history of aerobatics
All eyes on the ground are
fixated on the vintage World War II Stearman as it plummets from the sky,
spiralling downward toward certain disaster. The antique biplane falls
faster and faster, the growl from its powerful engine growing ever louder.
The doomed pilot has obviously lost control and is about to crash when
suddenly, just inches above the tarmac, the Stearman pulls back up and
roars off into the sky to the cheers of an admiring audience. Welcome to
the world of aerobatic flying!
Aerobatic flight, a specialized area of general aviation, is defined as
“precise manoeuvring in three-dimensional space.” Manoeuvring is broken
down to three components—position, velocity, and attitude. A textbook
aerobatic aircraft's position would be precisely controlled along all
three axes (pitch, roll, and yaw) and could be quickly reoriented to any
other position. Such an aircraft is a theoretical impossibility since it
must travel through, and is influenced by, an unpredictable ocean of air.
An idealized example of a true aerobatic vehicle can be conceptualized by
observing the Space Shuttle Orbiter's ability to manoeuvre on all three
axes when operating in the weightless vacuum of space and using this image
as a yardstick to measure earthbound aerobatic manoeuvres.
Lincoln Beachey is widely recognized as the “father” of aerobatic flying.
In his specially built Curtiss, he was the first American to “loop the
loop,” on November 24, 1913
Lincoln Beachey is widely
recognized as the “father” of aerobatic flying, even though his feats
were, at first, dismissed by none other than Orville Wright as mere
“optical illusions.” All such doubters were converted during a
now-legendary 126-city barnstorming tour in 1914 when Beachey, known as
“the flying fool,” dazzled crowds across the country flying stunts in his
airplane, the Little Looper. Luminaries such as Thomas Edison and Carl
Sandburg became aerobatic fans and even Orville Wright retracted his
original comments, describing Beachey's exhibitions as “poetry.”
Evolving directly from the early air racing and military training
airplanes, these initial aerobatic aircraft were usually oversized but
underpowered. Such factors combined to produce rather lacklustre aerobatic
performances (by today's standards) since aircraft manoeuvrability was
sluggish and the ability to climb vertically was limited.
In spite of equipment refinements that allow inverted flight capability
(such as upgraded airfoils, fuel, and oil systems), even the best
aerobatic aircraft cannot fly for long periods in unnatural flight
attitudes. Engine torque and wash from a spinning propeller cause an
aircraft to respond differently when manoeuvring to the right than it does
to the left—forcing aerobatic pilots to learn their manoeuvres in both
directions. These aerodynamic limitations are such that no aerobatic
aircraft in existence can efficiently fly on its side—the glowing claims
of “knife edge” climbs or spins notwithstanding.
Improved control during stall, snap roll, and spin manoeuvres cannot
completely offset the effects of engine torque during the ascent and
descent phases of flight. An aerobatic aircraft with sufficient thrust to
briefly “hang” on its propeller for a moment is soon overcome by engine
torque that, in turn, rotates the aircraft. The skilled aerobatic pilot
understands these design limitations and learns never to yield control of
an aircraft in order to escape from an aerobatic manoeuvre.
One of the most exciting aerobatic aircraft of the 1930s and 1940s was the
Grumman Gulfhawk II
A robust aerobatic
biplane, the Grumman Gulfhawk II, generated considerable excitement on the
air show circuit from 1936 to 1948, performing at the New York World's
Fair, the Cleveland Air Races, and the Miami All-America Air Show.
Originally built by Grumman for Gulf Oil, the Gulfhawk II was specifically
designed to bear up under the high structural stresses of aerobatic flying
and modified to endure inverted flying for durations of up to 30 minutes.
A German-built biplane, the Bücker Bü-133 Jungmeister, became the dominant
force in aerobatic competitions in the United States and Europe from the
mid-1930s until the outbreak of World War II. Agile and responsive to its
controls with ailerons on both upper and lower wings, the Jungmeister was
ideally suited for aerobatic flying because of its high power-to-weight
ratio. The Jungmeister also has a darker side to its history—it was used
as a training aircraft by a civilian German flying club known as the
Luftsportverband, whose pilots later formed a clandestine Air Force that
eventually evolved into the Nazi Luftwaffe.
In 1943 Curtis Pitts built the first of a line of aircraft
that dominated aerobatic competition throughout the 1970s and early
1980s-the Pitts Special
The face of aerobatic
flying changed forever in 1945 when Curtis Pitts built the first aircraft
specifically designed for aerobatics—the Pitts Special S-1. Pitts
envisioned an aircraft that could flout gravity and respond crisply on its
controls—a smaller aircraft than the war-era biplanes that could climb,
roll, and manoeuvre swiftly. Pitts abandoned the concept of a large radial
engine and designed a swept-wing aircraft powered by a smaller, lighter,
horizontally-opposed engine with a centre of gravity that allowed for
tight snap rolls (A snap roll is produced by flying just above the stall
speed, applying a sudden yaw with the rudder, applying the opposite
aileron, and pulling back on the yoke. One wing stalls and the plane rolls
The resulting Pitts line of aerobatic aircraft—small (with only a 17-foot
(5-meter) wingspan), lightweight, and extremely agile with a high
power-to-weight ratio—soon dominated aerobatic competitions. One of the
more famous Pitts aircraft, a hand-built S-1C model known as the Little
Stinker, was flown by another pioneer in aerobatics, Betty Skelton, who
won her first women's International Aerobatics Championship in 1949 at age
23 and won it again the following year. At a time when there were few
women aerobatic pilots, Skelton was a trailblazer and achieved acclaim as
the first woman to complete an aerobatic manoeuvre known as the “inverted
ribbon cut” in which an airplane flying upside down, only a few feet off
the ground, slices a two-foot (0.6-meter)-wide ribbon strung between two
poles. In fact, during her first attempt at the inverted ribbon cut, the
engine of her airplane stalled when flying upside down very close to the
ground. Somehow, she amazingly recovered from the stall, righted the
aircraft, and landed safely. From then on, the ribbon cut was the
highlight of her act.
An aerobatic kit plane
named the Stephens Akro inspired similar monoplane designs that overcame
the Pitts' major design drawback, the inability to climb vertically. The
lower drag from the single wing configuration translated into higher
airspeeds. Speed is not a necessity for an aerobatic aircraft but it is
often desirable since it can be translated into altitude.
The Akro-derived aerobatic designs were quickly overshadowed by
specialized aircraft, such as the German Extra 300, that continued the
evolution process by incorporating design refinements that separated them
from other conventional light aircraft. Increased structural strength
(including the use of composites), more powerful engines (which generate a
higher power-to-weight ratio), larger propellers, and improved aerodynamic
surfaces and controls have yielded aircraft that are well suited to the
demands of aerobatic flight.
Patty Wagstaff with an Extra 300
won the 1991 U.S.
National Aerobatic Championships flying an Extra 260 aerobatic aircraft,
becoming the first woman to win the title since the men's and women's
competitions were combined in 1972. She went on to defend her title for
the next two years, flying an Extra 260 in 1992 and an Extra 300S in 1993.
Air shows featuring aerobatic flying demonstrations have become enormously
popular in the United States and throughout the world. More than 27
million people annually attend air shows in the United States, making it
one of the country's top three spectator sports, ranking right alongside
Major League Baseball and NASCAR auto racing. It is also one of the most
dangerous: each year, several aerobatic pilots are killed due to pilot
error or equipment malfunction.
Aerobatic pilots accept and understand the inherent dangers of their
occupation. Striving to minimize their risks, professional aerobatic
pilots have honed their skills with years of constant practice and through
an in-depth understanding of both the physics of flight and the
performance characteristics of their specific type of aerobatic aircraft.
A dictionary of aerobatic flight, first published in 1961, listed every
conceivable aerobatic manoeuvre and position defined at that time, 3,000
in all. Today, this list has grown to more than 15,000 manoeuvres as
pilots experiment with the capabilities of their aircraft. This
demonstrates that aerobatic manoeuvres conform to the natural evolution of
flight that has occurred throughout history—as aircraft capabilities
continue to improve, skilled pilots learn to exploit those improvements.