Join the tumbling mirth

“You see flashes of sky/ground, sky/ground, and then you neutralize the controls when you lock onto something you recognize,” said Doug Vayda, a veteran aerobatic pilot who has performed countless tumbles in competitions and airshows. “It’s kind of like banging your head against a wall. It feels really good when you stop.”

Loosely translated, lomcovák means “headache” in Czech, and that’s an apt description for the maneuver that forever altered aerobatic flying when it was introduced in the 1980s. Instead of drawing exquisitely precise figures in the sky with classical grace and finesse, the lomcovák started an aerobatic arms race that emphasizes speed, brute force, and a heavy metal soundtrack.

Although the lomcovák was invented in a relatively dainty two-seat, 180-horsepower Zlin 526 Trener, the Czech national aerobatic team popularized the maneuver and its countless variations in the brawny, single-seat, 260-horsepower Zlin Z 50. The Z 50 also promoted trends in competitive aerobatics and airshow flying that continue today.

The Z 50 enforced monoplane supremacy, the efficacy of Lycoming engines, multiblade composite propellers, fixed tailwheel landing gear, and it started the reign of tumbling, out-of-control maneuvers. An engineering team at Zlin Aircraft designed the all-metal, low-wing, Lycoming-powered Z 50 to beat the Russian Yak 50, a 360-horsepower monoplane with retractable tailwheel landing gear that dominated international competition for a decade beginning in the mid-1970s.

Like other Eastern Bloc aircraft of its era, the Z 50 didn’t have a business case or a commercial market, and it didn’t need them. It was state funded for the sole purpose of winning international aerobatic competitions and, by so doing, raising national prestige and industrial prospects of Czech aviation firms. Czechoslovakia had been at the center of Eastern Bloc aircraft manufacturing since World War II, and it intended to stay there.

The Z 50 made its competition debut in 1976 when the Czechoslovak and Polish teams flew them in that year’s world aerobatic championship. Two years later, the aircraft won first and third in the individual competition, and Czechoslovakia won the team event.

The design underwent a series of upgrades throughout the 1980s and early 1990s with a more powerful, 300-horsepower Lycoming AEIO-540-L1B5D engine in the LS version, and additional fuel in the LX model. A total of about 80 were built.

By then, however, the Z 50 had been overtaken by even more powerful, higher-performing, composite monoplanes such as Sukhoi Su–26s from the Soviet Union, Extra models from Germany, and the CAP series from France.

After the fall of the Berlin Wall in 1989, Z 50s were sold to individual owners around the world as well as flying clubs throughout Europe, and several aerobatic formation teams acquired them. Five Z 50s were imported to the United States.

Francesco Pallozzi, an Italian-educated aeronautical engineer living in Delaware, owns and flies one of those U.S. airplanes. He learned aerobatic flying in a Zlin in Germany, then he came to the United States and bought a Z 50 that had been imported in the late 1990s. He plans to use it for aerobatic competition and recreation.

The airplane appealed to him because, as a structural engineer, he appreciates its clarity of purpose and its incredibly robust construction. “This airplane is virtually indestructible in the air,” he said. He also has long harbored a desire to master the tumbling maneuvers Z 50 pilots pioneered.

“Ever since I was a young boy watching the Frecce Tricolore [Italian national aerobatic team], I knew I wanted to be an aerobatic pilot,” Pallozzi said. “And when I watched the solo pilot intentionally tumble his airplane, it really captured my imagination. It became my dream to fly figures like that some day.”

Oddly warbirdish

The Z 50’s symmetrical wing, thick airfoil, solid rivets, and external tail brace show it’s not meant for speed. The airplane was meant to compete and win in a tiny, 1,000-meter aerobatic box, so additional drag wasn’t a penalty—it was a design feature.

Full-span metal ailerons get an aerodynamic boost from servo tabs on the trailing edges, as do the hefty, fabric-covered elevator and rudder. (Unlike other aerobatic airplanes, the Z 50 doesn’t use spades to lighten ailerons.) All the Zlin’s control surfaces seem oversized, a not-so-subtle hint about its extreme maneuverability.

This airplane, N50MX, was built in 1986 and its modifications include streamlined Grove main landing gear and wheel fairings, so it’s faster than a stock Z 50. I climb onto the left wing, then don a backpack parachute and slide into the semi-reclined seat and cinch down the five-point ratcheting harness. Inside the cockpit, the airplane’s military heritage is obvious.

The tight confines, gooseneck control stick, Spartan panel, industrial-strength switches, rudder pedal stirrups, and logical layout could have come from a MiG–21 (hundreds of which also were built in Czechoslovakia during the same period). With parts, instruments, and design features in common with other state-funded military projects, this aerobat feels oddly warbirdish.

Most of the instruments are familiar, or easy to figure out. There’s a big Russian windup clock with sweep hands, a turn coordinator (with L and P for the Czech equivalent of left and right), and manifold pressure in kilopascals instead of inches. I’m told 85 kPa is 75-percent power, but that’s academic in an aerobatic airplane with the throttle normally either wide open or idle.

The main fuel tank only holds 16 gallons, so I don’t intend to keep the thirsty engine at full power very long. (Two auxiliary fuel tanks can carry 13 additional gallons total.)

The swing-over canopy latches on the left side, and a small vent provides the only cooling. On a summer day on a black ramp, that provides an extra incentive to start the engine and get the fan blowing as soon as possible. Engine start and runup are normal, and visibility over the nose is excellent for a tailwheel airplane.

Takeoff acceleration is brisk, and the Z 50 is airborne after six seconds and an 800-foot ground roll. A cruise climb at 120 KIAS and 75 percent power on an 85-degree-Fahrenheit day at sea level produces a 1,600 fpm climb rate.

Breakout forces are higher than other aerobatic monoplanes, and there’s a crisp centering tendency in pitch, roll, and yaw. The pitch trim lever on the left side of the cockpit is sensitive, and I overcontrol on the first few adjustments.

Once in the aerobatic practice area, full-deflection aileron rolls at 150 KIAS show a roll rate of about 180 degrees per second. Inverted flight requires a slightly nose-high attitude and a small amount of forward stick to maintain altitude.

Upright, power-off, two-turn spins are conventional, and an abundance of rudder authority makes them unusually obedient. Snap rolls to the right at 100 KIAS are quick and result in remarkably little deceleration as the three-blade Hoffman prop digs in and pulls the airplane forward.

Over-the-top maneuvers such as loops and half-Cubans entered at 160 KIAS gain about 800 feet at the apex. A hammerhead entered at the same speed gains 900 feet—and the airplane spends a full five seconds drawing the vertical upline.

But the maneuver I’m most curious about is the lomcovák, so I set a 45-degree climb, let the airspeed diminish to 100 KIAS, roll knife-edge right, then hit it. Abruptly applying forward stick and left (top) rudder instantly results in 2.5 negative Gs, a stall break, and brisk rotation.

It’s essentially an inverted spin with an upward trajectory.

The sudden onset of negative Gs is an acquired taste that I’ve never acquired. But after the stall break, the spin itself is a surprisingly pleasant, zero-G affair. Recovery is instantaneous with idle power and neutral controls, and the airplane recovers in a wings-level, 45-degree dive.

I try a few variations with steeper and shallower entries, but the results are consistent: A spike of negative Gs, an outside snap (or two), and an immediate recovery.

Back in the landing pattern, I fly final approach at 90 KIAS, then wipe off the power in ground effect and touch down in a three-point attitude. The airplane tracks straight with no drama and decelerates to taxi speed after an 800-foot ground roll with light braking.

Pallozzi says it lands “just like a Citabria,” and he’s right.

Wild side

The Z 50 has a unique place in aerobatic history for popularizing the kinds of high-power, high-energy gyroscopic maneuvers that have become a mainstay of competition and airshow flying. It’s a pure aerobat with the sensibilities of a warbird. Like its nemesis, the Yak 50, the Zlin traces its heritage to World War II fighters that preceded it by 30 years.

The Sukhoi 26, Extra 260, and CAP 230 series quickly eclipsed the Z 50 at the top of the world stage. But those airplanes largely continued patterns that the Z 50 had already set. They just did it better and with greater refinement; more power; and lighter, stronger, more streamlined materials. Today, the Extra 330SC, Gamebird, and others are seeking to do the same thing to the Z 50’s successors.

The Z 50 remains popular among aerobatic purists and formation aerobatic teams for some very good reasons. It’s sturdy and robust, big and powerful, smooth and graceful.

The lomcovák reveals that it’s also got a wild side.

If that appeals to you, go for it. Then take two aspirin for your headache and call me in the morning.

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