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17-424: The J87 was a large turbojet, designed to operate as a paired unit, with a nuclear reactor power section. The complete power-plant was given the project designation X211 . The X211 was a relatively large multiple turbojet engine of conventional layout, save for the combustion chambers being replaced by a nuclear reactor where half of the total air-flow through the turbojet sections was used for direct-cycle cooling of

34-418: A liquid fuel instead of a solid fuel. The gas plenum is above the fuel and below a diving bell style vent for the reaction products. This allows for convection currents and fluid flow eliminating the possibility for gas products to build up and rupture as in a light water reactor. Airbox An airbox is an empty chamber on the inlet of most combustion engines. It collects air from outside and feeds it to

51-486: A peripheral skirt system, where the air from the lift fans is routed to a narrow slot around the edge of the hull, and bound by a flexible skirt. Distribution of this air from the fans to the periphery is through a large-volume plenum chamber, so as to provide even distribution of airflow without sensitivity to the length of the direct path. Molten salts consisting of chlorinated nuclear waste are contained in atomic fission reactor rods. This Alvin M. Weinberg et al design has

68-414: A varying manner, as the valves open and as piston speed varies through the stroke . Simple direct ducting would give problems where the nearest cylinders received more airflow. The pulsating demand from the cylinders would also show problems of either pressure waves in the duct, or a shortage of inlet air towards the end of the inlet phase. The solution is to provide a large-volume plenum chamber between

85-723: The SRAD models of the Suzuki GSX-R750 , the Kawasaki Ninja ZX-6R or the BMW S1000RR . Secondly, designers exploit a property of air cavities known as Helmholtz resonance . Flow through the airbox is optimal at its resonance frequency , which depends on airbox volume and the inlet area and length of the snorkel. The resonance is typically chosen to be at a medium speed where torque otherwise drops, caused by valve timing overlap. This motorcycle, scooter or moped-related article

102-537: The United States Air Force (USAF) decided that the proposed WS-125 bomber was unfeasible as an operational strategic aircraft. In spite of this, the X211 program was continued for another 3 years, albeit with no target application. It was finally terminated in mid-1959 and by 1961 all funding for nuclear propulsion was removed. The competing Pratt & Whitney indirect-cycle engines used J91 turbojet sections in

119-521: The X287 and X291 projects, which were also cancelled with the demise of the nuclear-powered bomber program. Data from Plenum chamber A plenum chamber is a pressurised housing containing a fluid (typically air) at positive pressure . One of its functions is to equalise pressure for more even distribution, compensating for irregular supply or demand. It is typically relatively large in volume and thus has relatively low velocity compared to

136-428: The heat of evaporation. Even so, at 50 °C the fuel-air mixture was still hotter than ideal, and the engine's volumetric efficiency remained somewhat impaired. The eccentric shaft's main bearings and the inlet manifolds were fed by oil-injection lubrication, and the fuel-air mix also carried residual mist of oil from the interior of the rotors, which helped to lubricate the rotor tips. Practical hovercraft use

153-420: The "vacuum system" which used a pressure below atmospheric. At a time when high pressure steam or hydraulic systems were well established, these were a distinct set of systems based on low pressure and high volume flows. Supercharged piston engines typically use many cylinders arranged in-line and one or two superchargers. Superchargers deliver air at a relatively constant rate, while cylinders demand it in

170-455: The core, used for starting, burning normal jet fuel to ensure cooling air flow for the reactor as soon as it was started-up. The reactor core sat in the middle of the combustion section, fed with cooling air from a large plenum chamber . Heated exhaust air was collected by another plenum chamber to be fed to the turbine sections. Testing of the X211 was confined to the XJ87 turbojet sections. In 1956,

187-543: The inlet and the cylinders. This has two benefits: it evens out the difference in path restriction between cylinders (distribution across space), secondly it provides a large-volume buffer against pressure changes (distribution over time). For non-supercharged / normally aspirated engines see Airbox . The Norton Classic was a motorcycle whose air-cooled twin-rotor Wankel engine was developed by David Garside at BSA . Wankel engines run very hot, so Garside gave this air-cooled motor additional interior air-cooling. Air

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204-486: The intake hoses of each cylinder. Older engines drew air directly from the surroundings into each individual carburetor . Modern engines instead draw air into an airbox, which is connected by individual hoses to each carburetor or directly to the intake ports in fuel-injected engines, thus avoiding an extra intake manifold. The airbox allows the use of one air filter instead of multiples, reducing complexity. Developments arising from concerns about engine emissions during

221-474: The late 1970s allow the airbox to collect pump gases from the crankcase and the tank air vent and re-feed them to the engine. Since the 1990s, engine designers also sought to exploit the properties of oscillating gas to improve performance. Many high-performance motorcycles have the airbox fed from funnels in the front of the bike, where increased pressure forces more air into the intake and thus improves power. Examples of this ram-air intake construction are

238-438: The notion that " nature abhors a vacuum ". These gave rise to the notion of 17th century 'plenum' as the opposite of vacuum , and all things "being either Plenum or Vacuum". By the 19th century, the development of mechanical fans and industrial machinery had provided another, more technical use. This referred to "a system of artificial ventilation", which used a pressure raised slightly above atmospheric pressure, in contrast to

255-489: The reactor. The J87 components featured variable-stator compressors and chemically-fuelled afterburners and a single nuclear reactor to supply heat to both J87 engines. Several arrangements for the X211 were studied but eventually the paired J87 was chosen and development was started at General Electrics Evendale factory. The air by-passed around the XMA-1A nuclear reactor passed through can style combustion chambers arranged around

272-444: The system's other components. In wind tunnels, rockets, and many flow applications, it is a chamber upstream on the fluid flow where the fluid initially resides (approximately at rest). It can also work as an acoustic silencer. Examples of plenum chambers include those used with: The term "plenum" was coined in the 1670s, derived from Latin adjective plenus ("filled, full"). The usage originates from classical theories of physics and

289-435: Was drawn through a forward-facing filter situated to provide a ram air effect. This air passed through the interior of the rotors and then into a large pressed-steel plenum before entering the combustion chambers via twin carburettors. The plenum (which doubled as the bike's semi-monocoque frame) enabled the transfer of much of the heat to the surrounding atmosphere. The carburation process further reduced temperatures via

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