February 1, 2011
Photography by Mike Collins
Rolling inverted, diving, pulling 4 Gs. In a split second, the split-S sends adrenaline flowing and blood pumping as full left aileron and rudder deflection flips the 1975 Citabria upside down, momentary forward pressure stabilizes it, and back-pressure forces the occupants of the tandem taildragger against their seats while plunging toward the Earth.
The fast-paced maneuver makes the previous 15 minutes of what had been awe-inspiring flight seem mundane. Departing Potomac Airfield (VKX) near the heart of the Washington, D.C., Flight Restricted Zone on a clear, crisp afternoon reveals a breathtaking view of the Washington Monument 10 nautical miles away—a view few pilots dare to experience because of the anxiety-inducing security hoops and flight procedures required to fly in the most sensitive airspace in the United States. But with Marianne Buckley, a CFII, MEI, and owner of Buckley Aviation based at the airport, the flight is serene. Those procedures are routine for her.
As the national monuments fade into the distance, the Citabria putters south out of the flight restricted zone and climbs to 3,000 feet upon reaching a stretch of shoreline where the Potomac River snakes into a V shape. That’s where the aerobatic workout begins: loops, hammerheads, rolls, Immelmans, Cuban eights, snap rolls, spins, and the split-S!
Watching aircraft dance across the sky at airshows in ways one wouldn’t think possible can give the impression that aerobatic maneuvers are complicated, but the basics have few steps. Buckley, a flight instructor when she’s not working as legislative staff on Capitol Hill, has more than 5,000 hours total time and has been teaching aerobatics since 1997. She explains the basics of the maneuvers simply and concisely—from the necessary control inputs to how the body will feel to what it would look like from the ground.
The maneuvers that the Citabria can do range in complexity, and nearly all are based on the loop and aileron roll. Each emphasizes stick-and-rudder flying and forces the pilot’s attention outside for positional awareness. For safety (and per the regulations), all must take place above 1,500 feet agl, and the occupants must wear parachutes. The chute, strapped tightly around the legs and chest, provides a sense of security (although the thought of using it is terrifying, especially prior to flight when learning how to jettison the cabin door, get out of the airplane, and pull the rip cord).
The 150-horsepower Citabria, loops start with a dive to 140 knots and 2,500 rpm and then transition into a full-power climb until the aircraft is inverted at the top. Relaxed back-pressure on the stick while inverted rounds the top of the loop. Power is reduced while descending on the back half of the maneuver so that the fixed-pitch prop stays below its rpm limit.
During an aileron roll, the pilot dives to 130 knots before pulling up 30 degrees above the horizon and then simultaneously applying full left aileron and coordinated rudder, the body pressing against the lap belt while inverted. Forward stick pressure while upside down maintains altitude until the roll continues around to upright.
Once these two maneuvers are learned, the pilot is ready to rock and roll by mixing various segments of each. Hammerheads begin like a loop, but the climb pitch should stabilize at 90 degrees, or straight vertical. “The rudder on the side of the turn is applied with opposite aileron, and the airplane will pivot on the wing tip and cut a straight line through the horizon,” Buckley says. This leaves the aircraft pitched down and turned 180 degrees (and gives new meaning to a 180-degree turn).
The Immelman combines the first half of a loop with a half aileron roll at the top to return to upright straight-and-level flight—while the Cuban eight adds half rolls to two loops, creating the track of a horizontal figure-8 in the air. Diving, climbing, and rolling in the Cuban eight overwhelms the senses at first. Sights of the ground, horizon, and sky flash by seemingly as quickly as tumbling in an Orbitron ride. Timing for both of these maneuvers is key. As Buckley described the Immelman, the pilot needs to know the right “nanosecond” to push the stick forward before rolling upright. In the Cuban eight, the roll from inverted to upright must occur while the aircraft is upside down at a 45-degree angle to the ground. Rolling late will cause the aircraft to gain too much speed.
Federal aviation regulations do not require formal training or an endorsement for aerobatic flight, but after experiencing it—with drastic pitch and bank changes and new sensations associated with higher-than-normal G forces—taking lessons to learn the maneuvers (and what to do in case of a mistake) is a wise, safe investment. The International Aerobatic Club (IAC), a division of the Experimental Aircraft Association, maintains a list of schools that offer aerobatic training.
Spins, while taboo for many pilots, are taught, practiced, and encouraged in aerobatics. (The snap roll maneuver is a horizontal spin.) “If you get into trouble, put it into a spin,” instructors counsel during aerobatic flight. Too often, spins are taught to be avoided, and spin recovery is a rote memory exercise.
Practicing spins takes the fear and mystery out of the maneuver and boosts confidence. Buckley teaches spins and spin recovery during the first of two aerobatic lessons, and that practice came in handy on the second. After messing up a hammerhead, the Citabria settled into a spin. The familiar rotation made the situation quickly identifiable and easy to rectify.
A concern for some might be the effects of Gs and unusual attitudes on the body. Of the maneuvers the Citabria can perform, the split-S pulls the most at 4 Gs. Even for a 135-pound pilot in average shape, the force of four times that weight pressing against the body is quite powerful for someone not used to pulling Gs. Squeezing the abs when pulling out of a dive or up for a loop can help correct and prevent the effects of positive Gs, in which the G force is applied from head to foot (on the vertical axis of the body), pushing blood away from the brain and causing a loss of peripheral vision.
“I swore I would never do aerobatics because my stomach and head just couldn’t handle it,” Buckley says, explaining that she would get woozy during 45-degree-bank turns. Buckley took two-hour naps after her first couple of aerobatic flights before building a tolerance.
For fear of getting sick in the aircraft, many are reluctant to eat beforehand; however, Buckley recommends snacking on something bland such as a bagel. She also encourages her students to tell her immediately when they feel queasy and she watches for some telltale signs of nausea. “You can tell sitting behind them,” she says: Perspiration beads up on the back of the neck. Opening the Citabria’s window and letting the student fly helps to settle the stomach, she says, as well as ending the flight early.
Pilots who experience feelings of nausea on their first aerobatic flight shouldn’t give up hope of learning to loop and roll. Try a few more lessons. “Typically, on your first few flights you may feel queasy after some number of maneuvers. With each flight, your tolerance will build,” the IAC website counsels. “Don’t let the initial discomfort discourage you. As you get used to unusual attitudes in your aircraft, the exhilaration and fun begin to dominate.”
During three hours of aerobatic instruction with Buckley, exhilaration dominated from the first maneuver, with each subsequent one deemed the new favorite. Twisting and turning around the axes of the airplane, grunting through G forces, and creating fluctuations in indicated airspeed from near stall to 140 knots in a matter of seconds is addicting. And for those precious minutes above the Potomac River shoreline, the dream of being an aerobatic performer is realized—at least at the basic level.
E-mail the author at firstname.lastname@example.org.
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