Tumbling with the Stars
Today’s airshow performers do it gyroscopically.
- By Debbie Gary
- Air & Space magazine, July 2009
Courtesy Greg Poe Airshows
When I started flying airshows, back in 1971, the edge of the known aerobatic world was a maneuver known as the lomcevak. The great-granddaddy of tumbles, the lomcevak (pronounced “LAHM-sha-vock”) took you to a wild place, where one minute the air under your wing was solid as a fist, and the next you were toppling tailwheel over nose cone into the abyss, as out of control as an unhinged car on a Ferris wheel.
Recently I watched aerobatic performer Greg Poe cartwheel his bright red Fagen MX-2 across the show line. A few beats later, the airplane began a tight, fast, vertical roll, which widened into a corkscrew and topped out around 2,000 feet. There it stayed, continuing to rotate, but now Frisbee-like, with its nose following the horizon. It hovered for a moment before flat spinning downward. Poe had seamlessly blended four maneuvers into a single magic trick. His routine is only one of a dozen on the airshow circuit today that make me realize: Tumbles have changed.
Nobody knows exactly how many kinds of tumbles there are now. If we could tally all the differences in the maneuvers that depend on aircraft design, center of gravity, entry and exit attitudes, control movements that change during the maneuvers, and the amount of experience and recent practice pilots have, the number would be overwhelming. Some show pilots have created—and named—signature tumbles. One of the most famous is Sean Tucker’s Centrifuge. Tucker’s Oracle Challenger Pitts leaps across the sky from tumble to tumble. Its nose twists over its right shoulder toward its tail 7, 8, 9 times—as if snarling at a demon behind it—10, 11, 12 times.
All the various tumbles have one thing in common: Pilots get into them by using the gyroscopic effect of a spinning propeller. Pushing on a spinning gyro moves it 90 degrees to the left or right of the direction the push came from. A pilot starts a roll, and, with the help of the propeller’s gyroscopic forces, skids the nose to point at an angle from the line of forward motion (see “Shoulder Roll,” opposite). The airplane behaves like a car going downhill fast, skidding sideways, then rolling over.
When the only game in town was the lomcevak, we entered the tumble in climbing roll, pushed the ailerons on our wings one way and the rudder on our tail the other way, then just hung on until the airplane spit us out into an inverted spin. The airplanes responded differently. For instance, my Pitts would tumble slightly cock-eyed, tail over wing, whereas Art Scholl’s Super Chipmunk would tumble forward, tail following nose as if the airplane were inside a squirrel cage. But we called them all lomcevaks—a Czech word for either a headache, a hangover, or a big slug of plum brandy; we’d heard all these translations.
We did them on purpose, of course, but three-time world aerobatic pilot Nikolay Timofeev says that Czech pilot Ladislav Bezak probably discovered the first one in his Zlin by accident, the way Soviet pilots discovered some of their tumbling maneuvers around 1976. “As soon as we receive Yak 50 we start to do negative snaps on vertical line,” he says (see “Vertical Roll,” left). “And we jump into gyroscopic inertia rotation because Yak 50 is not really good airplane for negative snaps, especially on vertical up lines. I believe same story in Czech Republic. Zlin 50 is also not excellent for negative snap on way up.”
Mistakes can be turned into maneuvers if pilots can figure out what they did in the first place. Former U.S. national aerobatic champion David Martin has perfected a forward tumble that is so straight and so tightly flown that it looks as if his CAP 232 is swinging by its tailwheel from a high wire. He has spent thousands of hours practicing aerobatics, particularly his tumbles.
“If you are talking something new that you want to do in an airshow,” he says, “you have to figure out how to do it; then you have to figure out how to consistently do it; then you’ve got to figure out doing it at a lower altitude. It takes a while. I practice purposely messing them up. Because if I am going to be doing them at low altitude, I need to know what is going to happen. So that is a lot of practice.”
The first time he did the one he calls the Good Tumble it was by accident, but luckily someone got it on video. “I looked at that video hundreds of times, trying to figure out exactly what I did,” he says. “It took a long time. At first, even after I figured out how to do it, I might get it 50 percent of the time, then it would be 75 percent, then finally I’ve got it now where it is. I won’t say it is 100 percent, but at least 90 percent of the time it will do what I want it to do.