Flight Literacy

Flight Training Educational Materials

Glider Flying

The Glider Fuselage and Lift/Drag Devices

Filed Under: Glider Components and Systems

The Fuselage

The fuselage is the portion of the airframe to which the wings and empennage are attached. The fuselage houses the cockpit and contains the controls for the glider, as well as a seat for each occupant. Glider fuselages can be formed from wood, fabric over steel tubing, aluminum, fiberglass, Kevlar® or other composites, or a combination of these materials. [Figure 2-7]

Figure 2-7. Components of a glider.
Figure 2-7. Components of a glider.

Wings and Components

Glider wings incorporate several components that help the pilot maintain the attitude of the glider and control lift and drag. These include ailerons and lift and drag devices, such as spoilers, dive brakes, and flaps. Glider wings vary in size and span from 12.2 meters (40 feet) to 30 meter (101.38 feet).

A wing may consist of a single piece attached to the fuselage to as many as four pieces (on one side).

The ailerons control movement around the longitudinal axis, known as roll. The ailerons are attached to the outboard trailing edge of each wing and move in opposite directions.

Moving the aileron controls with the control stick to the right causes the right aileron to deflect upward and the left aileron to deflect downward. The upward deflection of the right aileron decreases the effective camber (curvature of the wing surface), resulting in decreased lift on the right wing. [Figure 2-8] The corresponding downward deflection of the left aileron increases the effective camber, resulting in increased lift on the left wing. Thus, the increased lift on the left wing and decreased lift on the right wing causes the glider to roll to the right.

Figure 2-8. The wing camber remains the same physically, but the ailerons change the “effective” camber of the wing and increase or decrease lift to change lift vectors to affect turns.
Figure 2-8. The wing camber remains the same physically, but the ailerons change the “effective” camber of the wing and increase or decrease lift to change lift vectors to affect turns.

Lift/Drag Devices

Gliders are equipped with devices that modify the lift/drag of the wing. These high drag devices include spoilers, dive brakes, and flaps. Spoilers extend from the upper surface of the wing, interrupting or spoiling the airflow over the wings. This action causes the glider to descend more rapidly. Dive brakes extend from both the upper and lower surfaces of the wing and help to increase drag.

Flaps are located on the trailing edge of the wing, inboard of the ailerons, and can be used to increase lift, drag, and descent rate. [Figure 2-9] Each flap type has a use depending on aircraft design. When the glider is cruising at moderate airspeeds in wings-level flight, the flaps can sometimes be set to a negative value (up from trail or level) for high speed cruising in some high efficiency gliders. When the flap is extended downward, wing camber is increased, and the lift and the drag of the wing increase.

Figure 2-9. Types of lift/drag devices.
Figure 2-9. Types of lift/drag devices.

Gliders are generally equipped with simple flaps and these flaps can generally be set in three different positions which are trail, down or negative. [Figure 2-10] When deflected downward, it increases the effective camber and changes the wing’s chord line, which is an imaginary straight line drawn from the leading edge of an airfoil to the trailing edge. Both of these factors increase the lifting capacity of the wing.

Figure 2-10. Flap positions.
Figure 2-10. Flap positions.

Negative flap is used at high speeds at which wing lift reduction is desired to reduce drag. When the flaps are extended in an upward direction, or negative setting, the effective camber of the wing is reduced, resulting in a reduction of lift produced by the wing at a fixed angle of attack and airspeed. This action reduces the down force, or balancing force, required from the horizontal stabilizer.

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Glider Design

Filed Under: Glider Components and Systems

The earlier gliders were made mainly of wood with metal fastenings, stays, and control cables. Subsequent designs led to a fuselage made of fabric-covered steel tubing glued to wood and fabric wings for lightness and strength. New materials, such as carbon fiber, fiberglass, glass reinforced plastic (GRP), and Kevlar® are now being used to developed stronger and lighter gliders. Modern gliders are usually designed by computer-aided software to increase performance. The first glider to use fiberglass extensively was the Akaflieg Stuttgart FS-24 Phönix, which first flew in 1957. [Figure 2-1] Fiberglass is still used because of its high strength to weight ratio and its ability to give a smooth exterior finish to reduce drag. Drag has also been minimized by more aerodynamic shapes and retractable undercarriages. Flaps were installed when technology improved and are fitted to the trailing edges of the wings on some gliders to minimize the drag and to allow lower landing speeds.

Figure 2-1. The Akaflieg Stuttgart FS-24 Phönix, made in Germany, was first flown on November 27, 1957.
Figure 2-1. The Akaflieg Stuttgart FS-24 Phönix, made in Germany, was first flown on November 27, 1957.

Most high-performance gliders are built of composites, instead of metal or wood, with a gel-coat finish. The gel coat is susceptible to damage from exposure to ultraviolet (UV) radiation from the sun, as well as prolonged exposure to moisture. At some soaring sites, pilots can keep the glider assembled in a hangar, but the composite glider is more frequently rigged before flying and derigged after flying. The transition to high-performance gliders necessitates development of checklists and discipline during glider assembly and disassembly. Other considerations for gel-coat care include extreme cold soaking. There is evidence that flying a composite glider with a gel-coat finish to very high and cold altitudes followed by a quick descent to warmer levels can seriously reduce the life of the gel coat. Composite gliders appear to be more susceptible to flutter than metal gliders. Flutter is a function of true airspeed. The GFM/POH of composite gliders sometimes presents a table of the indicated VNE for different heights. For instance, a popular two-seat composite glider shows 135 knots as the sea level VNE, 128 knots at 10,000 feet MSL, 121 knots at 13,000 feet MSL, etc. Read the GFM/ POH carefully and obey the limitations set forth in the manual.

With each generation of new materials and development and improvements in aerodynamics, the performance of gliders has increased. One measure of performance is glide ratio. A glide ratio of 30:1 means that in smooth air a glider can travel forward 30 feet while only losing 1 foot of altitude. Glide ratio is discussed further in Chapter 5, Glider Performance.

Due to the critical role that aerodynamic efficiency plays in the performance of a glider, gliders often have aerodynamic features seldom found in other aircraft. The wings of a modern racing glider have a specially designed low-drag laminar flow airfoil. After the wing surfaces have been shaped by a mold with great accuracy, they are highly polished and painted with a gel coat (light fiberglass spray/sealer). Some high performance gliders have winglets installed at the ends of the wings. These winglets are computer designed to decrease drag and improve handling performance. [Figure 2-2] To continually ensure the best in aerodynamics, manufacturers use specially designed seals in the vicinity of the flight controls (i.e., ailerons, rudder, and elevator) to prevent the flow of air in the opposite direction through the control surface gaps, which causes turbulence over the area.

Figure 2-2. Schempp-Hirth Ventus-2 glider with factory winglets installed.
Figure 2-2. Schempp-Hirth Ventus-2 glider with factory winglets installed.

Additional high-technology designs include such items as bug wipers. These are very similar to a car windshield wiper. They may be installed to wipe the wings while in flight and remove insects that are disturbing the smooth flow of air over the wing by sliding back and forth along the leading edge of the wing. [Figure 2-3] Bug wipers can be operated by small electrical motors or by aerodynamics.

Figure 2-3. Mechanical bug wipers can be installed to slide back and forth along the leading edge of the wing.
Figure 2-3. Mechanical bug wipers can be installed to slide back and forth along the leading edge of the wing.

Modern competition gliders carry water ballast that can be jettisoned. This water acts as ballast in the wings and sometimes in the vertical stabilizer. The extra weight provided by the water ballast is advantageous if the lift is likely to be strong, and may also be used to adjust the glider’s center of gravity (CG) during flight. Moving the CG toward the rear by carrying water in the vertical tail section reduces some of the required down force from the horizontal stabilizer aerodynamics and the resultant drag from that down force. Although heavier gliders have a slight disadvantage when climbing in rising air, they achieve a higher speed at any given glide angle. This is an advantage in strong conditions when the gliders spend only little time climbing in thermals. The pilot can jettison the water ballast before it becomes a disadvantage in weaker thermal conditions. Another use of water ballast is to dampen air turbulence that may be encountered during ridge soaring. To avoid undue stress on the airframe, gliders may jettison any water ballast before landing. [Figure 2-4] This is discussed further in Chapter 5, Glider Performance.

Figure 2-4. Sailplane dropping water ballast before landing.
Figure 2-4. Sailplane dropping water ballast before landing.

Most gliders are built in Europe and are designed to meet the requirements of the European Aviation Safety Agency (EASA), similar to the United States Federal Aviation Administration (FAA). The EASA Certification Specification CS-22 (previously Joint Aviation Requirements (JAR)-22), defines minimum standards for safety in a wide range of characteristics such as controllability and strength. For example, it must have design features to minimize the possibility of incorrect assembly (gliders are often stowed in disassembled configuration with at least the wings being detached). Automatic connection of the controls during rigging is the common method of achieving this.

Throughout the years, flying gliders has not only been a recreational past time but are built and used for sport as well. Many glider pilots take part in gliding competitions that usually involve racing. Modern gliding competitions now comprise closed tasks; everyone races on an aerial route around specified turnpoints, plus start and finish points that bring everybody back to base. The weather forecast and the performance of the gliders, as well as the experience level of the pilots, dictate the length of the task. Today, most of the points are speed points, and the rule is to set the task so all pilots have a fair chance of completing it.

With the advent of global positioning systems (GPS), new types of tasks were introduced, such as speed or distance tasks within assigned areas and speed or distance tasks with pilot-selected turn points. Despite the use of pilot-selected turn points made possible by GPS, tasks over a fixed course are still used frequently. The Fédération Aéronautique Internationale (FAI), the world’s air sports federation, is a nongovernmental and nonprofit international organization with the basic aim of furthering aeronautical and astronautical activities worldwide. The FAI Gliding Commission is the sporting body overseeing air sports at the international level so that essentially the same classes and class definitions are followed in all countries.

The following is an overview of the seven classes of gliders that are currently recognized by the FAI and are eligible for European and World Championships:

  1. Standard class—no flaps, 15 meter (49.2 feet) wingspan, water ballast allowed.
  2. 15 meter class—flaps allowed, 15 meter (49.2 feet) wingspan, water ballast allowed.
  3. 18 meter class-—flaps allowed, 18 meter (59 feet) wingspan, water ballast allowed.
  4. Open class—no restrictions on wingspan, except a limit of 850 kg (1,874 pounds for the maximum all-up weight). Open classes may have wingspans in excess of 85 feet or more. [Figure 2-5]
  5. Two-seat class—maximum wingspan of 20 meters (65.6 feet), also known by the German name of Doppelsitzer. [Figure 2-6]
  6. Club class—this class allows a wide range of older, small gliders with different performance. The scores must be adjusted by handicapping. Water ballast is not allowed.
  7. World class—the FAI Gliding Commission, which is part of the FAI and an associated body called Organization Scientifique et Technique du Vol à Voile (OSTIV), announced a competition in 1989 for a lowcost glider that had moderate performance, was easy to assemble and handle, and was safe for low-hours pilots to fly. The winning design was announced in 1993 as the Warsaw Polytechnic PW-5. This allows competitions to be run with only one type of glider.
Figure 2-5. The Schempp-Hirth Nimbus-4 is a family of highperformance Fédération Aéronautique Internationale (FAI) open class gliders.
Figure 2-5. The Schempp-Hirth Nimbus-4 is a family of high-performance Fédération Aéronautique Internationale (FAI) open class gliders.
Figure 2-6. The DG Flugzeugbau DG-1000 of the two-seater class.
Figure 2-6. The DG Flugzeugbau DG-1000 of the two-seater class.

Glider airframes are designed with a fuselage, wings, and empennage or tail section. Self-launching gliders are equipped with an engine that enables them to launch without assistance and return to an airport under engine power if soaring conditions deteriorate.

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Common Glider Concepts

Filed Under: Gliders and Sailplanes

Terminology

There are a number of terms used in gliding that all glider pilots should be familiar with. The list is not comprehensive, but includes the following:

  • Knot—one nautical mile per hour (NMPH). A nautical mile is 6,076.115 feet as opposed to 5,280 feet in a statute mile. Rounded that is 6,000 feet, which divided by 60 minutes equals 100 feet per minute (fpm). Hence, this gives 1 on a variometer, which means one knot per hour or approximately 100 fpm. A 4-knot thermal lifts the glider at 400 fpm.
  • Lift—measured in knots, rising air lifting the glider higher.
  • Sink—falling air that forces the glider to lose height and is measured in knots.
  • Attitude—the orientation of an aircraft in the air with respect to the horizon. If the aircraft is diving, then it is said to have a “nose-down attitude about its lateral axes.” Attitude can also be a roll or bank as referenced to the longitudinal axis and pitch up or down as referenced to lateral axis.
  • Pitch—the up and down movement around the lateral axis for pitch. Increasing the pitch lifts the nose and drops the tail. Decreasing the pitch drops the nose and lifts the tail.
  • Roll—movement around a line between the nose and tail longitudinal axes. Rolling right drops the right wing while lifting the left wing.
  • Yaw—a turning motion in which the nose of the aircraft moves to the right or left about its vertical axis.
  • Cable—steel wire used to connect the glider to the winch. It is approximately 5mm wide and should be avoided at all times until after the correct training for safe handling. There are some winch operations using composite fiber cable that is stronger and lighter than steel.
  • Strop—a special part of the winch cable that is designed to be handled. The strop has the tost rings that are attached to the glider.
  • Weak link—a safety device in the winch cable or tow line. They come in various strengths (indicated by their color) and the correct one must be used with a given glider.
  • Elevator—a moveable section in the tailplane (the small wing at the back of the glider) that effectively controls whether the glider climbs or dives in flight.
  • Thermal—a bubble or column of warm rising air. Pilots try to find these columns of rising air and stay within them to gain altitude.

Converting Metric Distance to Feet

A glider pilot must also be able to convert distance in meters to distance in feet, using the following conversion:

1 meter = 3.2808 feet

Multiply the number of meters by 3.2808

To convert kilometers to nautical miles and nautical miles to kilometers or statute miles, use the following:

1 nautical mile (NM) = 1.852 kilometers (km)
1 nautical mile (NM) = 1.151 statute miles (SM)
1 km = 0.53996 NM


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Glider Certificate Eligibility Requirements

Filed Under: Gliders and Sailplanes

To be eligible to fly a glider solo, an individual must be at least 14 years of age and demonstrate satisfactory aeronautical knowledge on a test developed by an instructor. A student must also have received and logged ground and flight training for the maneuvers and procedures in 14 CFR part 61 that are appropriate to the make and model of aircraft to be flown. A student pilot must demonstrate satisfactory proficiency and safety. Only after all of these requirements are met can an instructor endorse a student’s certificate and logbook for solo flight.

To be eligible for a private pilot certificate with a glider rating, an individual must be at least 16 years of age, complete the specific training and flight time requirements described in 14 CFR part 61, pass a knowledge test, and successfully complete a practical test.

To be eligible for a commercial or flight instructor glider certificate, an individual must be 18 years of age, complete the specific training requirements described in 14 CFR part 61, pass the required knowledge tests, and pass another practical test. If currently a pilot for a powered aircraft is adding a glider category rating on that certificate, the pilot is exempt from the knowledge test but must satisfactorily complete the practical test. Certificated glider pilots are not required to hold an airman medical certificate to operate a glider. However, they must not have any medical deficiencies.

The FAA Practical Test Standards (PTS) establish the standards for the knowledge and skills necessary for the issuance of a pilot certificate. It is important to reference the PTS, FAA Advisory Circular (AC) 60-22, Aeronautical Decision Making, Pilots Handbook of Aeronautical Knowledge (FAA-H-8083-25), and the Risk Management Handbook (FAA-H-8083-2) to understand the knowledge, skills, and experience required to obtain a pilot certificate to fly a glider. For more information on the certification of the gliders themselves, refer to 14 CFR part 21, the European Aviation Safety Agency (EASA) Certification Specifications (CS) 22.221, and the Weight and Balance Handbook (FAA-H-8083-1).

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Glider Pilot Schools

Filed Under: Gliders and Sailplanes

Most airports or glider bases have some type of pilot training available, either through FAA-approved pilot schools or individual FAA-certificated flight instructors. FAA-approved glider schools usually provide a wide variety of training aids, special facilities, and greater flexibility in scheduling. A number of colleges and universities also provide glider pilot training as a part of their overall pilot training curricula. However, most glider training is conducted by individual flight instructors through a membership in a glider club. Also, there are several commercial glider companies located around the United States offering flight training, sightseeing glider rides, and glider towing services.

Choosing the right facility or instructor for your glider training should be both exciting and educational. Many factors need to be considered when choosing the right school, such as location, type of certification, part- or full-time training, and cost. The quality of training received should be the most important factor. Before interviewing schools, potential student pilots should be educated on the types of training curriculums that are available. Pilot training is conducted in accordance with one of two regulatory categories: Title 14 of the Code of Federal Regulations (14 CFR) part 141 or 14 CFR part 61. Students can receive exceptional flight training under either part 141 or 61 training programs, as both have the same teaching and testing requirements. What differs is the way you are taught in order to meet those same requirements.

14 CFR Part 141 Pilot Schools

Pilot schools that are certificated under 14 CFR part 141 provide a more structured training program with a standardized FAA-approved training syllabus. This ensures that all necessary skills are taught in a specific order through approved lesson plans. Under part 141, students are also required to complete a specific number of hours of formal ground instruction either in a classroom or one on one with an FAA-certificated flight instructor. Students are also required to pass the FAA knowledge and practical tests. In order to obtain approval and maintain their part 141 certification, pilot schools must adhere to several FAA regulations.

Because part 141 pilot schools must adhere to the approved training regiment, their students are allowed to complete the pilot certificate or rating in fewer flight training hours than required by part 61. However, most students generally exceed the reduced part 141 flight training hour requirements in order to meet the proficiency standards to pass the practical test.

14 CFR Part 61 Instruction

Pilot training conducted under 14 CFR part 61 offers a somewhat more flexible and less structured training program than that conducted under part 141. A part 61 training syllabus is not subject to FAA approval; therefore, flight instructors have the flexibility to rearrange lesson plans to suit the individual needs of their students. However, it is important to understand that flight instructors must adhere to the requirements of part 61 and train their students to the standards of part 61.

Training under part 61 does not require the student to complete a formal ground school. Instead, students have the following three options: (1) attend a ground school course, (2) complete a home-study program, or (3) hire a certificated flight or ground instructor to teach and review any materials that they choose. Regardless of which option a student chooses to take, all students are required to pass the FAA knowledge and practical tests for the pilot certificate or rating for which they are applying. The requirements for pilot training under part 61 are less structured than those under part 141, and part 61 may require more flight training hours to obtain a pilot certificate or rating than part 141.

Most glider training programs can be found on the SSA website at www.ssa.org. Once you choose a general location, make a checklist of things to look for in a training organization. By talking to pilots, visiting the facility, and reading articles in pilot magazines, a checklist can be made and used to evaluate your options. Your choice might depend on whether you are planning to obtain a sport or private pilot certificate or pursuing a higher pilot certificate or a flight instructor certificate toward becoming a professional glider pilot. The quality of training is very important and should be the first priority when choosing a course of training. Prior to making a final decision, visit the facility being considered and talk with management, instructors, and both current and former students. Evaluate all training requirements using a checklist, and then take some time to think things over before making a decision.

After deciding where to learn to fly and making the necessary arrangements, training can begin. An important fact: ground and flight training should be obtained as regularly and frequently as possible. This assures maximum retention of instruction and the achievement of proficiency for which every pilot should strive.

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Glider or Sailplane?

Filed Under: Gliders and Sailplanes

The Federal Aviation Administration (FAA) defines a glider as a heavier-than-air aircraft that is supported in flight by the dynamic reaction of the air against its lifting surfaces, and whose free flight does not depend principally on an engine. [Figure 1-5] The term “glider” is used to designate the rating that can be placed on a pilot certificate once a person successfully completes required glider knowledge and practical tests.

Figure 1-5. A Schleicher ASK 21 glider.
Figure 1-5. A Schleicher ASK 21 glider.

Another widely accepted term used in the industry is sailplane. A sailplane is a glider (heavier-than-air fixed-wing aircraft) designed to fly efficiently and gain altitude solely from natural forces, such as thermals and ridge waves. [Figure 1-6] Older gliders and those used by the military were not generally designed to gain altitude in lifting conditions, whereas modern day sailplanes are designed to gain altitude in various conditions of lift. Some sailplanes are equipped with sustaining engines to enable level flight even in light sink, or areas of descending air flow. More sophisticated sailplanes may have engines powerful enough to allow takeoffs and climbs to soaring altitudes. In both cases, the powerplants and propellers are designed to be stopped in flight and retracted into the body of the sailplane to retain the high efficiency necessary for nonpowered flight.

Figure 1-6. A sailplane is a glider designed to fly efficienctly and gain altitude solely from natural forces, such as thermals and ridge waves.
Figure 1-6. A sailplane is a glider designed to fly efficienctly and gain altitude solely from natural forces, such as thermals and ridge waves.

Gliding, that is flying a glider or sailplane, is relatively easy to learn, but soaring, which is gaining altitude and traveling without power, is much more difficult and immensely satisfying when accomplished. Soaring refers to the sport of flying sailplanes, which usually includes traveling long distances and remaining aloft for extended periods of time. Gliders were designed and built to provide short flights off a hill down to a landing area. Since their wings provided relatively low lift and high drag, these simple gliders were generally unsuitable for sustained flight using atmospheric lifting forces. Both terms are acceptable and are synonymous. Early gliders were easy and inexpensive to build, and they played an important role in flight training. The most well-known example today of a glider is the space shuttle, which literally glides back to earth. The space shuttle, like gliders that remain closer to the earth, cannot sustain flight for long periods of time.

Self-launching gliders are equipped with engines; with the engine shut down, they display the same flight characteristics as nonpowered gliders. [Figure 1-7] The engine allows them to be launched under their own power. Once aloft, pilots of self-launching gliders can shut down the engine and fly with the power off. The additional training and procedures required to earn a self-launch endorsement are covered later in this section.

Figure 1-7. An ASH 26 E self-launching sailplane with the propeller extended.
Figure 1-7. An ASH 26 E self-launching sailplane with the propeller extended.

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Gliders—The Early Years

Filed Under: Gliders and Sailplanes

The fantasy of flight led people to dream up intricate designs in an attempt to imitate the flight of birds. Leonardo da Vinci sketched a vision of flying machines in his 15th century manuscripts. His work consisted of a number of wing designs including a human-powered ornithopter, the name derived from the Greek word for bird. Centuries later, when others began to experiment with his designs, it became apparent that the human body could not sustain flight by flapping wings like birds. [Figure 1-1] The dream of human flight continued to capture the imagination of many, but it was not until 1799 when Sir George Cayley, a Baronet in Yorkshire, England, conceived a craft with stationary wings to provide lift, flappers to provide thrust, and a movable tail to provide control.

Figure 1-1. A human-powered ornithopter is virtually incapable of flight due to its poor strength-to-weight ratio.
Figure 1-1. A human-powered ornithopter is virtually incapable of flight due to its poor strength-to-weight ratio.

Otto Lilienthal was a German pioneer of human flight who became known as the Glider King. [Figure 1-2] He was the first person to make well-documented, repeated, successful gliding flights beginning in 1891. [Figure 1-3] He followed an experimental approach established earlier by Sir George Cayley. Newspapers and magazines published photographs of Lilienthal gliding, favorably influencing public and scientific opinion about the possibility of flying machines becoming practical.

Figure 1-2. Otto Lilienthal (May 23, 1848–August 10, 1896) was a German pioneer of human aviation.
Figure 1-2. Otto Lilienthal (May 23, 1848–August 10, 1896) was a German pioneer of human aviation.
Figure 1-3. Otto Lilienthal in flight.
Figure 1-3. Otto Lilienthal in flight.

By the early 1900s, the famed Wright Brothers were experimenting with gliders and gliding flight in the hills of Kitty Hawk, North Carolina. [Figure 1-4] The Wrights developed a series of gliders while experimenting with aerodynamics, which was crucial to developing a workable control system. Many historians, and most importantly the Wrights themselves, pointed out that their game plan was to learn flight control and become pilots specifically by soaring, whereas all the other experimenters rushed to add power without refining flight control. By 1903, Orville and Wilbur Wright had achieved powered flight of just over a minute by putting an engine on their best glider design.

Figure 1-4. Orville Wright (left) and Dan Tate (right) launching the Wright 1902 glider off the east slope of the Big Hill, Kill Devil Hills, North Carolina on October 17, 1902. Wilbur Wright is flying the glider.
Figure 1-4. Orville Wright (left) and Dan Tate (right) launching the Wright 1902 glider off the east slope of the Big Hill, Kill Devil Hills, North Carolina on October 17, 1902. Wilbur Wright is flying the glider.

By 1906, the sport of gliding was progressing rapidly. An American glider meet was sponsored by the Aero Club of America on Long Island, New York. By 1911, Orville Wright had set a world duration record of flying his motorless craft for 9 minutes and 45 seconds.

By 1920, the sport of soaring was coming into its own. Glider design was spurred on by developments in Germany where the World War I Treaty of Versailles banned flying power aircraft. New forms of lift were discovered that made it possible to gain altitude and travel distances using these previously unknown atmospheric resources. In 1921, Dr. Wolfgang Klemperer broke the Wright Brothers 1911 soaring duration record with a flight of 13 minutes using ridge lift. In 1928, Austrian Robert Kronfeld proved that thermal lift could be used by a sailplane to gain altitude by making a short out and return flight. In 1929, the National Glider Association was founded in Detroit, Michigan; by 1930, the first USA National Glider Contest was held in Elmira, New York. In 1937, the first World Championships were held at the Wasserkuppe in Germany.

By the 1950s, soaring was developing rapidly with the first American, Dr. Paul MacCready, Jr., taking part in a World Soaring Championships held in Sweden. Subsequently, Dr. MacCready went on to become the first American to win a World Soaring Championship in 1956 in France.

The period of the 1960s and 1980s found soaring growing rapidly. During this period, there was also a revival of hang gliders and ultralight aircraft as new materials and a better understanding of low-speed aerodynamics made new designs possible.

By the late 1990s, aviation had become commonplace with jet travel becoming critical to the world economy. Soaring had grown into a diverse and interesting sport. Modern high performance gliders are made from composite materials and take advantage of highly refined aerodynamics and control systems. Today, soaring pilots use sophisticated instrumentation, including global positioning system (GPS) and altitude information (variometer) integrated into electronic glide computers to go farther, faster, and higher than ever before.

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