An Intense “Headache”
Like artists in any medium, aerobatic pilots often go beyond the traditional boundaries—even beyond the maneuvers that can be created by combining the four fundamental aerobatic maneuvers above.
One of the most outrageous maneuvers doesn’t just break the basic aerobatic rules—it shatters them. It’s a wild, tumbling, cart-wheeling, out-of-control hodge-podge of a stunt called a “lomcevak” (pronounced LOM-shi-vahk), which is a Czech word meaning “headache.” A lomcevak is one of the most violent things you can do in an airplane besides crash. From the ground, it looks as though the airplane is having a fit. One second, the airplane’s flying along and everything seems fine. The next, it is tumbling chaotically, sometimes tail-first, sometimes wingtip first.
If you want to see an excellent display of silver-screen acrobatics, see Cloud Dancer, a 1980 film starring David Carradinc as an ill and aging aerobatics pilot The plot it threadbare, but the flying is spectacular. Some of the best stunt pilots in the business, including Charlie Hillard, Leo Loudcnslager, and Tom Pobererny, flew mind-blowing flying scenes that make Cloud Dancer a must-see, if hard-to- fsnd, film.
If it looks crazy from the ground, it’s even worse from the cockpit. Some aerobatic pilots like to say that once they start the lomcevak (usually with lots of engine power, forward elevator, and opposite rudder and aileron controls), they don’t have any better idea of how it will end than a spectator does. The question is whether the airplane will shake off its temporary madness with its nose pointed up, down, frontward, or backward. Once the in-flight flailing stops, the pilot has to gather his wits and decide how to keep the plane flying.
In actuality, there is a method behind the fayade of chaos. There is also plenty of concern for safety. For a trained pilot and a strong airplane, the maneuver is a safe one.
The roll, combined with the spin, the loop, the hammerhead turn, and inverted flight, make up the basic elements of aerobatics. Add variations like the snap roll and the lomcevak, put these tools into the hands of a great pilot, and you have aerobatic maneuvers that make for dramatic and inspiring entertainment.
Of Aerobatics and “Comfort Bags”
Aerobatic flying is one of the few forms of flying that requires the pilot to be as fit as an athlete. For the most part, nonmilitary flying is a
relatively sedentary pursuit. But aerobatics are a big exception. Aerobatic Hying puts enormous physical stress on pilots and takes a toll on the body during even a single flight.
The Pitts Special, with its distinctive biplane design and starburst paint pattern, has become synonymous with aerobatic flying. The plane’s spectacular performance and strength has made it a favorite of fans and pilots alike.
To understand the demands on the body during aerobatics, you have to understand gravitational forces, or “g-forces,” which is the nickname we give to the sensation of added gravity caused by centrifugal force. For example, if a pilot executes a loop that exerts 6 g’s during a portion of a loop, he feels as though he weighs 1,200 pounds, or six times the normal force of gravity.
Acceleration comes in two flavors, at least for our discussion—linear acceleration and angular acceleration. Liner acceleration is the force that pushes you back into your car seat or that makes you feel heavier on an elevator going up. Angular acceleration, also called “centrifugal force,” is what pushes you against the wall of the rotating carnival “tilt-a-whirl” ride or tends to fling you off a fast-turning merry-go-round.
Linear, or straight-ahead, acceleration is relatively easy to visualize, and is of concern to the aerobatics pilot—except when being launched from an aircraft carrier where a pilot is jolted with several g’s when accelerating from a stop to almost 200 m. p.h. in a couple of seconds.
Centrifugal force is a bigger concern for the aerobatics pilot. Centrifugal force is what causes the g-forces that can feel as though the pull of gravity was magnified beyond
the earth’s 1 g force we live with every day. Centrifugal force during flight can turn up the g-meter inside an aerobatic plane to 10 g’s or more.
Imagine holding a toy airplane on a string and spinning it around in a small circle. If you twirl it slowly, the plane goes round and round at pretty much the same distance from the ground that it was at rest. But if you really start spinning it quickly, the plane will move higher toward your hand and bring the string itself almost parallel to the ground.
Now imagine a miniature pilot inside your model plane. When you were spinning it slowly, if that miniature pilot dropped a pencil, it would not have dropped toward the floor you were standing on but toward the bottom of the airplane, which was slightly tilted because you were spinning it.
As you spun the airplane faster, a dropped pencil would still fall toward the bottom of the plane, even though to you the plane is flying sideways. And the pencil would drop much faster because of the increased centrifugal force caused by the faster spinning.
By the Book
Blackouts are what happen* when the brain is starved of оку – gen, and they usually last only a few seconds. As soon as the heavy g-forces subside, the oxygen is able to return to the brain. Aerobatic pilots sometimes experience the less severe "gray – oub" that can cause tunnel vision. Finally, even if a pilot doesn’t black out during heavy g-forces, the gravity can pull the eyelids down over the eye, causing a "redout" (the blood vessels in the eyelid give the sunlight a reddish hue).
Now think of the pilot himself. The force that pulled the pencil to the floor more quickly is also pulling the pilot. The pilot can’t fall like the pencil because he’s restrained in his seat, so he begins to feel heavier and heavier. In other words, the pilot is experiencing more g’s.
G-forces complicate an aerobatic pilot’s life because the body is designed to function in the presence of about 1 g, the gravitational force the earth exerts on us. When a pilot makes a sharp pull-up, as entering into a loop, for example, the g-forces can spike up to several g’s. Limbs feel heavy, skin sags, eyeballs flatten out somewhat in their sockets. Worst of all, the blood supply flows toward the pilot’s feet and rear end, and can cause a blackout.
To prevent blackouts and grayouts, pilots use their chest and neck muscles to prevent the blood from leaving their heads. The concentration necessary for flying perfect aerobatic maneuvers, plus the muscle strength needed to keep the blood in the brain, where it belongs, make an aerobatic performance as strenuous as playing a set of tennis or running a 5K race.