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.
One of the most exciting aerobatic aircraft of the 1930s and 1940s was the Grumman Gulfhawk II.
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 Little Stinker was the second Pitts Special constructed by Curtis
Pitts and it gained national and international recognition with
aerobatic pilot Betty Skelton.
The Extra 260 is a one-of-a-kind aircraft created by Walter Extra, a
German aerobatic competitor and one of the world’s premier aerobatic
aircraft designers and builders.
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All eyes on the ground are fixated on the vintage World War II Stearman as it plummets from the
sky, spiraling 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
maneuvering in three-dimensional space.” Maneuvering 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
maneuver on all three axes when operating in the weightless vacuum of space and
using this image as a yardstick to measure earthbound aerobatic maneuvers.
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 lackluster aerobatic performances (by
today’s standards) since aircraft maneuverability 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 maneuvering to
the right than it does to the left—forcing aerobatic pilots to learn their
maneuvers 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 maneuvers 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 maneuver.
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.
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 maneuver
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 center 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 over).
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 maneuver 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
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
maneuver and position defined at that time, 3,000 in all. Today, this list has
grown to more than 15,000 maneuvers as pilots experiment with the capabilities
of their aircraft. This demonstrates that aerobatic maneuvers 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.
—Roger
Guillemette
Sources:
Marrero, Frank. “Lincoln Beachey: The
Forgotten Father of Aerobatics.” Flight Journal (March/April 1999).
Szurovy, Geza, with Goulian, Mike. Basic
Aerobatics New York: McGraw Hill Professional Publishing, 1994.
Wagstaff, Patty, with Cooper, Ann L. Fire
and Air: A Life on the Edge. Chicago: Chicago Review Press, 1997.
Williams, Neil. Aerobatics. North
Branch, Minnesota: Specialty Press Publishers & Wholesalers, 1993.
Online Sources:
“Aerobatic Champions.” National Air &
Space Museum. http://www.nasm.si.edu/galleries/gal104/aerochamps/
Allison, Rick. A Short History of
Aerobatics. Model Aviation, August 1999. http://jmrc.tripod.com/fa/aero/aero1.htm
British Aerobatic Association. http://www.aerobatics.org.uk
“Bücker Bü-133C Jungmeister.” National
Air & Space Museum. http://www.nasm.si.edu/nasm/aero/aircraft/buckerbu133.htm
Carter Hummingbird Aerobatic Aircraft. http://www.esotec.co.nz
Dininny, Paulette. “The Little Plane That
Could.” (abstract from Smithsonian Magazine, December 2001.) http://www.kidscastle.si.edu/channels/air-space/articles/air-spacearticle11.html
“Extra 260 Aerobatic Aircraft.” National
Air & Space Museum. http://www.nasm.si.edu/nasm/aero/aircraft/extra260.htm
“Grumman G-22 Gulfhawk II.” National Air
& Space Museum. http://www.nasm.si.edu/nasm/aero/aircraft/grumman_gulfhwk.htm
International Aerobatic Club. http://www.iac.org
“Pitts Special S-1C Little Stinker.”
National Air & Space Museum. http://www.nasm.si.edu/nasm/aero/aircraft/pitts.htm
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