83-481: The Wright R-3350 Duplex-Cyclone is an American twin-row, supercharged , air-cooled, radial aircraft engine with 18 cylinders displacing nearly 3,350 cubic inches (54.9 L). Power ranged from 2,200 to 3,700 hp (1,640 to 2,760 kW), depending on model. Developed before World War II , the R-3350's design required a long time to mature, and was still experiencing problems with reliability when used to power
166-498: A half-life of 717,000 years. Excessive quantities of stable Mg have been observed in the Ca-Al-rich inclusions of some carbonaceous chondrite meteorites . This anomalous abundance is attributed to the decay of its parent Al in the inclusions, and researchers conclude that such meteorites were formed in the solar nebula before the Al had decayed. These are among
249-493: A magnesium-based engine . Magnesium also reacts exothermically with most acids such as hydrochloric acid (HCl), producing magnesium chloride and hydrogen gas, similar to the HCl reaction with aluminium, zinc, and many other metals. Although it is difficult to ignite in mass or bulk, magnesium metal will ignite. Magnesium may also be used as an igniter for thermite , a mixture of aluminium and iron oxide powder that ignites only at
332-412: A supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement . The current categorization is that a supercharger is a form of forced induction that is mechanically powered (usually by a belt from the engine's crankshaft ), as opposed to a turbocharger , which is powered by the kinetic energy of the exhaust gases. However, up until
415-620: A 3,350 in (54.9 L) displacement were run in May of the same year. Development was slow, due to the complexity, and the R-2600 receiving development priority. The R-3350 did not fly until 1941, after the Douglas XB-19 had been redesigned to use R-3350s instead of Allison V-3420 inlines. Things changed dramatically in 1940 with the introduction of a new contract by the USAAC to develop
498-526: A car’s exhaust note, while a supercharged engine maintains the louder exhaust note of a normally aspirated car. Turbocharged engines are more prone to heat soak of the intake air (since turbocharging can place the hot exhaust components near the intake air system), although this can be overcome through the use of an intercooler . The majority of aircraft engines used during World War II used mechanically driven superchargers because they had some significant manufacturing advantages over turbochargers. However,
581-499: A catastrophic failure. Early R-3350s used carburetors , though the poorly designed elbow entrance to the supercharger led to serious problems with fuel/air mixtures. Near the end of WWII, the system was changed to use gasoline direct injection which improved reliability. After the war the engine was redesigned and became popular for large aircraft, notably the Lockheed Constellation and Douglas DC-7 . Following
664-531: A common reservoir. Magnesium is the eighth-most-abundant element in the Earth's crust by mass and tied in seventh place with iron in molarity . It is found in large deposits of magnesite , dolomite , and other minerals , and in mineral waters, where magnesium ion is soluble. Although magnesium is found in more than 60 minerals , only dolomite , magnesite , brucite , carnallite , talc , and olivine are of commercial importance. The Mg cation
747-523: A dynamic compressor are: Common methods of driving a supercharger include: Fuels with a higher octane rating are better able to resist autoignition and detonation . As a result, the amount of boost supplied by the superchargers could be increased, resulting in an increase in engine output. The development of 100-octane aviation fuel, pioneered in the USA in the 1930s, enabled the use of higher boost pressures to be used on high-performance aviation engines and
830-510: A high purity product is easily achievable. China is almost completely reliant on the silicothermic Pidgeon process . Besides the Pigeon process, the second most used process for magnesium production is electrolysis . This is a two step process. The first step is to prepare feedstock containing magnesium chloride and the second step is to dissociate the compound in electrolytic cells as magnesium metal and chlorine gas . The basic reaction
913-415: A limiting factor in engine performance. Extreme temperatures can cause pre-ignition or knocking , which reduces performance and can cause engine damage. The risk of pre-ignition/knocking increases with higher ambient air temperatures and higher boost levels. Turbocharged engines use energy from the exhaust gas that would normally be wasted, compared with a supercharger which mechanically draws power from
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#1732772608429996-604: A long-range bomber capable of flying from the US to Germany with 20,000 lb (9,100 kg) of bombs. Although smaller than the Bomber D designs that led to the Douglas XB-19, the new designs required just as much power. When four preliminary designs were presented in mid-1940, three of them used the R-3350. Suddenly development was a priority, and serious efforts to get it into production began. In 1942 Chrysler started building
1079-573: A narrow range of load/speed/boost, for which the system must be specifically designed. Positive displacement pumps deliver a nearly fixed volume of air per revolution of the compressor (except for leakage, which typically has a reduced effect at higher engine speeds). The most common type of positive-displacement superchargers is the Roots-type supercharger . Other types include the rotary-screw , sliding vane and scroll-type superchargers. The rating system for positive-displacement superchargers
1162-476: A nominal 150-octane rating. Using such fuels, aero engines like the Rolls-Royce Merlin 66 and Daimler-Benz DB 605 DC produced power outputs of up to 2,000 hp (1,500 kW). One disadvantage of forced induction (i.e. supercharging or turbocharging) is that compressing the intake air increases its temperature. For an internal combustion engine, the temperature of the intake air becomes
1245-545: A similar 1,800 in (30 L) displacement that would easily compete with the single-row Cyclone. In 1935 Wright followed P&W's lead, and developed larger engines based on the Cyclone. The result was two designs, a 14-cylinder short stroke design of nearly 2,600 in (43 L) displacement that would evolve into the Wright R-2600 Twin Cyclone , and a much larger 18-cylinder design that became
1328-429: A solid solution with calcium oxide by calcining the mineral dolomite , which is a solid solution of calcium and magnesium carbonates: Reduction occurs at high temperatures with silicon. A ferrosilicon alloy is used rather than pure silicon as it is more economical. The iron component has no bearing on the reaction, having the simplified equation: The calcium oxide combines with silicon as the oxygen scavenger, yielding
1411-505: A total displacement of 426 cu in (7.0 L)). However, because 6–71 is the engine's designation rather than that of the blower, the actual displacement of the blower is less; for example, a 6–71 blower pumps 339 cu in (5.6 L) per revolution. Other supercharger manufacturers have produced blowers rated up to 16–71. Dynamic compressors rely on accelerating the air to high speed and then exchanging that velocity for pressure by diffusing or slowing it down. Major types of
1494-476: A two-stage inter-cooled supercharger with a more compact layout. Nonetheless, turbochargers were useful in high-altitude bombers and some fighter aircraft due to the increased high altitude performance and range. Turbocharged piston engines are also subject to many of the same operating restrictions as those of gas turbine engines. Turbocharged engines also require frequent inspections of their turbochargers and exhaust systems to search for possible damage caused by
1577-545: A variety of compounds important to industry and biology, including magnesium carbonate , magnesium chloride , magnesium citrate , magnesium hydroxide (milk of magnesia), magnesium oxide , magnesium sulfate , and magnesium sulfate heptahydrate ( Epsom salts ). As recently as 2020, magnesium hydride was under investigation as a way to store hydrogen. Magnesium has three stable isotopes : Mg , Mg and Mg . All are present in significant amounts in nature (see table of isotopes above). About 79% of Mg
1660-408: A very high temperature. Organomagnesium compounds are widespread in organic chemistry . They are commonly found as Grignard reagents , formed by reaction of magnesium with haloalkanes . Examples of Grignard reagents are phenylmagnesium bromide and ethylmagnesium bromide . The Grignard reagents function as a common nucleophile , attacking the electrophilic group such as the carbon atom that
1743-438: Is Mg . The isotope Mg is radioactive and in the 1950s to 1970s was produced by several nuclear power plants for use in scientific experiments. This isotope has a relatively short half-life (21 hours) and its use was limited by shipping times. The nuclide Mg has found application in isotopic geology , similar to that of aluminium. Mg is a radiogenic daughter product of Al , which has
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#17327726084291826-658: Is a gray-white lightweight metal, two-thirds the density of aluminium. Magnesium has the lowest melting (923 K (650 °C)) and the lowest boiling point (1,363 K (1,090 °C)) of all the alkaline earth metals. Pure polycrystalline magnesium is brittle and easily fractures along shear bands . It becomes much more malleable when alloyed with small amounts of other metals, such as 1% aluminium. The malleability of polycrystalline magnesium can also be significantly improved by reducing its grain size to about 1 μm or less. When finely powdered, magnesium reacts with water to produce hydrogen gas: However, this reaction
1909-486: Is a liquid metal. At the YSZ/liquid metal anode O is oxidized. A layer of graphite borders the liquid metal anode, and at this interface carbon and oxygen react to form carbon monoxide. When silver is used as the liquid metal anode, there is no reductant carbon or hydrogen needed, and only oxygen gas is evolved at the anode. It was reported in 2011 that this method provides a 40% reduction in cost per pound over
1992-585: Is as follows: The temperatures at which this reaction is operated is between 680 and 750 °C. The magnesium chloride can be obtained using the Dow process , a process that mixes sea water and dolomite in a flocculator or by dehydration of magnesium chloride brines. The electrolytic cells are partially submerged in a molten salt electrolyte to which the produced magnesium chloride is added in concentrations between 6-18%. This process does have its share of disadvantages including production of harmful chlorine gas and
2075-425: Is essential to all cells and some 300 enzymes . Magnesium ions interact with polyphosphate compounds such as ATP , DNA , and RNA . Hundreds of enzymes require magnesium ions to function. Magnesium compounds are used medicinally as common laxatives and antacids (such as milk of magnesia ), and to stabilize abnormal nerve excitation or blood vessel spasm in such conditions as eclampsia . Elemental magnesium
2158-482: Is first treated with lime (calcium oxide) and the precipitated magnesium hydroxide is collected: The hydroxide is then converted to magnesium chloride by treatment with hydrochloric acid and heating of the product to eliminate water: The salt is then electrolyzed in the molten state. At the cathode , the Mg ion is reduced by two electrons to magnesium metal: At the anode , each pair of Cl ions
2241-445: Is less commonly used in the 21st century, as manufacturers have shifted to turbochargers to reduce fuel consumption and increase power outputs. There are two main families of superchargers defined according to the method of gas transfer: positive displacement and dynamic superchargers. Positive displacement superchargers deliver an almost constant level of boost pressure increase at all engine speeds, while dynamic superchargers cause
2324-426: Is less dense than aluminium and is used primarily as a component in strong and lightweight alloys that contain aluminium. In the cosmos , magnesium is produced in large, aging stars by the sequential addition of three helium nuclei to a carbon nucleus. When such stars explode as supernovas , much of the magnesium is expelled into the interstellar medium where it may recycle into new star systems. Magnesium
2407-441: Is much less dramatic than the reactions of the alkali metals with water, because the magnesium hydroxide builds up on the surface of the magnesium metal and inhibits further reaction. The principal property of magnesium metal is its reducing power. One hint is that it tarnishes slightly when exposed to air, although, unlike the heavier alkaline earth metals , an oxygen-free environment is unnecessary for storage because magnesium
2490-401: Is oxidized to chlorine gas, releasing two electrons to complete the circuit: The carbothermic route to magnesium has been recognized as a low energy, yet high productivity path to magnesium extraction. The chemistry is as follows: C + MgO → CO + Mg A disadvantage of this method is that slow cooling the vapour can cause the reaction to quickly revert. To prevent this from happening,
2573-514: Is present within the polar bond of a carbonyl group. A prominent organomagnesium reagent beyond Grignard reagents is magnesium anthracene , which is used as a source of highly active magnesium. The related butadiene -magnesium adduct serves as a source for the butadiene dianion. Complexes of dimagnesium(I) have been observed. The presence of magnesium ions can be detected by the addition of ammonium chloride , ammonium hydroxide and monosodium phosphate to an aqueous or dilute HCl solution of
Wright R-3350 Duplex-Cyclone - Misplaced Pages Continue
2656-447: Is protected by a thin layer of oxide that is fairly impermeable and difficult to remove. Direct reaction of magnesium with air or oxygen at ambient pressure forms only the "normal" oxide MgO. However, this oxide may be combined with hydrogen peroxide to form magnesium peroxide , MgO 2 , and at low temperature the peroxide may be further reacted with ozone to form magnesium superoxide Mg(O 2 ) 2 . Magnesium reacts with nitrogen in
2739-430: Is that the intake air is warmer than at high altitude. Warmer air reduces the threshold at which engine knocking can occur, especially in supercharged or turbocharged engines. Methods to cool the intake air at ground level include intercoolers/aftercoolers , anti-detonant injection , two-speed superchargers and two-stage superchargers. In supercharged engines which use a carburetor , a partially-open throttle reduces
2822-458: Is the eighth most abundant element in the Earth's crust and the fourth most common element in the Earth (after iron , oxygen and silicon ), making up 13% of the planet's mass and a large fraction of the planet's mantle . It is the third most abundant element dissolved in seawater, after sodium and chlorine . This element is the eleventh most abundant element by mass in the human body and
2905-541: Is the second-most-abundant cation in seawater (about 1 ⁄ 8 the mass of sodium ions in a given sample), which makes seawater and sea salt attractive commercial sources for Mg. To extract the magnesium, calcium hydroxide is added to the seawater to precipitate magnesium hydroxide . Magnesium hydroxide ( brucite ) is poorly soluble in water and can be collected by filtration. It reacts with hydrochloric acid to magnesium chloride . From magnesium chloride, electrolysis produces magnesium. World production
2988-417: Is too large for the engine displacement. For this reason, supercharged engines are common in applications where throttle response is a key concern, such as drag racing and tractor pulling competitions. A disadvantage of supercharging is that the engine must withstand the net power output of the engine plus the power to drive the supercharger. Additionally, turbochargers provide sound-dampening properties to
3071-557: Is usually based on their capacity per revolution . In the case of the Roots blower, the GMC rating pattern is typical. The GMC rating is based on how many two-stroke cylinders - and the size of those cylinders - that it is designed to scavenge , with GMC's model range including 2–71, 3–71, 4–71 and 6–71 blowers. The 6–71 blower, for example, is designed to scavenge six cylinders of 71 cu in (1.2 L) each, resulting in an engine with
3154-663: The 1925 Delage , and the 1926 Bugatti Type 35C . Amongst the most famous supercharged cars is the Bentley 4½ Litre ("Blower Bentley"), which was introduced in 1929. In 1935, the development of screw-type superchargers reached a milestone when Swedish engineer Alf Lysholm patented a design for a rotary-screw compressor with five female and four male rotors. In the 21st century, supercharged production car engines have become less common, as manufacturers have shifted to turbocharging to achieve higher fuel economy and power outputs. For example, Mercedes-Benz's Kompressor engines of
3237-579: The Boeing B-29 Superfortress . After the war, the engine had matured sufficiently to be used in many civilian airliners, notably in its turbo-compound forms, and was used in the Lockheed L-1049 Super Constellation airliners into the 1950s. Its main rival was the 4,360 in (71.4 L), 4,300 hp (3,200 kW) Pratt & Whitney R-4360 Wasp Major , which first ran some seven years after
3320-557: The Dodge Chicago Plant , which was ready by early 1944. By 1943 the new Boeing B-29 Superfortress was flying with R-3350s. The engines remained temperamental, and the rear cylinders tended to overheat, partially due to inadequate clearance between the cylinder baffles and the cowl. A number of changes were introduced to improve cooling, and the aircraft was rushed into service in the Pacific in 1944. This proved unwise, as
3403-528: The Lockheed Constellation , and the C-124 Globemaster II . In the 1985 and 1986 World Rally Championships, Lancia ran the Delta S4 , which incorporated both a belt-driven supercharger and exhaust-driven turbocharger. The design used a complex series of bypass valves in the induction and exhaust systems as well as an electromagnetic clutch so that, at low engine speeds, a boost was derived from
Wright R-3350 Duplex-Cyclone - Misplaced Pages Continue
3486-719: The Reno Air Races use R-3350s. Modifications on one, Rare Bear , include a nose case designed for a slow-turning prop, taken from an R-3350 used on the Lockheed L-1649 Starliner , mated to the power section (crankcase, crank, pistons, and cylinders) taken from an R-3350 used on the Douglas DC-7. The supercharger is taken from an R-3350 used on the Lockheed EC-121 and the engine is fitted with nitrous oxide injection. Normal rated power of
3569-528: The gas turbine and a pre-turbine section of the exhaust system. The size of the ducting alone was a serious design consideration. For example, both the F4U Corsair and the P-47 Thunderbolt used the same radial engine , but the large barrel-shaped fuselage of the turbocharged P-47 was needed because of the amount of ducting to and from the turbocharger in the rear of the aircraft. The F4U used
3652-398: The 1.6 litre Mercedes 6/25 hp and 2.6 litre Mercedes 10/40 hp , both of which began production in 1923. They were marketed as Kompressor models, a term which was used for various models until 2012. Supercharged racing cars from around this time included the 1923 Fiat 805-405 , the 1923 Miller 122 the 1924 Alfa Romeo P2 , the 1924 Grand Prix season car from Sunbeam,
3735-538: The Duplex-Cyclone. The engine is commonly used on Hawker Sea Fury and Grumman F8F Bearcat Unlimited Class Racers at the Reno Air Races . In 1927, Wright Aeronautical introduced its "Cyclone" engine, which powered a number of designs in the 1930s. After merging with Curtiss to become Curtiss-Wright in 1929, an effort was started to design an engine in the 1,000 hp (750 kW) class. The new Wright R-1820 Cyclone 9 first ran in 1935, and became one of
3818-471: The German engines being significantly larger in displacement. Two-stage superchargers were also always two-speed. After the air was compressed in the low-pressure stage , the air flowed through a heat exchanger (" intercooler ") where it was cooled before being compressed again by the high-pressure stage and then possibly also aftercooled in another heat exchanger. While superchargers were highly used in
3901-604: The R-3350. A larger twin-row 22-cylinder version, the Wright R-4090 Cyclone 22 , was experimented with as a competitor to the 4,360 in (71.4 L) displacement four-row, 28-cylinder Pratt & Whitney R-4360 Wasp Major , but was not produced. With Pratt & Whitney starting development of their own 2,800 in (46 L) displacement 18-cylinder, twin-row radial as the R-2800 Double Wasp in 1937, Wright's first R-3350 prototype engines with
3984-623: The Spitfire and Hurricane planes powered by the Rolls-Royce Merlin engine were equipped largely with single-stage and single-speed superchargers. In 1942, two-speed two-stage supercharging with aftercooling was applied to the Rolls Royce Merlin 61 aero engine. The improved performance allowed the aircraft they powered to maintain a crucial advantage over the German aircraft they opposed throughout World War II, despite
4067-499: The United States patented the design for an air mover for use in blast furnaces and other industrial applications. This air mover and Birmingham's ventilation compressor both used designs similar to that of the later Roots-type superchargers . In March of 1878, German engineer Heinrich Krigar obtained the first patent for a screw-type compressor. The design was a two-lobe rotor assembly with identically-shaped rotors, however
4150-403: The air density at 30,000 ft (9,100 m) is 1 ⁄ 3 of that at sea level, resulting in 1 ⁄ 3 as much fuel being able to be burnt in a naturally aspirated engine, therefore the power output would be greatly reduced. A supercharger/turbocharger can be thought of either as artificially increasing the density of the air by compressing it or as forcing more air than normal into
4233-455: The air pressure within the carburetor. In cold conditions, this low pressure air can cause ice to form at the throttle plate. Significant quantities of ice can cause engine failure, even with the engine operating at full rated power. Magnesium Magnesium is a chemical element ; it has symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like
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#17327726084294316-649: The benefit to the operational range was given a much higher priority to American aircraft because of a less predictable requirement on the operational range and having to travel far from their home bases. Consequently, turbochargers were mainly employed in American aircraft engines such as the Allison V-1710 and the Pratt & Whitney R-2800 , which were comparably heavier when turbocharged, and required additional ducting of expensive high-temperature metal alloys in
4399-433: The boost pressure to rise exponentially with engine speed (above a certain threshold). Another family of supercharger, albeit rarely used, is the pressure wave supercharger . Roots blowers (a positive displacement design) tend to be only 40–50% efficient at high boost levels, compared with 70-85% for dynamic superchargers. Lysholm-style blowers (a rotary-screw design) can be nearly as efficient as dynamic superchargers over
4482-573: The corrosion rate of magnesium in a salt solution by a factor of nearly ten. Magnesium's tendency to creep (gradually deform) at high temperatures is greatly reduced by alloying with zinc and rare-earth elements . Flammability is significantly reduced by a small amount of calcium in the alloy. By using rare-earth elements, it may be possible to manufacture magnesium alloys that are able to not catch fire at higher temperatures compared to magnesium's liquidus and in some cases potentially pushing it close to magnesium's boiling point. Magnesium forms
4565-410: The cylinder every time the piston moves down on the intake stroke. Since a supercharger is usually designed to produce a given amount of boost at high altitudes (where the air density is lower), the supercharger is often oversized for low altitude. To prevent excessive boost levels, it is important to monitor the intake manifold pressure at low altitude. As the aircraft climbs and the air density drops,
4648-503: The design did not reach production. Also in 1878, Scottish engineer Dugald Clerk designed the first supercharger which was used with an engine. This supercharger was used with a two-stroke gas engine. Gottlieb Daimler received a German patent for supercharging an internal combustion engine in 1885. Louis Renault patented a centrifugal supercharger in France in 1902. The world's first series-produced cars with superchargers were
4731-780: The early 2000s (such as the C 230 Kompressor straight-four, C 32 AMG V6, and CL 55 AMG V8 engines) were replaced around 2010 by turbocharged engines in models such as the C 250 and CL 65 AMG models. However, there are exceptions, such as the Audi 3.0 TFSI supercharged V6 (introduced in 2009) and the Jaguar AJ-V8 supercharged V8 (upgraded to the Gen III version in 2009). In the 1930s, two-speed drives were developed for superchargers for aero engines providing more flexible aircraft operation. The arrangement also entailed more complexity of manufacturing and maintenance. The gears connected
4814-479: The early B-29s taking off at maximum weights, in the high temperature conditions of the B-29s tropical airfields, caused overheating that was not completely solved, and the engines also had a tendency to swallow valves. Because of a high magnesium content in the crankcase, engine fires could burn with a core temperature approaching 5,600 °F (3,090 °C) which could burn through the main spar in seconds, causing
4897-412: The engine. Therefore turbocharged engines usually produce more power and better fuel economy than supercharged engines. However, turbochargers can suffer from turbo lag (especially at lower RPM), where the exhaust gas flow is initially insufficient to spin the turbocharger and achieve the desired boost level, thus leading to a delay in the throttle response . This is often a result of a turbo charge which
4980-768: The extreme heat and pressure of the turbochargers. Such damage was a prominent problem in the early models of the American Boeing B-29 Superfortress high-altitude bombers used in the Pacific Theater of Operations during 1944–45. Turbocharged piston engines continued to be used in a large number of postwar airplanes, such as the B-50 Superfortress , the KC-97 Stratofreighter , the Boeing 377 Stratocruiser ,
5063-470: The increased exhaust heat meant a return to the engine destroying exhaust valves. The fuel burn for the PRT-equipped aircraft was nearly the same as the older Pratt and Whitney R-2800, while producing more useful power. Effective 15 October 1957 a DA-3/DA-4 engine cost $ 88,200. By this point reliability had improved with the mean time between overhauls at 3,500 hours and specific fuel consumption in
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#17327726084295146-424: The magnesium can be dissolved directly in a suitable metal solvent before reversion starts happening. Rapid quenching of the vapour can also be performed to prevent reversion. A newer process, solid oxide membrane technology, involves the electrolytic reduction of MgO. At the cathode, Mg ion is reduced by two electrons to magnesium metal. The electrolyte is yttria-stabilized zirconia (YSZ). The anode
5229-444: The mid-1900s and during WWII , they have largely fallen out of use in modern piston-driven aircraft . This can largely be attributed to the higher temperature and lighter alloys that make turbochargers more efficient than superchargers, as well as the lower maintenance due to less moving parts. Due to the reduced air density at higher altitudes, supercharging and turbocharging have often been used in aircraft engines. For example,
5312-406: The mid-20th century, a turbocharger was called a "turbosupercharger" and was considered a type of supercharger. The first supercharged engine was built in 1878, with usage in aircraft engines beginning in the 1910s and usage in car engines beginning in the 1920s. In piston engines used by aircraft, supercharging was often used to compensate for the lower air density at high altitudes. Supercharging
5395-549: The most used aircraft engines in the late 1930s and early 1940's, powering the Boeing B-17 Flying Fortress heavy bomber, General Motors FM-2 Wildcat fighter and Douglas SBD Dauntless dive bomber, among many others. By 1931 Pratt & Whitney had started a development of their single-row Wasp nine-cylinder engine into the larger and much more powerful fourteen-cylinder, twin-row R-1830 Twin Wasp with
5478-540: The oldest objects in the Solar System and contain preserved information about its early history. It is conventional to plot Mg / Mg against an Al/Mg ratio. In an isochron dating plot, the Al/Mg ratio plotted is Al / Mg . The slope of the isochron has no age significance, but indicates the initial Al / Al ratio in the sample at the time when the systems were separated from
5561-417: The order of 0.4 lb/hp/hour (243 g/kWh, giving a 34% fuel efficiency). Engines in use as of the 2020s are limited to 52 inHg (180 kPa) manifold pressure , giving 2,880 hp (2,150 kW) with 100/130 octane fuel (or 100LL) instead of the 59.5 inHg (201 kPa) and 3,400 hp (2,500 kW) possible with 115/145, a higher octane fuel, which is no longer available. Several racers at
5644-501: The original stock R-3350 was 2,800 hp (2,100 kW) at 2,600 rpm and 45 inHg (150 kPa) of manifold pressure. With these modifications, Rare Bear ' s engine produces 4,000 hp (3,000 kW) at 3,200 rpm and 80 inHg (270 kPa) of manifold pressure, and 4,500 hp (3,400 kW) with nitrous oxide injection. Data from Jane's . Related development Comparable engines Related lists Supercharger In an internal combustion engine ,
5727-453: The other alkaline earth metals (group 2 of the periodic table ) it occurs naturally only in combination with other elements and almost always has an oxidation state of +2. It reacts readily with air to form a thin passivation coating of magnesium oxide that inhibits further corrosion of the metal. The free metal burns with a brilliant-white light. The metal is obtained mainly by electrolysis of magnesium salts obtained from brine . It
5810-619: The overall reaction being very energy intensive, creating environmental risks. The Pidgeon process is more advantageous regarding its simplicity, shorter construction period, low power consumption and overall good magnesium quality compared to the electrolysis method. In the United States, magnesium was once obtained principally with the Dow process in Corpus Christi TX , by electrolysis of fused magnesium chloride from brine and sea water . A saline solution containing Mg ions
5893-443: The quantity of these metals improves corrosion resistance. Sufficient manganese overcomes the corrosive effects of iron. This requires precise control over composition, increasing costs. Adding a cathodic poison captures atomic hydrogen within the structure of a metal. This prevents the formation of free hydrogen gas, an essential factor of corrosive chemical processes. The addition of about one in three hundred parts arsenic reduces
5976-455: The salt. The formation of a white precipitate indicates the presence of magnesium ions. Azo violet dye can also be used, turning deep blue in the presence of an alkaline solution of magnesium salt. The color is due to the adsorption of azo violet by Mg(OH) 2 . As of 2013, magnesium alloys consumption was less than one million tonnes per year, compared with 50 million tonnes of aluminium alloys . Their use has been historically limited by
6059-530: The shores of the Great Salt Lake . In September 2021, China took steps to reduce production of magnesium as a result of a government initiative to reduce energy availability for manufacturing industries, leading to a significant price increase. The Pidgeon process and the Bolzano process are similar. In both, magnesium oxide is the precursor to magnesium metal. The magnesium oxide is produced as
6142-573: The solid state if it is powdered and heated to just below the melting point, forming Magnesium nitride Mg 3 N 2 . Magnesium reacts with water at room temperature, though it reacts much more slowly than calcium, a similar group 2 metal. When submerged in water, hydrogen bubbles form slowly on the surface of the metal; this reaction happens much more rapidly with powdered magnesium. The reaction also occurs faster with higher temperatures (see § Safety precautions ). Magnesium's reversible reaction with water can be harnessed to store energy and run
6225-452: The supercharger to the engine using a system of hydraulic clutches, which were initially manually engaged or disengaged by the pilot with a control in the cockpit. At low altitudes, the low-speed gear would be used, to prevent excessive boost levels. At higher altitudes, the supercharger could be switched to a higher gear to compensate for the reduced intake air density. In the Battle of Britain
6308-500: The supercharger. In the middle of the rev range, a boost was derived from both systems, while at the highest revs the system disconnected the drive from the supercharger and isolated the associated ducting. This was done in an attempt to exploit the advantages of each of the charging systems while removing the disadvantages. In turn, this approach brought greater complexity and affected the car's reliability in WRC events, as well as increasing
6391-403: The tendency of Mg alloys to corrode, creep at high temperatures, and combust. In magnesium alloys, the presence of iron , nickel , copper , or cobalt strongly activates corrosion . In more than trace amounts, these metals precipitate as intermetallic compounds , and the precipitate locales function as active cathodic sites that reduce water, causing the loss of magnesium. Controlling
6474-457: The throttle can be progressively opened to obtain the maximum safe power level for a given altitude. The altitude at which the throttle reaches full open and the engine is still producing full rated power is known as the critical altitude . Above the critical altitude, engine power output will reduce as the supercharger can no longer fully compensate for the decreasing air density. Another issue encountered at low altitudes (such as at ground level)
6557-510: The very stable calcium silicate. The Mg/Ca ratio of the precursors can be adjusted by the addition of MgO or CaO. The Pidgeon and the Bolzano process differ in the details of the heating and the configuration of the reactor. Both generate gaseous Mg that is condensed and collected. The Pidgeon process dominates the worldwide production. The Pidgeon method is less technologically complex and because of distillation/vapour deposition conditions,
6640-554: The war, the Turbo-Compound system was developed to deliver better fuel efficiency . In these versions, three power-recovery turbines (PRT) were inserted into the exhaust of each group of six cylinders, and geared to the crankshaft by fluid couplings to deliver more power. The PRTs recovered about 20% of the exhaust energy (around 450 hp (340 kW)) that would have otherwise been lost, but reduced engine reliability. Mechanics nicknamed them Parts Recovery Turbines, since
6723-546: The weight of engine ancillaries in the finished design. Twincharged engines have occasionally been used in production cars, such as the 2005-2013 Volkswagen 1.4 litre and the 2017-present Volvo B4204T43/B4204T48 2.0 litre four-cylinder engines. In 1849, G. Jones of Birmingham, England began manufacturing a lobe pump compressor to provide ventilation for coal mines. In 1860, the Roots Blower Company (founded by brothers Philander and Francis Marion Roots) in
6806-578: Was approximately 1,100 kt in 2017, with the bulk being produced in China (930 kt) and Russia (60 kt). The United States was in the 20th century the major world supplier of this metal, supplying 45% of world production even as recently as 1995. Since the Chinese mastery of the Pidgeon process the US market share is at 7%, with a single US producer left as of 2013: US Magnesium, a Renco Group company located on
6889-567: Was used to vastly increase the power output for several speed record airplanes. Military use of high-octane fuels began in early 1940 when 100-octane fuel was delivered to the British Royal Air Force fighting in World War II. The German Luftwaffe also had supplies of a similar fuel. Increasing the octane rating became a major focus of aero engine development for the remainder of the war, with later fuels having up to
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