Modifying F-1231F Latch Plate For A Micro Switch

Whittling down on the punch list of things that will be easier to do prior to mating the tail cone brought me to the Van’s notification dated 14-05-22 which entails adding a micro switch onto the canopy latch plate. The DOG Aviation procurement department ordered all the necessary items minus the micro switch … there was already one left over from the stall warning modification where a micro switch with a slightly longer arm was used in place of the Van’s supplied micro switch. The micro switch used for the canopy latch is the same micro switch that Van’s uses for the stall warning.

The F-1231F-1 latch plate is the new replacement for the existing F-1231F latch plate.  RV-12 builders that used solid rivets to attach the latch plate to the roll bar assembly may want to consider utilizing the method described below to modify the existing latch plate to accept the micro switch.

Because solid rivets were used to build the roll bar/latch plate assembly, I was not too keen on drilling out the four solid rivets securing the latch plate onto the roll bar assembly and was hopeful the new latch plate could be used as a drill template.  The two parts look identical except for the addition of two mounting holes for the micro switch and an additional mounting hole for the C-1214 latch block.

Existing F-1231F latch plate riveted onto the roll bar assembly.

Replacement F-1231F-1 latch plate with three additional holes.

To verify that the existing F-1231 latch plate could be modified in place, a red dot was placed onto the heads of all four rivets securing it onto the roll bar. The new F-1232F-1 latch plate was Clecoed on top of the latch plate. Washers the same height as AN470AD4 rivet heads were used to square up the assembly.

The washers placed between the two latch plates will allow the plates to sit square on top of one another when secured with Clecos using the two latch block mounting holes.

After the new latch plate was Clecoed on top of the existing latch plate, the red dots placed on the rivet heads were verified to be centered in the holes (no adjustment was necessary). Using the new latch plate as a guide, the small hole in the F-1231F-1 was drilled using a #43 drill bit … this hole is tapped later using a  #4-40  tap. The crescent slot was created by drilling two #30 holes and using the drill bit to remove the thin center area in-between the two holes, completing the crescent shape. Lastly the additional hole on the bottom of the latch plate was drilled to #30.

Drilling the #43 hole which will become the pivot point for the micro switch after being tapped to 4-40.

Drilling the two #30 holes that become the micro switch adjustment slot.

Latch plate after drilling. The slot still requires a little bit of filing to smooth it out.

The next step was to deburr all the newly created holes and file the slot smooth followed by tapping the #43 hole for #4-40 threads. A screwdriver style tap holder was used with good results.

Tapping the #43 hole for 4-40 threads.

Once the threads were tapped into the F-1231F canopy latch, it has now become transformed into a F-1231F-1 canopy latch and ready to accept the micro switch assembly.

Trial fit of the micro switch. All is well and there is a free range of motion from one side of the slot to the other.

The only part of the two latch plates that differed slightly was at the very tip of the latch ... the new latch plate is just slightly shorter as can be seen looking at the red markings in the previous photo. I seriously doubt this will be an issue, but marked it just the same … so if material needs to be removed by a few strokes of a file, it is marked.

WD-1216 Pushrod Secured To WD-1213 Flap Handle

Now that the flap handle has returned from powder coating, decided to work on the controls a little more. The one end of the WD-1216 pushrod attaches onto the WD-1213 flap handle and the other end receives a CM-4M rod-end bearing. The plans call for adjusting the length from the flap handle body to the centerline of the CM-4M rod-end bearing to 11 25/32".

Measuring 11 25/32" from the body of the flap handle to the center of the CM-4M rod-end bearing.

Found it easier to slide a bolt through the CM-4M rod-end bearing and place a line on a piece of paper so the bolt could be visually kept square for the measurement.

Completed pushrod/flap handle assembly. A piece of paper with a line drawn on it was used as an aid to keep the CM-4M rod-end bearing square while obtaining the proper length measurement.

After the correct measurement was obtained, the parts were secured with jam nuts and a drop of blue Loctite.

Parts Return From Powder Coating

While the temperatures were in the single digits, direct work on the RV-12 was suspended but planning and parts ordering continued from the warmth of the house.  Micro Molex connectors and pins were ordered and received for wiring the control sticks, along with parts for the Van’s notification regarding the addition of a canopy latch micro-switch.

Research was also done on the new Dynon SV-AP-PANEL autopilot panel which will give one button access to various autopilot settings and modes … plus the discovery that it has a built in pitch trim controller with programmable speed controller (faster trim movement at slower speeds and slower trim movement at faster speeds to reduce twitchiness). The autopilot panel also has separate inputs for the pilot and copilot trim controls along with built in safeguards such as runaway trim protection and pilot input overrides copilot inputs. With this unit installed, the RV-12’s panel mounted trim switch will be fully functional as well as the control stick switches. The trim inputs are ground activated, so the DOG Aviation RV-12 will likely be wired so the RV-12’s panel mounted switch connects to the pilot trim inputs and the wires from both of the control stick trim switches connect to the copilot inputs … that way the panel mounted trim switch will take precedence over both pilot and copilot trim switches on the control sticks.

One part that was somewhat holding up instillation of the controls is the flap handle … which was sent out for powder coating along with all the firewall forward metal parts. All the parts have now returned from powder coating and look great. Thanks RH!.

Box of powder coated parts that will be installed firewall forward.

Flap handle returned from powder coating. Although the flap handle looks more blue in the photo it is actually a deep purple and looks gorgeous.

New Power Outlet For Air Compressor

RV-12 builders can ignore this post but those builders ever facing the need to rewire their air compressor motor from 110 volt to 220 volt service may want to read further.

With the Holiday hustle and bustle is behind us, time was spent at the DOG Aviation’s hangar 45 improving the infrastructure. Frequent readers of the DOG Aviation Blog may recall it was discovered a few months ago that there was not enough 110 volt power available at the hangar to run the air compressor … which necessitated temporarily borrowing a gas generator to power the compressor.

Now that the weather is getting cold and nasty, decided it was best to revisit the DOG Aviation hangar’s power issue so it will no longer be necessary to drag the gas generator outside when using the air tools … and there will be a lot of riveting in the coming months. There is a breaker box in the hangar for the folding door’s electric motor, so gave it a good perusal a while back and confirmed 220 volts is available there.

One of the considerations when the air compressor was first purchased was making sure it had a motor that could be wired for either 110 volt or 220 volt service. So knowing the motor would work with 220 volt power, decided to order a 220 volt NEMA 6-15P power cord for the compressor’s motor. The plan was to tap into the 220 volt power inside the breaker box for the hangar’s folding door motor and route it through a conduit run to the air compressor.

Mounting the outlet box onto the conduit and mounting plate.

As a safety concern, to make sure the compressor CAN NOT be accidentally plugged into a 110 volt electrical receptacle, the air compressor’s 110 volt power cord NEEDS to be changed. I chose to use a NEMA 6-15P power cord and an appropriate NEMA 6-15R power receptacle. Wiring the receptacle is easy, there are only 3 wires … two hot wires and a ground wire.

Finishing installation of the NEMA 6-15R power receptacle. A close look reveals the slots on the receptacle are horizontal as opposed to vertical as on a 110 volt receptacle.

The wires were pulled into the breaker box that powers the hangar’s folding door motor and attached onto the terminals below the two fuses that can be seen in the photo below. The two power wires where added to the screw down terminals along with the existing wires that power the hangar’s door motor. The green ground wire was attached to a ground bus bar at the top of the box along with the other green ground wires for the door motor control.

Pulling the three wires for the new 220 volt receptacle into the breaker box. The two hot wires (red and black) will attach to the terminals below each of the two fuses and the green ground wire will attach to the ground bus that can be seen at the top of the box where the other green wires are attached.

Now that the power receptacle has 220 volts, the compressor motor requires a little surgery. The motor has a chart on the side that shows the wiring for low voltage and high voltage.

Wiring chart on side of motor shows low voltage (110v) and high voltage (220v) wiring.

There is a small cover plate on the side of the motor which covers a wiring block. In my case, only two wires (orange and brown) needed to be moved to different terminals to convert the motor from 110 volt to 220 volt power … being slip on terminals, moving the wires was easy.

The original compressor motor wiring for 110 volt operation.

The compressor motor’s wiring after being changed over for 220 volt operation.

After the compressor motor’s internal wiring was changed for 220 volt operation, the existing 110 volt power cord was replaced with a NEMA 6-15P cord. This again was easy, but it was necessary to crimp connectors on the ends of the power cord’s wires before the cord could be installed. The power cord for an air compressor does not run directly to the motor it typically runs to a pressure switch which controls a contactor for the motor. My pressure switch cover only had one screw holding it on and was easily removed by lifting straight up.  In my case, the white and black power cord wires connected to the line inputs on the top of the contactor and the lower wires go to the motor (and do not need to be touched). The power cord ground wire is attached onto the base of the pressure switch housing with a screw.

Pressure switch with the cover off shows the power cord’s white and black wires going to the top of the contactor’s line terminals. The green ground wire attaches to the base of the pressure switch housing.

Installing the new NEMA 6-15P power cord in the air compressor’s pressure switch.

After the new power cord was installed and plugged into the new 220 volt receptacle it was time to turn on the switch and see if the compressor motor turns or burns. Much to my relief, the motor sprang to life! Success!!! The compressor runs great now!!!

Thumbs up! The air compressor motor is turning and not burning. The motor is running great on its new NEMA 6-15 220 volt receptacle and power cord.

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.

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.

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.