Detail Man

The devil is in the details, but Andy Paterson was up to the task, and this exceptional Glasair Sportsman is the result.


Remember how proud you were as a kid to build a model airplane that looked just as good as the one on the box cover? Then there was that other kid who didn’t build the model the way it came out of the box, but was always cutting up perfectly new parts and dragging pieces of other models into his creation. Did you ever wonder what happened to that guy?

Andy Paterson, serial craftsman.

He might as well be Andy Paterson of Fallbrook, California. A serial craftsman, Paterson has made his living constructing everything from cabinets to race cars, and he has never built anything that looked “just like the box cover” including this Glasair Sportsman. It was mainly assembled by partners Chuck Hayes and Kevin Williamson, but Paterson came on board to help the harried Williamson finish the details.

When Paterson came to the project, it was nearly 80% complete. The fuselage and wings were done but were not attached. The same goes for the horizontal stabilizer, and the windows and avionics had not been installed. The parallel-valve O-360 Lycoming had been beefed to over 200 horsepower by engine house Ly-Con, using Airflow Performance fuel injection, and it had been hung on the airframe and plumbed. So Paterson had the advantage of concentrating on the finish rather then the heavy lifting of basic construction.

You can’t help but think “clean” when sighting down the Sportsman’s flanks. Paterson molded fiberglass strips around all of the windows to fair them seamlessly into the structure. The NACA duct in the aft wingroot is another nice touch that provides ventilation to the aft cockpit.

His orders were to use his imagination in finishing the Sportsman, so he had nearly free rein. The result is a superb aircraft—with a twist. On one hand the jaunty taildragger is back-country capable and wears a splatter-paint interior—a fairly common Sportsman approach. But on the other hand, it sports stylishly uptown wheelpants that are cowled tightly, faired windows, custom hinges, wingtips and fairings, and a unique baggage compartment—not to mention showboat avionics.

Leaving the wings off as long as possible, Paterson finished what little remained of the basic airframe, then went to work on the interior panels, followed by the strut and gear-leg fairings, then back to the interior for the instrument panel and glareshield. Final work took place on the cowling, which was cut and scooped long after final painting by Williamson.

As is typical, refinement of the Sportsman project continued well after its first flight. Williamson flew it some, but discovered his needs had changed and sold it to John Cook, a South African expat and Walter turbine importer now living in DeLand, Florida. At last count Cook had Paterson adding more custom touches immediately prior to flying the Sportsman to its new Florida home, with promises to bring Paterson east for annuals and continued updates. So while the Sportsman looks complete, it will continue to evolve.

Tidying the under-panel area is this Paterson-built fiberglass console. The main goal was to present the fuel selector valve in a convenient yet protected way, but it also yields plenty of mounting area for the chart holder, etc. The two rocker switches are fuel-transfer-pump controls. Under the console is the Airflow Performance electric boost pump and fuel filter. Paterson’s only regret is that servicing the fuel filter is bound to be messy.

The Mods

Just before the Sportsman flew east to its new home, Paterson pointed out his handiwork. Some details are purely cosmetic, but most are clever ideas that make the Sportsman a little sleeker and easier to live with. Most of these mods involve composite materials, and admittedly the resin-and-cloth world is where Paterson is most comfortable. His history with composites is extensive. He and his brother Stewart designed, built and drove their own record-setting Formula Ford 2000 race car from scratch in the 1990s—and Paterson was the man in latex gloves when Tom Aberle’s shatteringly fast Phantom racing biplane was built. No surprise then that all of Paterson’s fairings for the Sportsman are built from E-glass.

Panel and Glareshield

Thinking a glareshield should actually shield from glare, Paterson modified the Sportsman panel top by extending it back 3 inches with a more defined lip, and gave it a more pronounced curve across its upper surface for looks. He also integrated mounting pads for the compass and avionics cooling vents along the top surface. It pops in and out of the finished airplane with ease to facilitate servicing the panel.

Still retaining their original heritage, the panel and glareshield were completely reworked. Besides better functionality, Paterson’s idea is to better integrate the complete cockpit by streamlining the intersection of the panel to the fuselage sides and tying colors and textures together into a more inviting space.
A closer look at the panel shows some of Paterson’s detailing at the recess for the radios just above the prop and mixture controls, layout of the instrument mounting hardware and subtle differences in texture on the panel insets. The main display is an Advanced Flight Systems AF-3500; the backup analog instruments are 2.25-inch UMI units.

The panel itself was also modified extensively, the contours reshaped to better fit the avionics and provide a more organic presentation. This is something of a quest of Paterson’s. With his ability to craft complex shapes in composites, he’s ready to move on from the flat-panel aesthetic in most aircraft to something more integrated and flowing. Even if it’s not immediately apparent, “There’s not a square inch on that panel I didn’t change,” Paterson said. Some of these changes are subtle, but modifications such as the recesses to clear the radios are readily visible to the practiced GlaStar owner’s eye.

The avionics were selected by the original builders, along with the backup instruments and associated switch work. Paterson executed the installation, angling the 496 Garmin and placing the analog dials relative to the electronic displays so that the mounting screws were in neat rows relative to each other. This is tedious work, but Paterson enjoys it because, “That’s what the pilot is staring at all the time.”

Whittled from aluminum billet on a CNC machine, the door hinges are self-limiting. The angled cut on the aft piece provides a built-in doorstop at about 70° of opening. It’s impressive how much of a jewelry effect these pieces give the Sportsman.

Door Hinges

The standard Sportsman door hinges are simple tabs that allow 180° of door opening. That makes them light and useful but also ugly, so Paterson had his own streamlined hinges whittled from billet aluminum. They double as cosmetic speed lines on the otherwise plain fuselage sides, matching the teardrop door handles.

Paterson cheated in a major way in crafting the hinges. He simply sketched what he wanted, and the pattern makers and machinists at Chuck Hayes’ joystick shop, CH Products, rapid-prototyped the hinges with stereo lithography gear. After Paterson approved the design, the hinges were executed in aluminum on CNC machinery, hence the factory-level fit and finish. Some may decry such sophisticated methods, but given that rapid-prototyping centers are currently under $15,000 for nylon “printers,” and these machines are already in the hands of advanced amateurs in the automotive field, it’s inevitable that Experimental aircraft will increasingly benefit from the technology.

In its final form, the cowling separates the cooling air from the engine-air inlet scoop under the spinner and the oil cooler air entering in the more squared-off inlet on the starboard side. The oil cooler air runs through a molded-in duct along the inner wall of the lower cowl to the firewall-mounted cooler and not through a yard of convoluted SCAT tubing.

The downside to Paterson’s swoopy hinges is that they add weight and give up much of the 180° opening of the stock door. As was the case with the originals, without detents the doors won’t stay open without a line or strap holding them. But the hinges are definitely showy stuff, and in the real world they have so far provided all of the opening desired.


With its pooched cheeks, round air inlet and under-spinner engine inlet there’s not much traditional Sportsman in this cowling. Hayes was looking for something a little different, and he had a Lancair Legacy top cowling in his shop, so he grafted the Lancair upper cowl to the Sportsman’s lower. The Lancair upper turned out to be a surprisingly close fit, with the lower section requiring much more trimming and refitting to mate with its imposter other half.

Applied to the Sportsman with a veritable forest of camlocks, the cowling originally routed all air—engine cooling, oil cooling and engine inlet—through just the two round nostrils. This was definitely a clean installation, but it violated Paterson’s control-freak philosophy of segregating air management duties.

Paterson demos the flip-out headset hanger he built, one of many details he designed and fabricated for increased utility and enjoyment of the airplane. The hanger, combined with behind-the-seat phone jacks, keeps the cords from draping over the seat fronts.

After the usual quick-fix attempts, Paterson hacked into the finished lower cowl, slitting it in two spots to form the lower portion of the inlet air scoop seen in the photos. By pulling the resulting flap of cowling material away from the cowling, filling as needed with foam blocks, shaping them and then glassing over the foam, the new scoop was made. This layup-over-foam method is a Paterson favorite because it is amazingly fast. The foam can be glued anywhere and cuts like warm butter. If he digs too deeply, he simply glues more foam over the hole and goes at it again with the rasp file and sandpaper. Once glassed and cured, the foam is scooped out and the part is finished.

About the only downside of this foam-and-glass tactic is that only a single part can be made from the lost-foam tooling. But like most of us, Paterson is in the one-off business, so that has not been an issue.

Floor up, floor down. Per the plans, the baggage compartments are simple and open. Paterson opted to mold in a series of ledges to support a convertible floor. The decking can be left out for maximum baggage volume, inserted for a flat loading floor or tilted upright against the front seat backs to form a third, rear-facing seat. The seat padding and safety belts were not installed during our photo shoot, and Paterson gives small chance to anyone actually sitting back there, but he figured it was a nifty option.
Starting with the fuller, rounder tricycle gear Sportsman wheelpants, Paterson fit them with a flush-mounted gear leg fairing and oval valve-stem access door. Even he admits that the fairing, which is split horizontally aft of the gear leg, was difficult to build. The valve-stem door is an old trick and comes out a little weighty in fiberglass.

Clean Performer

One glance at the finished Sportsman, and you know it doesn’t waste speed or fuel by dragging around a collection of gaping holes and misaligned panels. That and its O-360 are guaranteed to deliver better-than-average numbers, but exact figures are not available. Controlled flight-testing was not performed prior to the Sportsman leaving Southern California, but anecdotal reports regarding its performance are favorable—comparable to the 210-hp Sportsman’s, according to the new owner.

Left: “Cool!” is what folks invariably say the first time Paterson pulls down the upper gear leg fairing to expose its spring-loaded attachment. The idea is to float the fairing on the gear leg and against the fuselage to accommodate flexure, and a beautiful no-screw-head profile is the result. The springs pull on small cables that are affixed to tabs molded inside the fairing. Spring pressure keeps the fairings pulled tightly against the fuselage; tiny pulleys turn the cables 90° inside the aluminum mounts. The fairing is split along its trailing edge to get it over the gear leg. Right: Hanging the Scott 3200 tailwheel out in the breeze offended Paterson’s sense of aerodynamics, so he fabricated a cuff for it. The fairing is a simple fiberglass U. It attaches via a tab-and-slot hanging down from the fuselage in front and a single screw in the upper rear. The screw head is the only visible part of the mount.

With the Sportsman off exploring its new environs, Paterson is keeping his fabricating hand in at Aberle Custom Aircraft. His own Glasair I retractable project suffers somewhat from Cobbler’s Kids Syndrome: It’s tough to work on your own airplane after building the toys of others all day long. But as you might imagine, it is bound to be a finely detailed speedster when it finally emerges from the hangar.

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Tom Wilson
Pumping avgas and waxing flight school airplanes got Tom into general aviation in 1973, but the lure of racing cars and motorcycles sent him down a motor journalism career heavy on engines and racing. Today he still writes for peanuts and flies for fun.


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