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32-480: The General Aircraft Monospar ST-25 was a British 1930s light twin-engined utility aircraft. The Monospar ST-25 was a low-wing cantilever monoplane with a fabric-covered metal structure. The monospar name came from the use of a single spar in the wing structure, that had been developed by H J Stieger. The cabin was enclosed with five seats. It was based on the GAL Monospar ST-10 , with the addition of

64-548: A Warren truss layout — riveted onto the spars, resulting in a substantial increase in structural strength at a time when most other aircraft designs were built almost completely with wood-structure wings. The Junkers all-metal corrugated-covered wing / multiple tubular wing spar design format was emulated after World War I by American aviation designer William Stout for his 1920s-era Ford Trimotor airliner series, and by Russian aerospace designer Andrei Tupolev for such aircraft as his Tupolev ANT-2 of 1922, upwards in size to

96-452: A general aviation aircraft usually consists of a sheet aluminium spar web, with L- or T-shaped spar caps being welded or riveted to the top and bottom of the sheet to prevent buckling under applied loads. Larger aircraft using this method of spar construction may have the spar caps sealed to provide integral fuel tanks . Fatigue of metal wing spars has been an identified causal factor in aviation accidents, especially in older aircraft as

128-525: A cost of increased complexity and difficulty of packaging additional equipment such as fuel tanks, guns, aileron jacks, etc.). Although multi-spar wings have been used since at least the 1930s (for example, the World War 2-era Curtiss P-40 had 3 spars per wing), they gained greater popularity when the increasing speed of jet fighters demanded thinner wings to reduce drag at high speeds. The Mach 2 F-104 Starfighter used numerous slender spars to allow for

160-625: A crucial role in determining the mechanical properties of duralumin. Optimal aging conditions lead to the formation of finely dispersed precipitates, resulting in peak strength and hardness. Aluminium alloyed with copper (Al-Cu alloys), which can be precipitation hardened , are designated by the International Alloy Designation System as the 2000 series. Typical uses for wrought Al-Cu alloys include: German scientific literature openly published information about duralumin, its composition and heat treatment, before

192-456: A folding seat for a fifth passenger, extra side windows, and the addition of a radio receiver. On 19 June 1935, the prototype (G-ADIV) made its first flight at Hanworth Air Park . It was designated Monospar ST-25 Jubilee, to honour the 25th anniversary of the reign of King George V. Data from Jackson, 1973 General characteristics Performance Spar (aviation) Spars are also used in other aircraft aerofoil surfaces such as

224-620: A heavier-than-air aircraft structure occurred in 1916, when Hugo Junkers first introduced its use in the airframe of the Junkers J 3 , a single-engined monoplane "technology demonstrator" that marked the first use of the Junkers trademark duralumin corrugated skinning. The Junkers company completed only the covered wings and tubular fuselage framework of the J 3 before abandoning its development. The slightly later, solely IdFlieg -designated Junkers J.I armoured sesquiplane of 1917, known to

256-547: A wing of unusually thin section; the F-16 Fighting Falcon uses a similar construction. Other aircraft like the F-4 Phantom , F-15 Eagle and others use 3 or more spars to give sufficient strength in a relatively thin wing, and thus qualify as multi-spar aircraft. False spars, like main spars, are load bearing structural members running spanwise but are not joined to the fuselage. Their most common purpose

288-625: A “Duralinox” model that became an instant classic among cyclists. The Vitus 979 was the first production aluminium frameset whose thin-wall 5083/5086 tubing was slip-fit and then glued together using a dry heat-activated epoxy. The result was an extremely lightweight but very durable frameset. Production of the Vitus 979 continued until 1992. In 2011, BBS Automotive made the RI-D, the world's first production automobile wheel made of duralumin. The company has since made other wheels of duralumin also, such as

320-450: Is relatively soft and ductile. Solution Annealing: Duralumin undergoes solution annealing, a high-temperature heat treatment process that dissolves the alloying elements into the aluminium matrix, creating a homogeneous solid solution. Quenching: Rapid cooling (quenching) after solution annealing freezes the high-temperature solid solution, preventing the precipitation of strengthening phases. Aging (Precipitation Hardening): During aging,

352-481: Is to carry moving surfaces, principally ailerons . Duralumin Duralumin (also called duraluminum , duraluminium , duralum , dural(l)ium , or dural ) is a trade name for one of the earliest types of age-hardenable aluminium–copper alloys . The term is a combination of Dürener and aluminium . Its use as a trade name is obsolete. Today the term mainly refers to aluminium-copper alloys, designated as

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384-470: The ASG 29 . The increase in strength and reduction in weight compared to the earlier fibreglass-sparred aircraft allows a greater quantity of water ballast to be carried. Aircraft utilizing three or more spars are considered multi-spar aircraft. Using multiple spars allows for an equivalent overall strength of wing, but with multiple, smaller, spars, which in turn allow for a thinner wing or tail structure (at

416-587: The BD-5 , which was designed and constructed by Jim Bede in the early 1970s. The spar used in the BD-5 and subsequent BD projects was primarily aluminium tube of approximately 2 inches (5.1 cm) in diameter, and joined at the wing root with a much larger internal diameter aluminium tube to provide the wing structural integrity. In aircraft such as the Vickers Wellington , a geodesic wing spar structure

448-592: The Robin DR400 and its relatives. A disadvantage of the wooden spar is the deteriorating effect that atmospheric conditions, both dry and wet, and biological threats such as wood-boring insect infestation and fungal attack can have on the component; consequently regular inspections are often mandated to maintain airworthiness . Wood wing spars of multipiece construction usually consist of upper and lower members, called spar caps , and vertical sheet wood members, known as shear webs or more simply webs , that span

480-407: The tailplane and fin and serve a similar function, although the loads transmitted may be different from those of a wing spar. The wing spar provides the majority of the weight support and dynamic load integrity of cantilever monoplanes , often coupled with the strength of the wing 'D' box itself. Together, these two structural components collectively provide the wing rigidity needed to enable

512-767: The "Great Airship" era of the 1920s and 1930s: the British-built R100 , the German passenger Zeppelins LZ 127 Graf Zeppelin , LZ 129 Hindenburg , LZ 130 Graf Zeppelin II , and the U.S. Navy airships USS Los Angeles (ZR-3, ex-LZ 126) , USS Akron (ZRS-4) and USS Macon (ZRS-5) . Duralumin was used to manufacture bicycle components and framesets from the 1930s to 1990s. Several companies in Saint-Étienne, France stood out for their early, innovative adoption of duralumin: in 1932, Verot et Perrin developed

544-490: The 2000 series by the international alloy designation system (IADS), as with 2014 and 2024 alloys used in airframe fabrication. Duralumin was developed in 1909 in Germany. Duralumin is known for its strength and hardness, making it suitable for various applications, especially in the aviation and aerospace industry. However, it is susceptible to corrosion, which can be mitigated by using alclad-duralum materials. Duralumin

576-483: The aircraft to fly safely. Biplanes employing flying wires have much of the flight loads transmitted through the wires and interplane struts enabling smaller section and thus lighter spars to be used at the cost of increasing drag . Some of the forces acting on a wing spar are: Many of these loads are reversed abruptly in flight with an aircraft such as the Extra 300 when performing extreme aerobatic manoeuvers;

608-401: The distance between the spar caps. Even in modern times, "homebuilt replica aircraft" such as the replica Spitfires use laminated wooden spars. These spars are laminated usually from spruce or douglas fir (by clamping and glueing). A number of enthusiasts build "replica" Spitfires that will actually fly using a variety of engines relative to the size of the aircraft. A typical metal spar in

640-490: The factory as the Junkers J 4, had its all-metal wings and horizontal stabilizer made in the same manner as the J 3's wings had been, like the experimental and airworthy all-duralumin Junkers J 7 single-seat fighter design, which led to the Junkers D.I low-wing monoplane fighter, introducing all-duralumin aircraft structural technology to German military aviation in 1918. Its first use in aerostatic airframes came in rigid airship frames, eventually including all those of

672-911: The first light alloy crank arms; in 1934, Haubtmann released a complete crankset; from 1935 on, Duralumin freewheels, derailleurs , pedals, brakes and handlebars were manufactured by several companies. Complete framesets followed quickly, including those manufactured by: Mercier (and Aviac and other licensees) with their popular Meca Dural family of models, the Pelissier brothers and their race-worthy La Perle models, and Nicolas Barra and his exquisite mid-twentieth century “Barralumin” creations. Other names that come up here also included: Pierre Caminade, with his beautiful Caminargent creations and their exotic octagonal tubing, and also Gnome et Rhône , with its deep heritage as an aircraft engine manufacturer that also diversified into motorcycles, velomotors and bicycles after World War Two. Mitsubishi Heavy Industries , which

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704-479: The introduction of duralumin in 1909. The name, originally a trade mark of Dürener Metallwerke AG which acquired Wilm's patents and commercialized the material, is mainly used in pop-science to describe all Al-Cu alloys system, or '2000' series, as designated through the international alloy designation system originally created in 1970 by the Aluminum Association . In addition to aluminium ,

736-488: The main materials in duralumin are copper , manganese and magnesium . For instance, Duraluminium 2024 consists of 91-95% aluminium, 3.8-4.9% copper, 1.2-1.8% magnesium, 0.3-0.9% manganese, <0.5% iron, <0.5% silicon, <0.25% zinc, <0.15% titanium, <0.10% chromium and no more than 0.15% of other elements together. Although the addition of copper improves strength, it also makes these alloys susceptible to corrosion . Corrosion resistance can be greatly enhanced by

768-545: The metallurgical bonding of a high-purity aluminium surface layer, referred to as alclad -duralum. Alclad materials are commonly used in the aircraft industry to this day. Duralumin's remarkable strength and durability stem from its unique microstructure, which is significantly influenced by heat treatment processes. Solid Solution: After initial solidification, duralumin exists as a single-phase solid solution, primarily composed of aluminium atoms with dispersed copper, magnesium, and other alloying elements. This initial state

800-489: The outbreak of World War I in 1914. Despite this, use of the alloy outside Germany did not occur until after fighting ended in 1918. Reports of German use during World War I, even in technical journals such as Flight , could still mis-identify its key alloying component as magnesium rather than copper. Engineers in the UK showed little interest in duralumin until after the war. The earliest known attempt to use duralumin for

832-423: The spars of these aircraft are designed to safely withstand great load factors . Early aircraft used spars often carved from solid spruce or ash . Several different wooden spar types have been used and experimented with such as spars that are box-section in form; and laminated spars laid up in a jig , and compression glued to retain the wing dihedral . Wooden spars are still being used in light aircraft such as

864-449: The supersaturated solid solution becomes unstable. Fine precipitates, such as CuAl2 and Mg2Si, form within the aluminum matrix. These precipitates act as obstacles to dislocation movement, significantly increasing the alloy's strength and hardness. The final microstructure of duralumin consists of a predominantly aluminium matrix dispersed fine precipitates (CuAl2, Mg2Si) Grain boundaries. The size, distribution, and type of precipitates play

896-481: The then-gigantic Maksim Gorki of 1934. A design aspect of the Supermarine Spitfire wing that contributed greatly to its success was an innovative spar boom design, made up of five square concentric tubes that fitted into each other. Two of these booms were linked together by an alloy web, creating a lightweight and very strong main spar. A version of this spar construction method is also used in

928-486: Was developed by the German metallurgist Alfred Wilm at private military-industrial laboratory Zentralstelle für wissenschaftlich-technische Untersuchungen  [ de ] (Center for Scientific-Technical Research) in Neubabelsberg . In 1903, Wilm discovered that after quenching , an aluminium alloy containing 4% copper would harden when left at room temperature for several days. Further improvements led to

960-565: Was employed, which had the advantages of being lightweight and able to withstand heavy battle damage with only partial loss of strength. Many modern aircraft use carbon fibre and Kevlar in their construction, ranging in size from large airliners to small homebuilt aircraft . Of note are the developments made by Scaled Composites and the German glider manufacturers Schempp-Hirth and Schleicher . These companies initially employed solid fibreglass spars in their designs but now often use carbon fibre in their high performance gliders such as

992-519: Was prohibited from producing aircraft during the American occupation of Japan, manufactured the “cross” bicycle out of surplus wartime duralumin in 1946. The “cross” was designed by Kiro Honjo , a former aircraft designer responsible for the Mitsubishi G4M . Duralumin use in bicycle manufacturing faded in the 1970s and 1980s. Vitus nonetheless released the venerable “979” frameset in 1979,

General Aircraft Monospar ST-25 - Misplaced Pages Continue

1024-411: Was the case with Chalk's Ocean Airways Flight 101 . The German Junkers J.I armoured fuselage ground-attack sesquiplane of 1917 used a Hugo Junkers -designed multi-tube network of several tubular wing spars, placed just under the corrugated duralumin wing covering and with each tubular spar connected to the adjacent one with a space frame of triangulated duralumin strips — usually in the manner of

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