Supercharger

fuel efficiency). Similar dependencies affect the remaining aberrations in the list. Raising overall pressure ratio tends to improve specific fuel consumption (i.e. The second, coma is changes as a function of pupil distance and spherical aberration, hence the well known result that it is impossible to correct the coma in a lens free of spherical aberration by simply moving the pupil. Either way, raising core flow increases core power and, thereby, the net thrust or shaftpower of the engine. The first Seidel aberration, Spherical Aberration is independent of the position of the exit pupil (as it is the same for axial and extra-axial pencils). Core flow will increase if the original compressor outlet (corrected) flow size is maintained. They are always listed in the above order since this expresses their interdependence as first order aberrations via moves of the exit/entrance pupils.

Supercharging can also be achieved by improving the aerodynamics of the existing blading. They are now commonly referred to as the five Seidel Aberrations. If the fan flow is not increased, the bypass ratio will decrease. In 1857, Philipp Ludwig von Seidel (1821-1896) decomposed the first order monochromatic aberrations into five constituent aberrations. Pratt & Whitney PW4000) have gained core flow by adding one or more stages to the front of the gas generator, usually in the LP (or IP) compressor. Image aberrations can be broken down into two main classes, monochromatic, and polychromatic. Many of the large turbofan engine series (e.g. In reality, perfect mirrors and perfect lenses do not exist, so image aberrations in addition to aperture diffraction must be taken into account.

Converting a turbojet into a turbofan, by adding a fan spool, also supercharges the compression system, thereby raising core flow. Even if a reflecting telescope could have a perfect mirror, or a refracting telescope could have a perfect lens, the effects of aperture diffraction could still not be escaped. If stress considerations prevent any shaft speed increase, there is only a modest increase in airflow. No telescope can form a perfect image. non-dimensional) speed of original compressor should be maintained, by raising the mechanical shaft speed by a factor √(Tstage1new/Tstage1old). If greater resolution is needed at that wavelength, a wider mirror has to be built or aperture synthesis performed using an array of nearby telescopes. Ideally, the corrected (i.e. This means that a telescope with a certain mirror diameter can resolve up to a certain limit at a certain wavelength.

zero) stage to a compressor will not only increase the overall pressure ratio of the cycle, but induce more airflow into the unit, by supercharging the entry plane of the original compressor. This limit depends on the wavelength of the studied light (so that the limit for red light comes much earlier than the limit for blue light) and on the diameter of the telescope mirror. For example, adding an additional (i.e. This absolute limit is called the diffraction limit (or sometimes the Rayleigh criterion, Dawes limit or Sparrow's resolution limit). Supercharging is not confined to superchargers - jet engines rely on supercharging as one of the main routes to thrust growth and improved fuel efficiency. The phenomenon of optical diffraction sets a limit to the resolution and image quality that a telescope can achieve, which is the effective area of the Airy disc, which limits how close two such discs can be placed. It is also possible to drive the blower from the crank shaft and use an exhaust turbine for output power. See adaptive optics, speckle imaging and optical interferometry.

It also tends to run less hot. In recent years, some technologies to overcome the distortions caused by atmosphere on ground-based telescopes were developed, with good results. This is important in dragsters and small sports cars. Current research telescopes have several instruments to choose from such as:. The main advantage of an engine with a mechanically driven supercharger is better throttle response. After the photographic plate, successive generations of electronic detectors, such as the charge-coupled device (CCDs), have been perfected, each with more sensitivity and resolution, and often with a wider wavelength coverage. For this reason, both the economy and the power of a turbocharged engine are usually better. Later, the sensitized photographic plate took its place, and the spectrograph was introduced, allowing the gathering of spectral information.

The thermal efficiency, or fraction of the fuel/air energy that is converted to output power, is less with a mechanically driven supercharger than with a turbocharger, because the energy of the exhaust pressure is lost. Initially the detector used in telescopes was the human eye. This lag can be addressed by reducing the size of each individual unit such that the combined output is still as great as a single large turbocharger without having to suffer the lag-time required to reach operating speed. the Liverpool Telescope and the Faulkes Telescope North and South), allowing automated follow-up of astronomical events. This gives a large power increase for a given engine speed at the cost of increasing the lag-time for the exhaust to heat up sufficiently to drive the turbochargers. Many are robotic telescopes, computer controlled over the internet (see e.g. An alternative arrangement utilizes two turbochargers of the same type, known as a "twin turbo". These allow many astronomical targets to be monitored continuously, and for large areas of sky to be surveyed.

This gives the opportunity of fitting multiple turbochargers to a single engine, such as in a "sequential turbo", where one turbo is tuned to give increased performance at low engine speed and another turbo is tuned to increase the high-speed engine performance. Relatively cheap, mass-produced ~2 meter telescopes have recently been developed and have made a significant impact on astronomy research. The physical space occupied by a turbocharger is significantly less than its direct-drive counterpart. This technology has driven new designs for future telescopes with diameters of 30, 50 and even 100 meters. The size of the piping alone is a serious issue; consider that the Vought F4U and Republic P-47 used the same engine but the huge barrel-like fuselage of the latter was, in part, needed to hold the piping to and from the turbocharger in the rear of the plane. In this generation of telescopes, the mirror is usually very thin, and is kept in an optimal shape by an array of actuators (see active optics). Yet the vast majority of WWII engines used superchargers, because they maintained three significant manufacturing advantages over turbochargers, which were larger, involved extra piping, and required exotic high-temperature materials in the turbine. The largest current ground-based telescopes have primary mirrors of between 6 and 11 meters in diameter.

Better yet the amount of power in the gas is the difference between the exhaust pressure and air pressure, which increases with altitude, so turbochargers generally have much better altitude performance. Its example was followed by the Keck telescopes with 10 m segmented mirrors. Thus at low altitudes the turbo robs nothing and, as the altitude increases, it can use just as much power as it needs and no more. This has now been replaced by a single 6.5m mirror. In addition the power in the exhaust would otherwise be wasted (except to the extent that the exhaust itself provided thrust) whereas in the supercharger that power is being taken directly from the engine. A new era of telescope making was inaugurated by the Multiple Mirror Telescope (MMT), with a mirror composed of six segments synthesizing a mirror of 4.5 meters diameter. Since the turbo is driven off the exhaust gases, simply dumping some of the exhaust pressure is sufficient to drive the compressor at almost any desired speed. They have a pierced primary mirror, a Newtonian focus, and a spider to mount a variety of replaceable secondary mirrors.

It is interesting to compare all of this complexity to the same system implemented with a turbocharger. Most large research telescopes can operate as either a Cassegrain telescope (longer focal length, and a narrower field with higher magnification) or a Newtonian telescope (brighter field). The two-stage Merlin was losing 400 hp (300 kW) to turn the supercharger but developing between 1500 and 1700 hp (1125 to 1275 kW) at the propeller shaft, depending on model. For example:. At low altitudes one stage could be turned off completely. There are mountings even simpler than altazimuth, typically used for specialized instruments. After being compressed "half-way" in the low pressure stage the air flowed through an intercooler radiator where it was partially cooled down before being compressed the rest of the way in the high pressure stage and then aftercooled in another air/air or coolant/air radiator (heat exchanger). Modern large telescopes use computer-controlled altazimuth mounts, and for long exposures they rotate the instruments or have variable-rate image rotators in an image of the telescope pupil.

In order to avoid pre-ignition the "two stage" design was used. This is known as an equatorial mount. Compressing a gas always causes its temperature to rise, and an overcompressed fuel-air mixture may therefore prematurely ignite. The preferred solution for small astronomical telescopes is to tip the altazimuth mount so that the azimuth axis is parallel with the axis of the Earth's rotation. A final improvement was the use of two compressors in series, which were introduced to solve the pre-ignition problem. The last effect makes an altazimuth mount especially impractical for long-exposure photography with small telescopes. Ultimately it was found that for most engines (excepting those in high-performance fighters) a single-stage two-speed setup was most suitable. Even if this is done by computer control, the image rotates at a rate that varies depending on the angle of the target from the celestial pole.

These provided more flexibility for the operation of the aircraft although they also entailed more complexity of manufacturing and maintenance. When using an altazimuth for astronomy, both axes must be continuously adjusted to compensate for the Earth's rotation. In the 1930s two-speed drives were developed for superchargers. A Dobsonian mount is a type of altazimuth mount which has proven to be very popular as it is simple and inexpensive. Supercharging by itself could not have achieved these improvements; however, when married with fuel improvements, the engine could respond to both. A fork rotates in azimuth (in the horizontal plane), and bearings on the tips of the fork allow the telescope to vary in altitude (in a vertical plane). By mid-1940 another increased boost yielded 1310 hp (980 kW). It is similar to that of a surveying transit.

This allowed the boost on Merlin engines to be increased to 48 inHg (160 kPa) and the power to rise by more than 10% (from 1030 to 1160 hp, or 770 to 870 kW). A simple telescope mount is an altitude-azimuth or altazimuth mount. In 1940 a batch of 100 octane fuel was delivered from the USA to the RAF. These are more useful for astronomical viewing. This generally "flattened out" the power below the critical altitude. Newtonian or reflecting telescopes employ the reflective properties of light, and use mirrors and lenses. As the war progressed two-speed superchargers were introduced using better controllers and, notably, hydraulic clutches, that allowed the boost to be managed over a wide range of altitudes by operating at low rpm down low and at high rpm at higher altitudes. These can be used for both terrestrial and astronomical viewing.

For the early years of the war this was simply how it was and this led to the seemingly odd fact that many early-war engines actually delivered less power at lower altitudes, because the supercharger was still using up power to compress air that was not delivering any power back. Galilean or refracting telescopes employ the refractive properties of light, and are constructed of lenses. Also, due to the denser air at lower altitudes, the supercharger is not operating at its best efficiency, and this can cause an additional load on the engine. Optical telescopes are also divided into two types. Unless other measures are taken, this means that at least some of the power driving the supercharger is wasted. Telescopes are broadly classified into two main types. Below the critical altitude the supercharger is capable of delivering too much boost and must therefore be restricted lest the engine be damaged. Optical interferometer arrays and arrays of radio telescopes were developed much more recently.

British engines were generally able to outperform German ones. Later, Johannes Kepler described the optics of lenses (see his books Astronomiae Pars Optica and Dioptrice), including a new kind of astronomical telescope with two convex lenses (a principle often called Kepler telescope). Throughout WWII British superchargers generally had higher critical altitudes than their German counterparts and, when combined with higher octane fuels that the Americans supplied, that allowed for higher boost levels. Galileo's telescope consisted of a convex object lens and a concave eye lens, which is universally called a Galilean Telescope (used as a viewfinder in many simple cameras). The boost is typically measured as the altitude at which the supercharger can still supply sea level pressure (100 kPa or 1000 mbar) and is referred to as the critical altitude. Galileo is generally credited with being the first to use a telescope for astronomical purposes. A supercharger is only able to supply so much pressure because the compression increases the air temperature, and the engine is limited in maximum charge-air temperature before pre-ignition occurs. Galileo Galilei made his own telescope in 1609, calling it at first a perspicillum, and then using the terms telescopium in Latin and telescopio in Italian (from which the English word derives).

For this reason supercharged planes fly much faster at higher altitudes. Even if Lippershey did not make the first one, he publicized it. And while the engine might be fooled into thinking it's at sea level, the airframe is quite aware of the halved air density and the plane thus has half the drag. Some name that person as Hans Lippershey (c1570-c1619), but Jacob Metius and Zacharias Jansen also claimed to have invented a telescope during the same time period. Yet the benefits are huge, for that 150 horsepower (110 kW) lost, the engine is delivering 1000 hp (750 kW) when it would otherwise deliver 750 hp (560 kW). Leonard Digges is sometimes credited with the invention in England in the 1570s, but usually credit for assembling the first telescope is usually given to an unknown Dutch spectacle maker in about 1608. On the single-stage single-speed supercharged Rolls Royce Merlin engine for instance, the supercharger uses up about 150 horsepower (110 kW). The Visby lenses tentatively suggest that the technology was known to the Arabs and Persians then to the Vikings in the 10th century.

This can take some effort. Article. A supercharger remedies this problem by compressing the air back to sea-level pressures, or even much higher. The first telescopes may have been Assyrian crystal lenses. Since the charge in the cylinders is being pushed in by this air pressure it means that the engine will normally produce half-power at full throttle at this altitude. . As an aircraft climbs to higher altitudes the pressure of the surrounding air quickly falls off—at 6000 m (18,000 ft) the air is at half the pressure of sea level. The mirrors are usually a section of a rotated parabola.

A more natural use of the supercharger is with aircraft engines. They use ring-shaped "glancing" mirrors, made of heavy metals, that reflect the rays just a few degrees. There are three types commonly used in today's automotive world: Roots type supercharger, twin-screw type supercharger, and Centrifugal type supercharger. X-ray and gamma-ray telescopes have a problem because these rays go through most metals and glasses. Also, improperly installed or excessive boost will greatly reduce life expectancy of the engine as well as the transmission (which may not have been designed to cope with additional torque). Aperture synthesis is now also being applied to optical telescopes using optical interferometers (arrays of optical telescopes) and Aperture Masking Interferometry at single telescopes. Nevertheless, adding boost to a car will often void the drivetrain warranty. As of 2005, the current record is many times the width of the Earth, utilizing space-based Very Long Baseline Interferometry (VLBI) telescopes such as the Japanese HALCA (Highly Advanced Laboratory for Communications and Astronomy) [VSOP (VLBI Space Observatory Program) satellite].

Gas mileage can also be saved with a turbo because the engine does not have as much displacement, therefore not needing to inject as much petrol in the the cylinders. Radio telescopes are often operated in pairs, or larger groups to synthesize large "virtual" apertures that are similar in size to the separation between the telescopes: see aperture synthesis. This also results in better gas mileage, as mileage is often a function of the overall weight of the car and that is based, to some degree, on the weight of the engine. The dish is sometimes constructed of a conductive wire mesh whose openings are smaller than a wavelength. For this reason boosting is commonly used in smaller cars, where the added weight of the supercharger is smaller than the weight of a larger engine delivering the same amount of power. Radio telescopes are focused radio antennas, usually shaped like large dishes. Boosting used to be an effective way to dramatically shorten an engine's life but, today, there is considerable overdesign possible with modern materials and boosting is no longer a serious reliability concern. The word "telescope" usually refers to optical telescopes, but there are telescopes for most of the spectrum of electromagnetic radiation.

Boosting has made something of a comeback in recent years due largely to the increased quality of the alloys and machining of modern engines. Telescopes are used for astronomy and in many non-astronomical instruments including theodolites, transits, spotting scopes, monoculars, binoculars, camera lenses and spyglasses. Since then superchargers (as well as turbochargers) have been widely applied to racing and production cars, although their complexity and cost has largely relegated the supercharger to the world of pricey performance cars. Telescopes work by employing one or more curved optical elements - lenses or mirrors - to gather light or other electromagnetic radiation and bring that light or radiation to a focus, where the image can be observed, photographed or studied. It wasn't long after its invention before the supercharger was applied to custom racing cars, with the first supercharged production vehicles being built by Mercedes and Bentley in the 1920s. Telescopes increase the apparent angular size of distant objects, as well as their apparent brightness. This design is the basis for the modern Roots type supercharger. A telescope (from the Greek tele = 'far' and skopein = 'to look or see'; teleskopos = 'far-seeing') is an optical tool that gathers and focuses electromagnetic radiation.

His first superchargers were based on a twin-rotor air-pump design first patented by American Francis Roots in 1860. The 1-meter refracting Swedish Solar Telescope (SST) on La Palma, is currently the highest-resolution solar telescope in the world. In 1900 Gottlieb Daimler (of Daimler-Benz / Daimler-Chrysler fame) became the first person to patent a forced-induction system for internal combustion engines. It was a failure. By pushing the air into the cylinders, it is as if the engine had larger valves and cylinders, resulting in a "larger" engine that weighs less. The horizontal tube was 60 m long and the objective had 1.25 m in diameter. In cars, the device is used to increase the "effective displacement" and volumetric efficiency of an engine, and is often referred to as a blower. The telescope was aimed by the aid of a Foucault sidérostat, which is a movable plane mirror with a 2 m diameter, mounted in a large cast-iron frame.

. Its lens was stationary, prefigured so as to sag into the correct shape. In applications where a massive amount of power is more important than any other consideration, such as top-fuel dragsters and vehicles used in tractor pulling competitions, superchargers are extremely common. It was on display at the 1900 Paris Exposition. Superchargers may absorb as much as a third of the total crankshaft power of the engine, and in many applications are less efficient than turbochargers. The largest refractor ever constructed was French. It is similar in purpose to the closely related turbocharger, but a turbocharger is powered by the flow of the engine's exhaust gases driving a turbine. It was exceeded in size one year later by the 0.91 m refractor at the Lick Observatory.

A supercharger is powered mechanically by belt- or chain-drive from the engine's crankshaft. This was the last time the most powerful operational telescope in the world was located in Europe. The additional mass of oxygen that is forced into the cylinders allows the engine to burn more fuel, which improves the volumetric efficiency of the engine and makes it more powerful. The 0.76 m Nice refractor (in France) that became operational in 1888 was at that time the world's largest telescope. A supercharger (also known as a blower, or a centrifugal pump) is a gas compressor used to compress air into the cylinders of an internal combustion engine. The 1.02 m Yerkes Telescope (in Wisconsin) is the largest aimable refracting telescope in use. The telescope now has an adaptive optics system, and is still useful for advanced research.

In 1919, the telescope was used for the first stellar diameter measurements using interferometry. The mirror was made of green glass by Saint-Gobain. The 100 inch (2.54 m) Hooker Telescope at the Mount Wilson Observatory was used by Edwin Hubble to discover galaxies, and the redshift. The mounting is a special design of equatorial mount called a yoke mount, which permits the telescope to be pointed at and near the north celestial pole.

It has a single borosilicate (Pyrex™) mirror that was famously difficult to construct. The 200 inch (5.08 m) Hale telescope on Palomar Mountain was the largest conventional research telescope for many years. One of them is the Overwhelmingly Large Telescope (OWL), which is intended to have a single aperture of 100 meters in diameter. There are many plans for even larger telescopes.

The CHARA (Center for High Angular Resolution Astronomy) array is the telescope array that can currently (2005) produce the highest resolution images at near-infrared wavelengths. The Navy Prototype Optical Interferometer is the optical telescope (array) that can currently (2005) produce the highest resolution images at visible wavelengths. The four telescopes, belonging to the European Southern Observatory (ESO) and located in the Atacama desert in Chile, are usually operated independently for faint astronomical observations, but up to three telescopes can be operated together for aperture synthesis observations of bright objects. The Very Large Telescope array (VLT) is currently (2002) the record holder for total collecting area in an array of telescopes, with four telescopes each 8 meters in diameter.

The Keck telescopes are currently (2005) the largest, but will soon be superseded by the Gran Telescopio Canarias and Southern African Large Telescope. In this way the images can be diffraction limited, and used for coverage in the ultraviolet (UV) and infrared. The Hubble Space Telescope is in orbit beyond Earth's atmosphere to allow for observations not distorted by astronomical seeing. polarimeters, that detect light polarization.

spectrographs, useful in different regions of the spectrum. imagers, of different spectral responses. ball-and-socket (ancient and useless for astronomy). fixed with movable plane mirror for solar observing.

meridian transit (altitude only). Newtonian reflecting telescopes. Galilean refracting telescopes. Radio telescopes.

Optical telescopes.