Misplaced Pages

#587412

70-535: The Eberhart Aeroplane and Motor Company produced its first original plane in 1927—the XFG—as a shipboard fighter for the U.S. Navy. It was of welded steel tube and dural construction with fabric skinning. An unusual feature was the application of sweepback to the upper mainplane and forward sweep to the lower. The sole XFG-1 prototype, bureau number A7944 , was tested by the United States Navy in late 1927, and

140-792: A m {\displaystyle a_{m}} are the lattice parameter of the precipitate or the matrix. For modulus hardening, τ G p = 0.01 G ϵ G p 3 2 ( f r / b ) 1 2 {\displaystyle \tau _{G_{p}}=0.01G\epsilon _{G_{p}}^{\frac {3}{2}}(fr/b)^{\frac {1}{2}}} , ϵ G p = ( G p − G m ) / G m {\displaystyle \epsilon _{G_{p}}=\left(G_{p}-G_{m}\right)/G_{m}} , where G p {\displaystyle G_{p}} and G m {\displaystyle G_{m}} are

210-389: A p − a m ) / a m {\displaystyle \epsilon _{coh}=(a_{p}-a_{m})/a_{m}} , where τ {\displaystyle \tau } is increased shear stress, G {\displaystyle G} is the shear modulus of the matrix, a p {\displaystyle a_{p}} and

280-610: 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

350-551: A decrease in strength as is explained below. Elements used for precipitation strengthening in typical aluminium and titanium alloys make up about 10% of their composition. While binary alloys are more easily understood as an academic exercise, commercial alloys often use three components for precipitation strengthening, in compositions such as Al(Mg, Cu ) and Ti(Al, V ). A large number of other constituents may be unintentional, but benign, or may be added for other purposes such as grain refinement or corrosion resistance. An example

420-560: A finer particle spacing. The level of τ b {\displaystyle \tau _{b}} is unaffected by particle strength. That is, once a particle is strong enough to resist cutting, any further increase in its resistance to dislocation penetration has no effect on τ b {\displaystyle \tau _{b}} , which depends only on matrix properties and effective particle spacing. If particles of A of volume fraction f 1 {\displaystyle f_{1}} are dispersed in

490-409: A fixed particle volume fraction, this stress may decrease at larger values of r owing to an increase in particle spacing. The overall level of the curve is raised by increases in either inherent particle strength or particle volume fraction. The dislocation can also bow around a precipitate particle through so-called Orowan mechanism. Since the particle is non-deforming, the dislocation bows around

560-610: 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

630-400: A matrix can be hardened by precipitates, which could also be different for deforming precipitates and non-deforming precipitates. Deforming particles (weak precipitates): Coherency hardening occurs when the interface between the particles and the matrix is coherent, which depends on parameters like particle size and the way that particles are introduced. Coherency is where the lattice of

700-433: A matrix, particles are sheared for r < r c 1 {\displaystyle r<r_{c1}} and are bypassed for r > r c 1 {\displaystyle r>r_{c1}} , maximum strength is obtained at r = r c 1 {\displaystyle r=r_{c1}} , where the cutting and bowing stresses are equal. If inherently harder particles of B of

770-415: A particle is sheared by a dislocation, a threshold shear stress is needed to deform the particle. The expression for the required shear stress is as follows: When the precipitate size is small, the required shear stress τ {\displaystyle \tau } is proportional to the precipitate size r 1 / 2 {\displaystyle r^{1/2}} , However, for

SECTION 10

#1732869283588

840-406: A result, the material will become weaker as the precipitate size increases. For a fixed particle volume fraction, τ b {\displaystyle \tau _{b}} decreases with increasing r as this is accompanied by an increase in particle spacing. On the other hand, increasing f {\displaystyle f} increases the level of the stress as a result of

910-410: A tensile stress, whereas larger precipitate particles leads to a compressive stress. Dislocation defects also create a stress field. Above the dislocation there is a compressive stress and below there is a tensile stress. Consequently, there is a negative interaction energy between a dislocation and a precipitate that each respectively cause a compressive and a tensile stress or vice versa. In other words,

980-617: 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

1050-408: Is a dimensionless mismatch parameter (for example, in coherency hardening, ϵ {\displaystyle \epsilon } is the fractional change of precipitate and matrix lattice parameter), f {\displaystyle f} is the volume fraction of precipitate, r {\displaystyle r} is the precipitate radius, and b {\displaystyle b}

1120-413: Is a fully disordered IPB and there are no coherency strains, but the particle tends to be non-deforming to dislocations. The last one is a partially ordered IPB, so coherency strains are partially relieved by the periodic introduction of dislocations along the boundary. In coherent precipitates in a matrix, if the precipitate has a lattice parameter less than that of the matrix, then the atomic match across

1190-403: 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 the 2000 series by the international alloy designation system (IADS), as with 2014 and 2024 alloys used in airframe fabrication. Duralumin

1260-469: Is anti-phase boundary energy and accumulates gradually as the dislocation passes through the particle. However, a second dislocation could remove the anti-phase domain left by the first dislocation when traverses the particle. The attraction of the particle and the repulsion of the first dislocation maintains a balanced distance between two dislocations, which makes order strengthening more complicated. Except for when there are very fine particles, this mechanism

1330-471: Is carried out under conditions of low solubility so that thermodynamics drive a greater total volume of precipitate formation. Diffusion 's exponential dependence upon temperature makes precipitation strengthening, like all heat treatments, a fairly delicate process. Too little diffusion ( under ageing ), and the particles will be too small to impede dislocations effectively; too much ( over ageing ), and they will be too large and dispersed to interact with

1400-400: Is different than that of solid solution and coherency strengthening. Chemical strengthening is associated with the surface energy of the newly introduced precipitate-matrix interface when the particle is sheared by dislocations. Because it takes energy to make the surface, some of the stress that is causing dislocation motion is accommodated by the additional surfaces. Like modulus hardening,

1470-488: Is generally not as effective as others to strengthen. Another way to consider this mechanism is that when a dislocation shears a particle, the stacking sequence between the new surface made and the matrix is broken, and the bonding is not stable. To get the sequence back into this interface, another dislocation, is needed to shift the stacking. The first and second dislocation are often called a superdislocation. Because superdislocations are required to shear these particles, there

SECTION 20

#1732869283588

1540-412: Is more limited to equilibrium phases. The addition of large amounts of nickel and chromium needed for corrosion resistance in stainless steels means that traditional hardening and tempering methods are not effective. However, precipitates of chromium, copper, or other elements can strengthen the steel by similar amounts in comparison to hardening and tempering. The strength can be tailored by adjusting

1610-450: 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,

1680-408: Is strengthening because of the decreased dislocation motion. Non-deforming particles (strong precipitate): In non-deforming particles, where the spacing is small enough or the precipitate-matrix interface is disordered, dislocation bows instead of shears. The strengthening is related to the effective spacing between particles considering finite particle size, but not particle strength, because once

1750-436: Is the addition of Sc and Zr to aluminum alloys to form FCC L1 2 structures that help refine grains and strengthen the material. In some cases, such as many aluminium alloys, an increase in strength is achieved at the expense of corrosion resistance. More recent technology is focused on additive manufacturing due to the higher amount of metastable phases that can be obtained due to the fast cooling, whereas traditional casting

1820-764: Is the magnitude of the Burgers vector . According to this relationship, materials strength increases with increasing mismatch, volume fraction, and particle size, so that dislocation is easier to cut through particles with smaller radius. For different types of hardening through cutting, governing equations are as following. For coherency hardening, τ c o h = 7 G | ϵ c o h | 3 2 ( f r / b ) 1 2 {\displaystyle \tau _{coh}=7G\left|\epsilon _{coh}\right|^{\frac {3}{2}}(fr/b)^{\frac {1}{2}}} , ϵ c o h = (

1890-500: Is the particle radius, f {\displaystyle f} is the particle volume fraction, b {\displaystyle b} is the burgers vector, r f / b {\displaystyle rf/b} equals the concentration. The other one is modulus hardening . The energy of the dislocation energy is U m = G m b 2 / 2 {\displaystyle U_{m}=G_{m}b^{2}/2} , when it cuts through

1960-432: Is the particle radius. Dislocation loops encircle the particles after the bypass operation, a subsequent dislocation would have to be extruded between the loops. Thus, the effective particle spacing for the second dislocation is reduced to ( L − 2 r ′ ) {\displaystyle (L-2r')} with r ′ > r {\displaystyle r'>r} , and

2030-507: Is the surface energy. The maximum force between the dislocation and particle is F m a x = π r γ s {\displaystyle F_{max}=\pi r\gamma _{s}\,\!} , the corresponding flow stress should be Δ τ = F m a x / b L = π r γ s / b L {\displaystyle \Delta \tau =F_{max}/bL=\pi r\gamma _{s}/bL} . When

2100-438: The ϕ c {\displaystyle \phi _{c}} and must be included in the calculation. L’ is also equal to the effective spacing between obstacles L. This leaves an equation for strong obstacles: Considering weak particles, ϕ c {\displaystyle \phi _{c}} should be nearing 180 ∘ {\displaystyle 180^{\circ }} due to

2170-745: 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

Eberhart XFG - Misplaced Pages Continue

2240-463: The IPB leads to an internal stress field that interacts with moving dislocations. There are two deformation paths, one is the coherency hardening , the lattice mismatch is Where G {\displaystyle G} is the shear modulus, ε c o h {\displaystyle \varepsilon _{coh}} is the coherent lattice mismatch, r {\displaystyle r}

2310-681: The RZ-D. Precipitation hardening Precipitation hardening , also called age hardening or particle hardening , is a heat treatment technique used to increase the yield strength of malleable materials, including most structural alloys of aluminium , magnesium , nickel , titanium , and some steels , stainless steels , and duplex stainless steel . In superalloys , it is known to cause yield strength anomaly providing excellent high-temperature strength. Precipitation hardening relies on changes in solid solubility with temperature to produce fine particles of an impurity phase , which impede

2380-464: The analysis of interfacial area can be complicated by dislocation line distortion. Order strengthening occurs when the precipitate is an ordered structure such that bond energy before and after shearing is different. For example, in an ordered cubic crystal with composition AB, the bond energy of A-A and B-B after shearing is higher than that of the A-B bond before. The associated energy increase per unit area

2450-542: The annealing process, with lower initial temperatures resulting in higher strengths. The lower initial temperatures increase the driving force of nucleation. More driving force means more nucleation sites, and more sites means more places for dislocations to be disrupted while the finished part is in use. Many alloy systems allow the ageing temperature to be adjusted. For instance, some aluminium alloys used to make rivets for aircraft construction are kept in dry ice from their initial heat treatment until they are installed in

2520-463: The atmosphere, precipitation in solids can produce many different sizes of particles, which have radically different properties. Unlike ordinary tempering , alloys must be kept at elevated temperature for hours to allow precipitation to take place. This time delay is called "aging". Solution treatment and aging is sometimes abbreviated "STA" in specifications and certificates for metals. Two different heat treatments involving precipitates can alter

2590-632: The bypassing stress for this dislocation should be τ b ′ = G b / ( L − 2 r ′ ) {\displaystyle \tau _{b}'=Gb/(L-2r')} , which is greater than for the first one. However, as the radius of particle increases, L {\displaystyle L} will increase so as to maintain the same volume fraction of precipitates, ( L − 2 r ) {\displaystyle (L-2r)} will increase and τ b {\displaystyle \tau _{b}} will decrease. As

2660-401: The dislocation and the precipitate is Furthermore, a dislocation may cut through a precipitate particle, and introduce more precipitate-matrix interface, which is chemical strengthening . When the dislocation is entering the particle and is within the particle, the upper part of the particle shears b with respect to the lower part accompanies the dislocation entry. A similar process occurs when

2730-575: The dislocation exits the particle. The complete transit is accompanied by creation of matrix-precipitate surface area of approximate magnitude A = 2 π r b {\displaystyle A=2\pi rb\,\!} , where r is the radius of the particle and b is the magnitude of the burgers vector. The resulting increase in surface energy is E = 2 π r b γ s {\displaystyle E=2\pi rb\gamma _{s}\,\!} , where γ s {\displaystyle \gamma _{s}}

2800-402: The dislocation line cuts the precipitate. Also, the dislocation line could bend when entering the precipitate, increasing the affected length of the dislocation line. Again, the strengthening arises in a way similar to that of solid solution strengthening, where there is a mismatch in the lattice that interacts with the dislocations, impeding their motion. Of course, the severity of the interaction

2870-531: The dislocation line staying relatively straight through obstacles. Also , L’ will be: which states the weak particle equation: Now, consider the mechanisms for each regime: Dislocation cutting through particles: For most strengthening at the early stage, it increases with ϵ 3 2 ( f r / b ) 1 2 {\displaystyle \epsilon ^{\tfrac {3}{2}}(fr/b)^{\tfrac {1}{2}}} , where ϵ {\displaystyle \epsilon }

Eberhart XFG - Misplaced Pages Continue

2940-411: The dislocation line tension that they make. The line tension balance equation is: Where ϕ c {\displaystyle \phi _{c}} is the radius of the dislocation at a certain stress. Strong obstacles have small ϕ c {\displaystyle \phi _{c}} due to the bowing of the dislocation. Still, decreasing obstacle strength will increase

3010-412: The dislocation will be attracted to the precipitate. In addition, there is a positive interaction energy between a dislocation and a precipitate that have the same type of stress field. This means that the dislocation will be repulsed by the precipitate. Precipitate particles also serve by locally changing the stiffness of a material. Dislocations are repulsed by regions of higher stiffness. Conversely, if

3080-407: The dislocations cannot shear particles and cannot move past them, then dislocation motion is successfully impeded. The primary species of precipitation strengthening are second phase particles. These particles impede the movement of dislocations throughout the lattice. You can determine whether or not second phase particles will precipitate into solution from the solidus line on the phase diagram for

3150-474: The dislocations, leading to an increase in yield strength, similar to the size effect in solid solution strengthening. What differentiates this mechanism from solid solution strengthening is the fact that the precipitate has a definite size, not an atom, and therefore a stronger interaction with dislocations. Modulus hardening results from the different shear modulus of the precipitate and the matrix, which leads to an energy change of dislocation line tension when

3220-490: 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

3290-906: 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

3360-470: 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 ,

3430-426: The lattice atoms are located closer than their normal conditions while when the atomic volume of the precipitate is larger, there will be compression of the lattice atoms, as they are further apart than their normal position. Regardless of whether the lattice is under compression or tension, the associated stress field interacts with dislocations leading to decreased dislocation motion either by repulsion or attraction of

3500-488: 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

3570-453: The majority of dislocations. Precipitation strengthening is possible if the line of solid solubility slopes strongly toward the center of a phase diagram . While a large volume of precipitate particles is desirable, a small enough amount of the alloying element should be added so that it remains easily soluble at some reasonable annealing temperature. Although large volumes are often wanted, they are wanted in small particle sizes as to avoid

SECTION 50

#1732869283588

3640-545: 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

3710-409: The movement of dislocations , or defects in a crystal 's lattice . Since dislocations are often the dominant carriers of plasticity , this serves to harden the material. The impurities play the same role as the particle substances in particle-reinforced composite materials. Just as the formation of ice in air can produce clouds, snow, or hail, depending upon the thermal history of a given portion of

3780-486: 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

3850-456: The particle is strong enough for the dislocations to bow rather than cut, further increase of the dislocation penetration resistance won't affect strengthening. The main mechanism therefore is Orowan strengthening, where the strong particles do not allow for dislocations to move past. Therefore bowing must occur and in this bowing can cause dislocation loops to build up, which decreases the space available for additional dislocation to bow between. If

3920-488: The particles ( ϕ c = 0 {\displaystyle \phi _{c}=0} ), the stress required to effect the bypassing is inversely proportional to the interparticle spacing ( L − 2 r ) {\displaystyle (L-2r)} , that is, τ b = G b / ( L − 2 r ) {\displaystyle \tau _{b}=Gb/(L-2r)} , where r {\displaystyle r}

3990-415: The particles. Physically, this strengthening effect can be attributed both to size and modulus effects , and to interfacial or surface energy . The presence of second phase particles often causes lattice distortions. These lattice distortions result when the precipitate particles differ in size and crystallographic structure from the host atoms. Smaller precipitate particles in a host lattice leads to

4060-410: The precipitate and that of the matrix are continuous across the interface. Small particles precipitated from supersaturated solid solution usually have coherent interfaces with the matrix. Coherency hardening originates from the atomic volume difference between precipitate and the matrix, which results in a coherency strain. If the atomic volume of the precipitate is smaller, there will be tension because

4130-432: The precipitate causes the material to be locally more compliant, then the dislocation will be attracted to that region. In addition, there are three types of interphase boundaries (IPBs). The first type is a coherent or ordered IPB, the atoms match up one by one along the boundary. Due to the difference in lattice parameters of the two phases, a coherency strain energy is associated with this type of boundary. The second type

4200-415: The precipitate, its energy is U p = G p b 2 / 2 {\displaystyle U_{p}=G_{p}b^{2}/2} , the change in line segment energy is The maximum dislocation length affected is the particle diameter, the line tension change takes place gradually over a distance equal to r {\displaystyle r} . The interaction force between

4270-439: The same volume fraction are present, the level of the τ c {\displaystyle \tau _{c}} curve is increased but that of the τ b {\displaystyle \tau _{b}} one is not. Maximum hardening, greater than that for A particles, is found at r c 2 < r c 1 {\displaystyle r_{c2}<r_{c1}} . Increasing

SECTION 60

#1732869283588

4340-463: The shape of the τ − r {\displaystyle \tau -r} curve. There are two main types of equations to describe the two mechanisms for precipitation hardening based on weak and strong precipitates. Weak precipitates can be sheared by dislocations while strong precipitates cannot, and therefore the dislocation must bow. First, it is important to consider the difference between these two different mechanisms in terms of

4410-428: The strength of a material: solution heat treating and precipitation heat treating. Solid solution strengthening involves formation of a single-phase solid solution via quenching. Precipitation heat treating involves the addition of impurity particles to increase a material's strength. This technique exploits the phenomenon of supersaturation , and involves careful balancing of the driving force for precipitation and

4480-414: The structure. After this type of rivet is deformed into its final shape, ageing occurs at room temperature and increases its strength, locking the structure together. Higher ageing temperatures would risk over-ageing other parts of the structure, and require expensive post-assembly heat treatment because a high ageing temperature promotes the precipitate to grow too readily. There are several ways by which

4550-449: 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

4620-415: The thermal activation energy available for both desirable and undesirable processes. Nucleation occurs at a relatively high temperature (often just below the solubility limit) so that the kinetic barrier of surface energy can be more easily overcome and the maximum number of precipitate particles can form. These particles are then allowed to grow at lower temperature in a process called ageing . This

4690-469: The volume fraction of A raises the level of both τ b {\displaystyle \tau _{b}} and τ c {\displaystyle \tau _{c}} and increases the maximum strength obtained. The latter is found at r c 3 {\displaystyle r_{c3}} , which may be either less than or greater than r c 1 {\displaystyle r_{c1}} depending on

4760-820: 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 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

4830-507: 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,

4900-775: Was returned to Eberhart, where it was reconstructed as the XF2G with the addition of a single float and a new 400  hp (300 kW) Pratt & Whitney R-1340-D engine. The XF2G-1 prototype was sent back to the Navy for testing at Anacostia in January 1928, but in March 1928, the plane crashed during trials and was destroyed. No further production ensued. General characteristics Performance Duralumin Duralumin (also called duraluminum , duraluminium , duralum , dural(l)ium , or dural )

#587412