Liberty XL2

Good friends Hal and Michelee Cabot of Princeton, Mass., are inveterate travelers who own an immaculate, six-seat Cessna P210R specifically because it has enough room to haul all their stuff. The Cabots make regular trips all over the U.S.

Fact is, most of us rarely fly with a quartet of folks in our four-seat airplanes. Even pilots of rental aircraft tend to fly four-place machines when there are only two travelers, partially because four-seaters are more comfortable and also because two-seaters on the rental market often can't carry much more than two people---no dogs, no fold-up bicycles, not even much baggage.

The folks at Liberty Aerospace of Melbourne, Fla., have been heavily involved for six years developing a simple, comfortable, efficient two-seater with better performance than most entry-level four-place singles. It's been a long road to FAA approval largely because Liberty certified the XL2 to the more rigorous FAR 23 (rather than merely certifying the airplane under European JARs and applying for reciprocal approval). Dr. Jason Russell, Liberty's chief design engineer and an FAA/DER, headed the certification team. Under Russell's leadership, the XL2 was finally granted its normal category authorization in February and should have begun deliveries by the time you read this.

In some respects, the Liberty XL2 is a different kind of two-seater. The design is loosely based on the British Europa, an extremely popular, all-composite homebuilt airplane conceived in the late '80s by Ivan Shaw. "Loosely" is the operative term here, as the certified Liberty XL2 has only an aesthetic resemblance to that original homebuilt. The Europa is a Rotax-powered aircraft, balanced on a single, retractable gear with outrigger wheels at the wingtips for ground stability. It first flew in 1992, and some 1,000 kits have been sold in 34 countries.

The Europa's wide, comfortable fuselage was the major component retained in the Liberty design. Shaw fashioned the airplane around the cabin, a surprisingly large enclosure protected by a 4130-tube steel rollover cage. The wing, landing gear, powerplant, empennage and panel have only a distant resemblance to the homebuilt's equivalents. Even construction is now mostly metal, although the airframe retains some prepreg carbon-fiber materials.

The Liberty XL2's new wing is primarily the brainchild of Don Dykins, an airfoil expert with experience dating all the way back to the early Airbus and the Mach 2.0 Concorde. The Liberty settles for more like Mach .20, still excellent efficiency considering the horsepower. It seems practically every new aircraft design touts its natural laminar-flow wing, but Dykins' airfoil may be closer to that ideal, keeping the airflow attached to the surface for a greater percentage of the chord. Dykins' wing also features three sets of vortex generators on the outboard wing to improve aileron response at high angles of attack. If performance is any indicator, Dykins obviously must have done several things right.

For power, Liberty chose the IOF-240B Continental, a relatively new-generation engine rated for 125 hp at 2,800 rpm. As the name implies, the little Continental is injected, essentially the same mill used by Diamond Aircraft on the C1. Liberty opted for the Powerlink FADEC (Full Authority Digital Engine Controls) version, however, featuring a computerized electronic ignition system.

FADEC monitors all aspects of engine operation several times a second---throttle setting, rpm, density altitude, CHT, EGT, fuel pressure, temperature and pressure---and adjusts mixture and mag timing for all stages of flight, takeoff, climb, cruise and descent. By definition an all-electric system, the Continental's FADEC relies on the alternator and two batteries for redundancy. Accordingly, the Liberty center console couldn't be much simpler. Although it also houses fuel selector, trim, flaps, alternate air and brakes, the whole idea was to make engine operation as idiot-proof as possible. There's only a throttle lever for power control---push forward to go, pull back to stop.

Engine health reads out through a Vision Microsystems VM1000 that serves as an EICAS, airline speak for Engine Instrument and Crew Alerting System. The system reads power in percentage and warns if any parameter approaches tolerance limits.

Most pilots argue you can never have enough power, but with only 1,653 pounds to lift, the Liberty makes do very nicely with 125 hp. Grumman-American's Lynx, Piper's Tomahawk, Cessna's venerable 152 and the Beech Skipper lifted roughly the same weight with 108, 108, 112 and 115 hp, respectively, so the Liberty, with an average 10% more horsepower, enjoys a definite advantage in power loading. In combination with the 112-square-foot, NLF wing, the XL2 offers considerably better performance than the older airplanes, proof that the glass-is-half-empty pessimists are mostly half-wits.

One obvious advantage of the small wing is less drag, and that translates directly to more speed. In fact, you're unlikely to find anything in production aircraft ranks that will cruise alongside the XL2 on the same horsepower. Back in the bad ol' days of general aviation, we used to measure an efficient design by 1 mph/hp. In other words, any airplane that could score 150 mph on 150 hp was considered efficient. These days, the XL2 produces more like one knot per horsepower. In fact, it does even better, considering that the 132-knot cruise spec demands only 75% of 125 hp or 93 hp.

Another fringe benefit of the Powerlink FADEC computer control is an sfc in the sub .40 pounds/hp/hour area. According to Liberty, such efficiency generates a miserly 6.0 gph at max cruise, 5.3 gph at the recommended training power setting of 60%, the latter worth something like 110 knots. With 28 usable gallons aboard, that means you'll have an easy 3.5 hours plus reserve, over four hours at the recommended 60% instructional power setting. You could plan 450-nm cross-country flights with a reasonable reserve, realizing better than 20 nmpg in the process.

One of the greatest joys of an XL2 may be that it feels like a much bigger airplane on the inside. By two-seater standards, the cabin is huge, 48 inches across by 46 inches tall. Compare that to the 39-inch cross section of a 152 or even the 42-inch width of a Bonanza. The rudder pedals adjust for long-legged pilots, although seats are fixed in place. The folks at Liberty designed the cockpit to accommodate two big men, and it does so in both size and weight allowance.

As Americans continue to chunk up, the FAA is rethinking its 170-pound allowance per occupant for general-aviation airplanes. Even at 200 pounds per seat, the XL2 should have enough full fuel payload for two big pilots plus toothbrushes. Preliminary numbers suggest an empty weight of 1,065 pounds, leaving a 420-pound payload with full fuel.

Engine start with the FADEC system regulating all parameters of engine operation requires little more than hitting master and fuel pump, and engaging the starter. Taxiing is a little different in that it employs differential finger brakes rather than toe or heel brakes. Finger brakes take some getting used to, like thumb steering in an Aerostar, but they offer a good mechanical advantage, and once you've used them for a while, they're not that different. In combination with the full-castering nosewheel, directional control is nearly good enough to turn the airplane 180 degrees in its own wingspan.

Takeoff and climb are more enthusiastic than you might expect, closer to 1,000 fpm than the old 152 and Skipper's 600 fpm to 700 fpm. The more significant advantage comes at typical cruise heights where the XL2's extra power allows you to climb an extra 2,000 feet in minimal time. Service ceiling is listed at 14,000 feet.

The XL2's handling is quick with conventional joysticks for roll and pitch, but not so brisk as to be touchy. That's partially a function of push rods rather than cables for control activation. Ailerons are wide span, covering nearly 40% of the wing's trailing edge. Pitch control employs an all-flying stabilator rather than the more conventional horizontal stabilizer and elevator. One curious anomaly is electric pitch trim mounted on the panel rather than the yoke.

Visibility is excellent with the semi-bubble canopy providing Plexiglas all over the place. There's a small hinge area directly overhead and a narrow windshield frame, although neither restrict the view. The clamshell-style doors wrap back well past the pilot and passenger's shoulders, so you can look to both sides, back, up and forward with virtually no restrictions.

The Liberty XL2's gear features a wide track and a long wheelbase, both of which help to contribute to its easy landing characteristics. The Liberty XL2 design also employs wide-span, long-chord, slotted electric flaps that reduce stall speed from 52 knots all the way down to 45 knots. With such impressive low speed available, it's not hard to imagine approaches as slow as 55 knots, so runway requirements are short, which is under 800 feet. Even the over-50-foot numbers are only 1,250 horizontal feet. Pilots with a need to plunk it on and stop it short should find even modestly obstructed runways of 1,500 feet or longer more than adequate.

Liberty is promoting the XL2 as a private transport more than a trainer, but the airplanes will inevitably find homes on training flight lines across the country, especially those that were forced to switch to four-seaters when the older generation of trainers was retired in the '80s. Anthony Tiarks, founder of Europa in the late ’80s, and president and CEO of Liberty Aerospace, feels there's a strong market for a two-seater that can perform both missions.

At a base price under $140,000 for a VFR airplane and $160,000 for an IFR machine, the Liberty XL2's obvious competition is the Diamond C1, a formidable contender supported by an established company and priced at about the same level. Liberty's plant in Melbourne is geared up to produce as many as five XL2s a week. Current backlog is 53 orders, although that's sure to improve when more people have the chance to fly this quick, economical personal transport that Liberty hopes will impress private buyers as well as flight schools.

For more information, contact Liberty Aerospace at (800) 759-5953 or log on to www.libertyaircraft.com.

SPECS: 2004 Liberty XL2 N204XL