Soaring Society of America
The Soaring Society of America was founded at the instigation of Warren E. Eaton to promote the sport of soaring in the USA and internationally; the first meeting was held in New York City in the McGraw-Hill building on February 20, 1932. Its first objective was to hold a national soaring competition every year, but other roles were adopted. In 1954, the Society created the Soaring Hall of Fame. Today the SSA, with a nationwide membership of over 10,000, is headquartered in New Mexico, it is a 501 charity organization. The SSA is led by the 17 members on its board of directors and its executive committee, ten of whom are regionally elected by the general membership and serve for three years; the other seven at-large directors are elected annually by the other directors. In addition to the executive meetings of the board, full SSA Board meetings are held twice a year and are open to the general membership. A support staff administers the daily business of the society from the headquarters offices.
The main responsibilities of the SSA are: Flight training and safety Technological research and development Services to members, such as organising SSA conventions and verifying badge claims Sponsorship and monitoring of competitions Promoting the sport and contact with the media Representing members' interests at meetings with Federal agencies in matters such as airspace Publishing Soaring magazine Richard C. du Pont Memorial Trophy Soaring Society of America Soaring Hall of Fame at the National Soaring Museum Soaring Safety Foundation
A T-tail is an empennage configuration in which the tailplane is mounted to the top of the fin. The arrangement looks like the capital letter T, hence the name; the T-tail differs from the standard configuration in which the tailplane is mounted to the fuselage at the base of the fin. The tailplane is kept well out of the disturbed airflow behind the wing and fuselage, giving smoother and faster airflow over the elevators; this configuration may give more predictable design better pitch control. Responsive pitch control is crucial for aircraft flying at low speed, to allow effective rotation on landing; this configuration allows high performance aerodynamics and an excellent glide ratio as the empennage is less affected by wing and fuselage slipstream. A T-tail has a better effective aspect ratio, less interaction drag than a cruciform tail, a more efficient vertical tail, the horizontal tail plate increasing the aspect ratio of the fin by virtue of the'end plate' effect, reducing turbulence and hence the induced drag of the fin.
The rudder will be more effective due to decreased induced drag. Therefore, the T-tail configuration is popular on gliders, where high performance is essential. A T tailed aircraft is easier to recover from a spin than aircraft with other types of empennage, as the elevator is located above the rudder, thus creating no dead air zone above the elevator where the rudder would be ineffective in spin conditions; the aircraft may be prone to suffering a dangerous deep stall condition, where a stalled wing at high angles of attack may blank the airflow over the tailplane and elevators, thereby leading to loss of pitch control. The American McDonnell F-101 Voodoo jet fighter suffered from this throughout its service life; the vertical stabilizer must be made stronger and stiffer to support the forces generated by the tailplane. The T-tail configuration can cause maintenance concerns; the control runs to the elevators are more complex, elevator surfaces are much more difficult to casually inspect from the ground.
The loss of Alaska Airlines Flight 261 was directly attributed to lax maintenance of the T-tail. In order to mitigate some of these drawbacks, a compromise is possible; the tailplane can be mounted part way up the fin rather than right at the top, known as a cruciform tail. The Sud Aviation Caravelle is an example of an aircraft with this configuration; the T-tail is common on aircraft with engines mounted in nacelles on a high-winged aircraft or on aircraft with the engines mounted on the rear of the fuselage, as it keeps the tail clear of the jet exhaust. These layouts are found in military transport aircraft - such as the Ilyushin Il-76, Airbus A400M and the Boeing C-17 Globemaster III - and regional airliners and business jets such as the Pilatus PC-12, Beechcraft Super King Air, Embraer ERJ, British Aerospace 146, Learjet and Gulfstream families, it is seen in combat aircraft, although the Gloster Javelin, McDonnell F-101 Voodoo, Lockheed F-104 Starfighter interceptors all sported T-tails.
Pelikan tail Twin tail V-tail "T-tails and top technology". Flight International. 13 Oct 1979
The Glasflügel H-301 Libelle is an early composite 15-metre Class single-seat sailplane produced by Glasflügel from 1964 to 1969. In 1964 the H-301 Libelle received the first German and first U. S. Type Certificate issued to an all-fiberglass aircraft, it had water ballast and retractable landing gear. There are two canopy variants: the normal canopy and a sleeker, lower-profiled'racing' canopy with no side vent; the canopy is unique in that it has a catch that enables the front to be raised by 25 mm in flight to provide a flow of ventilating air instead of the more conventional small sliding panel used for this purpose. The American Wil Schuemann pioneered several performance-enhancing modifications to the type, including a re-profiled wing, converting the airfoil to a Wortmann section, various fairings, a new canopy and a reshaped fuselage nose. Aircraft incorporating these changes are informally known as'Schümanised' Libelles; the H-201 Standard Libelle was developed in 1967 as a Standard Class variant.
The Libelle was a influential design. Its light wings and easy rigging set a new benchmark. Handling is easy except that it is sensitive to sideslipping and has ineffective airbrakes that make short landings tricky for inexperienced pilots; the H-201 Libelle was superseded by the Hornet. The H-301 Libelle was superseded by the Mosquito. Wings: spar and shell of balsa or foam / reinforced plastic sandwich Ailerons: balsa or synthetic foam / reinforced plastic sandwich. Horizontal stabilizer: reinforced plastic Elevator: reinforced plastic Automatic connections for airbrakes and elevator. Ailerons are connected by a "pip" pin General characteristics Crew: 1 Capacity: 50 kg water ballast Length: 6.19 m Wingspan: 15.00 m Height: 1.25 m Wing area: 9.5 m2 Aspect ratio: 23.6 Empty weight: 180 kg Gross weight: 300 kg Performance Maximum speed: 200 km/h Maximum glide ratio: ca. 39 Rate of sink: 0.55 m/s Armament Aircraft of comparable role and era Berkshire Concept 70 Schleicher ASW 15 Related lists List of gliders Thomas F, Fundamentals of Sailplane Design, College Park Press, 1999 Simons M, Segelflugzeuge 1965-2000, Eqip, 2004 Sailplane Directory
Start + Flug H-101
The H-101 Salto is an aerobatic glider of glass composite construction, developed in Germany in the 1970s. Based on the Standard Libelle H-201, it was designed by Ursula Hänle, widow of Eugen Hänle, former Director of Glasflügel, it was first produced by Start + Flug GmbH Saulgau. The H-101 differs from the Libelle in having a V-tail, showing its ancestry to the V-tailed Hütter H-30 GFK. Four flush-fitting air brakes were fitted to the trailing edges of the wings, replacing the more conventionally sited air brakes of the Standard Libelle; the Salto's air brakes are hinged at their midpoints so that half the surface projects above the wing and half below. The Salto prototype first flew on 6 March 1970, 67 had been delivered by early 1977, when production at Start + Flug GmbH Saulgau ceased. Five more Saltos were built from 1993 to 1996 by the German company "LTB Frank & Waldenberger", bringing total output of Salto gliders to 72; the Salto was again made available in the late 1980s by Doktor Fiberglas, set up by Ursula Hänle at Westerburg in West Germany as the Hänle H 101 Salto, available in utility and aerobatic versions, with the Utility version available with either short or long-span wings.
Data from Jane's World Sailplanes & Motor Gliders,General characteristics Crew: 1 Length: 5.7 m Wingspan: 13.3 m'A' version15.5 m'U' versionHeight: 0.88 m Wing area: 8.58 m2 A version9.1 m2'U' versionAspect ratio: 20.6'A' version15.5 m'U' versionEmpty weight: 182 kg'A' version187 kg'U' versionMax takeoff weight: 280 kg'A' version310 kg'U' versionPerformance Stall speed: 70 km/h'A' version62 km/h'U' versionNever exceed speed: 280 km/h'A' version250 km/h'U' version 160 km/h on aero-tow 130 km/h on winch launchg limits: +7 -4.9'A' version Maximum glide ratio: 34.5'A' version at 94 km/h 37'U' version at 94 km/h Rate of sink: 0.6 m/s'A' version at 72 km/h at 250 kg 0.55 m/s'U' version at 72 km/h at 250 kg Wing loading: 32.6 kg/m2'A' version36.1 kg/m²'U' version 13.3 m wings 34 kg/m²'U' version 15.5 m wings Aircraft of comparable role and era Celair GA-1 Celstar Pilatus PC-11 AF SZD-59 Acro Related lists List of gliders Simons, Martin. Sailplanes 1965-2000. Königswinter: EQIP Werbung und Verlag G.m.b.
H. ISBN 978-3-9808838-1-8. Woollard, Mike; the Handbook of Glider Aerobatics. Shrewsbury: Airlife Pub. ISBN 978-1840371109. "EASA. SAS. A.028". Easa.europa.eu. Retrieved 19 January 2015. Http://www.frankundwaldenberger.de/index.php?firmengeschichte http://www.easa.europa.eu/ws_prod/c/doc/SAS/A.028/EASA. SAS. A.028_Haenle_H101_Salto_issue01.pdf
A glider or sailplane is a type of glider aircraft used in the leisure activity and sport of gliding. This unpowered aircraft uses occurring currents of rising air in the atmosphere to remain airborne. Gliders are aerodynamically streamlined and are capable of gaining altitude and remaining airborne, maintaining forward motion. Gliders benefit from producing the least drag for any given amount of lift, this is best achieved with long, thin wings, a faired narrow cockpit and a slender fuselage. Aircraft with these features are able to soar - climb efficiently in rising air produced by thermals or hills. In still air, gliders can glide long distances at high speed with a minimum loss of height in between. Gliders have either skids or undercarriage. In contrast hang gliders and paragliders use the pilot's feet for the start of the launch and for the landing; these latter types are described in separate articles, though their differences from gliders are covered below. Gliders are launched by winch or aerotow, though other methods: auto tow and bungee, are used.
Some gliders do not soar and are engineless aircraft towed by another aircraft to a desired destination and cast off for landing. Military gliders are single-use only, are abandoned after landing, having served their purpose. Motor gliders are gliders with engines which can be used for extending a flight and in some cases, for take-off; some high-performance motor gliders may have an engine-driven retractable propeller which can be used to sustain flight. Other motor gliders have enough thrust to launch themselves before the engine is retracted and are known as "self-launching" gliders. Another type is the self-launching "touring motor glider", where the pilot can switch the engine on and off in flight without retracting their propellers. Sir George Cayley's gliders achieved brief wing-borne hops from around 1849. In the 1890s, Otto Lilienthal built gliders using weight shift for control. In the early 1900s, the Wright Brothers built gliders using movable surfaces for control. In 1903, they added an engine.
After World War I gliders were first built for sporting purposes in Germany. Germany's strong links to gliding were to a large degree due to post-WWI regulations forbidding the construction and flight of motorised planes in Germany, so the country's aircraft enthusiasts turned to gliders and were encouraged by the German government at flying sites suited to gliding flight like the Wasserkuppe; the sporting use of gliders evolved in the 1930s and is now their main application. As their performance improved, gliders began to be used for cross-country flying and now fly hundreds or thousands of kilometres in a day if the weather is suitable. Early gliders had the pilot sat on a small seat located just ahead of the wing; these were known as "primary gliders" and they were launched from the tops of hills, though they are capable of short hops across the ground while being towed behind a vehicle. To enable gliders to soar more than primary gliders, the designs minimized drag. Gliders now have smooth, narrow fuselages and long, narrow wings with a high aspect ratio and winglets.
The early gliders were made of wood with metal fastenings and control cables. Fuselages made of fabric-covered steel tube were married to wood and fabric wings for lightness and strength. New materials such as carbon-fiber, fiber glass and Kevlar have since been used with computer-aided design to increase performance; the first glider to use glass-fiber extensively was the Akaflieg Stuttgart FS-24 Phönix which first flew in 1957. This material 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 been minimized by more aerodynamic shapes and retractable undercarriages. Flaps are fitted to the trailing edges of the wings on some gliders to minimize the drag from the tailplane at all speeds. With each generation of materials and with the improvements in aerodynamics, the performance of gliders has increased. One measure of performance is the glide ratio. A ratio of 30:1 means that in smooth air a glider can travel forward 30 meters while losing only 1 meter of altitude.
Comparing some typical gliders that might be found in the fleet of a gliding club – the Grunau Baby from the 1930s had a glide ratio of just 17:1, the glass-fiber Libelle of the 1960s increased that to 39:1, modern flapped 18 meter gliders such as the ASG29 have a glide ratio of over 50:1. The largest open-class glider, the eta, has a span of 30.9 meters and has a glide ratio over 70:1. Compare this to the Gimli Glider, a Boeing 767 which ran out of fuel mid-flight and was found to have a glide ratio of 12:1, or to the Space Shuttle with a glide ratio of 4.5:1. Due to the critical role that aerodynamic efficiency plays in the performance of a glider, gliders have aerodynamic features found in other aircraft; the wings of a modern racing glider have a specially designed low-drag laminar flow airfoil. After the wings' surfaces have been shaped by a mold to great accuracy, they are highly polished. Vertical winglets at the ends of the wings are computer-designed to decrease drag and improve handling performance.
Special aerodynamic seals are used at the ailerons and elevator to prevent the flow of air through control surface gaps. Turbulator devices in the form of a zig-zag tape or multiple blow holes positioned in a span-wise line along the wing are used to trip laminar flow air into turbulent flow at a desired location on the wing; this flow control prevents the formation of laminar flow bubbles and ensures t
The Glasflügel BS-1, sometimes called the Björn Stender BS-1 or the Stender BS-1, is a West German, high-wing, single seat, T-tailed, FAI Open Class glider, designed by Björn Stender and produced by Glasflügel. The prototype BS-1 was designed by Stender. Two prototypes were built by him and his three assistants in 1962, he was a young engineering student and designed the aircraft at the request of a South African sailplane pilot and industrialist, producing a design, advanced for its time. While the designer was test flying of one of the prototypes in 1963 the aircraft suffered an in-flight structural failure and Stender was killed. Glasflügel took over the project and re-engineered the design, based on their experience producing the Glasflügel H-301 Libelle; the company went on to build 18 production aircraft. The BS-1 is constructed from fiberglass and features an 18.0 m wing with flaps and dive brakes. For further glidepath control the BS-1 has a tail-mounted parachute; the landing gear is a retractable monowheel.
A planned improved model, the BS-1b, was never produced. The BS-1 was considered one of the first soaring "super ships" and was one of the most high-performing gliders of its time, the mid-1960s. Alfred Rohm of West Germany flew a BS-1 to a world 300 km speed record of 135.3 km/h in 1967. Thierry Thys of San Leandro, California flew a BS-1 on a 917 km flight in 1970. At that time it was the third-longest soaring flight made. Frontiers of Flight Museum National Soaring Museum - one, listed as in "storage" Data from Sailplane Directory and SoaringGeneral characteristics Crew: one Wingspan: 18.0 m Wing area: 14.09 m2 Aspect ratio: 23:1 Empty weight: 310 kg Gross weight: 450 kg Performance Maximum glide ratio: 44:1 at 84 km/h Rate of sink: 0.543 m/s at 80 km/h Wing loading: 32 kg/m2 Aircraft of comparable role and era Schempp-Hirth Cirrus Related lists List of gliders
Air brake (aeronautics)
In aeronautics, air brakes or speed brakes are a type of flight control surfaces used on an aircraft to increase drag or increase the angle of approach during landing. Air brakes differ from spoilers in that air brakes are designed to increase drag while making little change to lift, whereas spoilers reduce the lift-to-drag ratio and require a higher angle of attack to maintain lift, resulting in a higher stall speed; the earliest known air brake was developed in 1931 and deployed on the wing support struts. Not long after, air brakes located on the bottom of the wing's trailing edge were developed and became the standard type of aircraft air brake for decades. In 1936, Hans Jacobs, who headed Nazi Germany's Deutsche Forschungsanstalt für Segelflug glider research organization before World War II, developed blade-style self-operating dive brakes, on the upper and lower surface of each wing, for gliders. Most early gliders were equipped with spoilers on the wings in order to adjust their angle of descent during approach to landing.
More modern gliders use air brakes which may spoil lift as well as increase drag, dependent on where they are positioned. Characteristics of both spoilers and air brakes are desirable and are combined - most modern airliner jets feature combined spoiler and air brake controls. On landing, the deployment of these spoilers causes a dramatic loss of lift and hence the weight of the aircraft is transferred from the wings to the undercarriage, allowing the wheels to be mechanically braked with much less chance of skidding. In addition, the form drag created by the spoilers directly assists the braking effect. Reverse thrust is used to help slow the aircraft after landing. All jet powered aircraft have an air brake or, in the case of most airliners, lift spoilers that act as air brakes. Propeller driven aircraft benefit from the natural braking effect of the propeller when the engine is throttled back, but jet powered aircraft have no such innate braking effect and must use air brakes to control descent speed.
Many early jets used parachutes as air brakes after landing. The Blackburn Buccaneer naval strike aircraft designed in the 1950s had a tail cone, split and could be hydraulically opened to the sides to act as a variable air brake, it helped to reduce the length of the aircraft in the confined space on an aircraft carrier. The F-15 Eagle, Sukhoi Su-27 and other fighters have an air brake just behind the cockpit. An air brake is a panel conforming the shape of an aircraft that can be opened with hydraulic pressure in order to create drag, similar to spoilers which are on the edges of the aircraft wings and open in an upward position forcing the plane towards the ground. Air brakes are used when the aircraft needs to reduce its airspeed, while spoilers are only able to be opened when the airplane is approaching the runway and about to touch down. Lift dumpers, a type of air brake, are mounted on the top of a fuselage; when the panel is opened, it acts as a small spoiler pushing the aircraft down.
Flaps increase drag and decrease airspeed, but are for reducing the stall speed, allowing the aircraft to land at a slower speed. Following the invention of powered flight, the rapid development of fixed-wing aircraft in the early 20th Century, man endeavoured for several decades to make airplanes faster than before. A universal goal for all manufacturers for some time, was to reach the speed of sound 740 miles per hour. Apart from the challenge of developing an engine capable of producing such a speed, preventing the aircraft from breaking apart under the stress, one major concern was how to keep the aircraft in stable flight and return it to a normal flying speed using a stronger braking system. In the 1930s, air brake systems were still using simple flaps that were manually controlled by a lever in the cockpit, with mechanical devices running through the wings. However, in order for the air brakes to be effective at 740 mph, they needed to be mounted on the fuselage for improved wing control, operated through some form of dampener or hydraulic system, allowing the pilot to physically pull a lever in order to create an excessive amount of air resistance.
The concept of fuselage-mounted air brakes, or speed brakes, spread throughout the 1930s becoming more commonplace in the 1940s. In the 1930s, pilots would land with the nose of the plane tilted upwards at a 45-degree angle for short landings in order to effect rapid deceleration. With this method, "the drag or resistance is increased by 300 percent, the distance required to land is cut down to one third of the usual stopping distance". However, there was an urgent need to develop an alternate way of drastically reducing speed on landing that would not cause the pilot to lose sight of what was ahead of him; this led to the development of a new air braking system with additional flaps, mounted on the wing, that opened in two directions simultaneously. This wing-mounted design allowed the effective surface area of the flaps to be increased by 100 percent for landing, producing more drag than the conceptual fuselage design and resulting in a sharper reduction in air speed; this meant that the pilot was able to see the landing strip in front of the aircraft as there was no longer the need to tilt the nose upwards at a steep angle at close to stalling speeds.
The rate of deceleration and foot pounds of force applied to each brake is dependent upon where the brake is located. Upper and lower surface flaps positioned along the wings provide the steadiest braking curve, but the flaps are subjected to greater stresses at theoretically hi