The Boeing B-29 Superfortress is a United States Army Air Forces long range, strategic heavy bomber that was produced in many experimental and production models from 1943 to 1946.
61-593: The XB-29 , Boeing Model 345, was the first accepted prototype or experimental model delivered to the Army Air Corps , incorporating a number of improvements on the design originally submitted, including more and larger guns and self-sealing fuel tanks . Two aircraft were ordered in August 1940, and a third was ordered in December. A mockup was completed in the spring of 1941, and it first flew on September 21, 1942. Testing
122-633: A mockup , which is an inert representation of a machine's appearance, often made of some non-durable substance. An electronics designer often builds the first prototype from breadboard or stripboard or perfboard , typically using "DIP" packages. However, more and more often the first functional prototype is built on a "prototype PCB " almost identical to the production PCB, as PCB manufacturing prices fall and as many components are not available in DIP packages, but only available in SMT packages optimized for placing on
183-538: A second (thus defining the speed of light to be 299,792,458 meters per second). In many sciences, from pathology to taxonomy, prototype refers to a disease, species, etc. which sets a good example for the whole category. In biology, prototype is the ancestral or primitive form of a species or other group; an archetype. For example, the Senegal bichir is regarded as the prototypes of its genus, Polypterus . Flak Too Many Requests If you report this error to
244-425: A PCB. Builders of military machines and aviation prefer the terms "experimental" and "service test". In electronics , prototyping means building an actual circuit to a theoretical design to verify that it works, and to provide a physical platform for debugging it if it does not. The prototype is often constructed using techniques such as wire wrapping or using a breadboard , stripboard or perfboard , with
305-526: A favorite among US Military modelers), railroad equipment, motor trucks, motorcycles, and space-ships (real-world such as Apollo/Saturn Vs, or the ISS). As of 2014, basic rapid prototype machines (such as 3D printers ) cost about $ 2,000, but larger and more precise machines can cost as much as $ 500,000. In architecture , prototyping refers to either architectural model making (as form of scale modelling ) or as part of aesthetic or material experimentation , such as
366-586: A modified aircraft to show that it could still be used if the R-3350 development was not successful. Since the R-3350 did not have significant enough problems to prevent its use, no XB-39s were ordered. In 1945, three B-29s were forced to land in Soviet territory after a bombing raid on Japan because of lack of fuel. Since the Soviet Union was not at war with Japan at the time, the aircraft and crew were interned. Eventually,
427-422: A real, working system rather than a theoretical one. Physical prototyping has a long history, and paper prototyping and virtual prototyping now extensively complement it. In some design workflow models, creating a prototype (a process sometimes called materialization ) is the step between the formalization and the evaluation of an idea. A prototype can also mean a typical example of something such as in
488-499: A time to the initial prototype. In many programming languages , a function prototype is the declaration of a subroutine or function (and should not be confused with software prototyping). This term is rather C / C++ -specific; other terms for this notion are signature , type and interface . In prototype-based programming (a form of object-oriented programming ), new objects are produced by cloning existing objects, which are called prototypes. The term may also refer to
549-468: A way that the Planck constant h is prescribed a value of exactly 6.626 070 15 × 10 joule-second (J⋅s) Until 1960, the meter was defined by a platinum-iridium prototype bar with two marks on it (that were, by definition, spaced apart by one meter), the international prototype of the metre , and in 1983 the meter was redefined to be the distance in free space covered by light in 1/299,792,458 of
610-518: Is a form of functional or working prototype. The justification for its creation is usually a data migration , data integration or application implementation project and the raw materials used as input are an instance of all the relevant data which exists at the start of the project. The objectives of data prototyping are to produce: To achieve this, a data architect uses a graphical interface to interactively develop and execute transformation and cleansing rules using raw data. The resultant data
671-513: Is becoming practical to eliminate the creation of a physical prototype (except possibly at greatly reduced scales for promotional purposes), instead modeling all aspects of the final product as a computer model . An example of such a development can be seen in Boeing 787 Dreamliner , in which the first full sized physical realization is made on the series production line. Computer modeling is now being extensively used in automotive design, both for form (in
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#1732859075067732-414: Is then evaluated and the rules refined. Beyond the obvious visual checking of the data on-screen by the data architect, the usual evaluation and validation approaches are to use Data profiling software and then to insert the resultant data into a test version of the target application and trial its use. When developing software or digital tools that humans interact with, a prototype is an artifact that
793-490: Is used as the standard of measurement of some physical quantity to base all measurement of that physical quantity against. Sometimes this standard object is called an artifact . In the International System of Units ( SI ), there remains no prototype standard since May 20, 2019 . Before that date, the last prototype used was the international prototype of the kilogram , a solid platinum-iridium cylinder kept at
854-409: Is used to ask and answer a design question. Prototypes provide the means for examining design problems and evaluating solutions. HCI practitioners can employ several different types of prototypes: In the field of scale modeling (which includes model railroading , vehicle modeling, airplane modeling , military modeling, etc.), a prototype is the real-world basis or source for a scale model—such as
915-516: The B-50 , which served throughout the 1950s in the U.S. bomber fleet. A number of B-29s were converted to serve as test beds for new systems. These all received variant designation, even though many existed only as a single converted aircraft. The XB-29E for fire-control systems (one converted) was a model B-29-45-BW. The B-29F for cold-weather operation in Alaska were six converted B-29-BWs. The B-29
976-574: The Bureau International des Poids et Mesures (International Bureau of Weights and Measures) in Sèvres France (a suburb of Paris ) that by definition was the mass of exactly one kilogram . Copies of this prototype are fashioned and issued to many nations to represent the national standard of the kilogram and are periodically compared to the Paris prototype. Now the kilogram is redefined in such
1037-635: The F-13/FB-29 s were redesignated RB-29 and RB-29A . Six B-29A/F-13As were modified with the Wright R-3350-CA-2 fuel injected engines and designated at YB-29J s. These were then converted to RB-29J s. In January 1949, RB-29s were assigned to the 91st Strategic Reconnaissance Wing and moved to Yokota AB , Japan in December 1950; to provide support to the Korean War and attached to the 15th Air Force , Far East Air Force . The SB-29 'Super Dumbo'
1098-515: The Forty Wall House open source material prototyping centre in Australia. Architects prototype to test ideas structurally, aesthetically and technically. Whether the prototype works or not is not the primary focus: architectural prototyping is the revelatory process through which the architect gains insight. In the science and practice of metrology , a prototype is a human-made object that
1159-524: The Prototype Javascript Framework . Additionally, the term may refer to the prototype design pattern. Continuous learning approaches within organizations or businesses may also use the concept of business or process prototypes through software models. The concept of prototypicality is used to describe how much a website deviates from the expected norm, and leads to a lowering of user preference for that site's design. A data prototype
1220-512: The UK over the Atlantic. They were also used to fly into the eye of a hurricane or typhoon to gather information. Following nuclear weapons tests, some WB-29s used air sampling scoops to test radiation levels. On 3 September 1949, a WB-29 returning from Yokota AB , Japan, to Eielson AFB , Alaska, recovered radioactive debris in air sampling scoops from the cloud generated by the first atomic bomb test by
1281-623: The XXI Bomber Command — felt that a (lighter) faster bomber would better evade Japanese flak . In the B-29B, as with the atomic raid-dedicated Silverplate versions earlier, all defensive armament was removed except for that in the tail turret. Initially the armament was two .50 in AN/M2 machine guns and one 20 mm M2 cannon which was soon changed to three .50 in AN/M2s. The weight saved by removing
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#17328590750671342-421: The styling and aerodynamics of the vehicle) and in function—especially for improving vehicle crashworthiness and in weight reduction to improve mileage. The most common use of the word prototype is a functional, although experimental, version of a non-military machine (e.g., automobiles, domestic appliances, consumer electronics) whose designers would like to have built by mass production means, as opposed to
1403-819: The B-29 crew members were returned, but the aircraft remained in Russian hands. Seeking a modern long-range bomber, Joseph Stalin ordered the Tupolev OKB to reverse-engineer the Superfortress. The resulting aircraft first flew on May 19, 1947, and immediately began series production, totalling 847 Tu-4s. Although largely identical in appearance to American B-29s, the Tu-4 ( NATO reporting name : "Bull") had Soviet-designed defensive guns and had been re-engineered to suit production using material of metric thicknesses, resulting in an aircraft that
1464-593: The B-29 program, issuing a scathing report, prompting the Army Air Forces to take control of the program. The YB-29 was an improved XB-29 and 14 were built for service testing. Testing began in the summer of 1943, and dozens of modifications were made to the planes. The engines were upgraded from Wright R-3350 -13s to R-3350-21s. Where the XB-29 had three-bladed props, the YB-29 had four-bladed propellers. Various alternatives to
1525-587: The B-29, the Tu-4 , was used as the platform for a Chinese experimental airborne early warning aircraft, the KJ-1 AEWC , in the 1970s. A study for the conversion of B-29s to long-range cruise missiles was conducted by the Air Materiel Command between 1946 and 1950; given the designation MX-767, it was given the codename Project Banshee. Flight tests were conducted, however no full conversions were carried out before
1586-580: The Soviet Union on 29 August. In 1951, three B-29s were modified for use in the Airborne Early Warning program . The upper section of the forward fuselage was extensively modified to house an AN/APS-20 C search radar, and the interior was modified to house radar and Electronic Counter Measures (ECM) equipment. This development led to production radar picket aircraft, including the EC-121 Warning Star . (×3, converted) A Soviet-built copy of
1647-502: The Tu-4 airframe in the KJ-1 AWACS aircraft. Prototype A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics , design , electronics , and software programming . A prototype is generally used to evaluate a new design to enhance precision by system analysts and users. Prototyping serves to provide specifications for
1708-658: The aircraft, unable to climb, crashed into the Frye meat-packing plant. The crash demolished the majority of the packing plant and killed all eleven XB-29 crew, 22 employees at the plant, and one fireman. Many leading Boeing personnel involved in the design perished in the accident; the pilot, Allen, was chief of the Research Division. After the crash, the United States Army Air Forces and a congressional committee headed by then- Senator Harry S. Truman investigated
1769-407: The cycle returns to customer evaluation. The cycle starts by listening to the user, followed by building or revising a mock-up, and letting the user test the mock-up , then back. There is now a new generation of tools called Application Simulation Software which help quickly simulate application before their development. Extreme programming uses iterative design to gradually add one feature at
1830-506: The designation included B-29s modified solely for that purpose. Their most important role was serving as radar targets in the 1950s when the United States Air Force was developing intercept tactics for its fighters. The WB-29 s were production aircraft modified to perform weather monitoring missions. An observation position was fitted above the central fuselage section. They conducted standard data-gathering flights, including from
1891-568: The disassembled aircraft, awaiting future restoration to flyable status. BuNo 84030 and 84031 were later modified into anti-submarine patrol bombers and redesignated P2B-2S. The XB-39 Superfortress was a single YB-29 modified to use water-cooled Allison V-3420 -17 Vee type engines. Since the Army Air Force was concerned that problems might develop with their first choice of engine, the Wright R-3350 , they contracted General Motors to test
Boeing B-29 Superfortress variants - Misplaced Pages Continue
1952-620: The early 1960s, being replaced by more modern aircraft such as the Tupolev Tu-95 . Although the Tu-4 had never delivered any explosive payload with offensive intent, it influenced Soviet aircraft technology, particularly airframe construction and onboard systems. Advanced transport and bomber variants of the Tu-4 design such as the Tu-70 , Tu-75 , Tu-80 , and Tu-85 , were developed and built, but none of these achieved series production. The People's Liberation Army Air Force of China attempted to use
2013-480: The final production costs due to inefficiencies in materials and processes. Prototypes are also used to revise the design for the purposes of reducing costs through optimization and refinement. It is possible to use prototype testing to reduce the risk that a design may not perform as intended, however prototypes generally cannot eliminate all risk. Building the full design is often expensive and can be time-consuming, especially when repeated several times—building
2074-528: The final production design. This is due to the skill and choices of the designer(s), and the inevitable inherent limitations of a prototype. Due to differences in materials, processes and design fidelity, it is possible that a prototype may fail to perform acceptably although the production design may have been sound. Conversely, prototypes may perform acceptably but the production design and outcome may prove unsuccessful. In general, it can be expected that individual prototype costs will be substantially greater than
2135-530: The forward dorsal turrets was doubled to four beginning with production block 20. Where the wings of previous models had been made by the sub-assembly of two sections, the B-29A wing was built up from three. This made construction easier, and increased the strength of the airframe. The B-29A was produced until May 1946, when the last aircraft was completed. It was employed up to, and through, the Korean War , after which it
2196-464: The full design, figuring out what the problems are and how to solve them, then building another full design. As an alternative, rapid prototyping or rapid application development techniques are used for the initial prototypes, which implement part, but not all, of the complete design. This allows designers and manufacturers to rapidly and inexpensively test the parts of the design that are most likely to have problems, solve those problems, and then build
2257-508: The full design. In technology research, a technology demonstrator is a prototype serving as proof-of-concept and demonstration model for a new technology or future product, proving its viability and illustrating conceivable applications. In large development projects, a testbed is a platform and prototype development environment for rigorous experimentation and testing of new technologies, components, scientific theories and computational tools. With recent advances in computer modeling it
2318-690: The guns increased the top speed from 357 mph to 364 mph (575 km/h to 586 km/h). Also incorporated on this version was an improved APQ-7 "Eagle" bombing-through-overcast radar that was fitted in an airfoil-shaped radome under the fuselage. All 311 B-29Bs were built at the Bell plant in Marietta, Georgia ("Bell-Atlanta"). The B-29C was a modification of the B-29A re-engined with improved Wright R-3350 Duplex-Cyclone engines. The Army Air Force originally ordered 5,000, but cancelled its request when World War II ended and none were built. The B-29D
2379-475: The impact of these differences on the intended role for the prototype. For example, if a visual prototype is not able to use the same materials as the final product, they will attempt to substitute materials with properties that closely simulate the intended final materials. Engineers and prototyping specialists seek to understand the limitations of prototypes to exactly simulate the characteristics of their intended design. Prototypes represent some compromise from
2440-421: The oil coolers have separate air intakes. Two were later converted to aerial refueling tanker prototypes, and redesignated YKB-29J . The remainder were used for reconnaissance , and designated RB-29J . The EB-29 (E stands for exempt), was used as a carrier aircraft in which the bomb bay was modified to accept and launch experimental aircraft. They were converted in the years following World War II . One EB-29
2501-478: The project was abandoned. The U.S. Navy acquired four B-29-BWs from the U.S. Army Air Forces on March 14, 1947. These aircraft were modified for long-range patrol missions and given the designation P2B-1S with Navy Bureau Numbers (BuNo) 84028, 84029, 84030 and 84031. BuNo 84029, previously AAF Ser. No. 45-21787, was modified to carry the Navy's Douglas D-558-2 Skyrocket high-speed research aircraft. The bomb bay
Boeing B-29 Superfortress variants - Misplaced Pages Continue
2562-411: The prototyping platform, or replace it with only the microcontroller chip and the circuitry that is relevant to their product. Prototype software is often referred to as alpha grade , meaning it is the first version to run. Often only a few functions are implemented, the primary focus of the alpha is to have a functional base code on to which features may be added. Once alpha grade software has most of
2623-438: The real EMD GP38-2 locomotive—which is the prototype of Athearn 's (among other manufacturers) locomotive model. Technically, any non-living object can serve as a prototype for a model, including structures, equipment, and appliances, and so on, but generally prototypes have come to mean full-size real-world vehicles including automobiles (the prototype 1957 Chevy has spawned many models), military equipment (such as M4 Shermans,
2684-406: The remote-controlled defensive systems were tested on a number of them, particularly the fourth one delivered. After alternative arrangements had been fully tested, defensive armament was standardised at ten .50-calibre machine guns in turret-mounted pairs. The YB-29 also featured a better fire control system . The B-29 was the original production version of the Superfortress. Since the new bomber
2745-463: The required features integrated into it, it becomes beta software for testing of the entire software and to adjust the program to respond correctly during situations unforeseen during development. Often the end users may not be able to provide a complete set of application objectives, detailed input, processing, or output requirements in the initial stage. After the user evaluation, another prototype will be built based on feedback from users, and again
2806-459: The result being a circuit that is electrically identical to the design but not physically identical to the final product. Open-source tools like Fritzing exist to document electronic prototypes (especially the breadboard-based ones) and move toward physical production. Prototyping platforms such as Arduino also simplify the task of programming and interacting with a microcontroller . The developer can choose to deploy their invention as-is using
2867-493: The sense of a mark left by a blow, then by a stamp struck by a die (note "typewriter"); by implication a scar or mark; by analogy a shape i.e. a statue, (figuratively) style, or resemblance; a model for imitation or illustrative example—note "typical"). Prototypes explore different aspects of an intended design: In general, the creation of prototypes will differ from creation of the final product in some fundamental ways: Engineers and prototype specialists attempt to minimize
2928-457: The two jet fighters) and their crews were lost in a crash on April 24, 1953. Early B-29/B-29As that were modified for photo reconnaissance carried the F-13/F-13A designations, with "F" meaning 'photo'. The aircraft (118 modified B-29BWs and B-29As) carried three K-17B, two K-22 and one K-18 cameras. Between the end of World War II (1945) and 1948 the designation was changed to FB-29J . In 1948,
2989-509: The use of the derivation ' prototypical '. This is a useful term in identifying objects, behaviours and concepts which are considered the accepted norm and is analogous with terms such as stereotypes and archetypes . The word prototype derives from the Greek πρωτότυπον prototypon , "primitive form", neutral of πρωτότυπος prototypos , "original, primitive", from πρῶτος protos , "first" and τύπος typos , "impression" (originally in
3050-539: Was a version of the B-29 adapted for air-sea rescue duty after World War II . Sixteen B-29s were modified to carry a droppable A-3 lifeboat under the fuselage; redesignated SB-29, they were used mainly as rescue support for air units that flew long distances over water. The first SB-29s were received by the Air Rescue Service in February 1947. With the exception of the forward lower gun turret, all defensive armament
3111-489: Was an improved version of the original B-29 design, featuring 28-cylinder Pratt & Whitney R-4360 -35 Wasp Major engines of 3500 hp (2600 kW) each — nearly 60% more powerful than the usual Duplex-Cyclone . It also had a taller vertical stabilizer and a strengthened wing. The XB-44 was the testbed designation for the D model. When World War II ended, the B-29D was given the quartet of Wasp Major engines to become
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#17328590750673172-522: Was an improved version of the original B-29 production model. This is the definitive wartime variant of the B-29. All 1,119 B-29A's were built at the Boeing plant in Renton, Washington , formerly used by the United States Navy . Enhancements made in the B-29A included a better wing design and defensive modifications. Due to a demonstrated weakness to head-on fighter attacks, the number of machine guns in
3233-606: Was assigned the NACA number 137. As of May 2013, this aircraft was in the collection of Kermit Weeks at his Fantasy of Flight aviation museum in Polk City, Florida . The forward fuselage section was restored and briefly displayed at the Florida Air Museum in Lakeland, Florida . It has since been relocated to Fantasy of Flight's "Golden Hill" storage facility along with the remainder of
3294-410: Was conducted on the XB-29 until February 18, 1943, when the second prototype crashed. The flight was conducted by Boeing 's chief test pilot, Edmund T. "Eddie" Allen on a two-hour powerplant performance test. The accident happened when leaking fuel from a filler cap in the wing leading edge ran down inside the leading-edge and ignited. The fire spread to the engines, and due to the much reduced power,
3355-506: Was converted to carry the famous Bell X-1 until it was replaced by a B-50 . Another was used to carry and test the XF-85 'parasite fighter' . This fighter was intended to be carried by the Convair B-36 on long-range missions to protect it from Soviet fighters. Another EB-29 was used to carry two EF-84B Thunderjet fighters as part of Project Tom-Tom . All three Tom-Tom aircraft (the B-29 and
3416-527: Was modified to carry the Skyrocket II under the belly and drop for supersonic speed testing. The first Skyrocket test flight occurred on September 8, 1950, with test pilot William B. Bridgeman, and George Jansen flying the B-29. Scott Crossfield later broke Mach 2 flying the Skyrocket on November 20, 1953; the last Skyrocket flight was in December 1956. The P2B-1S "mother-ship" was nicknamed Fertile Myrtle and
3477-554: Was retained; the aircraft additionally carried a variety of radio equipment, provisions, survival kits , and extra crew . The SB-29 was used operationally throughout the Korean War into the mid-1950s. It received its nickname from Dumbo , the Disney character, whose name was given to the aircraft used in previous missions to pick airmen up when they crashed at sea. The TB-29 was a trainer conversion of B-29 used to train crew for bombing missions; some were also used to tow targets, and
3538-588: Was slightly heavier and slower than the B-29. The Tu-4 presented a significant leap forward in Soviet strategic bombing. Not only did the Soviet Air Forces have the means to deliver nuclear weapons, but the Tu-4 had sufficient range to reach the United States on a one-way trip. On October 18, 1951, a Tu-4 was used in the first air-drop test of a Soviet atomic bomb . The Tu-4 had been phased out of Soviet service by
3599-544: Was then quickly phased out when the B-47 Stratojet became operational. Washington B Mk 1 – This was the service name given to 88 B-29As supplied to the Royal Air Force . The B-29B was a modification used for low-level raids, designed with the intent of firebombing Japan . Since fighter opposition was minimal over Japan in late 1944, many of the Army Air Force leadership — most notably Curtis LeMay , commander of
3660-597: Was urgently needed, the production design was developed in tandem with the service testing. In fact, the first B-29 was completed only two months after the delivery of the first YB-29. Forty-six B-29s of this variant, built by the Glenn L. Martin Company at its Omaha plant, were used as the aircraft for the atomic bomb missions, modified to Silverplate specifications. Some 2,513 B-29s were manufactured by Boeing-Wichita (1,620), Bell-Atlanta (357), and Martin-Omaha (536). The B-29A
3721-777: Was used in the development of jet engines . Stripped of armament, a converted B-29B-55-BA (44-84043)(Bell) designated the XB-29G carried experimental jet engines in its bomb bay, which were extended into the airstream for testing during flight. This plane was used to test the Allison J35 , General Electric J47 and J73 jet engines. The XB-29H to test armament configurations was a converted B-29A. Experimentation in piston engines continued. Six B-29s (redesignated YB-29J ) of various designation were upgraded to R-3350-79 engines. Other engine-associated items were also upgraded, including new Curtiss propellers , and 'Andy Gump' cowlings, in which
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