Completing Service Bulletin SB-00023 WD-1221 Engine Mount Standoff Inspection/Replacement

Service Bulletin SB-00023 involves inspection/replacement of the RV-12’s WD-1221 upper engine mount standoff. There have been a few RV-12 aircraft that have developed cracks near weldments on the WD-1221 upper engine mount standoff discovered during inspections. Van’s took quick action and redesigned the WD-1221 using tubing double the thickness thereby “theoretically” making the areas where the cracking occurs much more robust.

Service Bulletin SB-00023 requires inspections of the WD-1221 upper engine mount standoff be conducted every 100 hours and ongoing log book entries be made unless a crack is found … which, if discovered, requires a mandatory replacement using the new WD-01221-1 upper engine mount standoff. Figured while I still had access to the engine hoist I borrowed from Tom (a fellow RV builder at the airport putting the finishing touches on his RV-10 for his first flight), may just as well go ahead and replace the WD-1221 standoff (even though mine is not cracked) and just be done with it.

All and all, with the exception of dealing with the two sets of double Adel clamps that attach onto the WD-1221 upper engine mount standoff, the process of changing out the standoff was not all that difficult. Fortunately, no fuel, oil lines or wiring needed to be removed (all those items were installed following Van’s suggested path). It was tight but there was enough room to shoehorn the old mount out and install the new mount without jumping through a lot of hoops.

Design and outward visual appearance of the two upper engine mount standoffs seem identical ….however, the new standoff appears to have a tiny hole on the endcap. The new part number for the redesigned WD-1221 upper engine mount standoff is now WD-01221-1. The following  photo shows the new WD-01221-1 standoff and the next two photos show the existing WD-1221 standoff and Adel clamp placement.

As one can see from this photo of the new WD-01221-1 upper engine mount standoff it visually looks identical to the original, which can be viewed in the two Adel clamp photos bellow.

Photo of the pair of Adel clamps used to secure the main firewall forward wiring harness to the WD-1221 upper engine mount standoff. Reattaching these Adel clamps after the upper engine mount has been changed out will be a challenge. Fortunately, there are tricks that help ease the pain … but it still presents a challenge because there is not a lot of room for good access.

This photo is of the second pair of Adel clamps attached to the WD-1221 standoff … these clamps are used to secure the throttle and choke cables to the WD-1221 upper engine standoff.

Unfortunately, accessing the bolts that secure the WD-1221 upper engine mount standoff to the firewall requires removing the F-1240 upper forward fuselage skin. Once the F-1240 upper forward fuselage skin is removed, closing the canopy will allow great access to the WD-1221 standoff’s mounting bolt heads … as such, this can be done as a one person operation. There was one unexpected complication involving removal of the two mounting bolts that created a little extra work. The bolts could not be completely removed because they contacted the F-00055 com supports.  Solving this issue required placing a sawhorse under the tail cone and jacking the engine until the tail cone contacts the sawhorse … then jacking just a little more causing the isolation mounts to separate from the WD-1221 standoff so the isolation mounts could be removed to garner the enough room to slide the WD-1221 standoff forward far enough to clear the bolts protruding the firewall. Guess I could have bent the lower ear on the com supports … but really did not want to do that.

This photo shows how the F-00055 com supports prevent the mounting bolts from being completely removed.

This photo shows when the bolt was pulled aft to the point of touching the com support, there was still quite a bit of the bolt extending beyond the firewall.

With the WD-1221 upper engine mount standoff rotated upward, it can easily be fished out towards the left side of the aircraft.

The new WD-01221-1 upper  engine mount standoff is slid in from the pilot's side of the aircraft following the same path used to remove the old mount,  then it is rotated down and slid aft over the protruding bolts. Next the isolation mounts are reinstalled. Also of note: Rotax recommends replacing the rubber isolation mounts as part of their 5 year rubber replacement protocol …  so all of the engine’s isolation mounts have been replaced (forgot to mention that in the last posting). After all the bolts are inserted, the castle nuts are torqued to 160 in lbs … after torqueing to 160 in lbs, if a castellation is not yet aligned with the hole in the bolt, the castle nut is tightened more until a cotter pin can slide into the hole in the mounting bolt. The upper limit for the torque is 190 in lbs. so there should be enough margin to allow a castellation to align with the hole in the mounting bolt without over torqueing.

The new WD-01221-1 upper engine mount standoff installed and ready for the two pairs of double Adel clamps to be attached.

The new WD-01221-1 upper engine mount standoff completely installed … the new mount looks identical to the old WD-1221 standoff with the exception of the tiny hole in the endcap.

The last item left to do is reinstalling the two pairs of double Adel clamps … this is a challenge. Adel clamps are very springy and want to spring open so even if there is plenty of room to get your fingers on them, they are a challenge. That difficulty is upped dramatically when reinstalling the two pairs of Adel clamps onto the new WD-01221-1 upper engine mount standoff. There just is not much room for fingers and tools …. especially when reinstalling the two Adel clamps that support the firewall forward main wiring harness. Even using the tricks I know, reinstalling these Adel clamps was an exercise of patience.

Best photo I could get showing both double sets of Adel clamps attached to the new WD-01221-1 upper engine mount standoff.

Builder tip: The easiest way I have found to install double Adel clamps is to use Adel clamp pliers in conjunction with safety wire. First squeeze each Adel clamp separately and wrap a thin safety wire around the clamp to keep the clamp from fully opening when the pliers are removed. Then align the two clamps together and place the Adel pliers over the two clamps, tighten the pliers, then slide the alignment awl through the bolt holes in the clamps. When the holes are aligned, quickly remove the awl and insert the bolt. Here is where it gets a little dicey …. usually, the bolt is not long enough to allow a nut to be installed because the thickness of the Adel pliers takes up a lot of room. So what usually works well is to press down on the head of the bolt, then slide out the pliers and reposition pliers on top of the bolt head and tighten the pliers again. This should leave enough threads beyond the pliers to get a nut threaded onto the bolt. Once the nut has caught a few threads, remove Adel pliers and thread the nut on the bolt a little more. Next remove the safety wire, final position the Adel clamps, then tighten the mounting bolt. Below is a photo sequence of the steps involved.

Adel clamp pliers and the awl that comes with the pliers.

Using Adel clamp pliers to squeeze the clamp’s ears together so thin safety wire can be wrapped around the clamp. Leave the ends of the wire long so the wire can be unwrapped by easily by hand.

Example of how the awl that comes with the Adel clamp pliers is inserted through the holes of both Adel clamps to align the holes so a bolt can pass through the clamps.

As can be seen here, typically an AN3-3 bolt is not long enough to allow a nut to be threaded onto the bolt because of the thickness of the pliers.

Once the AN3-3 bolt is inserted through the pliers and Adel clamps,  forcefully press down on the bolt head then remove the pliers. Quickly reposition the Adel pliers to capture the head of the bolt …. this allows the threads of the bolt to extend beyond the pliers just enough to thread on a nut.

This photo shows how repositioning the Adel clamp pliers to press on the head of the bolt will allow enough threads extend beyond the pliers to allow a nut to be threaded onto the AN3-3 bolt.

As one can see, clamping the bolt head with the Adel clamp pliers allows a nut to be threaded onto an AN3-3 bolt. Now remove the safety wire, final position the Adel clamps and finish tightening the nut and bolt.

As mentioned previously, completing Service Bulletin SB-00023 was not that difficult … but dealing with the two sets of double Adel clamps located in tight quarters is actually the most challenging aspect of replacing the WD-1221 upper engine mount standoff with the new WD-01221-1 standoff.

DOG Aviation RV-12 Receives Off-White Base Color

The base paint color chosen for the DOG Aviation RV-12 is an off-white (not quite as dark as I would have preferred). When looking at color chips for a creamish off-white that leans towards brown, I found an off-white that was a tad lighter than what I wanted and the next darker paint chip seemed too dark for my liking so I went with the lighter off-white. Not wanting to step into the world of custom mixed paint, decided to just go with the lighter off-white color. Sure, could have opted for a custom mix … however, should a touchup be required in the future, hopefully having chosen a standard color from the color chart will result in a closer match. Interestingly, when looking at the paint for the first time after it was sprayed, it seemed really white to me … however, when compared to a bright white airplane just painted at the shop with Matterhorn white paint, it is truly a darker creamish off-white color.

Painted canopy sitting on the wooden canopy frame I made specifically for this purpose (mentioned in the previous post). The wooden frame keeps the thin edges of the canopy skirts that protrude below the canopy frame off the saw horses … this prevents the skirts from becoming bent and scraping paint off the fuselage where the canopy overlaps.

Fuselage and stabilator ready for reassembly.

Side view of the fuselage from the front.

Painted right wing, flaperons, rudder and anti-servo tabs. Jeff the painter taking a well-deserved coffee break.

The fiberglass parts …. wheel pants, intersection fairings, tail cone fairing and gear leg fairings.

Jeff wanted me to begin assembly of the tail section so it could be masked off for the accent trim colors while on the airplane. This will involve reinstalling the vertical stabilizer and horizontal stabilator along with temporarily pinning the rudder in place. The rudder will receive the accent colors while off the airplane. The wings will also be attached so masking can be applied to the fuselage and the wing tips for the trim colors.

Tail section and canopy reattached and cowlings installed.

Note to fellow RV-12 builders: Those that have completed the service bulletin for the bearing bracket on the stabilator will discover that attaching the stabilator onto the tail cone is a tougher challenge now. A few suggestions … grind down two AN4-12A bolts to remove the threads and put a small taper on them so they can be used as “pins”. Raise the nose wheel and place it into one of the holes in a standard concrete block. Tape really thin foam wrap sheets onto the side of the fuselage to prevent scratches. Place the stabilator onto the 25” saw horses you made to prop up the fuselage … the alignment will be close enough to work with. Have two helpers hold each end of the stabilator and insert the counter weight into the fuselage and slide the stabilator forward so the counterweight arm bolts can be installed. Carefully move the stabilator forward and in position. Forget about installing the washers on either side of the bearings and just temporarily use the tapered bolts to “pin” the stabilator in place. At this point, only one person needs to hold the stabilator in position as each “pin” is removed one at a time and replaced with the AN4-12A bolt and the required washers. I would suggest wearing a miner’s light (preferably one with an incandescent bulb to reduce glare) and use a comfortable creeper … you will be on your back for quite a while. If you don’t have a washer holding tool, use painters tape to tape each washer onto a thin metal ruler and slide the washer in place and slip the bolt through it. It sounds easy … but it is not … IT IS an exercise in patience … lots and lots of patience. Frankly, I think this is one of the toughest tasks to perform on the RV-12 … it is amazing how difficult inserting two bolts through two bearings and four washers can be. I also found using a small piece of vinyl tubing with a wire tie wrapped around the bolt and back through the tubing made for a very easy way to hold the bolts for initial insertion into the holes in the bearing brackets. I've installed the stabilator three times now and although it has become somewhat easier to do, it is not a task that can be done quickly … at least not for me.

Two AN4-12 bolts that have had the threads ground off and a slight taper placed on them so they can be used as “pins” to quickly get the stabilator in position without worrying about the washers on either side of the bearing. Once the stabilator in position, the “pins” are pulled one at a time and replaced with a threaded AN4-12 bolt and the appropriate washers. The vinyl tubing and wire tie shown makes a great tool for holding the bolts for insertion into the bearing bracket assembly since there is really not much room for a hand.


After the tail section was installed, work began preparing the wings for installation. The wings were placed in the wing cradle and the flaperons were attached to each wing.

Freshly painted wings attached to the fuselage.

 In the past, I’ve used a couple of pieces of metal bent into a" V" and taped  them onto the outer edge of the wing and flaperon with duct tape to secure the flaperons from moving while the wings are off the airplane. Not long ago I read a post on the forums where a guy suggested using a welding rod inserted through the very aft edge of the wing and slid into the aft portion of the flaperon to capture it. This worked really well … and I can wholeheartedly recommend using this method to secure the flaperons during wing removal/instillation.

Two welding rods with 90° bends on at the ends makes it easy to lock the flaperons for wing instillation/removal.

As can be seen in this photo, the aft edge of the outboard portion of the wing has a gap just large enough to insert a welding rod.

The gap along the aft edge of the flaperon aligns with the gap along the aft edge of the RV-12’s wing.

Looking closely one can see the welding rod in the gap between the inboard edge of the wing and outboard edge of the flaperon. The welding rod captures the flaperon securing it in the neutral position. Using the welding rod to “pin” the flaperon means the flaperon no longer needs to be held during wing instillation or removal.

The next step involves Jeff interpreting a picture made of my desired color scheme which I overlaid onto a photo of a RV-12 using a photo editing program. Jeff will use the edited picture as a reference for applying the masking for the trim colors and N numbers. When the masking is completed, the two trim colors will be applied to the DOG Aviation RV-12.

Installing Nose Gear Wheel Pants On The DOG Aviation RV-12

Work on the nose gear fairings for the RV-12 begins by preparing the U-00005A&B nose gear front and aft fairing halves. The process is much the same as the main gear fairings, in that, trimming is required to get close to scribe lines, then fine tuning the fit by careful sanding. Unlike the main gear fairings where a joggle is used to mate the fairing halves, the nose gear fairings are mated via two U-00006B splice strips. The splice strips need to be hand formed to conform to the shape of the U-00005-A front fairing. Although the splice strips will be placed inside the front fairing, I found it easier to first hand bend the splice strips to conform to the outside shape of the front fairing. After the proper shape was obtained, each splice strip was moved to inside the front fairing and tweaked accordingly.

Hand bending the U-00006-B splice strips to conform to the outside shape of the U-00005-A front fairing.

Hand bent splice strip ready for instillation on the U-00005-A front fairing … one down one to go.

After both splice strips are bent, each splice strip is installed on the inside of the front fairing using three Clecos. With both splice strips in place, the remaining rivet holes are match drilled into the U-00005A front fairing.

Both U-00006B splice strips in place on the U-00005A front fairing.  Next step is to match drill all the remaining rivet holes in the splice strips into the front fairing.


After all the holes in the splice strips are match drilled to #40 and with the splice strips still  secured to the front fairing with Clecos, the U-00005B aft fairing is mated to check the overall fit. It will be necessary to bend the splice strips at various locations with fluting pliers/and or flat nose pliers until there is no interference between the splice strips and the aft fairing preventing a proper fit.

My fingers are pointing to the areas of the U-00006B splice strips that required the most tweaking to allow the aft fairing to seat properly onto the splice strips.

As can be seen here, after tweaking the splice strips the aft fairing mates nicely to the front fairing. More adjustments will be made later after the stiffeners and mounting brackets are installed. Of note, blue tape was placed adjacent to areas that required more sanding and the tape was marked …. when the parts were removed, a little sanding was performed on the areas adjacent to the tape.


Next on the agenda is machine countersinking all the #40 rivet holes in the front fairing that will be used to secure the splice strip to the front fairing. The rivet holes in the U-00006B splice strips that will be used for installing the nutplates require dimpling. While the splice strips are still secured to the front fairing with Clecos, masking tape is placed on the splice strips and on the inside of the front fairing adjacent to the splice strip. The reason for the masking tape is a mixture of epoxy resin and flox will be applied under the splice strips prior to riveting. The masking tape will allow for an easy cleanup and prevent the flox from getting onto the portion of the splice strips that will later mate with the aft fairing.

Machine countersinking the freshly drilled rivet holes in the U-00005A front fairing for AN426AD3-3.5 rivets.

The splice strips and inside of the front fairing covered with masking tape ready for the bonding/riveting phase.

The next step involves removing all the Clecos and mixing up a batch of epoxy resin and flox. The splice strips and fiberglass area underneath the splice strips need to be sanded well to scuff up the mating surfaces for the flox mixture. A mixture of epoxy resin and flox is mixed to the consistency of peanut butter and then slathered onto the front fairing in the area under the splice strips. Before the epoxy mixture cures, the splice strips are Clecoed onto the U-00005A front fairing then riveted using AN426AD3-3.5 rivets.


Now that the U-00006B splice strips have been riveted/bonded in place, the U-00006A-1 wheel fairing brackets are riveted onto the splice strips. I deviated from the plans at this point and used AN426AD3-4 solid rivets to rivet the U-00006A-1 wheel fairing brackets to the splice strips. Van’s would have the builder use CCR-264SS-3-2 pop rivets here because the recommended 3” yoke for the rivet squeezer will not clear the bracket. However, there is a longeron yoke in the DOG Aviation tool cart and it clears the bracket enough to allow access so solid rivets can be used.

Setup for the longeron yoke – tall rivet set on the yoke and a thin rivet set on the plunger of the pneumatic squeezer. This combination allowed for enough clearance to rivet the wheel fairing bracket onto the splice strip using solid rivets as opposed to using pop rivets.

Riveting the U-00006A-1 wheel fairing brackets onto the U-00006B splice strips using solid AN425AD3-4 rivets. The longeron yoke allows for just enough clearance to get the job done using solid rivets in lieu of pop rivets.


(Of note: If installing the fairings on the older WD-01230 nose wheel fork the U-00006C drill template would be used along with the brackets WITHOUT the -1 after the part number.. Because the DOG Aviation RV-12 has the new, thicker WD-01230-1 nose wheel fork, it requires the template and mounting brackets be the versions with the -1 on the end of the part number).


The forward and aft fairings are mated together so the U-00006C-1 drill template can be used to create mounting holes in the U-00006A-1 wheel fairing brackets. The wheel fairing brackets will end up sitting directly on top of the nose wheel fork and screw into the U-00006E-1 fairing bracket mounts which have already been riveted onto the nose wheel fork for at least a year. The drill template insures the mounting holes drilled into the U-00006A-1 wheel fairing brackets will align with the holes pre-drilled in the U-00006E-1 fairing bracket mounts attached to the nose gear fork. The drill template is temporarily installed with two screws … one screw into the aft hole of each wheel fairing bracket. Once in place, a line is drawn along the edge of both wheel fairing brackets onto the drill template. The line in the following photo is very hard to see because I only had a black sharpie available at the time the photo was taken.  The reason for the lines is because the holes in the drill template can’t be drilled with the aft fairing installed … however, the shape WILL change when the aft fairing is removed. So the lines drawn onto the drill template will allow the builder to clamp the drill template onto the wheel fairing bracket in the exact position as marked when the aft fairing was installed.

With the U-00006C-1 drill template (bare aluminum) attached, a line is drawn onto the template down along the edge of the U-00006A-1 brackets. Hard to see in this photo because black ink was used, but the line can be seen as a dark shadow. This line will be used as an alignment aid when the aft fairing is removed to allow access for drilling.


After the lines were drawn onto the drill template, the aft fairing was removed and the drill template was clamped so the lines drawn were in the same position as when the aft fairing was mated with the front fairing. Using the holes in the drill template, the remaining four holes were match drilled into the wheel fairing brackets. The newly drilled holes are then used to temporarily attach the U-00006D-1 doubler plates onto the U-00006A-1 wheel fairing brackets. Existing rivet holes in the U-00006D-1 doubler plates are used to match drill into the wheel fairing brackets.


Here is where I ran into a BIG problem … The next step calls for dimpling the newly drilled #40 holes in the U-00006A-1 wheel fairing brackets.  I ran into a bit of a problem here that will likely affect all builders that have the new thicker nose wheel fork. The thicker nose wheel fork required Van’s to change the mounting brackets and doublers to accommodate the MUCH thicker material used on the nose wheel fork. The new brackets and doublers have a -1 after the part number and give the builder just barely enough room to create the required dimples. Clearances are so tight, the yoke on the rivet squeezer touches the fiberglass preventing the dimple die from being square with the rivet holes along the outboard edges of the U-00006A-1 brackets. To complicate matters even more, assuming the yoke would have enough clearance, the standard dimple die would not clear the already installed nutplates and, if used, a standard dimple die would cut into the radius or fillet of the bracket and likely create a lopsided dimple that is too shallow not to mention probably creating  a gouge in the fillet. Not good.

As one can see, even if the squeezer yoke would clear the fiberglass, the rivet holes are too close to the flange on the U-00006A-1 wheel fairing bracket which will cause the male dimple die to cut into the radius or fillet.

Even assuming the dimple die would clear the fillet, the rivet holes adjacent to the already installed nutplates are so close  a standard dimple die won’t clear the nutplate  … as can be seen here.


To more or less solve the issue, the DOG Aviation Procurement Department ordered a 3/32” close quarters die set from Cleaveland Aircraft Tool … the part number for the dies is DIE4263CQ.  For those not familiar with close quarters dimple dies, the dies are typically used in areas where the yoke on a squeezer is too thick to allow access. Close quarters dimple dies are made with a hole through the center of the dies which allows a nail to be inserted through the dies. The nail is placed in a hand rivet puller and as the rivet puller is squeezed, it pulls up on the nail compressing the two dies together …. thus creating the dimple in the aluminum skin.


There is a small problem using the close quarters dimple dies for dimpling the wheel fairing bracket ….  the bracket is much thicker metal than the dies are designed to dimple. Close quarters die sets were primarily developed for use on control surfaces that are typically made from .016” aluminum. The wheel fairing bracket is much thicker than that … which poses a slight problem because it requires more force to create a deep dimple. The main issue is the copper nails supplied with the dies are WAY too soft for the tension required to form dimples in the thicker aluminum used on the brackets … and the steel finishing nails, although slightly stronger, are also not up to the task because of the tiny head on the nail. My solution was to obtain some 6D 2” box nails which have the same diameter as the holes in the 3/23” close quarter dies.

The Cleaveland Aircraft Tool 3/32” close quarters die set comes with the copper nails and steel finishing nails shown on the top row. I purchased the 6D x 2” box nails separately because they can take more force and will dimple the thicker metal on the wheel fairing brackets. The 6D nails will still fail if an excessive amount of force is used … but you WILL have a dimple to work with.

As can be seen here, the male close quarter dimple die is too large of a diameter and will cut into the radius or fillet of the bracket … so it will be necessary to grind down one side of the die so it will clear the radius of the bracket.

After grinding to create a little taper on one side of the male close quarter dimple die, the die will now clear the radius or fillet on the wheel fairing bracket.


To use the 6D nail a small amount of filing is necessary. The tip of the nail requires a little dressing so the nail will slide through the holes in the dimple dies. Also, the area near the head of the nail and the portion of the nail that has the groves will also need some minor filing so the head of the nail will sit flat on the male dimple die. The modified close quarter’s dies were used with a hand rivet puller to create dimples on the row of holes closest to the radius of the angle.


The down side: Because of the thickness of the wheel fairing brackets, the formed dimples were not quite deep as I would have preferred. The simple solution … now that dimples are formed, they can be made a little deeper by using a C clamp. A short nail was used to keep the dies aligned and a C clamp was used to squeeze the dies a little more to tweak the dimples making them a little deeper.

The C clamp, close quarter dimple die set and a short nail will be used to make the dimples slightly deeper.

The shortened nail will go into the male die as shown here.

Using a C clamp and the tiny piece of nail to keep the close quarter dies aligned, the depth of the already formed dimple was improved. The curious may be asking themselves “John, why didn’t you use the C clamp in the first place”? Answer … because the male die is tapered, there is no guarantee the dimple won’t start sinking into the aluminum at an angle when using a C clamp …. Pulling a nail that sits flat to the dimple die assures the male die stays relatively centered in the rivet hole as the dimple forms. Once there is a dimple to work with, the male die will be nicely seated and there won't be a chance for the die to wander.


After all the dimples have been formed in the U-00006A-1 wheel fairing brackets, the underside of the U-00006D-1 doublers need to be machine countersunk at every #40 hole so the doubler will nest on top of the wheel fairing bracket. The countersink cage was set to a couple of clicks deeper than flush to insure the dimples in the U-00006A-1 brackets nested nicely in the U-00006D-1 doublers. Finally, the doublers were riveted onto the brackets with AN426AD3-4 rivets.

Top view of the completed U-00005A front wheel fairing.

Bottom view of the completed U-00005A front wheel fairing ready for instillation on the RV-12’s nose gear. Note how well the flush rivets on the outboard row turned out … had to unexpectedly jump through a few hoops to get to this point … but now all is well.

Assembled forward and aft fairing sections. I'm pleased with the overall fit.

Time to take all the parts to the hangar and begin the final fitting process on the DOG Aviation RV-12.


Normally, work would  continue by installing the U-00006E-1 fairing bracket mounts onto the new thicker WD-01230-1 nose wheel fork. I performed this step when the nose wheel fork was upgraded to the new stronger WD-01230-1 nose wheel fork … so it is time to move on to the trial fitting of the U-00005A front fairing on the RV-12's nose wheel fork.




As with the fairings for the main gear, the nose wheel fairings require the same ½” of clearance all around between the tire and the fairing. In addition, the nose wheel fork needs to be rotated from stop to stop and the fiberglass material needs to be removed from the U-00005A fairing until there is at least  1/8”of clearance between the front fairing and the WD-1201 nose gear leg throughout the nose wheel fork's full range of motion. After that was accomplished, the U-00005B aft fairing was attached and checked for at least 1/8” of clearance between it and the WD-1201 nose gear leg. The aft fairing also requires trimming along the edges to obtain the required ½” clearance between the fairing and the tire.

Initial trial fit of attaching the U-00005A front wheel fairing to the U-00006E-1 fairing bracket mounts on nose wheel fork. Fortunately, all the mounting holes aligned nicely.  Here again the ½” wide piece of aluminum will be used as a gauge for obtaining the required ½” clearance between the fairing and the tire.

Both the U-00005A front and U-00005B aft fairings mounted in position on the nose wheel fork. The fit is excellent but a little fiberglass still needs to be removed from the forward edge of the aft fairing under the gear leg to obtain the required 1/8” clearance. In addition, both fairings require fiberglass removal to obtain the required ½” clearance between the tire and the forward and aft fairings.


After the desired fairing clearances are obtained, the next item in the plans calls for working on the U-00007 nose leg fairing trim. HOWEVER, I have decided NOT to install the nose leg fairing trim on the DOG Aviation RV-12. The reason being, I’m not really thrilled about the thought of drilling two holes into the nose gear leg and tapping them for 8-32 threads just so the U-00007 trim piece can be mounted onto the WD-1201 nose gear leg. So I’m taking a pass on this one.


There was one place along the bottom bend of the fairings where the curve was off slightly between the two fairing halves … this was easily fixed by tightening all the screws up and using a heat gun to gently soften the fiberglass while pressing on it with a block of wood to gently reshape the curve. As can be seen in the above photo, the curve is now perfect.


At this point, other than paint, the nose gear fairing is complete!!!.