A few months ago, we visited our friends at the Tempest Aero Group and watched as they made hundreds of oil filters and spark plugs every hour. Watching filter production (in the post-COVID world) was like watching wartime production in action; it was all hands to the pumps, getting as many out the door in as short a time as possible. The spark plug area was more sedate but equally interesting—a mainly automated process with a large machine centered around a carousel where the plugs grew before your eyes as components were added. As I said, very interesting…but at the same time, amusing because while there will always be a great demand for the products in the certified airplane world where aviation spark plugs are mandatory, the Experimental world is quickly leaving them behind in exchange for the ubiquitous BR8ES automotive spark plug because so many builders and owners are switching to electronic ignition systems and leaving their old Slick and Bendix mags behind.

The NGK BR8ES (or DENSO W24ESR-U) can be purchased in quantity from many sources and in a couple of different flavors. First tip: The BR8ES (also search for as BR8-ES, BR-8ES or any other variation of where the dash goes) comes in two different types—one with a screw-on tip for the spark plug wire and one with a solid tip. The first has a part number of 5422 and is very common. The other has a part number of 3961 and is less common, but it is the one you want for your airplane. Why? Because some folks have reported that the screw-on end can get loose and cause RFI that shows up as radio noise. The solid tip can’t do this. Whether this is true or just an old wives’ tail, it is not that hard to find the 3961s (as I write this, www.rockauto.com has them for $1.88 each), and there is no disadvantage to the solid tip so, why not?

Of course, you can use aviation plugs with some electronic ignitions, but with aviation plugs going for north of $30 each, it’s hard to pass up those $1.88 plugs and throw them away each time. I personally have four Lycoming engines, all with electronic ignitions, so I buy several dozen BR8ES plugs at a time and keep a bunch on the shelf. All my wonderful aviation spark plug tools (used for cleaning and gapping) sit in a drawer, used only when I have to work on someone else’s plane that still has mags. The NGKs are so cheap that while you can clean them, it is simply easier to throw them away every couple hundred hours and drop in new ones. It’s just economics.

Adapting

Of course, automotive spark plugs don’t just screw into a Lycoming engine—they are too small. Automotive plugs screw into a 14mm hole, whereas aviation plugs traditionally are 18mm. That means you’ll need an adapter for each plug, and these are usually supplied by your electronic ignition provider. They are generally made of brass, but some have been known to be steel. We’ve used both, but generally use the brass sets because they are more generally supplied.

Using an adapter means that there are two seals for every spark plug: one that seals the plug to the adapter and one that seals the adapter to the cylinder head. The first comes on the automotive plug and is generally a crush washer—hollow soft steel that crushes down when you torque the plug in place. While most mechanics will remove a plug and put it back in place again, the engineer who designed them probably considers these crush washers to be single use. I haven’t heard of problems (such as leakage or a plug backing out) from reusing them; I generally will only put one of these plugs in and out a couple of times. Again, they are cheap to simply replace.

The seal between the adapter and the cylinder head is accomplished the old-fashioned way—with a copper gasket. These gaskets come with aviation plugs (and can be bought separately by the thousands) and when new are in an annealed condition, which is to say “soft.” Using them properly (with a torque wrench) crushes them, providing a seal and adding tension that prevents the spark plug (or adapter) from backing out. Many mechanics routinely reanneal old gaskets and use them over, while many others declare that those who reuse them are just cheapskates—so why not use new ones every time? I personally reuse them sometimes because I enjoy the process of heating them up with a torch, watching them change color and then letting them cool down. Of course then you have to clean them to make them pretty…the whole process taking more time than simply buying a bag of new ones from Aircraft Spruce. It’s a religious argument; do what you’d like!

The Torque Problem

Automotive spark plugs get torqued to 18–25 foot-pounds. Aircraft spark plugs get torqued to about 35 foot-pounds. The difference is in the size of the thread (14mm versus 18mm) as well as the type of gasket used that provides a sort of spring retaining force. This means that to make everything happy in your Lycoming installation, you have two different torques in the assembly. If you torque both the plug and the adapter to 18 foot-pounds, you haven’t preloaded the copper gasket on the adapter sufficiently. If you torque the assembly to 35 foot-pounds, you’ve crushed the heck out of the spark plug’s built-in gasket. So what to do?

The answer is to torque them both separately, in series—but to do this, you need a couple of different wrenches. One thing you don’t want to do is torque the brass adapter in place without a spark plug screwed in; the soft adapter can be twisted and crushed out of true if there is nothing in the hole. The different electronic ignition builders have different techniques they recommend, but surveying the various options and simply looking at the joints has helped us build this procedure. The advantage is that it gives each “joint” the proper torque (not over, not under) and allows for easy removal of the plugs for maintenance. Ideally, once you have used this method, the adapters will stay in the engine—and we find that works about 70% of the time.

The Process—and Tools!

The way we do it is this: Take a new plug out of the box and screw it hand tight into the adapter using the appropriate anti-seize (which is the topic of an entirely different article!). Now screw the assembly finger-tight into the cylinder (same comment on anti-seize). Now take out your automotive spark plug socket, slide it on the plug and torque it to 18 foot-pounds. The net result is that both the plug and the adapter will be torqued into their holes at 18 ft-lb.

Next, take that automotive socket and put it aside. What you want next is a 7/8-inch deep socket that is long enough to allow it to fully cover the “flats” on the adapter, yet let the spark plug nest inside. The socket we have found that does this is a Craftsman 1/2-inch drive deep socket—ours is probably 40 years old, but it appears they still make the same thing. Note that a standard aircraft spark plug socket from Champion, Tempest or Autolite doesn’t work because it has a shoulder about 3/4 inch inside that will interfere with the automotive plug and not let the socket sit full down onto the adapter. You need a 7/8-inch socket that has “flats” all the way from the mount to the top (see picture). Now you probably don’t have a 1/2-inch torque wrench—or if you do, it will not work down at 35 foot-pounds, as it’s designed to work on big tractors—so find a “cheater” adapter to fit your ⅜-inch drive wrench onto the 1/2-inch drive socket.

Now you can slide this deep socket over the plug and onto the adapter and torque the adapter to the appropriate 35 foot-pounds to crush the copper washer properly—and you’re done. Next time you pull the plugs, you should theoretically be able to use an automotive plug socket and simply remove the plugs since they are torqued to a lower value than the adapters. This means you’re going to need a 14mm compression tester spud, of course. And as we noted, sometimes the adapters will still come out—so you’ll need both spuds for compression testing…maybe.

The Baffling Question

OK, so the process described above works fine until you get to a spot where the baffles (think top plugs) get in the way of that long 7/8-inch socket. Sure, it fits in place, but you don’t have room to put the torque wrench on there! What you need is a much “shorter” way to drive the big socket—and for this, you can make a special tool—if you have a lathe and welder (or know someone with the right skills and tools). The idea is to make something short that plugs into the ½-inch drive and allows you to use a crowfoot on the end of your torque wrench.

What we did was take a cheap 1/2-inch to 3/8-inch drive adapter and a short 1/2-inch bolt from the hardware store. We chucked the bolt up in the lathe and cut off all the threads, leaving a 3/4-inch hex head with a cylindrical 3/8-inch diameter shaft. We then chucked up the adapter and drilled out the inside about 1/4 inch deeper using a 3/8-inch drill bit. We cut as much off the open end of the adapter as we dared while leaving enough material to create a sturdy assembly, then cut enough of the “shaft” off the ¾-inch hex head so that it nested fully down into the adapter. Then it was a simple stop at the TIG welding table to join the two things together, and we had a 3/4-inch hex head to pop into the big socket. Use the 3/4-inch crowfoot on your torque wrench, and you’re ready to go.

An alternative is to use a mill to put “flats” on the end of the big socket and use the appropriate (larger) crowfoot directly on the socket. Essentially, it duplicates the configuration of a standard aircraft plug socket wrench that has both a ratchet drive socket and a hex head (usually for a 7/8-inch wrench) as well. This is easier if you don’t have access to a welder, but you have a friend with a mill—or you have a vise, a mill bastard file and some patience. You can start with a Craftsman CMMT47528 (1/2-inch drive, 7/8-inch deep socket—available at Ace Hardware or your favorite online retailer) and use a carbide end mill to do the work. The socket is very hard and it simply laughed at our regular (cheap) end mills that we use for aluminum. This solution gives you the best fit for top plugs where cooling baffles might be in the way, while also preserving the option of using a 1/2-inch-drive torque wrench directly. The spark plug and adapter fit snuggly inside this particular Craftsman socket.

One final solution is the cheapest (but won’t always work with baffles). Harbor Freight sells a set of square-drive socket caps (part number 67011) that give you the same thing as the welded adapter we described above—but where’s the building fun in that?

The Simple Solution

Automotive plugs are a simple solution for experimental Lycomings when using any of the popular electronic ignition systems. They fire great with a factory gap of about 0.032 inch, and they are cheap so that you will never worry about maintaining them. I have heard less discussion about lead fouling with these plugs than in the old days, when everyone used massive-electrode aviation plugs. I don’t know if this is because people do a better job of leaning on the ground, the plugs are less prone to fouling or people just throw them away before fouling becomes an issue!

It’s hard to break the habits of decades of aircraft maintenance, but not having to clean and re-gap plugs is a boon to those of us that have spent years of our lives digging out little lead balls and sandblasting expensive plugs. I first used the BR8ES in two-stroke jet skis, where the tuning process was to run the engine hard, then pull the safety lanyard off at high rpm, killing the motor instantly and preserving the combustion signatures on the plugs. You pulled the plugs, looked at the color of the deposits, threw the plug away, retuned, put in a new plug and did it over. Yeah, we went through a ton of plugs, but they were even cheaper back then.

Experimental aviators now have the option of using and throwing away plugs the same way—but we should always remember that the consequences of a blown-out plug in an airplane are much more dire than having to swim your jet ski back to shore or coast your late-model car to the side of the road. So use proper techniques and torques when installing plugs, and enjoy the convenience and savings of the modern ignition world!

Photos: Paul Dye and Marc Cook (sidebar).

The post Automotive Plugs in Lycomings appeared first on KITPLANES.

“Some wounds never heal, and for me it was the Honda Mini Trail I couldn’t have,” says seven-time Reno Sport class champion Jeff LaVelle. “It was $280 back then and it might as well have been $280 million.” And so began Jeff’s obsession with speed and freedom and winning and, eventually, airplanes. He couldn’t swing that little Mini Trail burning a hole in his heart as a boy and it’s been bugging him ever since. “Yeah, fill that damn hole up with stuff you don’t need.”

At least Jeff has been filling it with some pretty interesting stuff. The Glasair III we’re looking at here is just one of Jeff’s hole fillers, one that’s been the contender at the Reno National Air Races for years.

Besides unfortunately marking the end of the Reno era, this September also denotes the first quarter century of Sport class racing and our last chance to see this highly developed machine in action around the sport’s modern temple in the Nevada desert. So it’s time we take a close look at the class’s winningest combination of pilot and plane: Jeff LaVelle and Race 39.

Certainly Jeff is the logical candidate to represent the exciting, relevant Sport action. His debut in 2007 was during the transition from Sport’s putative years into a mature, stable class. He’s been active ever since, so his experience spans flying with the immortal Darryl Greenamyer and early Sport-class kingpin Jon Sharp to giving today’s developing crop of Sport racers the target to hit. He’s run the same Glasair III throughout—it’s a man-and-machine pairing with the stats to back up the reputation.

To hit the statistical highlights, Jeff has entered 14 of the 24 Sport races run to date, qualifying on the pole an amazing 10 times and winning seven. When Jeff shows up, odds are he’ll be on the pole nearly three quarters of the time and win half of the races against meaningful competition. When he finishes, he’s never been lower than second in 13 years—so your only real hope of beating him is to have him not show up or break. Good luck. He was the second inductee to Sport’s exclusive 400-mph club—Jon Sharp and Andrew Findlay are the only other members. (Jim Rust should join this September if he brings his own Glasair III.) And it’s possible Jeff’s Glasair has run more of those thrilling all-out laps than any other Sport racer.

Jeff LaVelle

A Seattle native who never left, there isn’t much aviation predestination in LaVelle’s background. Neither parent was a pilot or worked in aviation, other than his dad built and flew U-control balsa-and-tissue airplanes. As for schooling, Jeff laughs, “the school of hard knocks…I think I drove past a college once.” Instead he latched onto machining in high school, progressively turning that talent and experience into owning a series of machine shops, some rather large, before retiring to commercial real estate.

Like many, Jeff had a passing interest in airplanes but found motorcycles a more accessible and engaging passion, especially dirt bikes. “I had a bunch of them,” he says, and was neck deep in wrenching and racing them (and is still riding). Busy with work and life, Jeff didn’t have any money for airplanes as a young adult.

But in the latter 1980s he was constantly driving by Paine Field, as his machine shop was located next to the airport, and his customers were aerospace companies. And he was eyeing the Cessna 150s and such that were around in those days because they looked kind of fun. It took a few years and growing success in business but stressed by work and an ongoing divorce he impulsively blurted, “Oh, screw it!” during his commute and steered into the FBO’s parking lot. It didn’t take more than a few lessons in a little Cessna for Jeff’s initiative and performance lust to kick in. “So I bought a Mooney 201.”

The complex speedster required a new instructor—Jeff was still working on his private ticket—which led him to Bob Chase, an ex-Navy Corsair jockey. “He couldn’t hear very well,” says Jeff, “but he had all the skills he’d never lost.” We suppose drumming around behind a Pratt & Whitney R-2800 really would keep you on your toes—and your ears ringing.

After flying the Mooney for maybe five years—Jeff is too engaged in the present to keep a diary of the past—he ordered his Glasair III kit, the same airplane he’s racing today. “There was no Sport class racing then or it was just getting started, so I didn’t build the plane to race it. I wanted it because it was small, aerobatic and fun looking.”

While the Glasair was under construction Jeff, no doubt gnawed by a racer’s need to keep moving, also bought a Decathlon to horse around in and, like a proven planeaholic, he still has it. Still not sated, Jeff also bought an RV-4 and fell in with the Black Jacks, a regionally famous formation flying group working out of Arlington, Washington. Jeff cites his time with the Black Jacks as fundamental to building his airmanship and professionalism due to the large number of battle-hardened Vietnam-era military vets running the show. “They’d just love to kick your ass,” says Jeff about the Black Jack culture. “I can’t tell you what an opportunity that was.”

Race 39

Built with low weight and maximum performance in mind, Jeff’s Glasair is a product of his motorcycle racing mindset, even if it was intended for general duty, not air racing. Constructed via Glasair’s builder-assist program, his plane started with kit purchase in May 1998 and took only about a year and a half to completion, sans paint. Although Jeff was a frequent participant at the Arlington build center, “Jim Muldoon, the leader at Glasair’s assist program, built the fuselage and did the final assembly,” says Jeff. “I’d go up there and he’d laugh at me because I was chasing all the details.” The Glasair shop was a laid-back, fun-loving place, resorting to the occasional tape ball fight, says Jeff, who’d interrupt with his hard-core dirt bike racing mindset. Sweating weight details, he played the concerned customer. Or, as Jeff put it, “They thought I was a lunatic.”

While the fuselage was going together in Arlington, Ted Backus of Emerald Aircrafters in Troutdale, Oregon, built the all E-glass wing. This is an involved task because of the large number of parts the builder actually lays up, along with the responsibility to square them into a straight wing. At least the design is straightforward, with the spars and ribs taking shape as foam core and E-glass sandwiches with vinyl ester resin. But by today’s standards there’s plenty of hand fitting required to arrive at a straight, untwisted airfoil. It’s also worth noting that if such slow-build kits take time and build skills, they also give the builder more control over the finished product. In Jeff’s case that meant an emphasis on stopping weight creep.

Glasair shipped wing kits with the full-span, one-piece main spar built and bonded to the lower wing skin with the rest done by the builder. Thus, the builder’s critical first task is to construct a full-span table to serve both as a workbench and jig for the one-piece wing. As the table determines many wing characteristics, including dihedral and washout, it has to be exact. In practice that means a good amount of measuring, shims and tweaks until it’s right.

Rib formation begins by cutting out paper patterns supplied by Glasair and bonding those to whatever rigid material the builder chooses. This produces the stiff templates used to cut out the foam cores, which are then glassed over to make a rib, and then are finished with the addition of separate rib caps. Once these ribs and the rear spar are glassed into the wing they’re followed by precisely fitting the upper skin to the rib caps via numerous trial fits. Gaps between the rib caps and upper skin are checked with clay while temporarily laying on the upper skin. This reveals the high and low spots, which are either sanded or built up with micro or flox. As the wing is wet with fuel, there is the added issue of sealing the fuel bays from the dry areas. Jeff added to this by closing out the aileron bays for extra tankage near the wingtips. His wing holds 33 gallons of fuel per side.

Finally, the big day came when the upper skin was bonded to the wing assembly, closing the entire wing. This involves wetted, heavy, thick structural cloth along with a lightweight top skin.  As the final skin goes on it’s a blind job as the skin covers up the structure. Not only is getting the wing’s top skin accurately placed critical for achieving the best wing shape possible, it’s also a difficult step requiring “a lot of touch labor and eyeball…it’s a craftsman thing to put this on correctly,” says Jeff. “You’ve got to make it perfect the first time because it’s a done deal” once the upper skin has bonded in place.

When it was time to close out his wing Jeff brought Jim Muldoon to Emerald Aircrafters alongside Backus, a bit of dirty pool as Jeff figured having two principal builders on hand would spur each to their best and thus produce the lightest, strongest, straightest and smoothest wing. It seems to have worked.

Once together in early 2000, Jeff flew his Glasair for a couple of years in primer behind a stock 300-hp, IO-540 Lycoming. From the first flight Jeff was pleased to find he had achieved his goal of building an exceptional Glasair III airframe. Crediting the main builders, Backus and Muldoon, Jeff found his plane just a little bit lighter and a touch faster than other Glasairs he came across. “It’s above average speed-wise,” he says. “It’s lighter and straighter…a little better than average.”

While enjoying his new go-fast machine, Jeff found himself assisting an Unlimited air-racing team based nearby. He sped parts from Seattle to Reno during the Pylon Racing Seminar, and there he saw the Sport class in action. You can guess what happened next.

Race Power

Jeff’s first Reno race was in 2007. He ran his stock, naturally aspirated 540 Lycoming, giving us an accurate baseline on what a stock Glasair III can do around Reno’s pylons. The effort netted an 11th-place qualifying speed of 292.193 mph and a sixth-place finish in the Sport Gold race at 283.251 mph.

This was one of the four years where the Sport racers were broken into Sport Gold and either Sport Super Gold in 2007 and 2008 or Super Sport in 2009 and 2010. Thus, for comparison we’ll note Jon Sharp qualified his twin-turbo Nemesis NXT first at 387 mph and won the Sport Super Gold race in 2007 while Jeff was puttering around at 292 mph.

Clearly needing turbo power, for 2008 Jeff’s then crew chief Grant Semanskee “bought a cheap engine out of Spokane,” recalls Jeff. A company was converting Piper Mirages to PT-6A power and “were almost giving them away,” LaVelle notes. This stone-stock Lycoming TIO-540-AE2A angle-valve engine was rated at 350 hp (for five minutes) using 42 inches of manifold pressure. What do you think—did Jeff run it longer than that?

For packaging the intercooled Mirage engine in a Glasair, a new intake plenum was built by John Kerner while Bruce Hamilton fabbed a new carbon fiber cowling. Jeff said the combination “was fine…a good starter package” with its stock 7.3:1 compression ratio and running 100LL fuel. In 2008 he “got into first but detonated, maybe an injector clogged. I had just passed Lee Behel and was going to get my watch (Reno has awarded custom Breitling watches to race winners for many years) and then I detonated a jug and had to land the airplane.”

Now past the getting-started phase, Jeff’s next move was to call Ken Tunnell at engine shop Ly-Con to have him prep the Lycoming. This confederacy of Ly-Con building the core power section out of stock Lycoming engine cases, crankshafts and angle-valve jugs (with plenty of Ly-Con speed secrets) coupled to Jeff’s turbo and systems installation has remained his power source to this day. Ly-Con has Jeff ship them the core engine every year for inspection and freshening, a process that actually shows little wear (unless a connecting rod is sticking out) but lately includes a brand-new crankshaft out of hard-earned caution. That’s what running an engine at three times its rated power does to durability.

In 2008 and ’09, these were 540-cubic-inch engines but since 2010 they’ve been 580s. As usual, Ken Tunnell just goes “aw shucks” when pestered about how much power the deep-breathing 580 makes. In truth he doesn’t really know. “My dyno only reads to 1200 foot-pounds of torque and Jeff’s 540 pegged my dyno way below race power. Now he’s running a 580.” Like other Sport racers, Jeff says his current engine makes 850 hp or so. It could be over 900 hp but whatever the number is, it’s stout and a real accelerated wear test of everything inside it.

As for the 580 internals, they are mainly stock Lycoming bits augmented with Ly-Con’s cryogenic heat treatment, anti-friction and heat-barrier coatings, a custom-grind camshaft, CNC-ported heads, an O-ring case treatment and a subterranean 5.8:1 compression ratio via Ly-Con’s custom NFS pistons. The super-low compression greatly supports elevated manifold pressure while racing, but makes for a lazy dog with a fuel drinking habit at low or no boost. A fly-to-breakfast engine this is not, even if Tunnell says it’s “basically a drive-around-the-block engine,” when referencing its lack of exotic high-rpm parts.

ADI

Jeff followed the lead of many Unlimited and other Sport Gold racers in 2021 by removing air-to-air intercoolers in favor of increased ADI flow. ADI—anti-detonation injection—is a 50/50 water/methanol mix sprayed into the intake manifold. As the water evaporates it provides a powerful cooling effect that keeps combustion temperatures from spiking. It provides more combustion cooling than intercooling with much less aerodynamic drag.

Originally Jeff had a single ADI lawn sprinkler in the intake manifold but found it gave poor distribution among cylinders and was essentially impossible to tune. So, from a central ADI manifold he plumbed “water” lines to each intake runner, giving six tunable nozzles for much more efficiency. Two other lines feed the turbo outlets for additional general cooling as well. ADI fluid is kept in a 5-gallon tank in the cockpit for weight and balance reasons. It sits next to a 12-gallon spray-bar tank that spritzes distilled water onto the outside of the engine and oil cooler to increase heat rejection via evaporation. Like the ADI tank, the plastic spray bar tank is, “straight out of the Summit [Racing] catalog.” Distilled water is used in both to reduce nozzle clogging and water spots all over the engine compartment. “We go to Walmart and clean the shelves off,” says Jeff when asked where he gets his water.

Fuel System

To get sufficient fuel flow and control over 65 inches of manifold pressure, racers have successfully abandoned mechanical fuel injection for electronic injection (and ignition), mainly from SDS and EFII. Busy with other issues and an old-school guy at heart anyway, so far Jeff has stuck with Bendix mechanical fuel injection modified by Precision Airmotive in Arlington. Jeff Sitter at Precision has specified an RSA-10 fuel servo, along with a Romec fuel pump running a nominal 90 psi but sometimes hitting upward of 100 psi. That’s nearly three times the stock pressure. This extra pressure is used to both supply more fuel and overcome the boost pressure in the intake manifold. The rear-entry fuel servo layout dates from the original Mirage engine, with the servo rotated 180° to ease packaging the throttle linkage and fuel lines, which feed larger injector jets.

A fuel system improvement came during Jeff’s major landing gear upgrade in 2021. This required removing the wing, allowing enlarging the tank-to-fuselage fuel lines from 3/8- to 1/2-inch diameter plus replacing the stock Glasair 90° bulkhead fittings (where the fuel lines pass from the wings to the fuselage) in favor of mandrel-bent tubing. Seemingly minor, this change eliminated a fundamental stumbling block to achieving sufficient fuel flow.

Also of note, the stock Glasair III fuel system uses two wing tanks, plus a header tank in front of the instrument panel. Not wanting a lap full of fuel, Jeff eliminated the header tank during the plane’s initial build, saying they tend to leak and make working on the avionics more difficult. Jeff has no preference which wing fuel tank he draws from while racing, even admitting that prior to enlarging the fuel lines he did race in the “both” position, a desperate move in a low-wing airplane as it might unport the fuel pickup. It never did and he now runs just fine off of one tank with the enlarged fuel lines.

As for the fuel itself, 100LL was good when naturally aspirated, but his minimum fuel for high-boost operation is the old 115/145 purple avgas, which VP Racing Fuel mixes for Reno racers. VP also developed 160-octane Strega fuel for that P-51 team in the 1980s and several teams run it today, including Jeff for 2023. And what’s “high boost?” At least 85 inches of manifold pressure—likely into the low 90s when pressed.

Ignition

What’s remarkable about Jeff’s ignition system is how stock it is: a pair of Bendix 1200 magnetos timed to 20° in deference to all that manifold pressure, igniting AC Delco twin-electrode iridium spark plugs. Jeff actually has had an SDS electronic ignition system in-house for several years, but wants to run it on a non-race engine first to learn its ways. He hasn’t had the time so far. One ignition curiosity is that the Unlimited folks say the Strega fuel rapidly eats the iridium off the ground electrode and they’re constantly installing new spark plugs. Jeff hasn’t had that issue and runs the same plugs all year. Must have something to do with the huge boost the Merlin boys run.

Wing and Gear Modification

If Jeff did everything he could during his plane’s build to ensure a perfectly formed wing, it was still a stock Glasair III wing fitted with slotted flaps and stock Glasair landing gear. As soon as he began racing the under-wing flap tracks had to go due to their great aero drag, so he bolted the flaps shut and cut off the flap tracks. No other changes were made to Race 39’s wing for years, but entering the COVID era Jeff was suffering gear doors hanging open and the easy fixes weren’t working. A solution came from an unexpected source, Robbie Grove at Grove Aircraft. Unexpected because Robbie and partner Jim Rust from Whirlwind Propellers are direct competitors to Jeff in Sport Gold, running their own very fast Glasair III. But if they’re competitors they’re also part of the tight racing brotherhood, and where Grove and Rust had borrowed many firewall forward ideas from Jeff, they were ready to reciprocate with Grove’s redesigned Glasair landing gear.

Recognizing the stock Glasair III gear was unsuitable at high speeds, Grove had already developed and installed on his Glasair racer a totally new gear door and gear actuation system, retaining the stock Glasair gear legs and not much more. Grove’s goal was to completely enclose the gear when retracted—stock Glasair practice exposes some of the main gear tires—using flat, flush, tightly closed doors held shut with hydraulic pressure. This requires new half forks, hydraulic cylinders, sequencing valves and supporting pieces. But that’s just half of it as the Grove system interferes with the flap linkage and even the aileron linkage. Thus, the flaps must be abandoned and an all-new control system fitted, starting with the control stick, torque tube and extending all the way to a reversing bell crank in the aft fuselage for the elevators!

Grove built the new system for his and Jim Rust’s racer with no intention of offering it as a kit. But they had a few spare hydraulic cylinders (Grove makes his own) and he gave these to Jeff, along with sketches, tooling and other bits so he could replicate the system in Race 39. Installing the Grove gear should take place during the initial build before the wing is joined to the fuselage, not on a flying Glasair. But with the 2020 races canceled due to COVID, Jeff opted to take the huge step of separating the wing from 39’s fuselage to install the Grove gear. With a weary tone Jeff says the wing and gear job, “is a horrifically involved process. The [new] actuator requires a whole new flight control system, and a new fuel system to clear the flight control system. The time to do this is when you’re building; to convert an existing wing involves a lot of demolition. I did a lot of research before we just started hacking away at stuff, but man, I could have built a whole RV.” Yes, but the Grove gear works flawlessly.

While he was there, Jeff could also tend to other details. The bolted-shut flaps were removed and the area glassed-in using hot-wired foam shapes provided by Grove. Also, the stall strips were sanded off and new root fairings developed. Barely finishing in time for the 2021 races, Jeff was pleased to find his plane flew better than ever and to have his gear door issues a thing of the past. He was even more pleased to win convincingly—over Grove and Andrew Findlay—that year, too.

Continuous Improvement

A casual observer might think Race 39 hadn’t changed in years as it’s always worn the same paint job and has seen no highly visible changes such as wing clipping, but Jeff says it’s changed “radically” since he started racing it. Of course there have been many engine improvements over the years, plus the Grove landing gear, and these are not visually apparent from the grandstands.

But what we’ve been missing is Jeff’s tireless pursuit of weight reduction. Built lightly from the beginning, Race 39 has not seen the usual weight creep of developing airplanes thanks to Jeff’s constant efforts. Replacing aluminum and E-glass with carbon fiber is one reason. The cowling, wingtips, gear doors, seatback and belly pan have all gone to carbon, as have other hidden parts. As Jeff was the first Sport racer to dedicate his airplane to racing and give up sport flying it the rest of the year—a highly desirable move almost all his competitors were late to adopt themselves, if ever—this has enabled less weight and arguably greater safety. The nav lights and wiring were removed, the instrument panel pared to the minimum and the cockpit stripped to single-seat utility, all weight-saving moves. Ditching the intercoolers was another big help, as was closing out the flaps, which eliminated the flap structure, hinges, linkage and body filler used to fair in the bolted-shut flaps.

Even Jeff has been amazed at how lightweight his plane has become. When first turbocharged it scaled just over 1700 pounds, but “after COVID and the big mods I thought it might be 1700 pounds and under, but wow, it was 1570 pounds without the water tanks. I was really wondering after glassing the flaps [shut]; before it was always pulling right, but after the wing mod it felt really light and flew straight.”

2023 & Beyond?

With one more Reno race to run, Jeff is still improving. He’s working on downsizing his engine-cooling exhaust tunnels and trying new tailpipes. Different brand turbo wastegates are going on—one failed last year, causing him to mayday out of the Gold race—and there is the usual engine overhaul at Ly-Con yet to go at our deadline. The plane will definitely be a contender at the last-ever Reno speed fest.

After that, the entire sport of air racing faces an unknown future. The Sport class is working on new races around North America—see the Rear Cockpit column—and the Reno organizers are searching for a new venue. Whether these stimulating, expensive, all-out Sport Gold contenders can survive the new order remains to be seen. But, somehow, we don’t think we’ve seen the last of Jeff or heard Race 39 making that delicious, deep thrumming moan as man and machine zoom by at 400-plus mph.

The Woodshed

In our July 2023 issue we stumbled over our own wheel chock in our story on Jeff LaVelle and his Reno-winning Glasair lll. On page 13 in the Multi-time Sport Class Champions sidebar we correctly listed Darryl Greenamyer’s 4 Sport + 5 Unlimited championships, but credited Jon Sharp with just his 4 Sport championships, overlooking his unprecedented 11(!) Formula 1 wins. Kitplanes regrets the oversight, especially as Sharp’s combined 15 Gold wins is the all time Reno win record.
Photos: Tom Wilson and Tim O’Brien (action).

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The arrival of the engine also seems to be a common turning point with this type of project, providing a needed boost in builder dedication and the drive for completion. That has been the case for me as well with this one. I have been dreaming and thinking about how the relatively lightweight 220-hp turbo engine will perform in my 750SDX. I want to see this thing in the air!

Putting on Pounds

There are plenty of other small weight gains in the works as well between adding plumbing for fuel and getting the wiring into the wings. Even though I have taken extra time to lighten certain kit parts (as discussed in the previous article in the April 2023 issue), most of those are now being installed. I’m happy to report that it’s coming together really nicely.

Working on this project, I continue to find it truly amazing how far the latest CNC’d kits have come when you compare them to early airplane kits. The CNC final-size match-drilled parts allow you to simply Cleco parts together. Many of them have hole spacings that only allow the part to be put together in the correct position or orientation and it is spectacular to see these pieces go together so precisely without any cutting or drilling required. I’ve been able to leave a lot of my old building tools in the toolbox while doing the basic assembly because they just aren’t needed for the 750SD.

There is really no comparison between the newer Zenith kits and the 701 kit I bought in 2016 (which eventually turned into the Super701). The older kit took a lot of extra time and tools to achieve a similar-quality fit and finish to what I am now getting easily on the 750SD with only a set of Cleco pliers. Remembering how I spent all day building the older rudder and then being able to assemble a rudder from a new kit in only 10 minutes has left me very appreciative of the improvements made by the technology Zenith is now using in manufacturing its kits.

Wing Work

I am getting very close to permanently buttoning up the wings. The fuel system in an airplane is something that needs a great deal of consideration because it has to work, period. I used rubber hoses to plumb the fuel system in the Super701, but am planning to build aluminum fuel lines to connect the wing tanks in the 750SD build.

If done correctly, the aluminum lines should require less maintenance over the life of the airplane whereas hoses would need to be inspected and replaced periodically. The aluminum lines also have a mostly uniform inside diameter even through the fittings. Since sometimes fittings for a rubber hose can have a much smaller diameter port inside the barbed nipple, I am hoping using the aluminum lines will optimize fuel flow in the relatively small-diameter tubes by eliminating that potential bottleneck. In addition, the aluminum lines should have the benefit of being slightly lighter.

I will be running a header tank in the rear fuselage, just like I have done before. All the venting in the tanks will be handled through the vented fuel caps, leaving only one wing tank outlet for the main fuel supply line to the header tank and one small drain/check valve in the bottom of the wing. Although not having an extra vent line running from the header tank back to the wing tank is probably a hot topic, this setup has worked without a glitch in my Super701 for 700 hours and it really helps to keep things simple by eliminating the extra return lines and several connections.

The only other thing required before final assembly of the wings is installing the wiring for navigation, strobe and landing lights. This is a relatively easy task but it is taking some careful planning to install everything correctly through the spars and ribs and to get it all secured properly across the length of the wing. I will be using AeroLEDs lighting, just as I did on the Super701. In my experience, it is an excellent lightweight, bright and effective lighting system that requires less power consumption than most of the older bulbs.

I catch myself thinking a lot about how to make the wiring and plumbing connections as clean as possible, especially where the wings join the fuselage. I have several ideas in mind, but integrating an idea into a finished product can sometimes be a challenge. While I tend to like challenges, I also want to get this thing in the air—and challenges always cost time.

Forward Fuselage Planning

Getting closer to having fully assembled wings is also forcing me to start looking at the forward fuselage again. It is about time to get more things moving along there, like preparing the upper cabin area for the upcoming wing joining. At the moment, the forward fuselage is all Clecoed together and not yet riveted because I am still doing some planning.

On the list of stuff I’m still figuring out in this area are things like the instrument panel, engine mount, controls, seat and several other things. Some of it may require modifications to the cabin frame and other chrome-moly components that I’d like to paint before they are assembled. There is also some work to do with the landing gear, firewall and pedal assembly.

Weight and Balance

While my current focus has been on the wings, once the engine is delivered I will most definitely switch to working on the fuselage. On the top of that task list is figuring out the engine mount and trying to make sure things come out the way I want with the weight and balance of this airplane. I created a weight and balance spreadsheet on my computer and have been crunching all kinds of numbers so I can get the center of gravity positioned just where I want it.

It shouldn’t surprise anyone at this point that I’m aiming for a CG that is optimal for STOL operations. In my opinion, there is a fine line between having the CG optimally located and keeping it just forward of the rear CG limit. Basically, I want this airplane to be right at the rear CG limit when it is loaded in its most aft load configuration—buying myself some “margin” by having the airplane more nose-heavy doesn’t do its STOL performance any favors.

There is an engine mount available for the 750SD/520T combination. However, with my very specific ops in mind, I am looking at custom-building a shorter engine mount in order to move the empty CG back and make this plane handle just the way I want for my mission. ULPower, which makes the mount, has made it work for more of a real-world kind of loading. I have a feeling creating my own mount will involve a lot of work, but I am almost ready to tackle it!

Circuit Breaker System

Pretty soon, I will be looking at the interior and working on things like seats, controls, the door assembly, the instrument panel and electrical system. Among the growing pile of electronics on the back workbench waiting to be installed is a Vertical Power electronic circuit breaker system. I am excited about this particular system because I have used it before on the Super701 and it definitely helps to clean up the instrument panel real estate and the wiring.

The Vertical Power system eliminates the need for a bunch of individual mechanical circuit breakers and many of the switches by replacing them with one small, remotely mounted solid-state module controlled through the EFIS. From the EFIS screen, you can monitor the current (amps) of each electronic device, reset any circuit and also turn circuits on and off without the need for any external switches or breakers.

The Vertical Power website has a very thorough planning tool that works great for electrical systems. Once you plug in all your desired electronics and enter the parameters for each device, the tool will configure it and give you a map of how to put everything together. This even includes wire sizing, pinouts and planning for the connectors. The online planner creates a config file for you to download that will program all of your preplanned parameters into the Vertical Power system and configure it, eliminating the need to sit in the cockpit pondering how to integrate everything. I can’t say enough good things about this system. It has performed amazingly well in my Super701 and I am looking forward to continuing that trend with another VP-X in the 750SDX.

Taking Advantage of Show Season

I plan to be at Sun ’n Fun  2023, where I will talk with vendors such as Beringer, DUC Propellers, Garmin and Levil Aviation in hopes of figuring out exactly what I need to complete this project and securing the products necessary to keep it moving along. If you are looking at building an airplane, I highly recommend you to go to shows like SnF and AirVenture to check out all the planes and vendors and to talk with other builders and flying enthusiasts. There is a huge wealth of knowledge—and also some extra motivation—at these events to help you get going with your own project.

Videos of Humberd’s builds—and some of the fun that can be had with flying a STOL airplane—can be found at www.youtube.com/@TNFlyingFarmer.

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The good news is that the dreary weather has made for some consistently long days in the hangar making great progress on the Hummingbird. I am beginning to get optimistic about an early spring 2023 completion—if I don’t cause any more problems for myself. Did I tell you I cracked the left windshield while installing it? A new set cost $1800! I realized why when I saw the part number was for a Bell helicopter. I like the idea that the Hummingbird is stout and made with a lot of FAA/PMA parts, but I did forget about the pricing that comes with that. I was very careful cutting and installing the new ones and managed to get them completed without any problems, except for a lot of stress!

Engine and Avionics Update

Lycoming completed my Thunderbolt engine in December, as promised. I will detail all of that in a future update, but suffice it to say that I had it completely installed and ready to run and decided to remove the exhaust system and have it ceramic coated to help get rid of some heat. I saw a picture of a recently completed Hummingbird in flight at dusk and the exhaust system was glowing red! I’ve seen turbocharged engines do that in a test cell, but not normally aspirated engines. Perhaps it is due to the engine running at 3200 rpm in the helicopter, as well as there not being the same amount of cooling air going over the exhaust system as in a more tightly cowled aircraft installation. I don’t really know, but I do know it is best to have the exhaust ceramic coated before it is used.

Speaking of heat, there weren’t any provisions for cabin heat. So, I sent the mufflers off to Vetterman Exhaust and Clint Busenitz welded some fittings on the muffler and installed a heat muff.

The other good thing is that Advanced Flight Systems delivered on the promise to code some software to display the transmission oil pressure on the EFIS. I really didn’t want an analog oil pressure gauge on the panel.

I also managed to get all the electrical completed. The Advanced Control Module and associated components were all installed, and then the instrument panels were sent off to AFS for powder coating and labeling. They came back looking beautiful, were accompanied with the long-awaited AF-6600 EFIS and now are completely installed. Everything powered up without any smoke, and I even have traffic displaying on the screen in the hangar! Seeing everything working was quite motivational, especially since I ran many individual wires, such as the intercom and engine sensors. I must admit I did install the wrong wire from the EMS to the manifold pressure sensor but realized that as soon as I powered it up, as there was no value displayed. It was a quick fix, and I sure felt relieved.

Fuel System and Interior

Toward the end of any aircraft I’ve built, it seems like the need for project management and forward thinking increases dramatically. Some things need to get done in an order such that they don’t cause delays in other areas. Paint and interior seem to cause a lot of consternation. The interior certainly needs to be built and then taken completely apart to paint those pieces that aren’t covered. Even the painting process for the outside of the aircraft seems to take some planning.

To start the interior required completing the fuel cell. On the Hummingbird, the fuel tank is a large 57-gallon bladder underneath the rear seats. It is protected by sheets of Conolite on the bottom and sides to help prevent a puncture in the event of an accident. Once all of that was installed, the fuel cell area was cleaned, vacuumed and wiped multiple times. You don’t want any metal shavings or rivet stems abrading the rubber bladder. Then, all seams and protrusions, such as rivet heads, bolt heads and nuts, were generously covered in multiple layers with very high-quality duct tape. I used almost two complete very large rolls. Then, some very strong Velcro pieces were added to the tops and sides of the cell that matched the Velcro on the bladder. The Velcro holds the fuel bladder in place and keeps it from collapsing when it is empty.

Next, it was time to close out the fuel cell. I installed the float-type quantity sensor and adjusted it for the best low-quantity reading. The instructions called for cork gaskets and Permatex for all of the access panels to the fuel cells, including the sensor, but I used Pro-Seal without gaskets instead. My experience is that the cork and Pro-Seal seem to dry out over time and leak. I haven’t put any fuel in it yet, as I plan to calibrate the sensor when I do that.

One of the main contributions to accidents in the amateur-built aircraft world is modification of the fuel system. As a DAR I always ask if any modifications have been made. In this case, I admit that I have made one modification, as I added the ability to remotely turn the fuel supply off. Since the fuel tank is at the aft end of the cabin, and there is only one tank, there are no fuel lines to route to a fuel-selector valve. There’s no sense routing fuel lines unnecessarily, but I wanted the ability to turn the fuel off in case of an accident and for maintenance. In this installation the fuel was routed from the bottom of the tank at the rear of the aircraft directly to the gascolator on the aft side of the firewall. It was simple enough to place a high-quality cutoff valve right where the connection is made to the sump. I worked out the geometry on the bench such that the slipstream and cable are always working to keep it in the open position.

There are a lot of cables routed on the exterior bottom of the cabin, such as brake lines, control cables, throttle/mixture, etc. Again, the gantry crane I’ve mentioned in earlier columns came in very handy. The cabin sits pretty low to the ground, so lying underneath it was not very comfortable. Raising it using the gantry crane made the work very easy, including installing the chin windows, parking brake and landing lights. Yes, I added a parking brake, which I intend to use for rotor start-up and shutdown. Since this helicopter is on wheels, not skids, the initial torque at rotor engagement will cause the nose to turn without using the brakes. As a funny side note, I don’t think I ever broke the habit of stepping on the pedals in the Hughes 269 helicopter whenever I started the engine, even though it was on skids and had no brakes. Some habits die hard from flying fixed-wing aircraft. Now, it will seem natural to check the brakes.

Once everything was installed we took the time to make templates for the interior panels and carpet, allowing Carol to get started on fabricating them. The cabin is huge, so it required a number of complex panels in order to have an organized installation process.

Another area that I needed to address was cockpit ventilation. Yes, we can fly it with the doors off, which is a lot of fun in a helicopter, but there’s a good portion of the time that the doors remain installed, and that huge bubble canopy makes for a really hot cabin on sunny days. Luckily, I had two Snapvents left over from an earlier project, as that company doesn’t seem to be in business any longer; they don’t answer the phone and every distributor shows them as indefinite backorder. I will install the two I have in the front door windows, and I added sidewall vents from Van’s Aircraft on each of the doors. I also designed the cabin heat system so that I can route cool air through it in the summer months.

I painted the interior of the doors first, so that I could get the plexiglass installed. When installing plexiglass, don’t forget to use a plexiglass drill bit, and drill the hole larger than the diameter of the fastener so that there is room for expansion. Otherwise, there’s a high probability that it will crack.

Painting the Tail Cone. Again.

In Part 4, I mentioned that I had painted the tail cone, but I wasn’t happy with the way it turned out. It’s my own fault, as this was the first time I was using Superflite paint. I’ve painted all my own aircraft over the years, but painting is one of those skills that deteriorates if you don’t use it regularly. Once every five to six years is probably not enough and coupled with a different brand of paint than I had previously used, it showed. As I progressed through painting the rest of the aircraft, my results improved. Unfortunately, that tail cone was staring us in the face as we walked by it every time on our way to the hangar. Carol was kind enough to not say anything, but I knew she wanted to.

Then a lightbulb went off, or on, as I should say. I thought we had lit up the paint booth well and had even added some extra lights outside the booth shining into the windows. But the paint was black, and it was hard to see. Perhaps it’s my old eyes, and I’ll use that as an excuse, but I decided to try something different. The bottom of the cabin was going to be quite hard to paint, and I was wrestling with how to do it. The gantry crane process I had been using to work underneath it was not going to work in the paint booth, so I decided I needed to raise it another way. Brad Clark mentioned that pumping the struts up all the way would help, and I decided that jacking it just a little higher would even be better. I figured out a way to do that, but it still left me with the hard-to-see black paint.

I needed more light and it had to be underneath the helicopter. I don’t know when it hit me, but the brightest light I know is the sun. So, one evening when the weather conditions were perfect—no wind, low humidity, no bugs, etc.—we placed a big tarp on the taxiway, and as the sun got lower on the horizon it lit up the bottom of the cabin beautifully. I managed to get a gorgeous paint job on the bottom that exceed my expectations. The trick was the light, so we found the brightest LED cone lights we could find for the booth, and it made a huge difference.

I know you are wondering, and yes, I sanded down the tail cone and repainted it in the booth with all the extra lighting. It’s gorgeous now, too.

From there we proceeded to paint the red and silver on the rest of the aircraft. Painting is very time-consuming and tedious work, especially with multiple colors. You end up going through a lot of consumables, such as tape, masking paper and filters, coupled with a lot of extra time cleaning the booth between colors. Carol is ruthless about cleaning the booth, and it really makes a difference. I do wear paint suits, along with a fresh-air breathing system, gloves and head covers, so no skin is exposed. It’s kind of cumbersome in the booth dragging the hoses around and trying not to bump into the pieces as you paint them. Carol stays outside the booth and constantly drains the compressor of any moisture every few minutes, even though I have moisture traps and in-line desiccant filters.

While it’s not perfect, we are pleased with the results. It looks so different now that it is painted, but it’s also added to the stress of being more careful to not scratch anything.

Next update I will highlight the engine installation for you, and by then the engine should be making good noises. I’ve even started the paperwork for an airworthiness inspection, just to keep the fun factor alive. Did I tell you we received the registration? The FAA completed it in less than 10 days. I had heard they give new amateur-built applications a sense of urgency, and I was shocked at the turnaround. The Hummingbird is a model 300L, so we have N300VC, a 300 for Vic and Carol.

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Question:

Answer: The regulations do not differentiate between gliders with or without an engine. There should be no problem with adding an engine as you propose. However, since this will be a very major modification, you should talk with your local FSDO or proposed DAR and see how they want to handle it. You will definitely need to submit a new airworthiness application because of the “change of engine type” aspects of this modification.

Question: I bought a Sonex that was completed in 2007. The builder received the initial airworthiness certificate but passed away four days later. The aircraft was never flown and one year later the family donated it to a museum where it sat until being given away in 2022. It was then sold to me a month later. I’ve been able to transfer registration and ownership but all builder’s logs have been lost long ago. Can this aircraft ever be certified for flight without any documentation of the build?

Answer: I’m not sure I understand the question. If the original airworthiness certificate was issued then the airplane is certified for flight. The only reason you would need the build documentation would be to apply for the repairman certificate, but you are not eligible for that anyway. Depending on your location, you may need to have the operating limitations amended to change the flight test area for Phase I. Also the airplane will need a current condition inspection before flight.

Question: When you’re looking at an airplane of a known design and the builder has decided to increase the maximum gross weight above the factory’s number, what is your response? Do you approve this because he’s the builder? Do you ask for documentation? Do you tell him tough luck?

Answer: Typically I ask to see documentation. If he cannot provide some kind of engineering documentation, I will discuss how he justifies such a change. If he cannot convince me that the increase is safe, I will ask him to redo the weight and balance to match the designer’s limits. What he does after I leave is between the builder and the FAA. I have no control after certification. I only have what I approved (with backup data in my records).

Question: What date of manufacture is used on the E-LSA Airworthiness Certificate 8130-6 application and on the aircraft data plate? Must the date of manufacture listed on the Statement of Compliance (Box 4) be used or may I use the date close to the date I expect DAR airworthiness issuance? The date on the Statement of Compliance 8130-15 from Van’s Aircraft for my RV-12 is the date they signed this statement.

Answer: For kitbuilt E-LSAs, the date the airworthiness certificate is issued is the date of manufacture for aircraft. This information is not required on the data plate. The only information required on the data plate is make (for E-LSAs this is the kit manufacturer), model (this is the model designated by the kit manufacturer) and serial number (this is designated by the kit manufacturer).

The post Sailplane to Motorglider, Museum Rescue, Gross Weight Change appeared first on KITPLANES.

Just like every other metal-aircraft builder, I have had to develop fiberglass skills—doing layups, filling pinholes and smoothing out contours with resin and micro (or other fillers). It’s a love/hate relationship. I actually love the fact that you can do pretty much anything with fiberglass—and if you aren’t happy with the results, you can “erase” it with a sanding tool and start again. But I simply hate the mess and the repetitive nature of sanding, filling, sanding, filling…ad infinitum.

I have had to make composite tips (tail and wing) fit by cutting and re-bonding. I have had to fix warped parts with  filler and lots of sanding. And I have performed major surgery on cowls and fairings to get the air to move past discontinuities properly. It’s just part of the road to finishing—a road with few shortcuts. Unless you know a good glass airplane builder who will trade you their skills for a nice set of engine baffles.

Today’s Challenge

So what prompted this particular set of musings on the “joys” of composite work? Well, it turned out that the cowling for our eXenos project needed to be lengthened as part of the process of mounting a completely different powerplant than what the original design called for.

Why? It’s the pain of being an early adopter. As one, I received an engine mount for the electric propulsion system that was longer than intended. Bad news for me but the good news is that all of the production versions will be the correct length to allow use of the standard, unmodified Xenos cowling. Progress!

When all was said and done, with the early, too-long motor/battery mount and installing the electrics, the stock cowling was about 2.5 inches short of reaching the firewall when the front was butted up against the back of the propeller. Rather than wait for the new mount, we modified the cowling.

While we could have attached the cowling to the firewall and done considerable re-contouring up front, the thought of forming shapes in foam and reworking contour lines lost out to the simple task of bonding in flat strips on the sides and bottom to match the slab nature of the fuselage. We had to do some work to make the curved top fit properly, but at least we could do that without making molds.

So let’s take a walk through the process we used to lengthen the cowling for this project. You will be tempted to say, “Hang on, this simply isn’t relevant to me. I am going completely stock and my factory cowl will fit perfectly!” Let me point out that a lot of metal airplane builders over-trim their stock cowl and end up making it too short—so they need to add some back in. Why does this happen? Composite cowlings are a little like octopus skins—they keep changing shape until they are in their absolute final position. So trimming a little that seems just right when the cowl is not in its final position often means you end up a quarter-inch too short. It doesn’t fit until it, uh, doesn’t fit! Love/hate, remember?

Establishing “Truth”

In many airplanes, both the fuselage and the cowling are tapering toward the nose, so getting a good fit is not always easy. Tapers and compound curves are hard to fit. Add to that the fact that most cowls are split—either top to bottom or side to side (ours is side to side). As a result, you quickly find that the cowling doesn’t want to hold any particular shape until it is actually mounted—but you can’t mount it until you freeze the shape. Catch 22. (If you caught Larry Larson’s multipart series in our March, April and May 2023 issues on fitting the RV cowling, you know part of the story already.)

The way to deal with this is to figure out how to establish a baseline, a “truth,” if you will. Once you pin the cowling in a specific position, you can then adjust from there to get a good fit. With a cowling that is too short, the problem is compounded because it is literally floating in space until you lengthen it somewhere.

For our project, the slab side of the fuselage provided a good place to establish truth, so the first point of attack was to add some material to the back edge of the sides. Once we added material to the sides, we could trim and fit those to where it could be Clecoed in place. Then we could deal with the curved top or the flat bottom—whichever seemed more appropriate when we got to that point. But once the sides we pinned, we had truth and everything else could be adjusted to fit.

Lengthening With Scarf Joints

How do you add material? Well when it is flat, it’s pretty easy—you start with a scarf joint. What this means is that you want to taper the surface to which you want to attach the new material. An aggressive sanding disk on an angle grinder or hand sander will generally do the trick. We laid the cowl on the workbench, outside down, then ran the sander along the edge, tapering it to a fine knife edge. With a layer of gelcoat on the outside, this was easy—you could tell that you were down to the knife edge when you saw the white appear. We then tapered the joint in about an inch, uncovering the layers of the original cowl like sedimentary rock on the edge of a reservoir. This taper is the key to a good scarf joint—the added material will be tapered in the opposite direction and the overall thickness will remain the same all the way from the old part to the new part, with the outside edges lining up due to the knife-edge taper.

With the joint prepared, I now needed a mold—this was nothing but a backing surface that was straight and flat, covered in something to which the fiberglass resin wouldn’t bond. Plastic sheeting or clear packing tape is good for this. I found a nice flat piece of particle board in my scrap bin, laid it on the workbench, then laid the cowl “side down” on that, leaving sufficient board sticking out to add the 3 inches of glass that I needed. I then drilled a couple of #40 holes in the cowl and through into the board and used silver Clecoes to hold the cowl to the board.

Yes, I’m drilling extra holes in the cowling I won’t need later. Not a big deal. You are going to be doing a lot of finishing and filling on the cowl anyway so filling a couple of tiny holes is in the noise. Make your job easier—fasten things down now and fill the holes later. It’s really better this way.

With the cowl and mold prepared, it was time to cut some fabric and make a mess! I used a roll of BID (bidirectional) cloth and cut progressively narrower layers—because I wanted an overlap of 3 inches, I started with two layers 3 inches wide, then one layer 3.5 inches wide, another 4 inches wide, one more 4.5 inches wide and then, finally, one 5 inches wide. This gave me a taper to match the scarf on the existing cowl. This bundle of layups went on plastic sheeting to be saturated by activated resin, another layer of plastic, complete wetting out of the matrix and finally, application to the cowl and the mold sheet. A layer of Dacron peel-ply finished it off, with a final squeegeeing of excess resin.

Curing time complete, it was a simple matter of separating the peel ply from one side, then popping the cowl with its new 3-inch extension off of the mold. I now had 3 more inches to work with on the sides (I repeated the process for the other half of the cowl of course).

Now came the usual fit/trim cycle—using the back of the prop as “truth,” I trimmed the new back edge (on each side) until it was close enough to Cleco to the cowling’s attach points (in this case, hinges). Two holes drilled for silver Clecoes held each side rigidly in position so that I could continue trimming and fitting, eventually drilling all of the holes to the attaching hinges. I now had the cowl positioned so that I could work on the top. The bottom was going to be a simple job and its final position might depend on how the top turned out, so I left it for last.

Getting in Deeper

Creating the curved extension on the top was similar to the process for the sides, except that the “mold” needed to be curved to follow the contours of the existing cowl. A curved backing isn’t all that hard to create, however, so long as you’re dealing with a single curvature—or something close to it. I suspect that there is a bit of compound curving going on with the Sonex cowl, but it was small enough that we could get away with using a piece of heavy poster board for the curved mold, taping it securely to the outside of the top portion of the cowl, then laying the material into it. Care had to be taken in trimming because this truly is a case of “it doesn’t fit until it fits,” so you have to sneak up on the final trim.

Once the sides and top were more or less in place, we fit the center seam—which, in all the perversity of working with fiberglass, now had a gap that had to be filled. We did this to a final fit by building a “bridge” of scrap aluminum, Clecoed in place on the outside after covering it with packing tape. Working inside the joined cowl, I laid in the necessary glass to re-joint the two halves. When it was all set, the entire cowl gets Clecoed back in place to check the fit, then split the cowl down the middle, leaving the specified 1/16-inch gap. You’ll see in the pictures that we made a strip of aluminum match-drilled to our hinge and used that on the outside instead of trying to use the hinge on the inside during all this fitting. The same thing was done on the bottom.

Finally, the bottom needed to be extended and, again, this was as simple as the sides. With some rough trimming and aluminum splices holding the bottom center seam together, we simply added 4 inches to the back of the bottom, then trimmed to fit. Since an exit is required for cooling air, we simply didn’t do the extension in the middle area as shown on the plans and finished the back with hinge material as per the standard Sonex design. We now had a cowl that fit all the way around and matched the fuselage nicely.

One Step at a Time

When first faced with a project like lengthening a cowl, it seems like a daunting challenge and trying to figure out how it is all going to fit is a puzzle. But just like all aircraft building, you have to stop trying to look at the whole picture at once—you need to break the project down into single steps. Determine how much you have to add all around and add some margin for error—maybe 20%–25%. Figure out the easiest place to add material so that you can “pin” the project in position to figure out the next step. Scarf your joining surface. Prepare your layout. Saturate with resin. Lay it in place. Let it cure. Then mount and trim to fit. Now begin the next area.

It isn’t all that hard, just messy. But so is drilling lots of repetitive holes or spraying metal primer—or if you’re doing tube and fabric, sanding all that area again and again! If you’re a wood builder, tell me about all those rib pieces and gussets! Airplane building is messy, no matter the material. In the case of fiberglass, wear old clothes, cover anything in the shop that doesn’t react well to dust and find yourself a good set of safety glasses and a dust mask. Then have at it!

And as I said at the start—if you don’t like the results, sand or cut them away and start again. That’s the beauty of non-structural fiberglass work—it’s all art and it can all be fixed.

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Such a custom display is a not a trivial design project. Here we will describe one particular system implementation for a particular set of features. Yours most likely will be substantially different, depending on what you would like to display and how you want it to look. This project may seem imposing and realistically will require some basic electronics and programing skills—but don’t be afraid to learn something new! And as you will see further on, these display devices include remarkable capabilities and support that make the job much less complicated.

Display Choice

Scouring what was available in flat panel displays, it became apparent there were three levels of integration. At the lowest are simple matrix displays with minimal low-level hardware support for pixel addressing and enabling. These require all higher-level functionality to reside in an external processing system, for example an Arduino, which in turn would also have to implement intermediate display hardware manipulation capabilities in firmware before application-level functions could even be considered. Displays at the next level include some of that display hardware manipulation firmware in hardware included with the display, but still leave at least application firmware to be housed externally. Displays at the highest level include all of the lower-level functionality as well as integrated processing to implement the full application, such that the display unit could conceivably be the complete system.

Additionally, there are OLED—organic LED—and TFT LCD display types. The former are brighter, but unfortunately are not readily available in sizes much over 1.5 inches diagonal. I was looking for around 3 to 4 inches diagonal, so LCD it was. Finally, the company I found, Australia’s 4D Systems, features a comprehensive line of fully integrated displays ranging from 2.4 to 7 inches diagonal, 240×320 to 480×800 pixels resolution, with multiple A/D inputs, multiple discrete I/Os and an incredibly broad set of firmware features, making it relatively easy to build your system.

Display Unit Hardware and Software Overview

The display unit chosen is the gen4-uLCD-35D, which is a non-touch basic version. This display is also available in resistive or capacitive touch, and with a bezel. It features a 3.5-inch color TFT LCD display with 320×480 resolution and RGB 65K “true to life colors.” The onboard Diablo 16 embedded graphics processor provides a mind-bogglingly rich and comprehensive high-level instruction set for graphics, math (including floating point), I/O, text, memory management, sound and much more. The display includes a micro SD card slot for storage of images, video and audio files, and there’s a highly detailed 554-page instruction set manual, which includes examples for each instruction.

Development Environment

To further simplify the development effort, 4D Systems offers a hardware interface card, which connects to a USB port on your computer, as well as providing direct access to all the display’s I/O interfaces. On the computer side, there is a free comprehensive firmware development system providing three levels of possible development. The highest includes numerous widgets and precooked graphic designs for various components such as gauges, meters, etc. The lowest level allows you to create all your own graphics. I chose the low level because I had specific ideas about what I wanted all the graphic components to look like. The graphic support in the instruction set, even programming at the low level, is so good  that it is still very easy to create display items with minimal code. We’ll have some examples later.

Hardware Design

My display items were four fuel-tank levels in vertical bar graph form and fuel flow in gallons per hour in a circular gauge. Battery voltage is shown, along with battery charge/discharge information, and there’s an audio alert on/off indicator. Take a look at the photo for a view of the completed display.

Here’s the format of the input data: 0 to 5 volts for each of the fuel tanks, fuel flow is pulses from the fuel-flow sender, and actual bus voltage is used for battery volts. The audio alert on/off is from a momentary push button, and the battery charge/discharge is a 0/1 binary input from a custom comparator circuit of my design, which looks at which direction current is flowing in the battery ground strap. (This is a positive indication of health of the battery/alternator community, as the direction of current in flight should never be discharging—the alternator should always be providing all the load current. The battery should only be charging  after engine starting, with discharge due to the plane having sat for some time or operating electrical loads without the engine running.)

The 4D display provides four analog-to-digital inputs. The fuel tanks, battery voltage and fuel flow are six analog signals, so an external analog multiplexer was needed. In addition, since the fuel-flow data is a variable frequency pulse train, a frequency-to-voltage converter was needed. All this added up to the total system hardware consisting of the 4D display plus the 4D I/O adapter board and my added interface hardware on a separate small board. See the system hardware block diagram and photo of the completed unit for details. Again, the intent here is not for you to necessarily build this exact same design, but rather to learn how you can create a design of your own for your particular display items.

Firmware

Take a look at the high-level block diagram of the firmware design. The actual code is here. In any case, the process of writing code is greatly simplified by the excellent 4D examples and extensive application notes organized by typical functions. Without going into the details of the entire firmware for this design, let’s examine a couple of the pieces of the design to see how simple it is to create a display.

The fuel tank graphic consists of four vertical rectangles, each having a red outline, three white separator bars and a blue fill for the level. Here’s what it takes to create the red outlines: In the Diablo16 code set there is a graphics instruction “gfx_Rectangle(x1, y1, x2, y2, colour).” (Yes, that’s how they spell color—remember, this is an Australian company!) You simply supply the coordinates of the lower left and upper right corner and color code for the desired rectangle and, voilà, it’s done. So, for the outline of the four fuel gauges there are four such instructions. Of course, you need to do a bit of homework to figure out those rectangle coordinates in terms of where they should end up in the 320×480 pixel display. But the development environment makes this super easy, as you can write code, load it into your display in seconds and see what you’ve got, and interactively modify and incrementally grow your code base one piece at a time.

Similarly, the fuel flow gauge semi-circular red line is created with one simple “gfx_RingSegment(x, y, Rad1, Rad2, starta, enda, colour)” instruction, in which you supply an x-y center coordinate, an inner and outer radius, a start angle, an end angle and a color. This is an example of the richness of graphics instructions available to let you do just about anything for your desired display look—and also an example, once you get the hang of it, of the simplicity of creating graphics on these displays. Text creation is also simple: a location instruction, followed by an instruction that includes the text, font, size and color. And just like that, it appears on the screen.

Mechanical and Installation

Notice the bezel in the photo of the completed unit. I created it to match other items in the panel by machining it out of black Corian. The display is mounted in a recess in the back of the bezel, and the outer flange has tapped holes for screws to mount the unit through the panel. A bent aluminum cover completes the housing.

Growth Features

Once you have such a capable home-brew item in the panel, you can think up additional functions to add. If the I/O capacity is still available, say for an additional serial port, then functions and displays can be added with the appropriate re-layout of the graphics. For example, I am currently working on an affordable radar altimeter feature, which will have the sensor hardware mounted in the bottom of a wing access cover, communicating with the display through a serial link. The remainder of the needed functionality is easily provided by some additional programming for a height readout on the display, which I may omit—just audio callouts are probably preferable. That’s the beauty of these devices; they include sound capabilities, with instructions to play prerecorded WAV audio files (e.g., “50 feet,” “40 feet,” etc…) to a pulse width modulation (PWM) output that just needs some external filtering to send it to a miscellaneous input on your audio panel. Using this feature, I’ve already added some audio alerts that announce low or high battery voltage and battery discharge. The data for these was already there in the unit, and all that was needed was additional code and the appropriate WAV files for the audio, stored on the micro SD card.

The post Build a Custom Display for Your Panel appeared first on KITPLANES.

Eleven years ago, I broke my leg. Or, rather, I had it broken for me. Regardless, it was miserable. For an extended period of time I was hobbling around on crutches and couldn’t do much, let alone fly, because I couldn’t get my leg into an airplane. Not one to totally leave aviation alone, I took the opportunity to go to a small local airport for a casual fly-in. While crutching across the ramp in the Colorado summertime heat, I took a break huffing and puffing in the shade of the wing of a biplane. When I caught my breath, I started chatting with the couple who owned it. It turned out that we had some professional friends in common; later I ran into them again at other events and ultimately we became great friends.

Fast forward a few years and they had a dream: to fly in New Zealand. There was an international air safari coming up in New Zealand that they really wanted to take part in and were hoping to defray some of the cost and share the adventure with friends. So, guest of a weird twist of fate, I had the opportunity to travel to New Zealand and spend two weeks flying in a large figure eight around the North and South Islands. They went out a few weeks before and got their New Zealand pilot licenses, and together we all rented a Cessna 172 to take part in the air rally.

My better half did not have the opportunity to join us, courtesy of the U.S. Navy, which insisted she take a delightful cruise with 5000 of her not-so-closest shipmates.

Over several weeks we had an absolutely delightful trip, starting at Masterton, which is at the southern tip of the North Island. On the first leg we crossed the Cook Strait to the South Island. Over the next few days we looped around past Milford Sound and Wānaka, which are absolutely stunning, and then headed back north past Christchurch, across the Strait again and then clockwise around the North Island. Each day was a planned takeoff with a timed start and the goal of crossing certain waypoints and landing at an interesting destination. Most of the airfields have their own flying clubs, which conveniently also have nice pubs attached. We got really used to hangar flying with their spectacular and oh so refreshing beer at the end of each day. Along the way, we got to do some air-to-air photography with members of the Royal New Zealand Air Force, as well as fellow participants in the air safari. We were also able to trade rides in different aircraft.

A Day at the Airshow

The air rally ended at the biannual Classic Fighters airshow at Omaka Aerodrome, in Blenheim, on the northern side of the South Island. For those who don’t know, this show alternates years with the Warbirds Over Wānaka event. Both are absolutely unbelievable airshows highlighting the best of New Zealand aviation and showcase a number of incredibly unusual and rare aircraft in amazing natural amphitheaters.

Omaka Aerodrome is in a natural half bowl, with mountains circling the backdrop to the south. The timing of the airshow usually lends itself to spectacular lighting and excellent photography. The site is also home to the Omaka Aviation Heritage Centre, which features film director Peter Jackson’s collection of WW-I aircraft. Personal items belonging to Eddie Rickenbacker, Manfred von Richthofen, René Fonck and other aces are also on display.

The first day when the airshow started, I had the opportunity to get on an elevated stand for photographers. Being in New Zealand, surrounded by amazing aircraft at a terrific venue, I was as happy as a pig in, well, you know…

There was an English gentleman—I later learned his name was Nigel Hitchman—next to me on the stand. Throughout the show we chatted a bit, but not too much. I didn’t want to interfere with anything he was doing or distract him, and I was trying to take everything in and do my own photography. Also, I tend to be somewhat introverted.

During a break between aircraft, we finally started talking more, and it turned out he is a captain with British Airways. He travels quite a bit visiting different museums, airshows and generally anything aviation related around the world. Being only a private pilot myself, I didn’t have much expertise to offer to a BA captain, although I think I held my own with historical trivia. Eventually the topics wandered around to different aircraft we’ve both flown, and he asked what I was flying currently. I mentioned that I had built a GlaStar and have flown it around most of the Western U.S. I pulled up a picture of my aviation baby and he commented, “Oh yes, I’ve flown that plane.”

“You’ve flown a GlaStar?” I replied.

“No, well yes, I’ve flown a GlaStar,” he said. “In fact, that GlaStar.”

Now I was confused. I had never met this gentleman before, and I’m not sure when he would have seen or actually flown my aircraft, being that I built it and no one else has ever owned it.

“Ummm…when?” I was wrinkling my forehead and genuinely confused. Perhaps my new friend was prone to misremembering?

“Oh, in California, last year,” Nigel replied. “At a Bücker fly-in held at Gillespie Field.”

Mystery Solved!

Suddenly it all came together! The prior year the same friends I was in New Zealand with were planning on flying their Bücker Jungmann to that gathering in San Diego—the very same Bücker I had met them under years before. However, their Bücker had mechanical issues and was grounded.

While it’s a bit like loaning your baby out, we managed to make things work for them to take my plane instead of the Bücker and still make the trip. While there, they had taken Nigel up for a flight in my GlaStar. Questions answered and the mystery solved. Neither of them knew the other was going to be at that event!

It’s rather mind-blowing. Here I was in New Zealand, meeting a gentleman from the U.K. with a mutual aviation connection in the U.S. The distances are vast, but the aviation world is small. In the time since then, we have become great friends and have crossed paths consistently. We’ve seen each other at airshows and fly-ins all over the globe and have shared many meals, pints of beer, laughter and great times.

When you stop to think about it, the coincidences are amazing: From a broken leg, to a bit of shade, to friendships and flying a borrowed plane from Colorado to California, to realizing a dream to fly in another country, to sharing a photography stand and striking up a conversation—it seemed to come full circle. Many times since then we’ve laughed about this weird turn of events and wondered how they could have come to pass. But, then again, how could they not? After all…it is a small world.

The post “What Do You Mean, You’ve Flown My Plane!” appeared first on KITPLANES.

After realizing that some people build their own airplanes, I started seriously contemplating it. Inspired by the five different Van’s RVs that Stan Lawrence, my CFI, had built, it seemed very possible if I put my mind to it.

Most of my time is spent at the Sacramento Executive Airport (KSAC), which I call “the land of the RVs.” I’d say about half of my friends there own or have owned a Van’s RV at some point. This means that I’ve gotten to ride in quite a few, which proved to be an excellent way to figure out what I would be interested in. I’ve been in an RV-4, RV-6A, RV-7, RV-8A, RV-10 and RV-14. The one that stood out the most, however, was the RV-6 because of the side-by-side seating. Not that I would mind having an RV-7 or RV-14 but the Six is way more friendly to the purse strings.

My dear friend Kim Owen, one of the key people who got me into flying, owns an RV-6A that lives in Stan’s hangar with the RV-14 and the RV-4. After having the opportunity to fly in it, I knew that was what I wanted. (Kim and I even got to fly together in her RV-6A to Oshkosh last year!)

When I first expressed interest in building an airplane, most people supported me. But, there were a few comments about how I needed to understand what I was getting myself into, and that it might be a better idea to save up and buy something that flies first. Upon finding an RV-6 restoration project, it seemed like the perfect compromise.

Which Gear?

For a new pilot, a reasonable question would be: which gear? Both the nosewheel RV-6A and taildragger RV-6 are well known. But having earned my private pilot certificate in a tailwheel RV-14, built and owned by Stan, I had the tailwheel bug. Tailwheel airplanes are more expensive to insure and a little more tricky to fly but I felt I could manage those aspects.

The challenge of flying a tailwheel is appealing to me. I was just learning how to do wheel landings, and didn’t want to give up that style of fun for a nosewheel airplane…so my sights were set on tailwheel aircraft.

With more than 2700 completed since 1985, the RV-6 is the most popular/common Van’s aircraft. For good reason. Even with a smaller engine, the RV-6 has excellent performance—a top speed of 210 mph, cruise around 170 mph and range of 720 miles—and the low wing and bubble canopy allow for excellent visibility. Plus, the side-by-side seating allows for easy interaction and a pleasant experience for your passenger.

Even if I were to ignore the seating arrangement, the truth is that there are more RV-6s out there than the earlier RV-4 and later RV-8. There’s also a much wider price range, partly because they’ve been built over many years and equipped many different ways. An RV-6 may be as high as $90K (newer builds with modern avionics) and as low as $40K (older ones with older avionics). The RV-4 ranges from $55,000 to $65,000 and the RV-8 soars well over $100K. So the Six seemed to offer the best opportunity at “affordability.”

Cons of a Van’s RV-6

The only thing my RV might not be able to do for me is carry my equipment for the adventures I want to do. I’m going to do everything I can to fit my bike into the back, which may be possible if a seat is removed. And, I’m going to create an opening in the rear  bulkhead to fit two pairs of skis. With help, I will make this change without affecting the structural integrity and the torsional stiffness of the fuselage.

Another big difference reflects the evolution of the RV design. Most of the RV-6s were built before matched-hole kit construction became a thing. This means that each RV-6 is kind of custom-built, in a way. If you need to replace a part of your airplane, you may find yourself redrilling a new piece of metal or re-fiberglassing parts to make it all fit correctly. It also means the quality of the construction is much more in the hands of the original builder than in how the factory made any given part.

Finding My RV-6

When you’re thinking about buying an airplane, it becomes very easy to spend excessive amounts of time on Barnstormers, which is exactly what I did. Stan was excited, too, and did the same. He sent me links to lots of different airplanes to look at.

With airplanes leaving the country or being retired faster than they can be built or manufactured, the supply is definitely trailing demand. Compared to just a few years ago, there are fewer RV-6s for sale and the asking prices are higher. But they’re still out there. The only way for me to buy an affordable RV-6 was to get a partially completed airplane or a restoration project such as this one. When I saw a tailwheel RV-6 that was in my price range, I leapt.

The RV-6 I finally purchased, N2165U, was originally listed for $40K in Colorado. While it was flyable, it was being sold as a project because there was a lot that had to be done to it. It had a 180-hp Lycoming O-360 with 1100 hours. Built by Austin Snider, this RV-6 got its registration in September of 1992—ah, six and a half years before I was born.

I expected it to need some work. But the seller didn’t disclose to me how much work it needed. And, they didn’t tell me that it had been in a crash. Yes, I know now that I should have gotten it inspected. But with excitement and instant gratification combined with the feelings of urgency to buy when the price was lowered to $30K, my bank somehow broke and all my money fell out. Oops!

And boy, was I in over my head.

A New Home for N2165U

In hindsight, it was risky wiring money to a stranger and not inspecting the airplane in the first place. I was relying purely on my limited knowledge and on the word of others—and I’m sure I’m not the first to do this. After talking to the seller, we decided that I was too low-time of a pilot and without having flown or seen the plane before, it would be risky for me to fly it over the mountains. We arranged to have a gentleman ferry it out to California from Colorado.

Stan wasn’t there the day it arrived, but Kim and her husband, Mike, were. I remember being so happy to have company there with me on such an important and exciting day. Kim has been with me through my whole aviation journey, from my first flight to connecting me with Stan, being there for my first solo and now there when I bought my first airplane.

The guy who flew it out, Jared Garretson, had a friend, Carl Mayer, who came with him. They had to take it to Kansas the night before, which, yes, does sound like the long way from Colorado to California. Afterward, they arrived at KSAC, then took my plane up to Chico, California, to look at a plane of their own and then returned to bring my plane to me.

I was ecstatic. My very own airplane. I remember seeing it pull up and the only thing I could think about was, “We are going to be best friends.”

I remember seeing the guys hop out of the RV and put their cowboy boots on. They were friendly folks from Kansas, not much older than me. We then did a good walkaround inspection of the plane. They showed me the fuel and the oil leaks. When I bought it, I knew the fuel tanks were leaking and that it would be a problem that I would have to solve. I was quickly discovering the rest.

They showed me the panel and what each switch, button and doohickey did. There were a lot of pieces, mostly switches and wires, that seemingly went nowhere, almost like someone had replaced a part and then forgotten to fully remove everything that was there before. Kim had me take a video of Jared explaining everything so that I could go back and reference it if needed. We exchanged paperwork and rolled the RV-6 into its new home, Hangar 32. I took Jared and Carl to lunch at a nearby Mexican restaurant as a thank you for everything. Afterward, I dropped them off at the airport, where they then continued their journey.

Soon after, N2165U and I got acquainted. I started cleaning and taking off some panels for inspection. Later that night, I dragged my mom out to the airport to show her my new toy/best friend—what all of my leftover college funds went toward. She was excited that I was excited. Afterward, we said goodnight to my baby and closed up the hangar. The journey was just beginning.

Photos: Kim Owen &Tenley Ong.

The post A Resto Begins appeared first on KITPLANES.

Now fast-forward six years to Air-Venture 2022. Lo and behold, that mockup is no longer just a mockup! Front and center at International Aerobatic Club (IAC) headquarters, displayed on the lawn to the right of the main entry, was SAW’s first flying REVO prototype. We were even lucky enough to speak with the designer, Eddie Saurenman, and his family.

The Man

Eddie was raised in an aviation household and was building his first aircraft at age 14. When he was a teenager, he funded his flying habit by having multiple part-time jobs, such as building 15-meter composite sailplanes for Aerotek in Albuquerque, New Mexico, and washing cars at a local dealership. When the Pitts S1 he was flying came up for sale, he was able to swing a bank loan as a 17-year-old through his sheer persistence and determination. He waited outside the bank for the doors to open for business for the day, with paperwork vouching for his character and cosigned by the sales manager of the car dealership he was working at, along with George Applebay of Aerotek. Needless to say, his enthusiasm impressed the loan officer, who went to bat for him. His loan request was approved and he managed to buy that Pitts.

His journey through the world of aviation took off and he has never looked back. Flying at least several hours a day, Eddie amassed over 1200 hours in his Pitts Special by age 20. When he was 18, he began flying airshows with legendary airshow pilots like Jimmy and Steve Franklin, Marion and Duane Cole, Harold Newman and Bob Heuer, just to name a few. Eddie continues to have a flying family, which includes his daughter, Hanna, who has the unusual rating combination of glider as well as jet-powered motorglider certifications. His wife, Birdie, is also extensively involved in aviation and is the president of SAW and a huge part of the company.

Aside from just flying aircraft, Eddie was also involved in construction and design starting early in his life. His résumé is riddled with experience working at multiple major aerospace manufacturing companies, including Cessna, Beechcraft, Learjet, Raytheon, Bombardier, Helio Aircraft and Aviat. Starting at the low end of the totem pole deburring parts, Eddie learned the industry from the ground up and moved on to tooling, assembly, manufacturing and planning, scientific information systems, airframe and system design, and eventually aerodynamics and structural technical analysis. Through all of this, he never lost his love for aerobatic aircraft. Later he concentrated specifically in the design and modification of specialized aircraft. Many of these are flown by leading airshow pilots, such as Sean D. Tucker, John Klatt (Screamin’ Sasquatch jet-powered WACO), Kyle Franklin (Dracula), Skip Stewart (Prometheus), Jeff Boerboon (Yak 110—twin Yak 55 fuselages attached to a jet engine), Rich Goodwin (Jet Pitts S2S) and others.

In 2016 Eddie was awarded the Curtis Pitts Innovation Aerobatic Design Award. He is now designing independently and continues to push aircraft boundaries with the SAW Revolution carbon fiber biplane and his super-lightweight aerobatic monoplane design, the REVO.

The Vision

The idea of an inexpensive lightweight aerobatic airplane began about three decades ago when Eddie realized there still wasn’t an aircraft fitting this criteria. The REVO itself began life seven years ago as what his friends and family affectionately called “Eddie’s airplane.” His original thoughts leaned toward a very light (about 300 pounds) machine with a sling seat and power from a snowmobile engine. However, as interest grew, design creep set in and slowly Eddie increased the overall size, power and weight to its current design, which is still quite light at 527 pounds. Initially, it was a test bed to explore manufacturing ideas and test numbers, with the goal being the ability to produce and distribute a light, affordable and very capable aerobatic aircraft.

At the time the REVO began coming together, Eddie was working with Orange Aerospace in the Netherlands, and they collaborated on the steel-tube fuselage and all the composite work that led to the design of the carbon fiber cowl and wings. Originally, the plan was for the aircraft to be manufactured in collaboration with Orange Aerospace. This subsequently never came together given the costs as well as issues with transportation to and from Europe. However, the partnership is ongoing, with plans for Orange Aerospace to produce the composite components, while overall manufacturing will be controlled by SAW.

In addition to being an inexpensive and capable aerobatic mount, another goal for the REVO is to make it easy to build, with no stringers or formers and an “irreducible minimum” of parts. For example, eight bolts attach the control system to the tail feathers and three fasteners secure the turtle deck. Eddie describes a vision for builders to sit on the couch watching their favorite movies while applying fabric to the small aircraft. If using a waterborne, low- or no-odor fabric system such as Stewart Systems, this vision might be entirely viable!

The Machine

The fuselage is a pre-painted steel tube framework that ultimately gets covered with fabric. The current prototype wings are carbon fiber, with plans for kits to be offered with that option or fabric-covered wings with an aluminum structure. The current carbon fiber wings have a symmetrical airfoil, while the fabric-covered wings have a cambered airfoil and an additional nine square feet of surface area over the carbon fiber wings.

The aluminum structures are designed around an I-beam type front and rear spar and include drag/anti-drag wires and ribs. As prototype testing comes together and data is incorporated into the design, the next set of wings is anticipated to be 30 to 40 pounds lighter than the current set. While the carbon fiber symmetrical wings have what is tongue-in-cheek described as “Eddie’s snow-cone airfoil,” the airfoil of the fabric wings is an Eppler 361 design with a slight reflex to reduce the pitching coefficient to 0. The wing itself is a high-lift design, which of course means that it increases drag as speed increases. Control surfaces are activated by push-pull rods versus torque tubes. As the REVO moves forward, there will most likely be a symmetrical airfoil available with fabric wings, although this hasn’t been finalized yet.

While the airfare is small, it can accommodate pilots up to 6 feet 3 inches. Seat adjustments are accomplished by adding or removing cushions. The seat itself reclines at a 43° angle, which places the pilot’s knees and shoulders at the same level and increases the pilot’s G tolerance.

Getting into the stubby plane takes a moment to get used to. You back up to the leading edge of the wing on the left side, hike your derriere up onto the wing, slide back and spin around. The canopy is hinged to the right. Seated, you’re reclining as if you’re in your favorite chair. The controls move smoothly without any extra play through a full range of motion without hitting your knees. If you choose to add the ballistic parachute option, there isn’t the discomfort of sitting on a traditional aerobatic parachute pack for extended periods of time. The ballistic parachute also might inspire some to feel more comfortable with aerobatics.

The currently flying prototype is powered by a fuel-efficient 80-hp Rotax 912 and was planned to be a slow-speed aircraft with a cruise in the 100 mph range. However, as the envelope is further explored, the airspeed has been creeping up. After all, who doesn’t want more speed? Consideration is being given to other engines. As the cowling is currently configured, the Rotax as well as a ULPower engine can fit comfortably, making either engine a great option. A Continental O-200 could also fit but raises some weight and balance concerns and calculations.

The UL350iHPS is looking like the best powerplant combination for the REVO, and it has aerobatic approval in Europe. Inverted oil and fuel are already built into the engine, so the plumbing and valves are already in place and it’s air-cooled. The current version of the UL350iHPS produces 150 hp and weighs just under 200 pounds. The prototype aircraft is currently flying a with Whirl Wind fixed-pitch prop. However, for future versions Eddie would like to use a constant-speed propeller. Perhaps an electric constant-speed prop behind the ULPower engine?

For those interested in the overall engineering, flutter testing was performed utilizing finite element analysis. Also of note is that all design features of the REVO have flown on previous and current aircraft that Eddie has modified, been part of the design or has flown himself.

The REVO is very close to LSA standards with exception of the stall speed. However, given the increased wing area with the fabric wing, the projections are that it would be very close to LSA stall-speed requirements and may qualify for certification as an E-LSA. Time will tell, but it certainly would be fun to have a highly capable aerobatic craft within that category.

With the fuel tank in the fuselage, the aircraft will be easy to disassemble and trailer at the pilot’s preference. There’s a plan for a purpose-built trailer if the pilot decides down the road to transport the aircraft by ground. The trailer is envisioned to be something like a sailplane trailer, with stands and racks to store the fuselage and wings snugly and make assembly and disassembly manageable for a single person.

The Cloud Dancers

When the prototype took flight, it was located at the Saurenman facility in New Mexico. While the plane performed well, the decision was reached to move it closer to sea level to evaluate the aircraft without the density altitude component.

In entered Maurizio “Maz” Perissinotto. Maz is an Italian pilot who used to work for the airlines when not flying aerobatic airshow routines in his Pitts. He has logged over 4000 hours in 62 different types of aircraft and became involved with the REVO project several years ago.

After immigrating to the U.S. three years ago, Maz moved to Santa Paula, California. He lives in a hangar home with his wife, Ruth Charlesworth Perissinotto (crew chief, private pilot and model), along with their young daughters. He and his wife are known as The Cloud Dancers and have displayed many exotic aircraft around the world since 2010. According to the Saurenman Aero Works website, “Maz is rated in ultralights, seaplanes, jets, aerobatics, high-performance singles, twins, electric and many Experimental aircraft in three continents.” Previously, he was flying a Bede BD-5J jet but now has a Hiperbipe called the Hiper Viper.

With the initial test flights of the REVO behind it, the prototype was moved to Maz’s hangar where he has been doing most of the test flying. Since then he’s been exploring the envelope of the new design. At the time of this writing, he’s logged around 75 hours in the prototype.

According to Maz, the view from the cockpit is unparalleled and the plane is a delight to fly, with no play in the pushrod-activated controls. The prototype is heavier than the planned production aircraft. However, even with the 80-hp Rotax engine, the initial climb is around 1800 feet per minute. It cruises around 110 knots in level flight but the prop is felt to require some re-pitching and higher cruise speeds are anticipated. Overall, Maz describes the REVO as feeling like a “light Pitts or similar to an RV-4,” and it is straightforward and quite manageable to take off and land, with ground handling that even a fairly low-time tailwheel pilot could manage. Tweaking continues as flight testing progresses. However, Maz is already building the Serial Number 2 aircraft, with the goal of flying behind the ULPower engine.

The Takeaway

Going back to our impressions of the mockup at Sun ’n Fun, the first thought looking at the V-shaped tube fuselage was “Hey, that’s clever!” Considering how the shape cuts down on fuselage size and weight, it makes obvious sense. We took note of the fighter-like, G-tolerant, leaned-back seat, thick high-lift wings and overall “cute-as-a-bug” appearance.

Another design element that sparks a lot of conversation is the seemingly oversized ailerons. While one person jokes, “I guess you’ll never complain about lack of aileron authority,” another is wondering if the ailerons will act as large speed brakes. With a roll rate of 400° per second at 120 mph, we think the latter argument is not likely to be a concern.

Needless to say, we were quite thrilled to see the REVO at AirVenture last summer, a little further along in its development. The single-seat mid-wing design with its bubble canopy appears to be vaguely reminiscent of a shrunken Yak 55. The minimalistic panel is appealing and everything about the REVO declares that it is meant to fly without extra frills or extraneous weight. It is a mission-specific aircraft, and a unique one at that.

The end goal of the REVO has always been to bridge the gap between the wallet and performance. While an Extra NG is north of $500,000, the price point for a completed REVO is expected to be $60,000 to $70,000, with the builder doing most of the work. The initial price of the kit is around $35,000. Of course, if you hire help to complete the avionics, painting, etc., the price will likely increase significantly.

According to Eddie, “The objective is to deliver Extra performance at a fraction of the cost.” He suggests the REVO could easily be flown in the IAC Advanced category competitively and could possibly be flown in the Unlimited category.

Today’s aerobatic airplanes are economically out of reach for most young pilots, but a kit like the REVO could be a game changer. “If someone really wants to get into aero the way I did,” said Eddie, “the REVO gives them a way to do it. If it’s successful, it’ll create a new market without taking away from the current one.”

Summing up, the REVO offers aerobatic pilots superb visibility, excellent low-speed controllability and manageable ground handling in an airplane that is simple to build, fun to fly and economical to operate and maintain. Anticipated production dates for the first shipment of kits is the third quarter of 2023. For further information, check out the SAW website at sawcustomaero.com.

Photos: Evan Byrne and Jonathan and Julia Apfelbaum.

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