Scott Carterís Xtra-EZ
A tribute to Burt Rutan
By Patrick Panzera, EAA 555743, firstname.lastname@example.org
Scott Carter’s Xtra-EZ on display at AirVenture 2009
Thirteen must be Scott Carter’s lucky number. It took that many years to complete his first flying project, a Long-EZ, and it took the same number of years to complete his current one-off aircraft, the Xtra-EZ. And he and his wife (and copilot) Lynn Canatella had been together for 13 years when they made the first EAA AirVenture Oshkosh trip in the Xtra-EZ. Lynn has a little over 600 hours as pilot in command, single-engine land, whereas Scott has over 2,500, almost all of which were logged in his Rutan EZ. Lynn has been flying since 1993, but Scott started taking lessons in 1968. Scott’s military time was spent outside the cockpit turning wrenches, which was preceded by a rich childhood building model airplanes. By high school, Scott was an EAA member making annual treks to Rockford, and then Oshkosh. Lynn’s fire was lit by way of the back seat of a P-51 and has since been fed by the sense of camaraderie and the adventure—and the noise.
When not flying, Lynn works in commercial real estate sales whereas Scott babysits a Gulfstream G4, a G450, and a couple of Citations for a private individual, but in a very corporate-like environment. Scott has been an A&P since 1978, and his occupational title is director of maintenance. But before you think that Scott had the advantage of access to a shop full of aviation equipment, tools, and working space and was allowed to work on his plane at work during slow periods, let me assure you that Scott built his plane in his overcrowded 1-1/2 car garage, after work hours. When the plane became too large for that space, a hole was cut in the wall and garage door to accommodate a wingtip or two. Once the plane was just too large, period, the back patio became fair game.
What’s in a Name?
So if it started out as a Cozy Mark IV, why is it called an EZ? Scott gives credit back to his roots, his real roots. He has a fanatical respect for Burt Rutan and all that he’s done for aviation, especially experimental aviation. Nat Puffer did a great job designing the Cozy, and his evolution of the Long-EZ into the three-place and then four-place Cozy aircraft completed Burt’s family of canard aircraft. (See issue 10 of CONTACT! Magazine for the full Cozy story.)
The biggest difference between Scott’s Xtra-EZ and a Cozy Mark IV is the staggered seating up front and the fuselage stretch that allows for it, while retaining seating for two in the rear. Scott and Lynn wanted more shoulder room while preserving the intimacy of sitting side-by-side, and they didn’t want to widen the fuselage. The result has the added benefit of additional leg room for each front seat occupant, both in length and width.
Scott’s Long-EZ parked on the ramp at Burt’s 60th birthday bash. In the background: Scaled Composite’s Triumph, a pressurized eight-seat corporate aircraft.
It Began With an EZ
It was 1978, and Burt Rutan was beginning to make a name for himself. Over 1,000 people before him had already purchased their Long-EZ plans by the time Scott bought his. Intrigued with this “new” construction process, coupled with the inexpensive nature of the plans themselves and being able to build as he could afford (as opposed to shelling out big bucks all at once for any of the available kits on the market back then), Scott was hooked. “My Long-EZ has defined my life since 1980.” Thirteen years later, N24SK was hatched and began accumulating 2,500 hours in the air.
One notable trip logged by Scott in N24SK included a pilgrimage from Dallas, Texas, to Mojave, California (June 28, 2003), along with well over 100 other EZs and other variations on the theme, to help celebrate Burt Rutan’s 60th birthday and Dick Rutan’s 65th.
The EZ did a great job for Scott, being pushed along by a Lycoming O-320, but Scott is a builder and as such he needed another project. More than satisfied with the construction methods used to build his EZ, the strength and durability of which never let him down, it was a no-brainer that his next project would be similar.
Since the EZ and the Cozy are plans-built and are amenable to builder-designed changes, the designs have evolved but not necessarily in just one direction – there are branches. Some of the changes work really well, others work so-so, some only work for the builder who installed them, and others are miserable failures.
When Scott set out to build his new plane, he knew that he wasn’t going to build a stock Cozy, but he also knew than no single “branch” would work for him. So his creation is 100 percent unique, but he can’t take credit for any single element. He took all the ideas that he thought were good, or that he thought would work for him or his wife Lynn, and incorporated them into what he calls Xtra-EZ. Most aircraft designers aren’t pleased when people make modifications to their work, especially when the changes can be considered extreme.
Center of Gravity
As previously stated, the biggest change from the Cozy drawings is the fuselage stretch. It would seem reasonable that when the two lifting surfaces (wing and canard) are moved farther apart, there will be a change in the center of gravity (CG) range. Scott appropriately refers to the CG loading of his Xtra-EZ as a “balancing act.” Some of the effects of the stretch were canceled out by the heavier six-cylinder IO-540 (Cozy calls for a four-cylinder O-360) located aft, but placing the copilot closer to the CG means that this person can weigh quite a bit more (an easy 50 to 60 pounds more) than if they were moved forward. To visualize the changes to the fuselage, consider that the copilot is pretty much in the “stock” location and the left-seat pilot is moved forward with the stretch.
The envelope is “huge” as Scott describes it, not too different from his Long-EZ but certainly in a different place since there is a relationship change between the wing and the canard. Scott was diligent in exploring the full envelope during his initial flight testing.
In the state it was in when these photos were shot, the rear seat isn’t very welcoming with its lack of upholstery, but it was a work in progress; it’s just been a matter of time constraints. Scott and Lynn have every hope of happily flying occupants in the rear seats, which is why they built a four-place airplane.
Another innovative idea that’s been built into the airframe and made part of the pilot’s operating handbook is the relocatable ballast that does double duty as a toolbox. There are specific stations, one in the nose and one in the rear compartment, where the little red toolbox can be located (installed), depending on whether the plane is flown solo or not. When in the nose, it resides just in front of the copilot’s feet. Up to a certain weight, the ballast can remain in the nose, depending on the weight of the copilot at the time. In the rear location it’s very close to the CG, so it’s almost as if it was removed. But it’s a very complete toolbox and nice to have along in the event of emergencies. So far it’s not been called upon and let’s just hope it continues that way.
Please make it as large as possible
The canard is stock for a Cozy (Roncz 1145 airfoil), but the fairing that covers it isn’t. The original Cozy fairing is no bigger than the chord of the canard itself and is permanently affixed to it. A smallish forward hatch gives access to the canard attach fittings, the rudder pedals, and battery. Once disconnected, the canard lifts out of its mount, fairing and all. Scott has taken things to the next level, making the fairing and front cover all one piece and large enough to allow for an intricate sealing system which keeps water from seeping and wicking in. And with the use of a concealed fastening system, all one sees when the cover is installed is a fine line hinting that the hatch may be removable but leaving the observer wondering how. When it’s removed, it gives full access to the canard center section, making for easy removal during its annual inspection and great access to the wheel brake hydraulics.
Scott installed an oil cooler in the nose section to act as a heat exchanger to keep his feet warm in colder months and at altitude where the plane really performs well. His Long-EZ used a conventional heat muff from the exhaust manifold, but by the time heat was ducted all the way forward, it lost most of its energy. Additionally it can bring carbon monoxide with it, so the new system, borrowed from other aircraft, is safe and effective by comparison. Oil flows through rigid ½-inch aluminum lines to reduce the potential for a rupture. Cabin air is recirculated over the cooler when heat is needed, and when not, the same bilge blower (centrifugal fan), which circulates the cabin heat, dumps the heat overboard by means of a mechanical valve attached to a manual pull lever.
With the main oil cooler in the engine compartment, the engine oil system utilizes a vernatherm (oil cooler by-pass valve) so the engine oil can come up to temperature and maintain at least 180 degrees before any “excess” heat can be diverted to the forward oil cooler. Living in and operating from the Dallas area, Scott isn’t too worried that his system might leave his tootsies cold, but according to Scott, “I suspect if I lived in Minnesota it might be a problem. But not in Texas, and not at altitude so far – it does just fine.”
When heat isn’t needed, cool cabin air is brought in through a small but very effective hole in the point of the nose – very glider-esque, especially having the pitot tube concentrically located. With a length of SCAT tubing connected to the inlet and snaking its way to the instrument panel, the pilot is kept cool. The copilot and rear passengers are ventilated by a similar inlet cut into the leading edge of the port-side strake, at the fuselage junction.
Located in the leading edge of the copilot’s strake is the one of two discreetly located fresh air inlets.
The toe brakes aren’t original to the Cozy or the EZ but are adapted from a retrofit that Scott installed in his EZ, for which he credits Bruce Tifft, more known for his pusher propellers. “When I originally built my Long-EZ, the master cylinders were mounted in the back and were very ineffective because of the cable stretch. Bruce sent me a simple little drawing, I converted them, and they worked wonderfully, so that’s what I’ve installed here. That’s Bruce Tifft’s idea.”
Access panel with no external fasteners; offset nose gear; fresh air inlet with concentric pitot tube.
The nose gear on the Xtra-EZ is raised and lowered by way of an electric linear actuator (as opposed to the traditional Cozy hand-crank, made from a Craftsman ratchet wrench) so the plane can be occupied before getting the nose off the ground from its familiar “grazing” position. The gear is also offset toward the passenger’s side, leaving plenty of foot room for the pilot, comparable to that of the Long-EZ. The Cozy foot well is shared by both front seat occupants and isn’t twice as wide as the EZ, but unlike the EZ, the pilot doesn’t have to straddle the nose gear. On the copilot side, foot room is off the charts with virtually no restrictions or compromises since the seat is moved 12 inches aft. The castering nose gear fork was manufactured by the late Ken Brock, built for the Cozy Mark IV. One other modification was extending the nose gear pivot point forward 3 inches, allowing for a longer nose strut. This provides a positive three-point angle of 2.5 degrees, improving rotation on takeoff.
Retractable Main Gear
Following the theme of borrowing ideas and technology from other successful Rutan variants, Scott used the main landing gear legs manufactured for the Velocity RG. “I bought the gear legs, but I had to reinforce them and shorten the over-center mechanism, involving some welding. So I got to use my lesser-used skills that I gained from being an airplane mechanic.” Scott said.
The hydraulic ram is powered by a pump from the boating industry, designated to actuate the lower end units of inboard/outboard boats. The system overall is very simple. “It’s just an electric motor and a hydraulic pump and it runs the gear – pulls the gear up and down via a really long cylinder that does nothing more than pull two cables and break the over-center system,” Scott said. “The gear is held up by hydraulic pressure, and if there’s a problem with that hydraulic pressure, gravity will put the gear back down. Really simple, wonderful system, magical; well within the spirit of this airplane, which again, Burt is a master of simplicity and efficiency.” The best part of it is that, according to Scott, the gear weighs little more than a fixed landing gear (with wheel pants and the various fairings) for a Cozy Mark IV, according to Scott, and there’s less drag than with fixed gear. The wheels and brakes are from Grove Aircraft Company; the axles are from Aircraft Spruce.
With the leading edge of the closed canopy coming right up to the aft split line of the aforementioned hatch, the rear of the instrument panel is accessed by removing a few screws from a dust cover that’s otherwise hidden by the closed canopy glare shield. Once the cover is removed, the electrical system and the fuse blocks are exposed. Utilizing off-the-shelf aftermarket automotive fuse blocks and very few circuit breakers, Scott has followed Robert (Bob) Nuckolls’ AeroElectric Connection instruction manual when he wired his planes. “I picked a system and I stuck with it.” Scott claims.
Bob Nuckolls is the master of keeping things simple and affordable, not a fan of spending hundreds of dollars on aviation circuit breakers when $20 worth of fuses mounted in a simple fuse block will do the same job. But Scott states, “I am an airplane guy, so there are a few things that I ran circuit breakers to, very few.” Subscribing further to Bob’s philosophies, Scott has installed a “normal” battery buss as well as an “endurance” or “essential” buss in the event of an alternator failure or need for it to be taken offline. Since the plane is plastic, there’s no easy way to chassis ground a lot of the equipment and accessories. So nested in the nose is what Scott calls his “forest of grounds,” which might be considered a departure from Nuckolls’ convention.
In next month’s issue, we’ll continue our tour of the aircraft systems of Scott Carter’s award-winning Xtra-EZ, with an up-close look at the battery installation, ergonomics, instrumentation, engine and controls, the canopy, and much more.