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Complete superflight covering; Wings, Flaps and Ailerons painted white; Leading edge slats painted yellow; Aeroled lights ($1000 plus value) 24 gal tank each side; Wing length 184.5” Flap length 80” chord 17.5” Aileron Length 106” chord 17.5” Wing tips 12” Call for more info – 307-358-5700. According to the comparison chart posted below, the Poly Fiber covering system is '42' pounds lighter than the Superflite system!!

Fabric covering of a de Havilland Tiger Moth showing rib stitching and inspection rings.

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 being an example of this technique, and on 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, this method is often used in the restoration of older types that were originally covered using traditional methods.

Purpose/requirements[edit]

The purposes of the fabric covering of an aircraft are:

  • To provide a light airproof skin for lifting and control surfaces.
  • To provide structural strength to otherwise weak structures.
  • To cover other non-lifting parts of an aircraft to reduce drag, sometimes forming a fairing.
  • To protect the structure from the elements.

Early use[edit]

A Lillienthal flying machine replica

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.[1] 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)[2]

WWI/Post WWI[edit]

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.[3] 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 Hindenburgairship.

WWII[edit]

Damaged Vickers Wellington showing burnt and missing fabric covering

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.[3] 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.

Introduction of modern materials[edit]

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.[3][4]

An Ultraflight Lazair covered using Ceconite and the Hipec process.
Superflite

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.[3]

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.[3] 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.[4][5][6]

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.[7][8]

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.[3]

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.[9][10]

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.[3][11]

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.[12]

Lanitz Aviation introduced a new process in 2001 manufactured in Germany under the trade name Oratex6000.[13] Oratex has received a European EASASupplemental Type Certificate (STC),[14] Canadian STCs,[15][16] and a US STC.[17] 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.[18]

Covering processes[edit]

Traditional methods[edit]

Laced panels and stitched undercambered airfoil of a Sopwith Pup

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.[19]

Modern methods[edit]

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.[3][20]

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.[21]

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See also[edit]

  • Radio-controlled aircraft, on which either doped-on fabric or prepared iron-on fabric (using heat from a clothes iron for adhesion and shrinkage) can be used for a covering material.

References[edit]

Superflite

Notes[edit]

  1. ^Penrose, Harald British Aviation: The Pioneer Years London: Putnam, 1967 p.323
  2. ^Some Notes on Fabric VarnishFlight International12 August 1911
  3. ^ abcdefghGoldenbaum, Jon: Aircraft Fabrics - Wrapping it up, AeroCrafter - Homebuilt Aircraft Sourcebook, page 31-34. BAI Communications. ISBN0-9636409-4-1
  4. ^ abAircraft Spruce and Specialty (2009). 'Poly-Fiber Fabric'. Retrieved 2009-08-08.
  5. ^Aircraft Spruce and Specialty (2009). 'Ceconite'. Retrieved 2009-08-08.
  6. ^Aircraft Spruce and Specialty (2009). 'Covering Material - Poly-Fiber'. Retrieved 2009-08-08.
  7. ^Aircraft Spruce and Specialty (2009). 'Covering Material - Randolph Coatings'. Retrieved 2009-08-08.
  8. ^Aircraft Spruce and Specialty (2009). 'Covering Material - Certified Coatings'. Retrieved 2009-08-08.
  9. ^Falconar Avia (July 2008). 'The Modern Method for Covering & Finishing'. Archived from the original on 2009-03-26. Retrieved 2009-08-08.
  10. ^Hunt, Adam & Ruth Merkis-Hunt: Finishing With Hipec, Kitplanes June 2001 pages 70-74. Belvoir Publications. ISSN 0891-1851
  11. ^Stewart Systems (2010). 'Stewart Systems'.
  12. ^Aircraft Spruce and Specialty (2009). 'Covering Material - Ultralight Sails - Quicksilver'. Retrieved 2009-08-08.
  13. ^Lanitz-Prena (2013). 'Lanitz-Prena'. Archived from the original on 2013-12-02. Retrieved 2013-11-15.
  14. ^European Aviation Safety Agency Supplemental Type Certificate 10045970
  15. ^Transport Canada. 'NICO: Certificate SA 1468'. wwwapps.tc.gc.ca. Retrieved 4 February 2019.
  16. ^Transport Canada. 'NICO: Certificate SP 0003'. wwwapps.tc.gc.ca. Retrieved 4 February 2019.
  17. ^Federal Aviation Administration (20 March 2017). 'Supplemental Type Certificate SA03898NY'. www.airweb.faa.gov. Retrieved 4 February 2019.
  18. ^Lanitz-Prena2 (2013). 'Lanitz-Prena2'. Archived from the original on 2013-12-03. Retrieved 2013-11-15.
  19. ^FAA AC.43.13, pp. 81-94.
  20. ^FAA AC.43.13, p. 84.
  21. ^FAA AC.43.13, p. 243.

Bibliography[edit]

  • Federal Aviation Administration, Acceptable Methods, Techniques and Practices-Aircraft Inspection and Repair, AC43.13.1A, Change 3. U.S Department of Transportation, U.S. Government Printing Office, Washington D.C. 1988.
  • Taylor, John W.R. The Lore of Flight, London: Universal Books Ltd., 1990. ISBN0-9509620-1-5.

External links[edit]

Retrieved from 'https://en.wikipedia.org/w/index.php?title=Aircraft_fabric_covering&oldid=944681654'
Hey Folks,
One of the things I had hoped to accomplish at Oshkosh this year was to educate myself on covering materials/manufactures and maybe get to learn more about the products. I couldn't find a Poly Fiber booth although I found a few vendors who sell the product.
I did however spend a good deal of time at the Superflight booth. Not only did they answer a lot of questions but they showed me (step by step) how to use their product. In fact.. They also explained everything to my girlfriend so she could point out what I was doing wrong later.
Anyhow.. while I was covering an elevator feather they feed my girlfriend snacks and looked over my shoulder. I had the chance to do pretty much everything short of applying primer and paint. Although the rib stitching was a little tricky, thanks to Roger at Superflight I feel confident I can cover my own plane. Those folks are a great bunch. I can't express how much I appreciate them taking the time to teach a newbie like me the ropes.
I'm curious why I don't hear more folks using this system. I figure if I could learn this system in a couple of hours it must be pretty user friendly. From what I understand a completed J3 is 3-4 pounds heavier than the Poly Fiber system. That doesn?t seem like a lot of weight and the shiny urethane really looks sharp!
Does anyone out there have any experience with this product they would care to share? I?m wondering if anyone has worked with both and could point out significant differences.

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