutplates were bent to match the curve of the parts and then held in position with a screw so the holes for the nutplates could be drilled.

Using a screw to hold the nutplate in position on the S-1202 spinner plate, #40 rivet holes are drilled into the spinner plate.

All the rivet holes for the nutplates are drilled to #40 and the nutplates are secured with Clecos.

After drilling all the rivet holes for the nutplates , all the rivet holes for the nutplates needed to be machine countersunk for flush rivets. I decided to leave the nutplates Clecoed in position to help keep the countersink bit from elongating the holes … likely unnecessary because the spinner plate and spinner bulkhead are made from fairly thick material. After the machine countersinking was completed, the nutplates were riveted onto the parts.

All the nutplate rivet holes in both the S-1202 and S-1203-1 require machine countersinking using the countersink cage outfitted with a #40 100 degree countersinking bit.

Using the pneumatic rivet squeezer to rivet the nutplates onto the S-1202 spinner plate using AN426AD3-4 rivets.

Next work item was drilling the nutplate rivet holes for the S-1202B back plates. After drilling, the parts were given a couple of coats of primer and then white paint and left to dry overnight.

Completed gap filler assembly with nutplates installed riveted onto the S-1202 spinner plate.

Installing propeller blades … Act 2 … A Déjà vu moment. Today all the parts that make up the gap fillers were quickly riveted together and then riveted onto the S-1202 spinner plate so it could be installed along with the propeller blades so the oil purge process could be completed while extra help was available. With the aid of Bernie and Mike K. the S-1202 spinner plate,S-1203-1 spinner bulkhead and the propeller hubs and blades were reinstalled. I did not want to hold the guys up so adjusted the propeller pitch later in the evening after the oil purge process was completed ... this will be covered in the next post. While performing the oil purge, the spinner was temporarily held in place with a couple of screws so the pitot tube could be protected from being inadvertently snagged while hand spinning the propeller.


Upon completion of the oil purge process the spinner was removed so the propeller pitch could be adjusted and bolts set to final torque. Once again the digital level was used to adjust the pitch of the propeller blades to 71.4 degrees which should be a good starting point for doing engine ground run-ups. The process begins by using a couple of equally thick blocks placed on the prop hub so the propeller blades can be leveled.

Because the center of the prop hub is rounded, two blocks of equal thickness are used to elevate the digital level so the roundness of the hub does not affect the level's reading when adjusting the blades to level.


Now that the propeller is leveled horizontally, the digital level is moved to the canopy rail and zeroed. Once zeroed on the canopy rail, the digital level is attached to the Van's prop adjusting tool (TOOL-00002) and placed on the propeller blade. (Because my digital level has a threaded mount for tripod use I drilled a hole in the adjustment tool and attached the tool to the level with a screw because I do not trust the magnets on the bottom of the level). The reason for zeroing the digital level on the canopy rail is it makes the canopy rail the reference point for the prop angle adjustment … so no matter what angle the airplane is sitting at, by zeroing out the digital level on the canopy rail it takes uneven ground or hangar floors out of the equation.

The digital level is zeroed to the angle of the canopy rail by pressing the bevel button then moved to the propeller blade being adjusted to acquire the 71.4° pitch angle.


Return from the future: One of the perks of sharing the building process of the Van’s RV-12 via the DOG Aviation Blog is the feedback received from around the world. After posting the photo below covering the process of using a digital level to set the pitch of the propeller, I received an Email from Nick a fellow RV-12 builder in Colorado saying one of us pitched the propeller wrong and would be saying “crap” …. well, that would be me …. Crap!


Nick referenced a photo on a page in the latest version of the plans that is not in my plans. I had looked at the new version online and it seemed simple enough, but I managed to mess it up by rotating the prop the wrong way to obtain the required 71.4 degrees. I would have had the first RV-12 in the fleet that could back into a hangar under its own power. Thanks Nick for the sharp eye and taking the time to write and get me pitched in the right direction.

Note: The above photo is incorrect ... the level should be leaning to the left and NOT the right. Leaving the photo on the Blog to show readers what NOT TO DO! Using the Van’s TOOL-00002 which was modified so a bolt could be used to attach the tool to the digital level. The propeller pitch is to be adjusted to 71.4 degrees after placing the digital level on the canopy deck and zeroing the level to the canopy deck.

This is the correct orientation for the digital level when setting the propeller blade pitch to 71.4 degrees using the Van's provided TOOL-00002 pitch tool.

Another perk of having the level orientated correctly is it will stay on the propeller on its own without needing a constant hand on it while obtaining the desired 71.4 degrees..


Once the propeller blade pitch was adjusted to 71.4 degrees, the bolts were snugged up and torqued in three stages of increasing torque to a final torque of 19 foot pounds. After the hardware was torqued, the S-1201 spinner was screwed in place.

Torqueing the propeller bolts to a final torque of 19 foot pounds.

Tightening one of the 18 Philips head screws that secures the spinner to the Rotax engine.

Finally a completed task … the Eagle now has a means of propulsion.