Leg and Intersection Fairings

I didn’t take any pictures of the start of this process, but you basically cut a paper template out of the plans and tape it to the fairings as instructed to mark and make the top and bottom cuts that align to the bottom of the fuselage and the wheel pant. I then placed them on the gear legs to test the fit.

Pretty good initial cut against the wheel pant.

You then cut the piano hinge to length and start marking where it will go to hold the trailing edge together. One slight deviation from the plans was to mark out the drill holes on the hinge and actually drill them with a 3/32″ drill ahead of time. The plans want you to drill through from the outside, but that goes back to the times when these fairings weren’t gel coated and were transparent. I then used the undersized holes in the hinge to match drill #40 into the fairing from the inside with a right angle drill.

First hinge mostly match drilled
Right angle drill used from the inside to match drill the hinge
Countersinking for flush rivets

You then re-install the leg fairings and insert the hinge pin, which is sort of a PITA. Once that task was over, the plans walk you through how to align the fairings properly. Getting this wrong can cause yaw, so you want them as perfectly aligned as you can. The plans have you wrap a string around the leg faring and clamp it to the step. I also feel that that plans walk you through placing a displaced centerline mark at a random location.. I basically reused the string I already had on the floor from the wheel pant install. The issue I ran into was my location.. and just some random location, as mentioned in the plans, isn’t the correct location when the string is perfectly level. So my advice would be to level the string, then use a plumb bob to mark the forward location of the string on the floor. Then duplicate the measurement from the airplane center line behind the step. Place the string that is the displaced centerline of the aircraft and use a plum bob to transfer the location to the step. You then move the aft part of the string to this mark on the step so the string ends up both level and parallel to the aircraft centerline.

Getting the string in place
Using a laser level to verify the string is perfectly level.
End result of the string level and parallel to the Center Line

You then adjust the rotation of the fairing until there is an equal distance between the trailing edge of the fairing and each side of the string.

Proper alignment.

To lock this positioning in place, you move on to install the intersection fairings. I used the intersection fairings from RVBits instead of the stock ones, which need lots more work. The lower left fairing was slid on using care to not change the alignment, which of course was re-checked multiple times.

Lower intersection fairing in place.
Front view.

I’ve decided to bond the lower intersection fairings directly to the wheel pant instead of using more screws to hold them in place. Doing this will require cutting these intersection fairings where the wheel pants separate from each other. It will also require me to add a flange onto the rear pieces so they stay locked in place under the front pieces with no way to get airflow under them.

I drilled a bunch of holes in prep to bond the 2 surfaces together.

The below picture was taken after I started taking clecos out, but I used a laser level to mark the fairing at the wheel pant split. I also decided to add a couple of additional clecos up at the top of the intersection fairing on either side of the cut. I did the same thing for the inside line as well (not visible here).

Cut line marked.

I then took things apart, cut the intersection fairing taped up the leg fairing so things wouldn’t stick together, and mixed up an epoxy/flox/cabo mixture putting things back together and letting them cure overnight.

All put back together and curing overnight.

The next morning I took the wheel pants off and the separation of the intersection fairings worked out well as shown below..

Rear fairing.
Front fairing.

A couple of pictures of the wheel pant put back together.

I then placed and drilled a small hole for clecos (for now) and placed the upper intersection fairing into position. This will later also attach to the wing root area.

Wheel Pants Part 2

With the jig leveled off and touching the bottom of the tire, the rear of the gear pant was put into place to trim a small amount to accommodate the gear leg. You continue trimming until the gear fairing extension hole is coincident with the aft “step” of the flange on the pant. then just make sure that you have some small gap all the way around the gear leg.

Rear pant in place

Then the same thing is done with the front pant. Trimming until you can fit it on the rear and have a small gap around the gear leg itself. One thing I did a little different on the right side (the 2nd one I worked on) was to mark out the extended centerline sooner and have the alignment of the pant at least close to where it needs to end up. On the left, I was slightly off and ended up trimming more than I should have. Nothing that the intersection fairing won’t cover up, but still a little too much. The plans don’t really have you aligning things to the centerline until after the trimming is done..

Front joined to rear to start the alignment.

I then dropped a plumb bob on the centerline of the plane and marked it with a string.

Aircraft centerline

I then took a square and measured a random distance over that would provide a good displaced centerline reference closer to the pant/jig itself. I also used a string to mark this on the floor.

Displaced centerline reference

The jig and pant combo was then aligned to the centerline by marking the centerline of the pant in the jig and making sure the measurements from the displaced centerline to the jig centerline matched as perfectly as possible front to back. It’s then that you drill the holes through the pants lining up with the holes in the fairing brackets. This is done by shining a light on the inside so you can see the outline of the hole against the gel-coated fiberglass surface. Once those holes are done and oblonged as needed to align things perfectly.. The area on the inside of the pant, where the screw goes through and mates with the fairing bracket needs to be beefed up with flox. This was done by drilling several small holes around the screw and squirting the epoxy/flox/cabo mixture into them with a syringe.

Closeup of rear screw locations while flox was curing
Closeup of front locations of the screws into the wheel fairing brackets.
Everything all aligned.

You then also beef up the area where the gear extension is with a flox/cabo mixture. After that cures, you take the pants apart and place nut plates for #6 screws where the cleco holes were.

Most of the screws are in place here.

All of the same things were repeated on the right side. Below are some better pics of the trimming reliefs for the gear leg.

Right pant all aligned.
Right pant done too.
Both main wheel pants done!

Engine Has Arrived!!

I was supposed to go to Aero Sport Power in Kamloops, British Columbia to help build my engine the week of April 19th, but that didn’t happen with the state of the world and the Canadian boarder still being closed. So instead they built my engine for me and have invited me to come at a later time for the experience when things are better. I plan to take them up on that offer. I won’t be building my engine, but it’ll still be the same engine.

After making the final payment, I received tracking info and had been watching it make its way across Canada and into NY. Seeing this was a freight company and a residential lift gate delivery.. I expected to get a call when the crate arrived at the regional distro center to schedule a delivery..

I’m currently working 50% from home and 50% from the office and it was my turn to be in the office.. I refreshed tracking around 10am and saw the crate was out for delivery… YIKES!! I’m at least 30 minutes away.. I quickly called the company to confirm and they said he should be there sometime around noon.. Fortunately, I had enough time to get home and get the tractor ready with the bucket forks in case I needed them to move the crate up to the garage.

The driver called when he was a few miles out and asked if I was home because he had noticed it wasn’t a scheduled item… I told him I was and what happened and he confirmed that they should have called me..

Happy I caught it in time to be there for the delivery. Seeing the crate was already on a pallet jack, the driver was nice enough to wheel it up my 600+ft driveway and into the garage for me.

Engine crate
I think I’ll take the plastic off.. 🙂

Below is a picture of the rear of the engine. Here you can see the secondary alternator in the upper right. The Airwolf remote oil filter adapter in a deep gold color below and to the left of the alternator. I will place the oil filter on the firewall in a more convenient place for draining the oil with hoses running back and forth to here. Note that the round gold covers with 3 holes in the middle cover the standard spot for magnetos to go. I’m using the SDS EFII system and these will house the ignition coils packs instead. Below the left-most magneto cover, there’s a sort of triangular shaped cover for where the engine based fuel pump goes. Again not needed with the SDS EFII system, so it is capped off. There are also various oil connections to and from the oil cooler, breather tube, sensors, and to connect the Barrett Cold air sump.

Rear view

A top view of the engine. Here you can see the SDS fuel rail mounted on top of the case split and the plumbing to each cylinder injector. I may later decide to move to a fuel block on the rear part of the engine baffling and route the runs to each cylinder from there. You can also see the white electrical wires that are the 2 (redundant) hall effect sensors that sense the location of the crank. This is done with small magnets that have been installed in the flywheel at specific positions so the ECU can know the relative position of where the engine is in its combustion cycle. The unfortunate thing is going with AC, I need to use a different flywheel that has 2 pully grooves, so I’ll have to get a new magnet set, drill holes in the flywheel and install per the SDS instructions.

And a couple of side pics

Right side view
Left side view

It is truly a thing of beauty!

Here are the full specs:

Aero Sport Power New Engine Kit IO-540-EXP Includes:

Factory New Lycoming Cylinders (Ported and Polished), SDS High Energy Ignition and Electronic Fuel
Injection with Dual ECU, Harness, Spark Plugs, Sky-Tec Light Weight Starter, Roller Tappet Camshaft and
Lifters, Oil Sump, B&C 60 Amp Primary and 30 Amp Stand by Externally Regulated Alternators, Full Tanis
Preheat System, Connecting Rods, Balanced Counterweighted Crankshaft, Crankcase, Ring Gear, Inner
Cylinder Baffles, Dipstick and Tube, Airwolf Remote Spin on Oil Filter Adapter (without oil hoses), Vacuum
Pump Adapter Housing. The engine was painted a 2 tone graphite and black. Additional upgrades:

  • 9:1 Cylinder compression ratio
  • Barrett Cold Air Induction sump.

Unfortunately Aero Sport doesn’t Dyno their engines, so I’m not sure how much horsepower this baby makes, but with the 9:1 compression ratio, the Cold Air Induction, and the port/polished cylinders I expect somewhere in the 280-300HP range over the 260HP stock IO-540-D4A5 engine.

Now to finish up the gear pants and leg fairings so I can get this mounted.

Wheel Pants Part 1

Another task to do before the engine arrives and gets hung is to install the wheel pants and leg fairings. This step requires you to jack the plane up to get the weight off the wheels. I’d like to get this step done now before the plane bulks up another approx. 400lbs. Otherwise I’d likely end up waiting until the wings are on and jacking it up by the tiedown locations, which means I’d probably procrastinate and have to do this after I’m flying.

You start the wheel pants by sanding the two halves of the pants where they are built up to make them fit together well. The plans then have you trim/sand the front flange as required to get a square fit. This was accomplished by running a sharpie around the circumference of the pant on a flat table. I then trimmed to that line.

Marking the trim line

The next steps have you find the vertical and horizontal center of the aft end of the pant. The use of a laser level helps here.

You then mark the locations to drill holes to mate the two parts as called out in the plans. I used a piece of tape with the various measurements needed to accomplish this paying attention to left vs right as the dimension are different on each side and are mirror images of each other.

Tape with measurements to mark hole locations
All holes drilled and held together with clecos

The next task is to mark the equivalent horizontal mid point on the front of the wheel pant. You use a wooden fixture to help hold the pant into position while making sure the aft end is at the plans specified height. Also making sure to make sure everything is plumb and square.

Aft end at proper height

Again a laser level makes easy work to transcribe this line to the front of the pant. I used the square with the tape mark on it to double check that is was correct.

Now comes the point where you need to jack up the plane. The plan is to place jacks under the main wing spar on either side of the plane and jack up the plane. Then you must make sure that the plane is in flight level attitude as described in the plans. Levels were used to confirm this. I had some adjustable screw-style jacks that I had planned to use for this, but what I found out is that the adjustable height nature of them made for too much wobble side to side, which made me very uncomfortable. The one thing you do need to make sure of is that you’re careful when jacking this thing up entirely off the ground. It can easily fall off the jacks and cause damage or worse injury… So I decided to go buy better jacks that I’ve seen many people use from Harbor Freight and have a local guy weld some bases on so they won’t tip over. I will most likely be using these on at least an annual basis during condition inspections to lift the plane up, so the investment is not wasted.

Jacks with welded bases on.

I then used some steel angle I picked up at the hardware store and a length of 2×6. I make 1/2″ holes on one side to go through the large hole at the top of the jack and a couple of holes to attach the 2×6 to the angle with a couple of bolts per side. I then added padding to the 2×6’s and the end result was much more stable.

Finished Jacks minus padding
Plane up on jacks in flight level attitude. Also note the wooden jig in place for test fitting

I then worked on making a jig to hold the pants into position for me as I’ve seen others do. This will help hold the pant perfectly in place the correct distance to the “floor”, which becomes the top surface of the jig. In each corner there are adjustable feet so I can get things perfectly level.

1 1/4″ spacer taped to the top of the wheel
Setting the proper height above the floor (jig) for each end of the pant.

Up next is to start drilling holes and getting the pants properly lined up on the wheel assembly itself.

Aerosport Interior Panels

Couple of small things to finalize about the gear installation prior to moving on to getting the interior panels trimmed.

First was to tackle the hardest bolt in the airplane to install. The bolt that holds down the nose gear donuts. This thing requires a lot of compression to even get the bolt hole to line up. Luckily, I have a tractor. So I strapped the engine mount to my bucket and let the hydraulics do the work. Even still, the bolt was stubborn. I feel for others who have said they’ve had family members hanging off the engine mount while someone pushed the tail upwards while trying to muscle that bolt in place.

Tractor comes in handy!
Hardest bolt installed!

I then got the plane repositioned in my garage. It’s now kiddie cornered across 2 stalls so I have room for the engine to be mounted and still move around it.

I also got the brake lines installed and taped to the gear legs.

Brake lines taped

While I’m waiting for my engine to arrive, I’m knocking off misc items still to do on my list.

I started getting the interior side panels trimmed to be able to paint them. I started with the rear panels as they don’t require too much trimming. I did have some adjustments to do as I did build up the door areas a little more than stock, but the trimming wasn’t too bad.

Left rear and baggage door panels
Right rear panels

There are 4-5 screws that need to be located and nut plates added to hold the panels in place.

Then it was time to tackle the front panels. These require a bit more trimming, especially around the front door frame where I built things out a bit more with micro.

Front left panel in place

One trick I saw used was to use a compass scribe a line matching the contour of the area around the door frame. Trimming to that line, gives a good fit. This marking and trimming around the frame was done progressively until everything fit well. Taking a little off at a time is key here.

I then placed the instrument panel in place to make additional trims around the air vent area until it all fit well.

This process was repeated for the right side. I do have AC hoses routed down the right side, so I additionally had to trim the front of the panel to alleviate interference as the hoses leave the firewall and start their journey down the right side. I can now paint these when I have some time..

Up on the Gear!

A very late post of this content that I found in my drafts.. Apparently I started on this, but never finished/published it.. so I’m doing it now.

The wheel fairing brackets needed to be modified to accommodate the Matco brakes. The AN fitting for the brake line interferes so a section needed to be cut out as marked below.

I added an extra piece os .125″ material riveted on where the piece was cut out, but offset to allow a pocket for the brake line AN fitting to sit in.

The wheels were prepped and the tubes and tires placed on them.

All 3 tires and wheels done.

Then the plane was lifted up onto the table with the help of several friends and family. It was much heavier than anticipated. I utilized a 2×4 through the wing spar area for a person on either side. One person lifting the tail and another lifting at the firewall. Yet one more person to help position the table.

Now that the plane was up on a table, I could then slide the gear legs up into the weldments. I used some grease (same as the wheel bearing grease I have) on the legs to help get them into place. Once close, I used a curved pair of tweezers to feel the edge of the hole in the leg itself. I made small adjustments to get the hole in the weldment aligned perfectly with the gear leg hole. Once I could “feel” the inside of the hole all around without any misalignments between the two, I then reamed out the hole to final size.

Bolt and washer(s) and nut were installed..

Left gear leg installed.

After priming the gear fairing bracket, I continued assembling the Brake assembly per the Matco and Van’s instructions.

The initial brake assembly was put into place and the axle was drilled for a bolt (which was later turned the other way to avoid interference)

Rotor and other pad in place.

The wheel bearings were then packed with grease using this nifty tool from Amazon.

Then the wheel was installed on the axle.

Rather than oblonging the axle nut hole as depicted in the Macto instructions, I opted to drill a 2nd hole a little farther inboard as depicted below. The Van’s instructions were followed to count the number of turns required to remove the nut.. then the wheel/tire were removed and the nut added back the same number of turns. The axle was then matched drilled to the hole in the nut.

The assembly was then put back together and cotter pins added through the axle nut and the wheel fairing extension.


The same steps were repeated for the right side.

The nose wheel fork was prepped and primed.

The nosegear leg was then put into place.

Initial fit of the nose wheel in place.

The rubber donuts for the nosegay were put into place, but not compressed down yet

With all of that done, the plane was pushed off of the table and onto its own gear for the first time!!! Pictures below of it wheeled out into the driveway and back into the garage afterwards. For now, a table is used to hold up the tail until the engine is put on.

A Major milestone complete!!!

Finishing the Windscreen Fairing

First up while the layup was curing was to make a 7″ radius sanding tool. I had a 4×4 piece of lumber that I ripped to be the same length as the width of the layup.. Then I marked the radius from the metal tool I had made onto the side. It took me a couple of tries to figure out how exactly to mark it (as you can see) in order to have it end up being correct. I then cut it out on my bandsaw and compared to me template.

Marking the 7″ radius
Comparing the result to the template.

I used this tool with 50 grit sandpaper glued on initially to sand the shape across the front. The shape is mostly flat as you approach the sides where the leading edge of the door is. In between the front center and the extreme edges, the contour continually changes making it hard to sand. I ended up using the 7″ radius block I had made angled at about 45 degrees and occasionally used circular motions as well. I feel like it worked well.

The idea here is there are 2 layers of electrical tape on the windscreen and the metal fuselage. You continue to sand until you’re just scuffing the surface of the top layer of tape. Once that happens, you take the top-most layer of tape off and continue sanding with finer grit until you start scuffing the bottom layer. This will help create a feathered edge onto the mating surfaces. Once I was done with sanding (several days worth.. ) I started to fill some low spots with epoxy and micro.

Getting closer

Once satisfied with the overall shape, you start to put a skim coat of epoxy down to seal up the final part and fill any pinholes. A very similar process to what I used to finish the overhead console. I used a squeegee and a foam roller to get good coverage and left it to cure overnight.

Closeup of the final shape
little bumps of epoxy will be sanded out once cured.

Once done, I pulled off the tape to see the result.. Here is a shot along the left side.

A view from the inside where you can see the really nice black line all the way around the base of the windscreen. Very happy with how this turned out!

I still have some touchup to do along the feathered edges and then I will be using some high-build primer to paint the fairing. I’ll leave it that way until paint.

Windscreen Part 2

The next part of this process is to do a fiberglass layup along the base of the windscreen and the metal fuselage. To start, you mark the boundaries of the fairing area with high quality electrical tape. For the boundary along the plexiglass, I used my 7″ radius tool to mark where it hit the plexiglass along the center and front areas. I also did that along the sides, but the curve starts changing from an inside radius to flat along the sides. So I sat inside and looked at it visually and adjusted it a little bit downwards until I got something that I thought was visually desirable. In order to make sure the fairing is at an equal height on both sides, I made a template aligned with the skin seam to mark the same location on both sides. Making sure to be as close to 90 degrees as possible to the joggle/Silpruf line I just finished.

Template for fairing height on each side
Upper Line for fairing

I then marked the line around the bottom part of the fairing on the metal fuselage. I came back approx 2″ from the base of the Plexiglas, but ended up adjusting the sides downward a bit later on.

Left side Fairing boundary
Right side fairing boundary

Everything was then sanded very well with 50 grit sandpaper to ensure proper bonding. I then cleaned the surface really well with distilled alcohol until no sanding residue came off. Next up was to mix up epoxy and micro to fill the gap at the base of the windscreen. I tinted this mixture with black tint. Another hint I got was to paint the insides of the clips that hold the windscreen in place black too, which I had done prior to riveting them in place. As the curve flattens out on the sides, more micro was added downwards to blend the the two surfaces.

Tinted micro and epoxy on left side
Micro/Expoxy from right side

Then I sanded the micro mixture down the next day after it cured. There were a couple of low spots mostly along the sides, so I added a little more and sanded the remainder the next day.

Sanded Micro on left
Sanded micro on right

Once the micro was sanded down I re-looked at the gap needing to be filled with fiberglass.

I decided to follow the video series that Van’s put together for the RV-14 here: https://www.vansaircraft.com/faq/canopy-fiberglass-fairing-how-to-video-series/. There are a couple of main differences between the videos and the RV-10 plans. First off the RV-10 plans have you start with small strips of glass and work your way to bigger and bigger strips. The RV-14 videos start with a layer of glass the goes the full width of the tape and it is also tinted so that it produces a completely opaque layer so all you’ll see from the inside is solid black where the layup is. Then the rest is done proceeding with narrow strips to wider strips until you get close to the edge of the first layer. This should create a nice feathered edge. One other slight difference is that the RV-14 videos show a couple of different large side pieces of glass that are cut somewhat on the bias. I cut these too and used them in a similar fashion to the videos.

The RV-14 videos refer to paper templates that come in the plans.. Well since there is no such thing for the 10, I ended up making templates for the first layer in 4 sections.

Two rightmost templates
leftmost template

I then got to cutting the first layer of glass per my templates, two of the larger side pieces per another template I made.. along with smaller side pieces (about 1″ smaller in all dimensions compared to the larger side piece) along with all of the the glass strips called out in the plans.. Adding a couple of 3 ft. 1/4″ strips too. I setup the bench to cut the glass with a craft fabric cutting board underneath along with a rotary cutter, which made fast work of the cuts.

Cutting glass strips

I then mixed up epoxy with the black tint and applied it to the faring area. One thing I noted is that it wasn’t very dark like I saw on the videos. I pressed on all the while thinking something wasn’t right, but figured it might darken up when it cures.. I followed the videos instructions for wetting out the first layers sandwiched in plastic wrap with the tinted resin. I cut them down to size with the templates and placed them into position using a brush to make sure there were minimal air bubbles underneath.

First layer from the outside

After the layer cured.. I just wasn’t happy. I knew I should have stopped when the resin applied to the windscreen was not thick and opaque like in the videos. Below you can see how translucent the first layer really was.. I talked with another builder who followed this process and a similar thing happened to him too. He also has a friend who has something similar and left it this way and is very unhappy with the results.. The bottom line is the videos depict that there isn’t much tint needed when you mix it up with the epoxy, when in fact I felt like I had to pour half my bottle in to get it to the thickness and opaqueness I desired… Thankfully it’s fiberglass and can be fixed… So I spent a few sessions over the next few days sanding away the layer along the window until I got back down to plexi again. Lesson learned… I didn’t bother sanding the layer on the metal too much other than to rough it up for adhering to the next layer.

Bad translucent first layer.. Not happy with it!
Sanding away the mistake…
Completely back to Plexiglas.

Now with the proper tint to epoxy mixture, I recut some glass from slightly modified templates and applied a new first layer to the windscreen area overlapping somewhat with the existing first layer on the metal.

2nd time view from the outside.
A view from the inside.. Much better!!!
Closeup of the inside.. Happy with this result.
A view of the first layers tinted in black from the outside

Then I didn’t take a whole lot of pictures as you’re working with the pre-cut glass strips, placing them into position and wetting them out with a brush and straight epoxy. Here I was getting close to 8 glass layers in place as I’m wetting out this piece. I also ran back to the cutting table and cut some smaller strips needed as I went along. It was a repetitive process of looking at things with the template and occasionally adding some small strips to build up some areas prior to adding the next wider piece for the next layer. I did do some adjustments along the sides too as there was a slight drop off from the plexiglass layer to the metal.I used small strips of cloth to raise that level up before adding some wider sections to finish off the sides and hopefully I’ll end up with a flat surface in that area.

About 8 layers in

As I approached done.. a Final check of the 7″ radius template shown below pretty close to perfect.

Gap filled in.
Final view of the finished layup.

The final step is to brush epoxy on and apply peel ply to finish it off.

Peel Ply!

So now this will cure for a couple days. Then I will be sanding it down with a 7″ radius sanding block across the front and other blocks along the sides. More on that and filling in any low spots on the next post..

I’ve also started working on the wheels/landing gear section while I’m waiting for this to cure… Next major step is to get this puppy on gear! That’ll be a huge milestone!

Windscreen part 1

A couple of pics of all 4 side windows now done with the front right window curing.

Left side windows
Right side windows

It was then time to start on the windscreen. It was masked off to help protect the plexiglass from getting scratched. Then began the process of trimming. Not too much trimming was needed with the Cee Baileys windows and this one was no exception. I marked the centerline of the fuselage and the window at both the top and bottom to make sure I was always putting it in basically the same position before each marking and trim session. I did trim some off of the front to tilt the window downwards a bit and alleviate the bottom corners bulging outward due to the plexiglass hitting the curved part of the upper forward fuselage. Once I was satisfied with that and made sure that the plexiglass was entirely sitting on the aluminum, I moved on to trim the top. This was solely to create the 3/16” gap which will follow the same Silpruf method as the side windows.

Placing the windscreen in position
Marking the centerline
Centerline marked on bottom of windscreen
Top gap trimmed

Then I fabricated clips to hold the bottom part of the windscreen in place and put them approx 12” apart along the bottom edge of the windscreen.

Clips being added
Final test fit with a couple of clecos

I then installed the Sulpruf standoffs along the joggle and made sure everything was masked around the window.

Standoffs

I then prepped the inside of the top part of the windscreen just like the windows with masking and eventually a boundary layer of Silpruf 12-24 hours ahead of putting the window in. I was a little conservative with the bead of Silpruf I put along the joggle, but wanted to have too much rather than too little. As Zach says in the videos: “ I’d rather you be an overgluer than an undergluer. “

Squeeze out
All done with masking removed
Front view
Left view

The whole masking process of the inside of the window produces a really nice black “line” along the window joggle once the window is in and the tape is pulled.

Silpruf “line”

Next up is to do the bottom interface between the plexiglass and the fuselage. This will be a fiberglass layup mostly following the plans, but I have watched the instructional videos the Van’s has put out on the RV-14, and I’m planning to do it more that way. It’s just a slightly different way to layup the fiberglass with the use of tinted fiberglass the full width of the layup as the first layer. This will provide a very uniform line along the base of the windscreen as you look at it from the inside. To start the process, I made a 7” radius tool to mark the upper bounds of the layup on the plexiglass. More on that fairing on the next post.

Window Install

I decided quite awhile ago that I wasn’t going to follow the plans for the window install. The main reason is the plans have you bonding the windows in with adhesive and then using fiberglass cloth over the gap between the plexiglass and the fuselage. With all the differing materials expanding and contracting differently, this fiberglass area is prone to cracking, even if done perfectly. I became aware of another process that other builders have been using and is outlined in a 5 part YouTube series here https://www.youtube.com/watch?v=A336SG-fsiI&t=405s . It is used quite extensively in the Glastar/Sportsman series of aircraft and involves using a silicon based Silpruf adhesive. This is the same stuff that is used to hold windows in skyscrapers. Hopefully it’ll be good enough for my lowly RV-10. 🙂

I spent a fair amount of time ordering supplies after watching the videos and taking notes. I began by fabricating a scribe tool from the cap of a wet erase marker. Fortunately my wife had a hot-glue gun, so one less tool to have to buy… 🙂 The idea here is to cut the cap so the pen fits in snug and have the tip of the wooden piece I cut from a popsicle stick be about 3/16″. This tool will be used to follow the indent of the window joggle and the wet erase marker will mark a line 3/16″ away on the window setting the visual gap you will have.

Below you can see the scribe line on one of the rear windows and the angle grinder used to trim the window with sandpaper. It’s helpful to have a white background while doing this to bring out the black line as you’re sanding, so I bought a white blanket and threw a white sheet on the floor.

Sanding with the Angle Grinder

Probably the hardest time I had was finding the right stuff for the using the angle grinder. I ended up buying a 5″ Phenolic disc from my local auto parts store similar to this: https://www.amazon.com/DEWALT-DW4950-5-Inch-Phenolic-Disc/dp/B00004RHAW. I also bought 5″ circular 80 grit sandpaper with adhesive backing. Then I needed to figure out the adapter I needed to hold the phenolic disc on and be flat. I ended up buying this and it worked great! https://www.amazon.com/gp/product/B000A8NM8O/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

Below you can see the uniform gap left between the edge of the trimmed window and window joggle.

Looking up the top edge of the window
Another angle
A little more trimming left in the corner
The final trimmed window.

After sanding the edge of the window to get rid of any marks from the sanding process along with putting a radius on the outer edge of the window, #40 holes were drilled along the edges of the window to hold wing-nut clecos with wooden bridges spanning the gap holding the window in place.

Once that is done, a sharpie is used to mark the outer edge of the window in the joggle. This will later be used as a line to mask to with tape. Additionally, the inside of the window was marked with a wet erase marker along the joggle edge. That line will be used to apply a specific masking tape pattern to the inside of the window.

Next up was to mask the inside of the window. This starts with a 1″ blue tape which is kept approx 3/16″ from the line. Then 1/4″ masking tape is used to mask as close to the line as possible without covering the wet-erase line at all. Once satisfied, the line is wiped away with a slightly damp cloth. A second application of 1/4″ tape is applied over the first with an overlap.

Blue masking and double 1/4″ masking done
Closeup showing the 2nd 1/4″ tape overlapping the first to cover its exposed edge.

The front edge of the window was covered in 2″ tape and back-cut with a razor blade. Additional tape was added to cover up any exposed glass.

The right rear window was being worked on at the same time.

After masking to the line in the window joggle and adding a bunch of extra tape (this is due to the Silpruf being silicone and if it gets on the surface of the plane it can cause fisheyes in the paint. So extra precautions were taken.) I got to placing previously Silpruf standoffs around the perimeter of the window. A few days prior, I had run beads of Silpruf out on some scrap metal and let them cure. I used Permatex ultra black gasket maker to adhere these standoffs to the window joggle. Once those cured, I took the window, put it in place, and progressively trimmed the standoffs down in groups of 3-4 at a time until the window was flush (or as flush as possible) with the fuselage.

Left rear standoffs
Right rear standoffs.

While this picture is after the window is in, it depicts how I used the razor blade to check to flush to fuselage.

Then when you are ready to install the window, you must lay down a bead of Silpruf on the exposed area of the window and spread it out with your finger. This is referred to as the boundary layer. The first 1/4″ tape is pulled leaving the second 1/4″ tapes edge clean and a small gap between this boundary layer and the tape. This must be done 12-24 hours ahead of actually installing the window so it has some time to partially cure.

Silpruf Boundary layer smeared on window
first 1/4″ tape pulled off.
Closeup of the gap left between the remaining 1/4″ tape and the boundary layer.

Then after 12-24 hours have elapsed, you spread a small amount of Silpruf to fill in that gap left. Put a generous bead of Silpruf on the window joggle so it’ll cover the entire width of the joggle with some squeeze out. The window is then put into position, cleaning of the squeeze out is done with an approx 1″ wide squeegee and clecos are inserted all around. Additional cleanup is done between the clecos. Then the tape around the perimeter of the window that was placed to the previously marked line was removed. Each cleco was taken out and the wooden bridge was flipped to avoid getting any Silpruf on the fuselage part of the airplane. There is some additional work to spread out the squeeze out on the inside of the window, culminating with the removal of that last 1/4″ tape. Below is a picture after the left rear window was completed. It’ll now sit for several days, of which I kept the garage heat on for the first 2 days.

Left rear window done and curing
View of the inside after complete and curing

Seeing I only really have enough clecos for 1 window at a time (and maybe I’m going a bit overboard with the 30-ish clecos I do have) I really want to have a good bond for these things, so it’s worth the extra few days of waiting for one window to cure prior to installing the next one. In the meantime, I’m trimming and getting the front windows ready for install.

View of the gap on the front left door window.
Left side windows in place (rear one curing)

Based on my schedule, I left the first window cure for 5 days prior to removing the clecos and moving on to installing the right rear window. Here you can see the finished results, which are a very nice black line around the permitter of the window, which is ascetically pleasing. After paint, the gap will be filled in with Silpruf forming the final look, but that is still quite a ways away.

Closeup of the finished window edge.
Slightly different view

Below you can see the right rear window is now installed and curing.

Right rear window installed and curing.

In the meantime, I’ve managed to get the front left door window all prepped and masked off. The Joggle is masked and standoffs are in place and trimmed. All that’s left is to install the window once I’m comfortable removing the clecos from the rear right window once it’s fully cured.

This process will be repeated for the front door windows, then it’ll be onto the windscreen, which is going to be part this process and part laying up a fiberglass base. More on that as I get to it.