Canopy Fairing Receives More Attention

Yesterday, in addition to painting a few firewall forward parts, decided to take advantage of the current 70 degree days and slather more microsphere filler on the fairing after smoothing out the last application.

To help with the sanding the DOG Aviation procurement department picked up a sanding block and sand paper that has an adhesive back so it sticks onto the block. The block has flat sides and a rounded end so it really does a fairly good job on the canopy fairing’s compound curves.

Sanding the fairing using the DuraBlock with self sticking sandpaper ... procured at a local automotive paint store.

Decided to trim the fairing’s bottom edge per the plans by extending the line of the canopy skirt using a long ruler. This was tough for one person to do so I used the assistance of a clamp to help hold the heavy metal in place while marking with a Sharpie. After marking, the Dremel outfitted with a cutting wheel was used to trim off the excess fiberglass. The cut was made purposely below the line about a 1/16" or so then the fiberglass was easily sanded to the line using 80 grit sandpaper.

Using a long ruler to extend the line of the canopy skirt. After marking with a Sharpie this will be the cut line.

Using the Dremel outfitted with a cutting wheel to trim off the excess material. Looking closely one can see the cut was made a little below the line.

Putting the finishing touches on the bottom edge of the fairing with 80 grit sandpaper. It is looking good.

I was going to continue trimming the fairing to the pattern supplied by Van’s but decided it would be in my best interest to take advantage of the warm afternoon and slather another small batch of microsphere filler onto the fairing to smooth out a couple of small valleys that existed. It is looking like this last application will be the end of the filling but there will likely be tiny spots here and there but all and all the fairing is truly looking good.

Today, the microsphere filler that was applied yesterday was sanded smooth and the laborious task of sanding down to the first layer of electrical tape began. I was using 180 grit sandpaper because I did not want to burn through the electrical tape and took my time carefully revealing the edge of the tape to the tune of four hours of sanding.  Because Van’s plans call for overlapping the electrical tape with resin, it takes quite a bit of careful sanding to reestablish the edge without burning through the tape or creating a grove in the lay-up below the electrical tape. Doing it again I would make sure that the edge of the tape is just barely overlapped with resin ... it would have made sanding much easier.

Results of four hours of sanding to slowly expose the edge of the red electrical tape and smooth the microsphere filler.

View from above after sanding to reveal the edge of the red electrical tape.

Good view of the final radius of the canopy fairing lay-up.

By in large most of the fairing is where it needs to be. May need to touch up a few small spots here and there, but the basic finished shape is there and ready for a professional paint shop to bring it all home.

The fairing still needed to be trimmed using the trimming template. Many weeks ago tracing paper was used to trace the trimming template so it would not be necessary to cut up the template drawing. The tracing paper was taped onto the fairing and the cut lines were marked with a green Sharpie pen.

Using the tracing paper template to mark the cut line with a green Sharpie pen.

Prior to cutting the fairing, I verified the tracing paper template matched the drawing … it was discovered it was off a little … many weeks ago it was perfect … humidity affecting the paper? Anyway, made a new template and remarked the cut line in red ink.

Remarked cut line is in red ink.

It was getting late so will cut the fairing first thing tomorrow and hopefully get back to sealing the carburetor drip trays with tank sealant.

Carburetor Drip Trays Assembled & ELT Bracket Mounted

It won’t be long until the Rotax 912 ULS engine will get prepared for instillation.  In removing the carburetors and intake manifolds to install the required air shroud … during reassembly, the Rotax 912’s carburetors will receive a drip tray.  The drip trays are comprised of four components, the FF-01226A drip tray, FF-01226B & FF-01226C stiffeners and FF-01216D drip tray doubler.  The drip tray and stiffeners are riveted together and after the riveting is completed the drip tray doubler is bonded onto the drip tray with fuel tank sealant.

The FF-01226A drip tray FF-01226B stiffeners require some trimming which was covered in a posting a week or so ago when the parts were prepared for primer.  Prior to assembling the drip trays, the plans instruct the builder to match drill the rivet holes in the upper right flange of each drip tray into the FF-01226B stiffener.

Match drilling the upper right flange on the FF-01226A drip tray into the FF-01226B stiffener using a #40 drill bit.

Next the plans call for machine countersinking the middle rivet hole on the upper left flange of both drip trays and the associated rivet hole in the inside of the FF-01226C stiffener so the rivet set in that location will sit flat on both sides.

Machine countersinking the second rivet hole from the top on the left flange of the FF-01226A drip tray using a #40 100 degree countersink bit. During the countersinking, the stiffener was left clecoed in position so the countersink bit would not elongate the rivet hole.

After the drip tray was machine countersunk, the corresponding rivet hole on the inside of the FF-01226C stiffener was machine countersunk using the #40 100 degree countersink bit. Both drip trays are to be machine countersunk at this same location.

My fingers are pointing to the second rivet hole down on the left flange of the FF-01226A drip tray and the associated rivet hole on the inside of FF-01226C stiffener that received machine countersinking.

The both drip trays were assembled using AN426AD3-3 rivets in the countersunk locations and AN470AD3-4 rivets in the remaining rivet holes.

Using the pneumatic rivet squeezer to assemble the carburetor drip trays using AN470AD3-4 rivets.

Completed riveting of both drip trays … one can see the middle rivet on the upper left flange of both drip trays is flush on both sides … because the associated rivet hole was countersunk on both sides.

The remaining tasks to complete the drip tray assembly requires using fuel tank sealant to bond the FF-01226D doubler onto the drip tray and to also seal the seams and gaps in the drip trays. It was getting on in the evening so decided to hold off and perform that task during the next work session. Because the drip trays only require a tiny amount of fuel tank sealant, decided to prepare a couple of locations that still require sealing so the excess can be used there.

The plans call for sealing the base of the instrument tray with fuel tank sealant to protect from water intrusion. Wanting to strive for a neat look, decided to take the time and mask off the areas with masking tape. This way I will be able to use a syringe to lay down a bead of sealant and then use a shaped wooden stick to tool the sealant and hopefully peal the tape away to create a clean edge …but fuel tank sealant has a mind of its own and may not play nice.

The area all along the base of the instrument panel on both sides of the RV-12 was masked to protect the paint from unwanted fuel tank sealant.

Before heading home for the evening decided, while the rivet squeezer was still out, to install the recently painted F-12122 ELT mounting bracket onto the F-1204F-R bulkhead. The ELT bracket mounts onto the bulkhead using two AN470AD4-4 rivets.

Positioning the pneumatic rivet squeezer to rivet the F-12122 ELT mounting bracket onto the F-1204F-R bulkhead using AN470AD4-4 rivets.

The RV-12 Receives Another EAA Tech Counselor Inspection

Knowing an EAA tech counselor visit was scheduled for Saturday, Friday was spent playing with the tail cone fairing and connecting the stabilator control cables. The previous post showed the tail cone fairing sitting roughly in position … so Friday the positioning of the tail cone fairing was tweaked a little then the fairing was drilled and Clecoed to the tail cone. The plans call for a minimum of 1/8" of clearance between the tail cone fairing and the skin of the horizontal stabilator … there was no position that achieved that without the need to do some filing so I picked a position that offered a good compromise.  After all the holes were drilled, the fairing was removed. The holes need to be final drilled to #27 and nutplates need to be installed … but placed that on hold due to the upcoming EAA tech counselor visit.

I wanted to have the upper and lower horizontal stabilator cables attached to the two horns on the stabilator so the horizontal stabilator would be totally functional for the inspection. This required connecting the aft end of the upper and lower stabilator cables onto the horns on the horizontal stabilator. Nothing special here, just a little grease, one bolt, three washers, a castle nut and a cotter pin per each cable attachment.

The upper and lower stabilator cables in the tail cone make up the aft half of the stabilator cables. Because each upper and lower stabilator cable is comprised of two sections … a forward and aft cable, the aft cables need to be joined together to the forward cables using a special threaded barrel. One end of the barrel has a ring grove machined into the metal which denotes that end of the barrel has reverse threads … this end needs to point aft. Following the directions in the plans, the forward and aft stabilator cables were connected together by getting on a creeper and rolling under the fuselage to reach in through an inspection access hole and threading the barrel onto the threaded ends of the cables. Following a sequence in the plans, each barrel is turned until the slack was taken out of the cables. I stopped at this point because the DOG Aviation procurement department still needs to purchase a cable tensiometer to finalize the tensioning on the cables. However, at this point I had a working horizontal stabilator which completed the instillation of the flight controls for the EAA tech councilor visit on Saturday.

The grove on the aft end of the adjustment barrels for the stabilator cables can be seen if looking closely. This grove denotes reverse threads and needs to face aft. Also: The cables in this photo are not fully adjusted yet … so they do not have the proper amount of threads showing, nor are the locking clips installed.

Saturday, the EAA tech counselor visit went quite well and no work corrections were pointed out. Jim the EAA tech councilor and his friend Don a fellow EAA chapter member came down from the Cleveland area to give the RV-12 a good looking over and gave it a clean bill of health. For being a small plane, both Jim and Don were impressed with the level of sophistication and complexity of Van’s RV-12 design.

Jim the EAA tech counselor in the foreground and his friend Don in the background looking over the DOG Aviation RV-12 project.

While there was extra muscle in the hangar, decided the time was right to lift the Rotax engine box out of the crate and unbolt the engine from the box so the engine could be set on the workbench. Prior to installing the engine on the firewall there are a few tasks that are required to be performed.  These tasks can be completed much easier if the engine is setting on a workbench.

The right side of the Rotax 912ULS engine. The mechanical fuel pump (two orange hoses attached to it) is just aft of the prop flange and the starter can be seen on the bottom left of this photo with the red label on it.

Front view of the Rotax engine … behind the flange for the propeller attachment is the gear reduction unit, the black oil filter is on the bottom left.

Left side of the Rotax engine. Just above and to the left of the Bing carburetor (center far right) one can se what looks like a silver radiator cap … which it is. This is the cap for the small black coolant reservoir.