Aircraft fabric covering is a term used for both the material used and the process of covering aircraft open structures. It is also used for reinforcing closed plywood structures. The de Havilland Mosquito is an example of this technique, as are the pioneering all-wood monocoque fuselages of certain World War I German aircraft like the LFG Roland C.II in its wrapped Wickelrumpf plywood strip and fabric covering.
Early aircraft used organic materials such as cotton and cellulose nitrate dope; modern fabric-covered designs usually use synthetic materials such as Dacron and butyrate dope for adhesive. Modern methods are often used in the restoration of older types that were originally covered using traditional methods.
The purposes of the fabric covering of an aircraft are:
Pioneering aviators such as George Cayley and Otto Lilienthal used cotton-covered flying surfaces for their manned glider designs. The Wright brothers also used cotton to cover their Wright Flyer. Other early aircraft used a variety of fabrics, silk and linen being commonly used. Some early aircraft, such as A.V. Roe's first machines, even used paper as a covering material. Until the development of cellulose based dope in 1911 a variety of methods of finishing the fabric were used.  The most popular was the use of rubberised fabrics such as those manufactured by the "Continental" company. Other methods included the use of sago starch.  The advent of cellulose dopes such as "Emaillite" was a major step forward in the production of practical aircraft, producing a surface that remained taut (eliminating the need for frequent re-covering of the flying surfaces) 
The air battles of World War I were mainly fought with fabric-covered biplanes that were vulnerable to fire due to the flammable properties of the cloth covering and nitrocellulose dope.  National insignia painted on the fabric were often cut from downed aircraft and used as war trophies. The German aircraft designer Hugo Junkers is considered one of the pioneers of metal aircraft; his designs started the move away from fabric covering. The highly flammable mixture of fabric, dope and hydrogen gas was a factor in the demise of the Hindenburg airship.
By the World War II era many aircraft designs were using metal monocoque structures due to their higher operating airspeeds, although fabric-covered control surfaces were still used on early mark Spitfires and other types. The Hawker Hurricane had a fabric covered fuselage, and they also had fabric covered wings until 1939. Many transports, bombers and trainers still used fabric, although the flammable nitrate dope was replaced with butyrate dope instead, which burns less readily.  The Mosquito is an example of a fabric-covered (madapollam) plywood aircraft. The Vickers Wellington used fabric over a geodesic airframe which offered good combat damage resistance.
An interesting case of ingenuity under wartime adversity was the Colditz Cock glider. This homebuilt aircraft, intended as a means of escape, employed prison bedding as its covering material; homemade glue and dope made from boiled millet were also used by the prisoners in its construction.
With the development of modern synthetic materials following World War II, cotton fabrics were replaced in civil aircraft applications by polyethylene terephthalate, known by the trade-name Dacron or Ceconite. This new fabric could be glued to the airframe instead of sewn and then heat-shrunk to fit. Grade A cotton would typically last six to seven years when the aircraft was stored outside, whereas Ceconite, which does not rot like cotton, can last over 20 years.  
Early attempts to use these modern fabrics with butyrate dope proved that the dope did not adhere at all and peeled off in sheets. Nitrate dope was resurrected as the initial system of choice instead, although it was supplanted by new materials too. 
One fabric system, developed by Ray Stits in the USA and FAA-approved in 1965, is marketed under the brand name Poly-Fiber. This uses three weights of Dacron fabric sold as by the brand name Ceconite, plus fabric glue for attaching to the airframe (Poly-Tak), fabric preparation sealer resin (Poly-Brush) and paint (Poly-Tone). This system is not dope and instead uses vinyl-based chemicals.  Ceconite 101 is a certified 3.5 oz/yd2 (119 g/m2) fabric while Ceconite 102 is a 3.16 oz/yd2 (107 g/m2) fabric. There is also an uncertified light Ceconite of 1.87 oz/yd2 (63 g/m2) intended for ultralight aircraft. This method requires physical attachment of the fabric to the airframe in the form of rib-stitching, rivets or capstrips, which are then usually covered with fabric tapes.   
In addition to Poly-Fiber, a number of other companies produce covering processes for certified and homebuilt aircraft. Randolph Products and Certified Coatings Products both make butyrate and nitrate-based dopes for use with Dacron fabric.  
Superflite and Air-Tech systems use a similar fabric, but the finishes are polyurethane-based products with flex agents added. These finishes produce very high gloss results. 
Falconar Avia of Edmonton, Alberta, Canada developed the Hipec system in 1964 for use with Dacron fabric. It uses a special Hipec Sun Barrier that adheres fabric directly to the aircraft structure in one step, eliminating the need for the riveting, rib-stitching and taping used in traditional fabric processes. The final paint is then applied over the sun barrier to complete the process.  
Newer systems were developed and distributed by Stewart Systems of Cashmere, Washington and Blue River (Ceconite 7600). These two systems use the same certified dacron materials as other systems, but do not use high volatile organic compounds, using water as a carrier instead, making them safer to use and less environmentally damaging.  
Many ultralight aircraft are covered with pre-sewn envelopes of 3.9 oz Dacron that are simply screwed, bolted or laced into place. These are produced in a wide variety of colours and patterns and are commonly flown untreated or with an anti-ultraviolet radiation finish to resist sun damage. 
Lanitz Aviation introduced a new process in 2001 manufactured in Germany under the trade name Oratex6000.  Oratex has received a European EASA Supplemental Type Certificate (STC),  Canadian STCs,   and a US STC.  Oratex differs from previous systems, which all require the application of many layers of special coatings (many of them toxic) along with the time, skill, equipment and safety precautions necessary to apply them. Oratex6000 is simply glued to the airframe and then shrunk tight and does not require any coatings. 
Traditional covering methods use organic materials, such as cotton.  Once the aircraft structure is prepared by sanding, the material is applied using dope as an adhesive. Rib-stitching is used on faster aircraft types and especially on undercambered airfoils to ensure that the fabric follows the aircraft structure. The distance between stitches is reduced in areas affected by the propeller wash. The covering would then be treated with tautening dope to remove wrinkles and increase structural strength, finish coats often containing aluminium powder would serve to protect the surface from ultra-violet light. Large fabric panels of the World War I era aircraft were often laced together through eyelets to ease access to the internal structure for maintenance. Some disadvantages compared to modern methods are the relatively short service life of the covering due to biological effects such as mildew and the labour required to achieve the end result. 
Modern covering methods follow the traditional method with minor differences. Synthetic materials are used, covering is adhered to the structure using dedicated glues. The shrinking process is achieved by applying an electric iron or heat gun. Once the covering is tight, rib-stitching is again used for heavier or faster aircraft. Cosmetic finish coats are usually applied, except in the case of Oratex which normally receives no coatings. A side effect of using modern covering materials on wooden structured aircraft is that due to the much longer life the structure remains covered and un-inspected for much longer time periods, this has resulted in special periodic inspections being mandated by aviation regulatory bodies.  
With both methods of covering it is normal for the aircraft to be re-weighed after renewal of the fabric to determine any change in mass and centre of gravity. 
The fuselage is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine, as well, although in some amphibious aircraft the single engine is mounted on a pylon attached to the fuselage, which in turn is used as a floating hull. The fuselage also serves to position the control and stabilization surfaces in specific relationships to lifting surfaces, which is required for aircraft stability and maneuverability.
Kapton is a polyimide film used in flexible printed circuits and space blankets, which are used on spacecraft, satellites, and various space instruments. Invented by the DuPont Corporation in the 1960s, Kapton remains stable across a wide range of temperatures, from 4 to 673 K.
Homebuilt aircraft, also known as amateur-built aircraft or kit planes, are constructed by persons for whom this is not a professional activity. These aircraft may be constructed from "scratch", from plans, or from assembly kits.
Homebuilt machines are machines built outside of specialised workshops or factories. This can include different things such as kit cars or homebuilt computers, but normally it pertains to homebuilt aircraft, also known as amateur-built aircraft or kit planes. Homebuilt aircraft or kit cars are constructed by amateurs. Homebuilt computers have been built at home for a long time, starting with the Victorian era pioneer Charles Babbage in the 1820s. A century later, Konrad Zuse built his own machine when electromechanical relay technology was widely available. The hobby took off with the early development of microprocessors and, since then, many enthusiasts have constructed their own computers. A homebuilt vehicle is a wider concept than a kit car. A homebuilt vehicle is a motor vehicle built by an individual instead of a manufacturer. These machines may be constructed "from scratch", from plans, or from assembly kits. Outside of the United States people wishing to build such complex machinery often have no professional networks to rely on for spare parts, plans, or advice in the matter and therefore have to rely on their ingenuity and intuition in order to build a machine that works.
The Pietenpol Air Camper is a simple parasol wing homebuilt aircraft designed by Bernard H. Pietenpol. The first prototype that became the Air Camper was built and flown by Pietenpol in 1928.
A former is an object, such as a template, gauge or cutting die, which is used to form something such as a boat's hull. Typically, a former gives shape to a structure that may have complex curvature.
In a fixed-wing aircraft, the spar is often the main structural member of the wing, running spanwise at right angles to the fuselage. The spar carries flight loads and the weight of the wings while on the ground. Other structural and forming members such as ribs may be attached to the spar or spars, with stressed skin construction also sharing the loads where it is used. There may be more than one spar in a wing or none at all. However, where a single spar carries most of the force, it is known as the main spar.
Warp knitting is a family of knitting methods in which the yarn zigzags along the length of the fabric; i.e., following adjacent columns, or wales, of knitting, rather than a single row, or course. For comparison, knitting across the width of the fabric is called weft knitting.
Aircraft dope is a plasticised lacquer that is applied to fabric-covered aircraft. It tightens and stiffens fabric stretched over airframes, which renders them airtight and weatherproof, increasing their durability and lifespan. The technique has been commonly applied to both full-size and flying models of aircraft.
The Wittman W-8 Tailwind is a popular two-seat light aircraft for homebuilding. It is a high-wing, braced cabin monoplane of taildragger configuration. It is constructed with a steel tubing fuselage, wood wings, and fabric covering. It offers exceptional cruising speeds and is economical to operate and maintain.
Madapollam is a soft cotton fabric manufactured from fine yarns with a dense pick laid out in linen weave. Madapollam is used as an embroidery and handkerchief fabric and as a base for fabric printing. The equal warp and weft mean that the tensile strength and shrinkage is the same in any two directions at right angles and that the fabric absorbs liquids such as ink, paint and aircraft dope equally along its X and Y axes.
The Oldfield Baby Great Lakes is a homebuilt sport biplane. The aircraft has many known names, including the Baby Lakes, Oldfield Baby Lakes, Baby Great Lakes, Super Baby Lakes, Super Baby Great Lakes, and Buddy Baby Lakes
The Howland H-3 Pegasus is an American ultralight aircraft that was designed by Bert Howland and made available by Howland Aero Design in the form of plans for amateur construction, with kits provided by Aircraft Spruce & Specialty Co. The H-3 first flew in 1988.
The Howland H-2 Honey Bee is an American homebuilt aircraft that was designed by Bert Howland and made available by Howland Aero Design in the form of plans for amateur construction, with kits provided by Aircraft Spruce & Specialty Co. The H-2 first flew in 1986.
Tube-and-fabric construction is a method of building airframes, which include the fuselages and wings of airplanes. It consists of making a framework of metal tubes and then covering the framework with an aircraft fabric covering.
The Stolp SA-500 Starlet is an American amateur-built aircraft. The aircraft is supplied in the form of plans for amateur construction by Aircraft Spruce & Specialty of Corona, California.
The Christavia Mk IV (Christ-in-Aviation) is a Canadian homebuilt aircraft that was designed by Ron Mason and produced by Elmwood Aviation of Frankford, Ontario. The aircraft is supplied in the form of plans for amateur construction.
The Kelly-D is an American homebuilt aircraft that was designed by Dudley R. Kelly of Versailles, Kentucky, in 1981. When it was available, the aircraft was supplied in the form of plans for amateur construction. Aircraft Spruce & Specialty Co still provides some spruce wing parts for the design.
Raymond M. Stits was an American inventor, homebuilt aircraft designer, aircraft mechanic and pilot. He designed the Stits SA-2A Sky Baby, which was the world's smallest aircraft in 1952, developed the Poly-Fiber aircraft fabric covering system and was the founder of Experimental Aircraft Association Chapter 1.
Textile stabilization is a conservation method for fiber and yarn-based cloth intended to mitigate damage, prevent degradation and preserve structural integrity. Stabilization is part of a broad set of techniques in the field of conservation and restoration of textiles typically undertaken by a specialist or textile conservator. Appropriate treatment is determined through risk assessment and close examination of a textile's characteristics and the nature of the damage. Organic and synthetic fibers become weak due to age, handling, and environmental exposure and display physical deterioration such as fraying, planar distortion, loss, and change in surface character. Treatment involves reinforcing tensile strength and reintegration of parts for aesthetic, functional, and historic preservation. Methods can include stitching, darning, reweaving, and the attachment of supports through overlays and underlays. Hand-sewing follows the mantra of “gently does it” using fine needles, supple yarns, and a light touch. Heavily damaged and fragile fabrics often require stabilization through adhesive consolidation, though this is less common. It is essential that conservators consider physical and chemical compatibility along with future treatability in choosing a stabilization technique.
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