How Aerobatics Works

Orville and Wilbur Wright may have been the first to perform an aerobatic move, but the real aerobatic pioneers were the barnstorming American and European pilots who performed exhibitions for paying audiences at fairs and air meets in the 1910s and 1920s. Spectators grew bored with mundane, everyday airplane maneuvers, so the entertainers began attempting increasingly fancy stunts. The scarier the stunts, the better.

One of the great showmen of that era was American pilot Lincoln Beachley who startled crowds with his "death dip," in which he flew to 5,000 feet (1,524 meters), turned off the engine, and then dove straight down at the ground, only to pull up at the last second. At times he added to the difficulty by flying under telegraph wires or through a grove of trees. After Russian military flyer Petr Nikolaevich Nestoy invented the loop in 1913, Beachley had aviation designer Glenn Curtis create a special plane made for the maneuver. He began performing the trick at shows, charging a fee of $500 for the first loop and $200 for each one afterward. After World War I, many returning fighter pilots, who used aerobatic maneuvers to win dogfights, began second careers as air show performers. In 1927, the first international aerobatics competition was held in Zurich, and trick flying gradually morphed into a sport with rules and standards [source: Sheffield].

Aerobatics has continued to evolve over the years. After World War II, the aircrafts' increased speed and other capabilities actually made some of the early pilots' maneuvers too dangerous to perform anymore. But clever pilots soon developed other moves to take their places. In the 1950s, Czech aerobatics flyers, for example, invented a maneuver called the lomcovak, a series of bizarre gyroscope twists during which the plane rotated on all three axes. Aerobatics pilots also have developed the ability to fly in nearly perfect circles and accurate figure eights, and to do maneuvers in formations so close that their wings almost appear to be touching [source: Sheffield].

Next, we'll take a look at some of the tricks aerobatics pilots perform.

Aerobatics tricks often have exotic names, like the Pugachev's Cobra -- names that are puzzling to all but those who are steeped in the sport. But listed below are some of the more familiar maneuvers. If the descriptions are too hard to visualize, check out the Web site of Sunrise Aviation, an aerobatics school, which provides animated graphics that illustrate most of these maneuvers.

Chandelle: This is a combination of a vertical climb and a turn. It's actually a basic flying fundamental, rather than a true aerobatic move. But you'll see stunt pilots do it as part of more complicated maneuvers [source: FullDeflection.com].

Dive: This one's just like it sounds. The plane's nose is turned downward, though the plane is not necessarily completely perpendicular to the ground. Diving causes an increase in air speed, which the pilot can use to pull up at the right moment [source: FullDeflection.com].

Loop: A loop is when an aircraft flies upward and then, at the top of its arc, begins to slow down, so that it turns down and completes the circle. You can do an inward or outward loop [source: FullDeflection.com].

Roll: A roll is a 360-degree revolution along the plane's longitudinal axis [source: FullDeflection.com].

Barrel roll: A barrel roll is a combination of a loop and a roll. The flight path is the shape of a corkscrew [source: FullDeflection.com].

Wingover: A wingover is a left or right 180-degree tight turn at the top of an upward quarter loop [source: FullDeflection.com].

Hammerhead or stall turn: Contrary to its name, this maneuver doesn't actually involve stalling. The plane soars upward and then abruptly turns 180 degrees and descends [source: FullDeflection.com].

Cuban eight: The plane does five-eighths of a loop to the 45 degree line, a half-roll, another five-eighths of a loop back to the 45 degree line again, another half roll, and then three-eighths of a loop to level out. If that's too complicated to picture, imagine a Hot Wheels car doing a figure eight on one of those loop-de-loop tracks. The variations include the Half Cuban Eight and the Reverse Half Cuban Eight [source: FullDeflection.com].

These maneuvers sound pretty dangerous, and we'll cover that topic on the next page.

So how do stunt pilots do those maneuvers without spinning out of control -- or worse, crashing and being killed? Sometimes they can't. Some of the most illustrious early aerobatics pioneers, like Lincoln Beachley, for example, ended up buying the farm via aerobatics. The possibility of injury or death performing a stunt is something a stunt pilot learns to live with and respect. Aerobatics isn't a sport for milquetoasts, or fools.

As explained in Geza Szurovy's and Mike Goulian's how-to textbook "Basic Aerobatics," one secret of staying alive and looking good in the process is to adeptly calculate and manage the amount of kinetic energy -- that is, airspeed -- used in a maneuver. If you don't go fast enough, the aircraft won't have enough kinetic energy to perform the stunt properly. On the other hand, if you're going too fast, you'll overstress the physical limits of the plane's structure and components. And the result can be very, very bad [source: Szurovy and Goulian].

Adept stunt pilots are masters of conserving energy by balancing the plane's air speed-kinetic energy against the potential energy in its altitude. During a typical aerobatic maneuver, an increase in air speed is balanced by a decrease in altitude, or vice versa. If that's a bit too abstract for you, here's an example. When an aerobatic pilot pulls up into an inside loop, he or she is converting kinetic energy (air speed) into potential energy (altitude). As the aircraft floats at the top of the loop, the potential energy is at its maximum, but the aircraft is slowing down, so that its kinetic energy is at the lowest point. As the aircraft descends, the potential energy decreases and the kinetic energy increases again [source: Szurovy and Goulian].

Of course, that's just one greatly oversimplified version of the scores of complex, delicate physics equations that a pilot must make while he or she is doing hair-raising tricks thousands of feet above the ground. He or she also must deal with other hazards, like the effect of acceleration and the resulting G forces on the human body. Too many Gs and the blood can be shunted away from the brain, causing a blackout. Inducing negative Gs, on the other hand, can pump too much blood into the brain, interfering with vision and hearing [source: Szurovy and Goulian].

For more on airplanes and flying, visit the links on the next page.

I've flown as a passenger in small aircraft and helicopters enough times to understand how precarious flight actually is. So it's utterly amazing to me that some pilots have the nerves and skill to attempt hair-raising stunts in the air. It was interesting to learn about the long history of stunt flying and that it dates back practically to the invention of the airplane itself. Those early aerobatics pioneers really had to have a lot of courage, since the aircraft they flew were far less sophisticated than the planes used for stunts today. It was also fascinating to learn that what appears to be random craziness in the air actually is an elaborately structured sport, with rules and standard maneuvers.

Sources

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