Wait! Did I Buy A Cozy?

With the elevator debacle under control I decided to sweep up the metal shavings and switch gears to Section 12–empennage fairings–one of the few tasks left to do. Section 12 covers the installation of composite fairings to elevator, rudder, and stabilizer tips. The molded tips come as part of the empennage kit but some must be modified by building up one side with raw fiberglass cloth. The plans are extremely basic, describing a two-step process through very clean-looking engineering drawings. Little did I know how much “character building” would be involved in saga that unfolded over the course of multiple weeks.

Some time ago I had ordered the composite practice kit from Aircraft Spruce. I ordered the version that comes with Burt Rutan’s “Moldless Composites Sandwich Homebuilt / Aircraft Construction” (a $15.50 value!), figuring it would be useful to learn from the master. For some reason this SKU was backordered (the kit with just the raw ingredients would have shipped immediately) and so it didn’t arrive until early January. When it arrived I wasn’t sure I’d made the right decision since the manual’s contents weren’t any more illustrative then what I can find online through EAA and YouTube.

Regardless, the kit came with everything I needed to get started, including West Systems resin and hardener, fiberglass cloth, flox and micro, cups, stirrers, gloves and more. The accompanying manual suggests several practice projects with which to get familiar with the materials and processes but, frankly, none seemed all that interesting. I suppose back when Rutan wrote the manual (apparently using a typewriter and ink pen) someone reading it would be mystified by this “magic” process. Today, when composite manufacturing is practically live-streamed (not only aircraft, but boats, custom cars, and more) you (or, rightly, me) feels like they understand what’s going on.

And thus I decided to jump right in.

The tasks called out in the plans are fairly straightforward and go something like this:

Trim excess material to ensure the fairing will mate with the matching aluminum part.
Remove any excess epoxy/gel coat from the joggle along the flange perimeter.
Match-drill the fairings using the pre-punched holes in the aluminum skins.
Dimple the skins and countersink the holes in the fairings.
For fairings with an open side, enclose with three layers of fiberglass cloth and resin.
Attach the fairings (except for the lower rudder fairing, which waits until lighting is sorted) using CS4-4 blind rivets

There are several considerations that affect the fit and finish of the fairings. Rather than provide a chronological narrative of the process (since that would result in a 70-page blog post) I will present some highlights of each stage along with lots of pictures as well as my observations, learnings and frustrations.

Mis en Place

As when making a great meal, each stage begins with prep work. First you must sand off any resin/gel coat in the “joggle” where the fiberglass parts get riveted to the aluminum structure:

I tried using a razor blade for the first few passes but this proved cumbersome and not all that effective. I found using a flat file much easier. Just hold the long edge of the file snug against the corner and work it back and forth until it’s square. It’s a bit hard to see in the image below but goal is to get a nice clean edge so there isn’t a gap when you rivet these onto the metal components.

Failed to get a picture of the technique but you can (kind of) see the results

The next step is to trim excess material from each part. I used a Dremel tool with a cutoff wheel as well as painter’s tape and a reference line to reduce splintering.

One thing to be careful of at this stage is the width of the flange. The plans specify a nominal width but I would recommend making it a bit oversize and then sanding to fit. Otherwise you risk not leaving enough material to support the rivets (see below).

Match-drilling and countersinking the fiberglass parts is pretty much the same as when working with aluminum, involving clecos, #30 and #40 drill bits, and countersink cage.

Match-drill #40 first, then final-drill #30

Where Are The Dressing Rooms?

One thing you might have noticed in the photos is that the fit between the rudder and rudder fairing was, er, not great. In case you missed it, here’s a close up:

Oh, by the way, see that cleco right above the counterweight attach screw? The placement of that rivet hole is ambiguous in the plans drawings (note the lack of handy-dandy dotted lines below) but the text states you need to use an odd number of CS4-4 rivets and there does appear to be a hole drawn on the forward end so I assumed a rivet was needed there. If my rudder falls off because I misinterpreted the plans then now you know why.

18 lines, 19 rivets–the story of my life…

In retrospect I would recommend prepping the fairings while assembling the tail section components so you can check the fit and attempt any adjustments. However, because the rudder was already built when I got the kit I didn’t have that opportunity. My first thought was to attempt to improve the fit with some composite treatment. (I had never used composites before and so assumed they were effectively magic materials.) After stewed on the issue, though, I decided to try to improve the fit of the aluminum skins. Keep in mind this piece has to line up with the vertical stabilizer tip fairing and I determined just slathering on fairing compound was not going to provide the finish I wanted.

My fix involved removing the rudder counterweight, filling in the top screw hole as well as the infamous 19th rivet hole with JB Weld epoxy (using duct tape over the holes), clamping the skins tight around the fairing, and re-drilling the holes.

You can see how much the top portion of the rudder skin squeeze together (about 1/4 inch) the final photo above. You can also see a layer of JB Weld I applied between the two skins after reassembling the skins. Eventually all this will be covered with a layer of composite material.

Sometimes You Can Be Too Trim

The rudder fairing was the first piece I tackled and (naturally) I took off a bit material more than needed. To avoid having the fiberglass crack at some point in the future I borrowed a tip from another builder and patched in a thin strip of 0.020 aluminum using a strip of bi-directional glass cloth and resin.

Hold me tight and I’ll hold you tight (but not too tight)

You can see that I only added the aluminum to the forward sections where the flange was too thin for my liking. Also, the tips of the cleco clamps are wrapped in packing tape to prevent them from becoming permanent fairing accessories.

I made a similar mistake when trimming one of the h-stab fairings, cutting it to close to the end, right through a rivet hole.

In this case, though, because I needed to build up the open side with fiberglass, I assumed (correctly for once!) that enough material would get laid down to provide a reasonable anchor point.

Cutting in Three Dimensions

One of the challenges of trimming these fairings in particular is getting the upper and lower curves to align with the elevator fairings. You want to follow the contour of the elevator tip and fairing, leaving just enough space to ensure the elevator can move freely but not leave so much clearance that it doesn’t look pleasing to the eye. As with my aspects of the build, the solution is to work slowly, making small adjustments as you repeatedly attach and remove the fairing using clecos.

You can see above that before you close out the aft portion of the h-stab fairing with fiberglass it protrudes a bit outside the edge of elevator fairing. My solution to this was to make the temporary foam rib (see below) a bit taller than the profile of the h-stab fairing, thus “tucking in” the outboard curve.

R V Serious?

See what I did there? Subtle Latin reference. I crack myself up sometimes!

One of the most mysterious aspects of constructing the fairings involves enclosing the open side of the elevator and vertical stabilizer fairings with fiberglass cloth. The diagram in the plans that tries to explain this is deceptively ambiguous.

The first stab is to fashion a temporary rib out of foam and shape it to the fairing profile. I ordered some PVC Divinycell foam from Aircraft Spruce for this even though the composite practice kit came with some blue foam insulation pieces. I figured I might need it for other projects at some point in the future. At this point he plans are not very explicit as to how to go about forming the rib. Here are a couple of things that I took away from the process:

You can approximate the profile of the fairing by firmly pressing it into the surface of the foam.
Given the curve of the elevator counterweight, the rib should be made somewhat concave, not straight as it is shown in the plans.
Unless you like digging out pieces of foam and epoxy from hardened fiberglass, consider wrapping the temporary rib in packing tape. Argh!
Rather than making the rib flush with the back of the fairing as shown, recess it 1/8″ or so to provide a “well” to fill with fairing compound/micro-balloons. Argh again!
Make sure to test fit the fairing and attach with clecos until you are happy with the profile. Yay!

First experience working with fiberglass and so far Virgin Galactic has not called with a job offer

As you can see from the last photo, the first layer of cloth detached from the fairings in a few places. I figured this was okay because most of the strength was going to come from the two layers applied inside the fairing. As long as I was happy with the shape (you can see this in one of the photos) I decided to move on. Also, because I did not apply packing tape there was some foam residue on the inside of the fairings but, again, since this was going to be saturated in resin in the next stage (and no one except me–and, well, you–would know about it) I felt it was okay.

The next two layers of fiberglass cloth went on pretty easily, though getting it to lay down in the tight inside curves was a but tedious. Incidentally, even though the composite kit came with calibrated pumps for the West epoxy system I found it easier to measure the resin and hardener by weight (5 to 1) since I was working with such small volumes. I used a small digital scale I had bought for the kitchen.

Super-sharp shop shears (alliteration!) and a Dremel tool with cutoff wheel made quick work of cleaning up the excess cloth and resin.

This Page Intentionally Left Blank

After reinforcing the fairings the next (and last) step in the plans is to rivet them on to the appropriate tailfeathers.

Fiberglass, meet Aluminum. Aluminum, Fiberglass.

While the plans don’t dictate anything beyond this I have seen numerous builders apply composites to the joint between the two materials to make a more visually pleasing interface. In fact, the junction between the two components did look pretty amateurish. I contemplated leaving them as-is to reinforce to the FAA that this aircraft was, in fact, built by a total noob but, in the end decided to attempt to replicate my esteemed peers’ work.

In retrospect, I have to question that decision for the sake of my sanity. What became apparent quite quickly is something I’m sure builders of Long-Eze, Glasair and other composite aircraft are well acquaint with–the frustrating and fruitless hunt for smooth perfection. In a way, it is the definition on irony. I am building an aluminum aircraft, where subtle ripples in the skill and rivet lines are part and parcel, but somehow believed the tiny pieces of fiberglass at each tailfeather tip needed to exhibit the characteristics of the Hubble telescope’s main mirror. In case you are similarly afflicted I’ll briefly describe the high points here but, in truth, I am reluctant to relive this portion of the build.

I started by applying a layer of West Systems 410 filler to the individual parts in order to create a semi-smooth surface. I followed this up with a sanding and a layer of epoxy and micro-balloons. More sanding and a second layer of micro–followed by more sanding–yielded satisfactory pieces which I then riveted on to the main structures. I varied sandpaper grit from 80 to 220 and found these Durablock sanding blocks to be super useful.

I was hungry and had to keep telling myself it wasn’t peanut butter

Once riveted, I applied a layer of painter’s tape to protect the aluminum skin and repeated the 410-sand-micro-sand process to file and feature the gaps between the fiberglass and aluminum parts.

Because I love things that take multiple steps separate by hours of curing time

Once I had achieved reasonable good contours I hit the tips with a coat of SEM self-etching primer, which helped highly any ridges, valleys and pinholes. (It also offers a layer of protection to the layer of Alclad sanded off during the process.) Then it was back to spot filling with thinner and thinner coats of micro and more sanding.

You can have it in any color as long as it’s gray

In the end I was reasonably happy, if exhausted. Remember that gnarly gap between the rudder and rudder fairing? Viola!

There was also a pretty nasty gap where the v-stab met the fairing that I was able to disguise.

Now, to see how it all goes together!

Why She’s “The One”

After the selection of a mate, selecting the type of aircraft to build is an important life choice. A fair number of other builder’s websites include some discussion of why those the particular make and model airplane to build. Since I am nothing if not a sheepish follower I thought I would do the same. It’s important to point out that choosing an aircraft model to build is a complex calculation–not unlike dating–and, like how I met my wife, I fell in love with the RV-10 over the Internet.

Well, perhaps love is too strong a term. Many well-known advocates of aircraft ownership talk about choosing an aircraft based on your ideal “mission”. Borrowing a term most associated with military maneuvers doesn’t lend itself to expression of primal emotions. So, to begin with, I should state that my prioritized list of kit aircraft requirements looks something like this:

Something I can build that results in a safe aircraft
Gets me and my “bestie” places we’d like to visit in reasonable time
Gives me joy when I take the controls
Takes advantage of state-of-the-art technology
Reasonable construction and maintenance costs
Cool looks

The relative orientation of #2 and #3 is the result of living with both an airplane and a spouse. When I ordered the Maule I pictured myself flying around the PNW (Pacific Northwest), visiting remote grass and dirt airstrips “just for the heck of it”. When I started looking for “the (human) one” I didn’t really think about how she’d react. I just assumed that any sane person would revel in the ability to slip “the surly bonds of earth” because, well, d’uh! What I discovered is that “she who I am forever devoted to” was okay with flying as long as it had a purpose, like visiting a cool place (or at least getting an awesome dinner). I didn’t want to make the same mistake twice.

Satisfying #3 is an allusive task. Joy can be measured in many dimensions and certainly there are times when flying is not joyful (I’m looking at you, low-level wind shear). Still, if you’re going to spend this kind of money you really need to love the end result. In my mind one thing that contributes to joy is an airplane that’s easy to fly 80% of the time. Pilots know the feeling of getting the power and trim just right so you can fly the airplane with one finger on the yolk or stick. I got to know my Maule well enough that this became subconscious and, when the winds were mild, created quiet a tranquil setting in the cockpit (the constant hum of a fuel-injected 540-cubic-inch engine notwithstanding).

One of the things that surprised me the most was how easy it would be to satisfy #4. Back when I gave up flying, “glass cockpits” were just starting to show up in light aircraft. The experimental market had led the way but, even so, the options available in 2004 were limited and relatively expensive and most builders were content to stick with traditional “steam gauges”.

ACTUAL STEAM GAUGES: “ROYAL HUDSON” LOCOMOTIVE AT WEST COAST RAILWAY HERITAGE PARK, SQUAMISH, BC

Fast-forward 16 years and my how things have changed! Pretty much everyone building an RV-10 is planning for a glass panel cockpit with integrated autopilot, XM satellite weather, cupholders–you name it! Many have elected to go with a Garmin avionics suite. The creators of the venerable G1000 series for certificated aircraft have an entire line of touch-screen based components for the experimental market.

SPACE SHUTTLE ASTRONAUTS WOULD BE JEALOUS

Now we get to #1 and #5 on the list. In some respects they are related. There are a myriad of companies out there that will sell you aircraft plans or kits. Many more have come and gone. Those that have lasted have done so because they offer solid designs that mere mortals can reproduce as well as great support. This carries over into long term ownership. Something that’s complicated to build in the first place is going to be hell to maintain.

There are numerous companies and designs that have the benefits of longevity and being able to fine tune the construction process which, generally speaking, breaks down along the lines of the main material used. There are still aircraft being built today using wood, steel tube and fabric. White it’s tempting to think of wood construction as something from a bygone era, several designs like the Falco (designed by an Italian, obviously) demonstrate that wood can be beautiful.

THE FALCO: AS SEXY AS A 1980’S POP MUSICIAN

My Maule, in fact, was a bit of a hybrid. It featured a fuselage formed from steel tubing a covered in fabric and aluminum wings.

FUTURE MAULES PLOTTING THEIR WORLD TAKEOVER

Another intriguing material used more and more in aircraft these days is generally referred to as “composites”. The Boeing 787 Dreamliner famously features a carbon fiber fuselage but most amateur aircraft builders don’t have access to multi-million-dollar fabrication machines. Scissors, brushes, and squeegees are readily available, though, which helps explain the popularity of fiberglass construction.

The world likely has one person to thank for the acceptance of fiberglass as a aircraft construction material (not to mention a resurgence of muttonchops), Burt Rutan.

IF YOU JUST DEISGN THE WINGS LIKE MY SIDEBURNS IT’LL FLY LIKE A DREAM

Before we was BFF with Richard Branson and designing vehicles designed to take millionaires to space (and hopefully leaving them there), Rutan designed and built several light aircraft using “mold-less composite construction”, a fancy term referring the process of shaping Styrofoam into airplane-like shapes and slathering it fiberglass fabric and resin until it was as stiff as back back after a night in a hotel room bed. His designs, such as the Vari-eze and Long-eze developed a devoted fan base and inspired other designers. One variation I seriously considered for a time was the Cozy (all Rutan-inspired designed must end in a ‘Z’ sound).

ALL RUTAN-INSPRIED DESIGNS LOOK LIKE THEY JUST CRASHED WHEN THEY’RE PARKED

The challenge with composite kit aircraft is that the builder needs to decide between two extremes: a mostly “plans” option, which is cheaper but requires more fabrication of major components, and a most “kit” option, where the kit provider does much of the complicated work–for a price. Both option result in a very sleek result and lots, lots of sanding. Either would have satisfied priority #6 but the latter was not in my budget. As such I would have been faced with a very complicated build with a material with which I had no experience.

That left what is probably the most popular–and historically voluminous–aircraft construction material: aluminum. While Junkers J1 is considered the first all-metal construction aircraft, the practice of building aircraft from metal didn’t really “take off” until the 1930’s. Driven by war, aluminum aircraft construction evolved into a process that anyone could accomplish. (After all, what was “Rosie the Riveter” riveting?)

PHOTO IS FROM 1943. TECHNIQUE IS FROM JUST NOW.

The list of available aluminum aircraft designs is long. Aluminum is inexpensive and the techniques to make it conform to an aerodynamic shape capable of flight is easy to teach (though tough to master). For a time I was intrigued by a designed called the Mustang II. It was a plans-built aircraft, meaning you paid someone to send you a boat-load of blueprints and his best wishes that you had the talent and skill to follow them.

ALL YOU REALLY NEED–THAT AND A CLOSE RELATIONSHIP WITH YOUR AIRCRAFT ALUMINUM SUPPLIER

I actually ordered a set of plans, if for no other reason to fantasize about how I was a construction mogul (who wore suits with thin ties and drank martinis), but realized this was probably too big for me to take on. (See prior blog posts re: sanity.) That left choosing a design from an established kit plane supplier with a reputation for the ability of its customers to successfully complete and safely fly their designs (see priority #1). Enter Richard VanGrunsven.

THE GODFATHER OF ALUMINUM KIT AIRCRAFT, SANS TUXEDO AND COTTON UNDER HIS LIP

VanGrunsven was an engineer by training who was intrigued by amateur-built aircraft and, after tinkering with someone else’s design, creating one of his own, the single seat RV-3, in the early 1970’s. People took notice and before long he was selling plans and parts that he fabricated himself in a small shop. Over the years the company he founded grew and introduced more designs (there are now 8 distinct aircraft that one can choose from). In the nearly 50 years since Van’s Aircraft started, over 10,000 aircraft of various models have been completed, an unequalled stat in the kit plane world. All that experience, combined with modern manufacturing techniques and a knowledgeable team of in-house experts (and a robust builder and third-party supplier community), has yielded airplane kits that anyone with moderate mechanical skills can safely construct. Priority #1 satisfied!

Now, having chosen a supplier, which model was right for me? Back in the early 2000’s, when I first got the idea to build, the choices were pretty straightforward. Van’s offered just a handful of designs, all two-seaters. The big decision was ultimately seating for pilot and co-pilot–tandem (one behind the other) or side-by-side. Having learned to fly in a Piper Cub (and being righthanded), tandem seating was appealing. You flew with your right hand and controlled the throttle with your left, plus the visibility out of both sides of the canopy was hard to beat. However, Van’s tandem seat models, the RV-4 and RV-8 tended to be a bit cramped, which would be tedious on long cross country flights. As for side-by-side models, the RV-6 was van’s most popular kit and the slightly roomier RV-9 was a great cross-country machine. With the exception of the RV-4 all could be built with either tricycle or convention (tailwheel) landing gear, giving me the option.

Then in 2003 Van’s introduced a completely new (and for them) radical design–the four-place RV-10. It featured the usual aluminum construction but with the addition of a fiberglass cabin top and gullwing doors instead of a plexiglass canopy. It only came with tricycle gear and was not aerobatic, but was roomy and still fast, utilizing six cylinder engines, rather the standard four on other models. The added seats meant I could take my entire family (of 3) and our luggage to a destination of our choice. Along with the scaled-up capabilities came a scaled up price tag (not only for the kit but for the requisite engine and propeller as well) but when you start accounting for the cost to build any aircraft that meets your needs the numbers because abstract very quickly.

The RV-10 buzzed patterns in my brain for the decade or so I was out of the flying game until late this year when I began riffling through the mental file cabinets under “Aircraft: Building”. As of last year almost 1,000 RV-10’s had been completed and Van’s has continued to refine the designs and plans. The aircraft has an exceptional accident record, with many issues attributed to builders not following the plans or making other stupid mistakes. While I had never flown in one (and demo rides had been suspended due to COVID) I had to put my trust in her reputation and what I could learn from her “online profile”. After consultation with “she who will have to deal with a crowded garage for the next several years” I was given the steady green light gun signal (a little pilot joke). On your mark! Get Set!

NOTE TO THE READER: Thus ends the bulk of my ruminations for now. It’s time to get into documentation the build process as it unfolders over the next months and years. Since this is likely to transpire in fits and starts (at least at first, while I await deliver of the next major component kit) be sure to subscribe to get notified when there’s a new blog post:

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