Wikicars - User contributions [en]

Template:Infobox Test

2006-05-31T03:54:29Z

Jrosenblum:

{| class="infobox bordered" style="width: 258px; text-align: left; font-size: 95%;" cellpadding="3"
| colspan="2" style="color: white; background: darkgreen; text-align: center; font-size: larger;" | '''{{{name}}}'''
{{#if:{{{image|}}}|<tr><td colspan=2>{{{image}}}</tr>}}
{{#if:{{{aka|}}}|<tr><th>Also called:<td>{{{aka}}}</tr>}}
|-
!width=100| [[List of automobile manufacturers|Manufacturer]]:
| {{{manufacturer}}}{{#if:{{{production|}}}|<tr><th>Production:<td>{{{production}}}</tr>}}{{#if:{{{predecessor|}}}|<tr><th>Predecessor:<td>{{{predecessor}}}</tr>}}{{#if:{{{successor|}}}|<tr><th>Successor:<td>{{{successor}}}</tr>}}{{#if:{{{class|}}}|<tr><th>[[Car classification|Class]]:<td>{{{class}}}</tr>}}{{#if:{{{body_style|}}}|<tr><th>Body style:<td>{{{body_style}}}</tr>}}{{#if:{{{platform|}}}|<tr><th>[[Automobile platform|Platform]]:<td>{{{platform}}}</tr>}}{{#if:{{{engine|}}}|<tr><th>[[Car engine|Engine]]:<td>{{{engine}}}</tr>}}{{#if:{{{transmission|}}}|<tr><th>[[Transmission (mechanics)|Transmission]]:<td>{{{transmission}}}</tr>}}{{#if:{{{wheelbase|}}}|<tr><th>[[Wheelbase]]:<td>{{{wheelbase}}}</tr>}}{{#if:{{{length|}}}|<tr><th>Length:<td>{{{length}}}</tr>}}{{#if:{{{width|}}}|<tr><th>Width:<td>{{{width}}}</tr>}}{{#if:{{{height|}}}|<tr><th>Height:<td>{{{height}}}</tr>}}{{#if:{{{weight|}}}|<tr><th>[[Curb weight]]:<td>{{{weight}}}</tr>}}{{#if:{{{fuel_economy|}}}|<tr><th>[[Fuel economy]]:<td>{{{fuel_economy}}}</tr>}}{{#if:{{{fuel_capacity|}}}|<tr><th>Fuel capacity:<td>{{{fuel_capacity}}}</tr>}}{{#if:{{{related|}}}|<tr><th>Related:<td>{{{related}}}</tr>}}{{#if:{{{similar|}}}|<tr><th>Similar:<td>{{{similar}}}</tr>}}{{#if:{{{designer|}}}|<tr><th>Designer:<td>{{{designer}}}</tr>}}
|}<noinclude>

== Usage ==
<pre>
{{Infobox Automobile
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| class =
| platform =
| body_style =
| engine =
| transmission =
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| length =
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[[Category:Infobox templates|Automobile]]
[[Category:Automotive templates|Automobile]]
[[Category:Templates using ParserFunctions|{{PAGENAME}}]]
</noinclude>

Main Page

2006-05-15T16:58:23Z

Jrosenblum: Added direct accord page link

* [[Honda]]

(or click here to go directly to the [[Honda Accord|Accord]] page)

Main Page

2006-05-15T16:52:03Z

Jrosenblum: Breaking taxonomy down into make/models

* [[Honda]]

GPS

2006-05-15T03:40:11Z

Jrosenblum: copied from wikipedia

[[Image:GPS_Satellite_NASA_art-iif.jpg|thumb|right|250 px|GPS satellite in orbit, image courtesy [[NASA]]]]
:'''''[[Navigation System|GPS]]''' redirects here. For other uses of the acronym '''[[Navigation System|GPS]]''', see [[GPS (disambiguation)]].''
The '''Global Positioning System''', usually called '''[[Navigation System|GPS]]''', is the only fully-functional [[satellite navigation system|satellite navigation system]]. A constellation of more than two dozen [[Navigation System|GPS]] satellites broadcasts precise timing signals by [[radio]] to [[Navigation System|GPS]] receivers, allowing them to accurately determine their location ([[longitude]], [[latitude]], and [[altitude]]) in any weather, [[real time|day or night]], anywhere on [[Earth]].

[[Navigation System|GPS]] has become a vital global utility, indispensable for modern [[Navigation System|navigation]] on land, sea, and air around the world, as well as an important tool for [[cartography|map-making]], and [[surveying|land surveying]]. [[Navigation System|GPS]] also provides an extremely precise [[time transfer|time reference]], required for telecommunications and some scientific research, including the study of earthquakes.

<div class="floatleft">
[[Image:NAVSTAR_GPS_logo_shield-official.jpg|105px]]
[[Image:50th Space Wing emblem.png|120px]]
</div>
[[United States Department of Defense]] developed the system, officially named '''NAVSTAR [[Navigation System|GPS]]''' ('''Nav'''igation '''S'''ignal '''T'''iming '''a'''nd '''R'''anging '''[[Navigation System|GPS]]'''), and the satellite constellation is managed by the [[50th Space Wing]]  at [[Schriever Air Force Base]]. Although the cost of maintaining the system is approximately US$400 million per year, including the replacement of aging satellites, [[Navigation System|GPS]] is available for free use in civilian applications as a [[public good]].

In late 2005, the first in a series of next-generation [[Navigation System|GPS]] satellites was added to the constellation, offering several new capabilities, including a second civilian [[Navigation System|GPS]] signal called '''L2C''' for enhanced accuracy and reliability. In the coming years, additional next-generation satellites will increase coverage of L2C and add a third and fourth civilian signal to the system, as well as advanced military capabilities.

The Wide-Area Augmentation System ([[WAAS]]), available since August 2000, increases the accuracy of [[Navigation System|GPS]] signals to within 2 meters (6 ft) <ref>[[Federal Aviation Administration]]. [http://[[Navigation System|gps]].faa.gov/Library/waas-f-text.htm FAA WAAS fact-sheet]. Accessed [[May 14]], [[2006]]</ref> for compatible receivers. [[Navigation System|GPS]] accuracy can be improved further, to about 1 cm (half an inch) over short distances, using techniques such as Differential [[Navigation System|GPS]] ([[Differential GPS|DGPS]]).

[[Image:Magellan GPS Blazer12.jpg|thumb|Magellan GPS receiver in a marine application.]]
[[Image:Navstar.jpg|thumb|Over fifty '''GPS''' [[satellite]]s such as this [[NAVSTAR]] have been launched since 1978. ]]

== Applications ==
* '''Military Applications'''
[[Navigation System|GPS]] allows accurate targeting of [[cruise missile]]s and [[precision-guided munition]]s (or "smart bombs"), as well as improved command and control of forces through improved locational awareness. [[Navigation System|GPS]] increases the accuracy of submarine launched ballistic missiles, since knowing the exact launching position allows for more accurate targeting of the missile. The satellites also carry nuclear detonation detectors, which form a major portion of the [[United States Nuclear Detonation Detection System]]. Commercial civilian [[Navigation System|GPS]] receivers are required to have limits on the velocities and altitudes at which they will report coordinates; this is to prevent them from being used to create improvised missiles.

* '''[[Navigation System|Navigation]]'''
[[Image:KyotoTaxiRide.jpg|thumb|right|250 px|This [[Taxicab|taxi]] in [[Kyoto]], equipped with GPS navigation, is an example of how '''GPS''' technology can be applied in routine activities. ]]
{{main|Automotive [[Navigation System|navigation system]]}}
[[Navigation System|GPS]] is used by people around the world as a [[Navigation System|navigation]] aid in cars, airplanes, and ships. The system can also be used by computer controlled harvesters, mine trucks and other vehicles. Hand-held [[Navigation System|GPS]] receivers can be used by mountain climbers and hikers. Glider pilots use the logged signal to verify their arrival at turnpoints in competitions. Low cost [[Navigation System|GPS]] receivers are often combined in a bundle with a [[Personal digital assistant|PDA]], car computer, or [[vehicle tracking system]].

* '''Surveying'''
More costly and precise receivers are used by land [[surveyors]] to locate boundaries, structures, and survey markers, and for road construction.

* '''[[Navigation System|GPS]] for the visually impaired'''
For information about [[Navigation System|navigation]] systems for the visually impaired, including MoBIC, Drishti, Brunel [[Navigation System|Navigation System]] for the [[blindness|Blind]], NOPPA, BrailleNote [[Navigation System|GPS]], and Trekker, refer to the main article [[GPS for the visually impaired]].

* '''Geocaching'''
[[Image:GPS Receivers.jpg|thumb|GPS receivers come in a variety of formats, from devices integrated into cars, phones, and watches, to dedicated devices such those shown here from manufacturers Trimble, Garmin and Leica (respectively, left to right).]]
The availability of hand-held [[Navigation System|GPS]] receivers for a cost of about $90 and up ([[as of 2005|as of March 2005]]) has led to recreational applications including [[Geocaching]]. Geocaching involves using a hand-held [[Navigation System|GPS]] unit to travel to a specific [[longitude]] and [[latitude]] to search for objects hidden by other Geocachers. This popular activity often includes walking or hiking to natural locations.

* '''[[Navigation System|GPS]] on airplanes'''
Most airlines allow private use of ordinary [[Navigation System|GPS]] units on their flights, except during landing and take-off, like all other electronic devices. Additionally, some airline companies disallow use of hand-held receivers for security reasons, such as unwillingness to let ordinary passengers track the flight route. On the other extreme, some airlines integrate [[Navigation System|GPS]] tracking of the aircraft into their aircraft's seat-back television entertainment systems, available even during takeoff and landing to all passengers.

[[Image:GPS roof antenna dsc06160.jpg|thumb|right|100px|Even fixed systems may use GPS, in order to get precise time. This antenna is mounted on the roof of a hut containing a scientific experiment needing precise timing.]]

* '''Precise time reference'''
Many [[synchronization]] systems use [[Navigation System|GPS]] as a source of accurate time, hence one of the most common applications of this use is that of [[Navigation System|GPS]] as a reference clock for [[time code]] generators or [[Network Time Protocol|NTP]] clocks. For instance, when deploying [[sensor]]s (for [[seismology]] or other monitoring application), [[Navigation System|GPS]] may be used to provide each recording apparatus with some precise time source, so that the time of events may be recorded accurately.

The [[atomic clock]]s on the satellites are set to "[[Navigation System|GPS]] time", which is the number of seconds since [[midnight|00:00:00]] [[Coordinated Universal Time|UTC]], [[January 6]], [[1980]]. Today, [[Navigation System|GPS]] time is 14 seconds ahead <ref>[[United States Coast Guard]]. [http://www.navcen.uscg.gov/[[Navigation System|gps]]/UTC_time_step_dec_2005.htm UTC Time step, December 2005]. [[July 27]], [[2005]]. Accessed [[May 14]], [[2006]]</ref> of [[Coordinated Universal Time|UTC]], because it does not follow [[leap second]]s. Receivers thus apply a clock-correction offset (which is periodically transmitted along with the other data) in order to display UTC correctly, and optionally adjust for a local time zone. New [[Navigation System|GPS]] units will initially show the incorrect time after achieving a [[Navigation System|GPS]] lock for the first time. However, this is usually corrected on the display within 15 minutes once the UTC offset message is received for the first time.

==History==
The design of [[Navigation System|GPS]] is based partly on the similar ground-based radio [[Navigation System|navigation]] systems, such as [[LORAN]] developed in the early 1940s, and used during [[World War II]]. Additional inspiration for the [[Navigation System|GPS]] system came when the [[Soviets]] launched the first [[Sputnik]] in 1957. A team of U.S. scientists led by Dr. Richard B. Kershner were monitoring Sputnik's radio transmissions. They discovered that, due to the [[Doppler effect]], the frequency of the signal being transmitted by Sputnik was higher as the satellite approached, and lower as it continued away from them. They realized that since they knew their exact location on the globe, they could pinpoint where the satellite was along its orbit by measuring the Doppler distortion. It was only a small leap of logic to realize that the converse was also true; if the satellite's position was known then they could identify their own position on Earth.

The first satellite [[Navigation System|navigation system]], [[Transit (satellite)|Transit]], used by the US Navy, was first successfully tested in 1960. Using a constellation of five satellites, it could provide a navigational fix approximately once per hour. In 1967 the US Navy developed the [[Timation]] satellite which proved the ability to place accurate clocks in space, a technology the [[Navigation System|GPS]] system relies upon. In the 1970s, the ground-based [[Omega Navigation System]], based on signal phase comparison, became the first world-wide radio [[Navigation System|navigation system]].

The first experimental Block-I [[Navigation System|GPS]] satellite was launched in February 1978. <ref>Hydrographic Journal. [http://www.hydrographicsociety.org/Articles/journal/2002/104-1.htm Developments in Global [[Navigation System|Navigation]] Satellite Systems]. April 2002. Accessed [[May 14]], [[2006]].</ref> The [[Navigation System|GPS]] satellites were initially manufactured by [[Rockwell International]] and now manufactured by [[Lockheed Martin]].

In 1983, after Soviet [[interceptor aircraft|jet interceptors]] shot down the civilian airliner [[KAL 007]] in restricted Soviet airspace, killing all 269 people on board, [[Ronald Reagan]] announced that the [[Navigation System|GPS]] system would be made available for civilian uses once it was completed.

By 1985, ten more experimental Block-I satellites had been launched to validate the concept. The first modern Block-II satellite was launched on 14th February 1989, and a complete constellation of 24 satellites was in orbit by 17th January 1994.

In 1996, recognizing the importance of [[Navigation System|GPS]] to civilian users as well as military users, President [[Bill Clinton]] issued a policy directive<ref>[[National Archives and Records Administration]]. [http://clinton4.nara.gov/textonly/WH/EOP/OSTP/html/[[Navigation System|gps]]-factsheet.html U.S. GLOBAL POSITIONING SYSTEM POLICY]. [[March 29]], [[1996]].</ref> declaring [[Navigation System|GPS]] to be a dual-use system and establishing an Interagency [[Navigation System|GPS]] Executive Board to manage it as a national asset.

In 1998, Vice President [[Al Gore]] announced plans to upgrade [[Navigation System|GPS]] with two new civilian signals for enhanced user accuracy and reliability, particularly with respect to aviation safety.

In 2004, President [[George W. Bush]] updated the national policy, replacing the board with the National Space-Based Positioning, [[Navigation System|Navigation]], and Timing Executive Committee.

The most recent launch was in September 2005. The oldest [[Navigation System|GPS]] satellite still in operation was launched in February 1989.

== Technical description ==
===Satellites===
[[Image: Global Positioning System satellite.jpg|200px|right|thumb|GPS satellite on test rack]]
The [[Navigation System|GPS]] system uses a [[satellite constellation]] of at least 24 active satellites in [[intermediate circular orbit]]s. The constellation also includes three spare satellites in orbit, in case of any failure. Each satellite circles the Earth exactly twice each day at an altitude of 20,200 [[kilometre]]s (12,600 miles). The orbits are aligned so at least four satellites are always within [[line of sight]] from almost any place on Earth. <ref>[[HowStuffWorks]]. [http://electronics.howstuffworks.com/[[Navigation System|gps]]1.htm How [[Navigation System|GPS]] Receivers Work]. Accessed [[May 14]], [[2006]].</ref>
There are four active satellites in each of six [[Orbital plane (astronomy)|orbital plane]]s. Each orbit is [[inclination|inclined]] 55 degrees from the [[equator|equatorial]] plane, and the [[right ascension]] of the ascending nodes are separated by sixty degrees. <ref>Dana, Peter H. [http://www.colorado.edu/geography/gcraft/notes/[[Navigation System|gps]]/gif/oplanes.gif [[Navigation System|GPS]] Orbital Planes]. [[August 8]], [[1996]].</ref>

The flight paths of the satellites are measured by five monitor stations around the world ([[Hawaii]], [[Kwajalein]], [[Ascension Island]], [[Diego Garcia]], [[Colorado Springs]]). The master control station, at [[Schriever AFB]], processes their combined observations and sends updates to the satellites through the stations at Ascension Island, Diego Garcia, Kwajalein. The updates synchronize the atomic clocks on board each satellite to within one [[microsecond]], and also adjust the [[ephemeris]] of the satellites' internal orbital model to match the observations of the satellites from the ground. <ref>[[USNO]]. [http://tycho.usno.navy.mil/gpsinfo.html NAVSTAR Global Positioning System]. Accessed [[May 14]], [[2006]].</ref>

Each satellite repeatedly re-broadcasts the exact time according to its internal atomic clock along with a digital data packet. The data includes the [[orbital elements]] of the satellite's precise position, satellite status messages, and an almanac of the approximate position of every other active [[Navigation System|GPS]] satellite. The almanac lets [[Navigation System|GPS]] receivers use data from the strongest satellite signal to locate other satellites.

===Receivers===
[[Navigation System|GPS]] receivers calculate their current position ([[latitude]], [[longitude]], [[elevation]]), and the precise time, using the process of [[trilateration]]. This involves measuring the distance to at least four satellites by comparing the satellites' coded time signal (PRN Code) transmissions. The receiver calculates the orbit of each satellite based on information encoded in their radio signals, and measures the distance to each satellite, called a [[pseudorange]], based on the time delay from when the satellite signals were sent until they were received.

In order to measure the delay, the satellite repeatedly sends a 1,023 [[bit]] long [[pseudorandom number generator|pseudo random sequence]]; the receiver calculates an identical sequence from a known [[random seed|seed number]], and shifts it until the two sequences match. Each satellite uses a different sequence, which lets them share the same radio frequencies, using [[CDMA|Code Division Multiple Access]], while still allowing receivers to identify each satellite.

Once the location and distance of each satellite is known, the receiver should theoretically be located at the intersection of four imaginary [[sphere]]s, one around each satellite, with a radius equal to the time delay between the satellite and the receiver multiplied by the speed of the radio signals. In practice, [[Navigation System|GPS]] calculations are more complex for several reasons. One complication is that [[Navigation System|GPS]] receivers do not have atomic clocks, so the precise time is not known when the signals arrive. Fortunately, even the relatively simple clock within the receiver provides an accurate comparison of the timing of the signals from the different satellites. The receiver is able to determine exactly when the signals were received by adjusting its internal clock (and therefore the spheres' radii) so that the spheres intersect near one point.

One of biggest problems for [[Navigation System|GPS]] accuracy is that changing atmospheric conditions change the speed of the [[Navigation System|GPS]] signals unpredictably as they pass through the [[ionosphere]]. The effect is minimized when the satellite is directly overhead and becomes greater toward the horizon, as the satellite signals must travel through the greater "thickness" of the ionosphere as the angle increases. Once the receiver's rough location is known, an internal mathematical model can be used to estimate and correct for the error.

Because ionospheric delay affects the speed of radio waves differently based on their frequencies, the second frequency band (L2) was used to help eliminate this type of error. Some military and expensive survey-grade civilian receivers can compare the difference between the L1 and L2 frequencies to measure atmospheric delay and apply precise corrections.

[[Navigation System|GPS]] signals can also be affected by multipath issues, where the radio signals reflect off surrounding terrain- buildings, canyon walls, hard ground, etc. This delay in reaching the receiver causes inaccuracy. A variety of receiver techniques, most notably [[Narrow Correlator spacing]], have been developed to mitigate multipath errors. For long delay multipath, the receiver itself can recognize the wayward signal and discard it. To address shorter delay multipath due to the signal reflecting off the ground, specialized antennas may be used. This form of multipath is harder to filter out as it is only slightly delayed as compared to the direct signal, causing effects almost indistinguishable from routine fluctuations in atmospheric delay.

Many [[Navigation System|GPS]] receivers can relay position data to a PC or other device using the [[NMEA]] 0183 protocol. NEMA 2000<ref>[[NEMA]]. [http://www.nmea.org/pub/2000/index.html NMEA 2000]</ref> is a newer and less widely adopted protocol. Both are proprietary, and are controlled on a for-profit basis by the US-based National Marine Electronics Association. References to the NMEA protocols have been compiled from public records, allowing open source tools like ''gpsd'' to read the protocol without violating [[Intellectual property]] laws.

===Frequencies===
Several frequencies make up the [[Navigation System|GPS]] [[electromagnetic spectrum]]:

* L1 (1575.42 [[megahertz|MHz]]):<BR>Carries a publicly usable coarse-acquisition (C/A) code as well as an encrypted precision P(Y) code.
* L2 (1227.60 MHz):<BR>Usually carries only the P(Y) code. The encryption keys required to directly use the P(Y) code are tightly controlled by the U.S. government and are generally provided only for military use. The keys are changed on a daily basis. In spite of not having the P(Y) code encryption key, several high-end [[Navigation System|GPS]] receiver manufacturers have developed techniques for utilizing this signal (in a round-about manner) to increase accuracy and remove error caused by the ionosphere. Recognizing the civilian need for increased accuracy, "modernized" IIR-M (IIR-14 (M) and later) satellites carry a civilian signal interleaved with an improved military signal on both the L1 and L2 frequencies.
* L3 (1381.05 MHz):<BR>Carries the signal for the [[Navigation System|GPS]] constellation's alternative role of detecting missile/rocket launches (supplementing [[Defense Support Program]] satellites), nuclear detonations, and other high-energy infrared events.
* L4 (1841.40 MHz):<BR>Being studied for additional ionospheric correction.
* L5 (1176.45 MHz):<BR>Proposed for use as a civilian safety-of-life (SoL) signal. This frequency falls into an internationally protected range for aeronautical [[Navigation System|navigation]], promising little or no interference under all circumstances. The first Block IIF satellite that would provide this signal is set to be launched in 2008.

===[[Navigation System|GPS]] and relativity===
The clocks on the satellites are also affected by both [[special relativity|special]] and [[general relativity]], which causes them to run at a slightly faster rate than do clocks on the Earth's surface. This amounts to a discrepancy of around 38 microseconds per day. To account for this, the frequency standard on-board the satellites runs slightly slower than its desired speed on Earth, at 10.22999999543 MHz instead of 10.23 MHz.<ref>Rizos, Chris. [[University of New South Wales]]. 1999[http://www.gmat.unsw.edu.au/snap/[[Navigation System|gps]]/[[Navigation System|gps]]_survey/chap3/312.htm [[Navigation System|GPS]] Satellite Signals]. 1999.</ref> This offset is a practical demonstration of the theory of relativity in a real-world system; it is exactly that [[predictive power|predicted]] by the theory, within the limits of accuracy of measurement.

Neil Ashby presented a good account of how these relativistic corrections are applied, why, and their orders of magnitude, in ''Physics Today'' (May 2002) <ref>[[Physics Today]]. [http://www.ipgp.jussieu.fr/~tarantola/Files/Professional/[[Navigation System|GPS]]/Neil_Ashby_Relativity_[[Navigation System|GPS]].pdf Relativity and [[Navigation System|GPS]]]. May 2002.</ref> Whether relativity must be considered as a mere correction to a Newtonian [[Navigation System|GPS]] theory, or, rather, as the necessary foundation of a cleaner (and more fundamental) [[Navigation System|GPS]] theory, is currently under debate. Bartolomé Coll has recently developed the basic notions necessary for a fully relativistic theory of Positioning Systems. <ref>Bartolomé Coll. [http://www.coll.cc Coll on relativity].</ref>

===Awards===
Two [[Navigation System|GPS]] developers have received the [[United States National Academy of Engineering|National Academy of Engineering]] [[Charles Stark Draper]] prize year 2003:

*[[Ivan Getting]], emeritus president of [[The Aerospace Corporation]] and [[engineer]] at the [[Massachusetts Institute of Technology]], established the basis for [[Navigation System|GPS]], improving on the [[World War II]] land-based radio system called [[LORAN]] ('''Lo'''ng-range '''R'''adio '''A'''id to '''N'''avigation).
*[[Bradford Parkinson]], teacher of [[aeronautics]] and [[astronautics]] at [[Stanford University]], developed the system.

One [[Navigation System|GPS]] developer, [[Roger L. Easton]], received the [[National Medal of Technology]] on [[February 13]] [[2006]] at the [[White House]].<ref>[[United States Naval Research Laboratory]]. [http://www.eurekalert.org/pub_releases/2005-11/nrl-par112205.php National Medal of Technology for [[Navigation System|GPS]]]. [[November 21]],[[2005]]</ref>

On [[February 10]], [[1993]], the [[National Aeronautic Association]] selected the Global Positioning System Team as winners of the 1992 [[Collier Trophy|Robert J. Collier Trophy]], the most prestigious aviation award in the United States. This team consists of researchers from the [[Naval Research Laboratory]], the [[U.S. Air Force]], the [[Aerospace Corporation]], [[Rockwell International|Rockwell International Corporation]], and [[IBM]] Federal Systems Company. The citation accompanying the presentation of the trophy honors the [[Navigation System|GPS]] Team "for the most significant development for safe and efficient [[Navigation System|navigation]] and surveillance of air and spacecraft since the introduction of radio [[Navigation System|navigation]] 50 years ago."

==Techniques to improve [[Navigation System|GPS]] accuracy==
The accuracy of [[Navigation System|GPS]] can be improved in a number of ways:

* '''[[Differential GPS]]''' '''(DGPS)''' can improve the normal [[Navigation System|GPS]] accuracy of 4-20 meters to 1-3 meters.<ref>[[Federal Highway Administration]]. [http://www.tfhrc.gov/its/ndgps/02072.htm Nationwide DGPS Program Fact Sheet]. Accessed [[May 14]], [[2006]]</ref> DGPS uses a network of stationary [[Navigation System|GPS]] receivers to calculate the difference between their actual known position and the position as calculated by their received [[Navigation System|GPS]] signal. The "difference" is broadcast as a local [[FM]] signal, allowing many civilian [[Navigation System|GPS]] receivers to "fix" the signal for greatly improved accuracy.
* The [[Wide Area Augmentation System]] ('''WAAS'''). This uses a series of ground reference stations to calculate [[Navigation System|GPS]] correction messages, which are uploaded to a series of additional satellites in geosynchronous orbit for transmission to [[Navigation System|GPS]] receivers, including information on [[ionosphere|ionospheric]] delays, individual satellite clock drift, and suchlike. Although only a few WAAS satellites are currently available [[as of 2004]], it is hoped that eventually WAAS will provide sufficient reliability and accuracy that it can be used for critical applications such as [[Navigation System|GPS]]-based instrument approaches in aviation (landing an airplane in conditions of little or no visibility). The current WAAS system only works for North America (where the reference stations are located), and due to the satellite location the system is only generally usable in the eastern and western coastal regions. However, variants of the WAAS system are being developed in Europe ([[EGNOS]], the Euro Geostationary [[Navigation System|Navigation]] Overlay Service), and Japan ('''MSAS''', the Multi-Functional Satellite Augmentation System), which are virtually identical to WAAS.
* A [[Local Area Augmentation System]] ('''LAAS'''). This is similar to WAAS, in that similar correction data are used. But in this case, the correction data are transmitted from a local source, typically at an airport or another location where accurate positioning is needed. These correction data are typically useful for only about a thirty to fifty kilometer radius around the transmitter.
* Exploitation of DGPS for Guidance Enhancement ('''EDGE''') is an effort to integrate DGPS into precision guided munitions such as the [[Joint Direct Attack Munition]] ('''JDAM''').
* A Carrier-Phase Enhancement ('''CPGPS'''). This technique utilizes the 1.575 GHz L1 carrier wave to act as a sort of [[clock signal]], resolving ambiguity caused by variations in the location of the pulse transition (logic 1-0 or 0-1) of the C/A [[Pseudorandom number generator|PRN]] signal. The problem arises from the fact that the transition from 0-1 or 1-0 on the C/A signal is not instantaneous, it takes a non-zero amount of time, and thus the [[cross-correlation|correlation]] (satellite-receiver sequence matching) operation is imperfect. A successful correlation could be defined in a number of various places along the rising/falling edge of the pulse, which imparts timing errors. CPGPS solves this problem by using the L1 carrier, which has a period 1/1000 that of the C/A bit width, to define the transition point instead. The phase difference error in the normal [[Navigation System|GPS]] amounts to a 2-3 m ambiguity. CPGPS working to within 1% of perfect transition matching can achieve 3 mm ambiguity; in reality, CPGPS coupled with [[Differential GPS|DGPS]] normally realizes 20-30 cm accuracy.
* Wide Area [[Navigation System|GPS]] Enhancement ('''WAGE''') is an attempt to improve [[Navigation System|GPS]] accuracy by providing more accurate satellite clock and [[ephemeris]] (orbital) data to specially-equipped receivers.
* Relative Kinematic Positioning ('''RKP''') is another approach for a precise [[Navigation System|GPS]]-based positioning system. In this approach, accurate determination of range signal can be resolved to an accuracy of less than 10 [[centimetre]]s. This is done by resolving the number of cycles in which the signal is transmitted and received by the receiver. This can be accomplished by using a combination of differential [[Navigation System|GPS]] (DGPS) correction data, transmitting [[Navigation System|GPS]] signal phase information and ambiguity resolution techniques via statistical tests—possibly with processing in real-time ([[Real Time Kinematic|real-time kinematic positioning]], RTK).
* Many automobiles that use the [[Navigation System|GPS]] combine the [[Navigation System|GPS]] unit with a [[gyroscope]] and [[speedometer]] pickup, allowing the computer to maintain a continuous [[Navigation System|navigation]] solution by [[dead reckoning]] when buildings, terrain, or tunnels block the satellite signals. This is similar in principle to the combination of [[Navigation System|GPS]] and [[inertial navigation]] used in ships and aircraft, but less accurate and less expensive because it only fills in for short periods.

==Selective availability==
When it was first deployed, [[Navigation System|GPS]] included a feature called '''Selective Availability''' (or '''SA''') that introduced intentional errors of up to a hundred meters into the publicly available [[Navigation System|navigation]] signals, making it difficult to use for guiding long range missiles to precise targets. Additional accuracy was available in the signal, but in an encrypted form that was only available to the United States military, its allies and a few others, mostly government users.

SA typically added signal errors of up to about 10 m horizontally and 30 m vertically. The inaccuracy of the civilian signal was deliberately encoded so as not to change very quickly, for instance the entire eastern US area might read 30 m off, but 30 m off everywhere and in the same direction. In order to improve the usefulness of [[Navigation System|GPS]] for civilian [[Navigation System|navigation]], '''[[Differential GPS]]''' was used by many civilian [[Navigation System|GPS]] receivers to greatly improve accuracy.

During the [[Gulf War]], the shortage of military [[Navigation System|GPS]] units and the wide availability of civilian ones among personnel resulted in disabling the Selective Availability. In the 1990s the [[Federal Aviation Administration|FAA]] started pressuring the military to turn off SA permanently. This would save the FAA millions of dollars every year in maintenance of their own [[radio navigation]] systems. The military resisted for most of the 1990s, but SA was eventually turned off<ref>[[Office of Science and Technology Policy]]. [http://www.ostp.gov/html/0053_2.html Presidential statement to stop degrading [[Navigation System|GPS]]]. [[May 1]], [[2000]].</ref> in 2000 following an announcement by then US President [[Bill Clinton]], allowing users access to an undegraded L1 signal.

The US military has developed the ability to locally deny [[Navigation System|GPS]] (and other [[Navigation System|navigation]] services) to hostile forces in a specific area of crisis without affecting the rest of the world or its own military systems. Such '''[[Navigation System|Navigation]] Warfare''' uses techniques such as local jamming to replace the blunt, world-wide degradation of civilian [[Navigation System|GPS]] service that SA represented.

Military (and selected civilian) users still enjoy some technical advantages which can give quicker satellite lock and increased accuracy. The increased accuracy comes mostly from being able to use both the L1 and L2 frequencies and thus better compensate for the varying signal delay in the ionosphere (see above).

*[http://pnt.gov/public/sa/ SA Announcements]

==[[Navigation System|GPS]] tracking==
[[Image: 100_0664.JPG|200px|right|thumb|GPS Navigation using the [[TomTom (company)|TomTom]] software]]
{{main|[[Navigation System|GPS]] tracking}}
A [[Navigation System|GPS]] tracking system uses [[Navigation System|GPS]] to determine the location of a vehicle, person, or pet and to record the position at regular intervals in order to create a track file or log of activities. The recorded data can be stored within the tracking unit, or it may be transmitted to a central location, or internet-connected computer, using a cellular modem, 2-way [[radio]], or satellite. This allows the data to be reported in [[real-time]], using either web browser based tools or customized software.

==[[Navigation System|GPS]] jamming==
{{further|[[SAASM|Selective Availability / Anti-Spoofing Module]]}}

Jamming of any radio [[Navigation System|navigation system]], including satellite based [[Navigation System|navigation]], is possible. The U.S. Air Force conducted [[Navigation System|GPS]] jamming exercises in 2003 and they also have [[Navigation System|GPS]] anti-spoofing capabilities. In 2002, a detailed description of how to build a short range [[Navigation System|GPS]] L1 C/A jammer was posted on a hackers' site by an anonymous author. There has also been at least one well-documented case of unintentional jamming, it traced back to a malfunctioning TV antenna preamplifier.<ref>[[Navigation System|GPS]] World. [http://www.gpsworld.com/gpsworld/article/articleDetail.jsp?id=43404&&pageID=1 The hunt for an unintentional [[Navigation System|GPS]] jammer]. [[January 1]], [[2003]].</ref> If stronger signals were generated intentionally, they could potentially interfere with aviation [[Navigation System|GPS]] receivers within line of sight. According to John Ruley, of AVweb, "IFR pilots should have a fallback plan in case of a [[Navigation System|GPS]] malfunction".<ref>Ruley, John. AVweb. [http://www.avweb.com/news/avionics/182754-1.html [[Navigation System|GPS]] jamming]. [[February 12]], [[2003]].</ref> [[RAIM|Receiver Autonomous Integrity Monitoring ]](RAIM), a feature of some aviation and marine receivers, is designed to provide a warning to the user if jamming or another problem is detected. There are also incidents of unintentional jamming, [[Navigation System|GPS]] signals can also be interfered with by natural [[geomagnetic storm]]s, predominantly at high latitudes.<ref>[[Space Environment Center]]. [http://www.sec.noaa.gov/nav/[[Navigation System|gps]].html SEC [[Navigation System|Navigation]] Systems [[Navigation System|GPS]] Page]. [[August 26]], [[1996]].</ref>

[[Navigation System|GPS]] jammers the size of a cigarette box are allegedly available from [[Russia]], their effectiveness is in question following their use in the Iraq war. The [[Federal government of the United States|U.S. government]] believes that such jammers were also used occasionally during the [[United States invasion of Afghanistan|U.S. invasion of Afghanistan]]. Some officials believe that jammers could be used to attract the precision-guided munitions towards [[non-combatant]] infrastructure, other officials believe that the jammers are completely ineffective. In either case, the jammers may be attractive targets for [[anti-radiation missile]]s. Low power jammers would have limited military usefulness and high power jammers would be easy to locate and destroy. During the Iraq war, the US military claimed to destroy a [[Navigation System|GPS]] jammer with a [[Navigation System|GPS]]-guided bomb. <ref>American Forces Press Service. [http://www.defenselink.mil/news/Mar2003/n03252003_200303254.html CENTCOM charts progress]. [[March 25]], [[2003]].</ref>

== Other systems ==
Russia operates an independent system called [[GLONASS]] ('''glo'''bal '''na'''vigation '''s'''ystem), although with only twelve active satellites [[as of 2004]], the system is of limited usefulness. There are plans to restore GLONASS to full operation by 2008. The [[European Union]] is developing [[Galileo positioning system|Galileo]] as an alternative to [[Navigation System|GPS]], planned to be in operation by 2010. China and France are also developing [[satellite navigation system|other satellite navigation systems]].

{{[[Navigation System|GPS]]}}

==See also==
{{commonscat|Global Positioning System}}
*[[Geographic coordinate system]]
*[[Wikipedia:WikiProject Geographical coordinates|Wikipedia Geographical coordinates project]] - adding [[Geographic coordinate system|geographic coordinates]] to WikiPedia articles
*[[Assisted GPS]]
*[http://confluence.org Degree confluence project] Use [[Navigation System|GPS]] to visit integral degrees of latitude and longitude. Pictures and narrative for each one.
*[[Geodashing]]
*[[GPX]] - [[Navigation System|GPS]] eXchange Format
*[[Location based media]]
*[[Waypoint]]
*[[m:WikiGPS|WikiGPS]], [[Wikimedia Foundation|Wikimedia]] proposed project.
*[[World Geodetic System]] - '''WGS 84''' defines a global reference frame for [[Navigation System|GPS]]

==External links==
===References===
<references/>

* [http://www.colorado.edu/geography/gcraft/notes/[[Navigation System|gps]]/[[Navigation System|gps]]_f.html Peter H. Dana: Global Positioning System Overview] - Large amount of technical information and discussion.
* [http://www.navcen.uscg.gov/pubs/[[Navigation System|gps]]/sigspec/default.htm [[Navigation System|GPS]] SPS Signal Specification, 2nd Edition] - The official (civilian) signal specification.
* [http://www.astronautix.com/project/navstar.htm History of [[Navigation System|GPS]]], including information about each satellite's configuration and launch.
* [http://www.navcen.uscg.gov/ftp/[[Navigation System|gps]]/ARCHIVES/gpsdoc/IOCLTR.TXT Announcement of Initial Operational Capability, December 1993]
* U.S. Army Corps of Engineers manual: [http://www.usace.army.mil/inet/usace-docs/eng-manuals/em1110-1-1003/toc.htm NAVSTAR HTML] and [http://www.usace.army.mil/inet/usace-docs/eng-manuals/em1110-1-1003/entire.pdf PDF (22.6 MB, 328 pages)]
* [http://gpsinformation.net/airgps/gpsrfi.htm Is it Safe to use a handheld [[Navigation System|GPS]] Receiver on a Commercial Aircraft?] - Discusses the safety of personal use of a [[Navigation System|GPS]] on commercial aircraft.
* [http://netlab18.cis.nctu.edu.tw/html/paper/2001_11_06/Challenges%20in%20bringing%20[[Navigation System|GPS]]%20to%20Mainstream%20Consumers.pdf The Global Positioning System: Challenges in Bringing [[Navigation System|GPS]] to Mainstream Consumers] Technical Article by Kanwar Chadha, BSEE (1998)
* [http://www.navcen.uscg.gov/[[Navigation System|gps]]/default.htm USCG [[Navigation System|Navigation]] Center]: Status of the [[Navigation System|GPS]] constellation, government policy, and links to other references. Also includes satellite [[almanac]] data.
* [https://www.schriever.af.mil/[[Navigation System|gps]]/archive/2005/ Schriever Airforce Base Webserver]: Even more up-to-date almanac data and NANUs
* [http://pnt.gov/ National Space-Based PNT Executive Committee] - Established in 2004 to oversee management of [[Navigation System|GPS]] and [[Navigation System|GPS]] augmentations at a national level.
* [http://[[Navigation System|gps]].losangeles.af.mil/ The [[Navigation System|GPS]] Joint Program Office ([[Navigation System|GPS]] JPO)] - Responsible for designing and acquiring the system on behalf of the US Government.
* The [[Federal Aviation Administration|FAA]] has more information on [[Navigation System|GPS]], WAAS, LAAS, and DGPS at http://[[Navigation System|gps]].faa.gov/FAQ/index.htm
* [http://www.defense-update.com/products/g/[[Navigation System|gps]]-guidance.htm [[Navigation System|GPS]] Weapon Guidance Techniques]

===Software===
* [http://earth.google.com Google Earth]
* [http://worldwind.arc.nasa.gov/ NASA World Wind]
* [http://www.gpsinformation.org/dale/Palm/pilotgps.htm Dale Priest's guide to [[Navigation System|navigation]] with [[Navigation System|GPS]] and Palm PDAs]
* [http://www.mgix.com/[[Navigation System|gps]]3d [[Navigation System|GPS]]3d, a 3D [[Navigation System|gps]] visualization tool]
* [http://gpsd.berlios.de/ GPSd, a [[Navigation System|GPS]] daemon program]
* [http://www.gpsbabel.org/ GPSBabel, which converts waypoints, tracks, and routes from one format to another]
* [[GpsDrive]], [http://www.kraftvoll.at/software/ external link] - '''GNU''' Map-based [[Navigation System|navigation system]]. It displays your position on a zoomable map provided from a [[NMEA]]-capable [[Navigation System|GPS]] receiver.
* [http://gpstk.sourceforge.net/ GPSTk: A free Open Source [[Navigation System|GPS]] Toolkit]
* [http://www.gpsvisualizer.com/ [[Navigation System|GPS]] Visualizer] - A free online utility that creates maps and profiles in [[Scalable Vector Graphics|SVG]], JPEG/PNG, or Google Maps/Google Earth format from [[Navigation System|GPS]] waypoints and tracks.
* [http://www.isrfleettrack.com/products/software.html ISR FleetTrack] - A powerful and robust suite of fleet tracking software working in tandem with its proprietary hardware to provide real-time and report data for fleet managers.
* [http://www.bernese.unibe.ch/index.html Bernese [[Navigation System|GPS]] Software] - scientific [[Navigation System|GPS]]/GLONASS post processing package
* [http://www.microsoft.com/streets/default.mspx Microsoft Streets & Trips with [[Navigation System|GPS]] Locator]
* [http://www.globaltrackingtech.com Global Tracking Technologies' Global [[Navigation System|GPS]] tracking system platform]
* [http://www.visualgps.net/VisualGPS/ VisualGPS] - software that parses NMEA sentences and displays the information.
* [http://sourceforge.net/projects/garble/ Garble] - software for downloading data from Garmin handsets.

===Makers of popular [[Navigation System|GPS]] hardware and vehicle [[Navigation System|navigation]] systems===
* [[Alpine Electronics]]
* [http://www.Becker.de/ Becker]
* [http://www.clarion.com/ Clarion]
* [http://www.cobra.com/ Cobra]
* [http://www.eclipse-web.com/ Fujitsu Ten]
* [[Garmin]]
* [[Lowrance Electronics]]
* [[Thales Group|Magellan]]
* [http://www.mobilecrossing.com/ Mobile Crossing]
* [http://www.navman.com/ Navman]
* [http://www.novariant.com/ Novariant]
* [http://www.novatel.com/ NovAtel]
* [http://www.pharosgps.com/ pharos]
* [[Pioneer Corporation]]
* [http://www.septentrio.com/ Septentrio]
* [[TomTom (company)|TomTom]]
* [http://www.vdodayton.com/ VDO Dayton]

===[[Navigation System|GPS]] software for car [[Navigation System|navigation]]===
* [http://www.alk.com/copilot/ CoPilot]
* [http://www.destinatortechnologies.com/ Destinator]
* [http://www.microsoft.com/uk/homepc/autoroute/default.mspx Microsoft Autoroute]
* [http://www.scytex.com/ Navi BT [[Navigation System|GPS]] Scytex]
* [http://www.pocketgps.ru/ PocketGPS Pro Moscow]
* [http://www.street-director.com/ street director]
* [http://www.shop.viamichelin.co.uk/csasp_editorial.asp?ID=96 ViaMichelin [[Navigation System|Navigation]]]

===Hardware===
* [http://www.globallocate.com Global Locate] Host-based A-[[Navigation System|GPS]] embedded in devices such as [[HP|HP]] iPAQ
*[http://www.oscilloquartz.com/ [[Navigation System|GPS]]-based Synchronization and Time Server solutions] [[Navigation System|GPS]]-based solutions for all telecom and timing Synchronisation needs
*[http://www.galleon.eu.com/products/ts.htm [[Navigation System|GPS]] Time Server solutions] Time Server solutions for all your computer time Synchronisation needs
* [http://www.isrfleettrack.com/products/hardware.html ISR FleetTrack Silent Position Monitor] The hardware component of ISR's total fleet tracking suite.
* [http://www.sirf.com SiRF Technology] Manufactures [[Navigation System|GPS]] Silicon and a complete range of software solutions for Location awareness.
* [http://www.septentrio.com/ Septentrio] - Makers of high-end receivers for precise applications
* [http://www.u-blox.com/products/index.html u-blox [[Navigation System|GPS]] products (chipsets, modules, receiver boards, antennas and accessories)]
* [http://www.timetools.co.uk [[Navigation System|GPS]] NTP Server] [[Navigation System|GPS]] time servers and NTP servers for computer network timing.
* [http://www.goandtrack.com Tracking Device Information] [[Navigation System|GPS]] tracking devices reviewed for a number of vertical market applications such as personal, vehicle and container tracking
* [http://www.ntp-time-server.com NTP time server] NTP time server for Windows NT 2000 XP NOVELL UNIX
* [http://www.arktime.com Arktime] Arktime NTP and [[Navigation System|GPS]] time servers for computer networks
* [http://www.gpstrackstick.com [[Navigation System|GPS]] Track Stick Logging Device] [[Navigation System|GPS]] Track Stick Logging Device
* [http://www.comtechm2m.com/gprs-modem/gprs-[[Navigation System|gps]]-modem.htm Intelligent [[Navigation System|GPS]] GPRS modem] [[Navigation System|GPS]] device for remote machines, assets and devices

===Usenet newsgroups===
* sci.geo.satellite-nav [news:sci.geo.satellite-nav Direct] or via the [http://groups-beta.google.com/group/sci.geo.satellite-nav Google Groups] web site.
* uk.rec.[[Navigation System|gps]] [news:uk.rec.[[Navigation System|gps]] Direct] or via the [http://groups-beta.google.com/group/uk.rec.[[Navigation System|gps]] Google Groups] web site.

===Other information===
*[http://gge.unb.ca/Resources/HowDoesGPSWork.html In Simple Terms, How Does [[Navigation System|GPS]] Work?]
* [http://www.u-blox.com/technology/[[Navigation System|GPS]]-X-02007.pdf u-blox [[Navigation System|GPS]] Tutorial] — Tutorial designed to introduce you to the principles behind [[Navigation System|GPS]]
* [http://www.geoplace.com Geoplace] — [[Navigation System|GPS]] & GIS Industry information
* [http://www-astronomy.mps.ohio-state.edu/~pogge/Ast162/Unit5/[[Navigation System|gps]].html [[Navigation System|GPS]] and Relativity]
* [http://www.livingreviews.org/lrr-2003-1/ Neil Ashby: "Relativity in the Global Positioning System"]
* [http://www.trimble.com/[[Navigation System|gps]]/ Trimble's Online [[Navigation System|GPS]] Tutorial] — excellent introduction for newbies
* [http://www.dbartlett.com The Practical Guide to [[Navigation System|GPS]] UTM]
* [http://www.rand.org/publications/MR/MR614/MR614.appb.pdf PDF document on the history of the [[Navigation System|GPS]] system]
* [http://www.openstreetmap.org/ Open Street Map] - a wiki street map project, a work in progress (creative commons license)
* [http://www.defense-update.com/products/g/[[Navigation System|gps]]-aj.htm [[Navigation System|GPS]] Anti-Jam Protection Techniques]

[[Category:GPS| ]]
[[Category:Camping equipment]]
[[Category:Backpacking]]
[[Category:Navigational equipment]]
[[Category:Navigation]]

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V6

2006-05-15T03:38:55Z

Jrosenblum:

[[Image:FordEssexV6.jpg|thumb|right|The [[Ford Essex V6 engine]]]]
{{Redirect2|V6|V-6}}

A '''V6 engine''' is a [[V engine]] with six [[cylinder (engine)|cylinder]]s. It is the second most common engine configuration in modern cars after the [[straight-4]]; it shares with that engine a compactness very suited to the popular [[front-wheel drive]] layout, and is becoming more popular as car weights increase.

The first V6 was introduced by [[Lancia]] in [[1950]] with the [[Lancia Aurelia]], other manufacturers took note and soon other V6 engines were in use. The design really took off after the 1962 introduction of the [[Buick Special]]. Though the model was not a spectacular success, it was the first mass-produced V6 engine.

==Vee angles==
A V6 is not a perfectly balanced engine and benefits from some [[balance shaft|counterbalancing]] and harmonic damping. The optimal angle to minimize vibrations in the V6 is 60°, and this is commonly used. The most common 60° V6s were built by Ford European subsidiaries : [[Ford Essex V6 engine (UK)|Essex V6]], [[Ford Cologne V6 engine|Cologne V6]] and the more recent [[Ford Duratec|Duratec V6]]. The [[Alfa-Romeo]] V6 is also common.

90° V6 engines have also been produced, often to take advantage of production-line machinery set up for V8 engines (for which 90° is optimal). This design was first used by [[Buick]] when it introduced its [[Buick V6 engine#198|198 in³ ''Fireball V6'']] as the standard engine in the [[1962]] [[Buick Special|Special]]. Other examples include the [[Maserati]] V6 used in the [[Citroën SM]], the [[PRV engine|PRV]] V6, [[Chevrolet]]'s [[GM Vortec engine#4300|4.3 L ''Vortec 4300'']] and [[Chrysler Corporation|Chrysler]]'s [[Chrysler LA engine#238|3.9 L ''Magnum V6'']] and [[Chrysler PowerTech engine#3.7|3.7 L ''PowerTech V6'']].

Narrow angle V6 engines are very compact but suffer from vibration. Lancia's [[1924]] engine was such a design; Lancia produced similar engines until the [[1970s]]. More recently, [[Volkswagen]] have used such a design, known as the [[VR6 engine]]. In this engine, both banks share the same cylinder head and are extremely close together.

Other notable V6 bank angles:
* The 10.6° and 15° [[Volkswagen]] VR6, a V6 with such a narrow angle it shares many characteristics with the [[straight-6]], such as its firing order and use of a single cylinder head.
* The 54° [[GM 54-Degree V6 engine|GM/Opel V6]], designed to be narrower than normal for use in small [[front-wheel drive]] cars.
* The 65° [[Ferrari Dino]] V6. The engine was originally fed by [[carburetor]]s. A 60° angle was limiting the size of the carburetors, while a 65° angle allowed to mount larger carburetors to the expense of a slight increase of vibrations.

==Odd and even firing==
Many V6 engines have been based on [[V8 engine]] designs. One characteristic of these engines is a notorious ''odd-firing'' behavior.

Purpose-built V6 engines use one crankpin per cylinder for a smooth ignition 120Â° ignition pattern. In contrast, most V8 engines share a common crankpin between opposite cylinders in each bank. That is, the [[crankshaft]] has just four pins for eight cylinders, and a cylinder fires every 90Â° for smooth operation.

V6 engines that are converted from V8 engines often have three shared crankpins arranged at 120Â° from each other, similar to an [[Straight-3|inline 3-cylinder]] with two pistons per crankpin. If the cylinder banks are arranged at 90Â° (as they commonly are in V8-derived V6s), this leads to a firing pattern with groups of two cylinders separated by 90Â° of rotation, and groups separated by 150Â° of rotation.

An example is the [[Buick V6 engine#231|Buick 231 odd-fire]], which has a [[firing order]] 1-6-5-4-3-2. As the crankshaft is rotated through the 720Â° required for all cylinders to fire, the following events occur on 30Â° boundaries:

Nissan use the firing order 1-2-3-4-5-6 in some of the V6 engines they make

<div align=center>
{| width=90%
|- align=left
|width=12%|'''Angle'''
|colspan=9 width=11%|0Â°
|colspan=9 width=11%|90Â°
|colspan=9 width=11%|180Â°
|colspan=9 width=11%|270Â°
|colspan=9 width=11%|360Â°
|colspan=9 width=11%|450Â°
|colspan=9 width=11%|540Â°
|colspan=9 width=11%|630Â°
|- align=left
|'''Odd firing'''
|colspan=9 width=11%|1
|colspan=15 width=18%|6
|colspan=9 width=11%|5
|colspan=15 width=18%|4
|colspan=9 width=11%|3
|colspan=15 width=18%|2
|-
|'''Even firing'''
|colspan=12 width=14%|1
|colspan=12 width=14%|6
|colspan=12 width=14%|5
|colspan=12 width=14%|4
|colspan=12 width=14%|3
|colspan=12 width=14%|2
|}
</div>

In [[1977]], [[General Motors Corporation|General Motors]] introduced a unique "split-pin crankshaft" in the [[GM 3800 engine]]. Using a crankpin that is 'split' and offset by 30Â° of rotation results in smooth, even firing. Such a 'split' crankpin is weaker than a straight one, but modern materials and manufacturing produce a crankshaft that is strong enough. In [[1986]] the similarly-designed 90Â° [[PRV engine]] adopted the same 30Â° crankshaft offset design to even out its firing.

==Racing use==
The V6 engine was introduced into racing by the Ferrari Dino V6. [[Alfredino Ferrari|Alfredo Ferrari]] (nicknamed Dino), the only legitimate son of [[Enzo Ferrari]], suggested to him the development of a 1.5 L [[DOHC]] V6 engine for F2 at the end of [[1955]]. Soon afterwards, Alfredo fell ill, suffering from [[muscular dystrophy]]. While in hospital, he discussed technical details with the engineer [[Vittorio Jano]]. Dino would never see the engine; he died on [[1956-06-30]] at the age of 24.

The Dino V6 underwent several evolutions, and—with an increased [[engine displacement]]—competed in the 2.5 L [[Formula One]].

Until the advent of wing cars, a wide 120° bank angle was appealing for racing engine designers as it permits a low [[center of gravity]]. It was even considered superior to the [[flat-6]] in that it leaves more space under the engine for exhaust pipes; thus the crankshaft can be placed lower in the car. A further evolution of the [[Ferrari]] Dino built for new Formula One 1.5 L regulations engines had this configuration.

This engine saw a new evolution in [[1966]] when it was adapted to road use and produced by a Ferrari-Fiat joint-venture for the Fiat Dino and Dino 206 GT (this car was made by Ferrari but sold under the brand Dino). This new version was redesigned by [[Aurelio Lampredi]] initially as a 65° 2.0 L V6 with an aluminum block but was replaced in [[1969]] by a 2.4 L cast-iron block version (the Dino car was renamed the 246GT).

The Fiat Dino and Dino 246GT were phased out in 1974, but 500 engines among the last built were delivered to [[Lancia]], who was like Ferrari already under the control of [[Fiat]]. Lancia used them for the [[Lancia Stratos]] which would became the most successful car in [[Rally racing]] history.

Another influential V6 design was the [[Renault]]-[[Gordini]] CH1 V6, designed by [[François Castaing]] and [[Jean-Pierre Boudy]], and introduced in [[1973]] in the [[Alpine (car)|Alpine]]-Renault A440. The CH1 was a 90° [[cast iron]] block V6, similar to the mass produced PRV engine in those two respects but otherwise dissimilar. It has been suggested that marketing purposes made the Renault-Gordini V6 adopt those characteristics of the PRV in the hope of associating the two in the public's mind.

Despite such considerations, this engine won the European 2 L prototype championship in [[1974]] and several European Formula 2 titles. This engine was further developed in a tubocharged 2 L version that competed in Sports car and finally won the [[24 Hours of Le Mans]] in 1978 with a Renault-Alpine A 442 chassis.

The capacity of this engine was reduced to 1.5 L to power the Formula One Renault RS01. Despite frequent breakdowns that resulted in the nickname of the 'Little Yellow Teapot', the 1.5 L finally saw good results in 1979.

Ferrari followed Renault in the turbo revolution by introducing a turbocharged derivative of the Dino design (a 1.5 L 120° V6) with the Ferrari 126.

Both Renault and Ferrari failed in their attempt to win the Drivers's Championship with V6 Turbo engine. The first turbocharged engine to win the championship was the [[Straight-4]] [[BMW]].

They were followed by a new generation of Formula One engines the most successful of these being the TAG V6 (designed by [[Porsche]]) and the [[Honda]] V6. This new generation of engines were characterized by odd V angles (around 80°). The choice of these angles was mainly driven by aerodynamic consideration. Despite their unbalanced designs these engines were both quickly reliable and competitive; this is generally viewed as a consequence of the quick progress of CAD techniques in that era.

==External links==
* [http://home.off-road.com/~merls_garage/oddfire.html Understanding the odd-fire V6]

{{Piston engine configurations}}

[[Category:Piston engine configurations|V-06]]

[[ja:V型6気筒]]

HP

2006-05-15T03:36:39Z

Jrosenblum: copied from wikipedia

:''This article is about the unit of measurement. For the machine which used horses to generate power, see [[horse power (machine)]]. For other uses of ''hp'', see [[HP (disambiguation)]]''.

:''SHP redirects here. For Sosyaldemokrat Halk Partisi, see [[Social Democratic People's Party (Turkey)]]''.

The '''horsepower''' ('''hp''') is the name of several non-metric [[units of measurement|units]] of [[Power (physics)|power]]. In scientific discourse the term "horsepower" is rarely used due to the various definitions and the existence of an [[SI]] unit for power, the [[watt]] (W). However, the idea of horsepower persists as a legacy term in many languages, particularly in the [[automobile|automotive]] industry for listing the maximum power of [[internal-combustion engine]]s.

There are two important factors to consider when evaluating a "horsepower" figure:
* Various ''[[#Definition|definitions]]'' for the unit itself
* Various ''[[#Measurement|standards]]'' for measuring the value
These factors can be combined in unexpected ways — the true power output for an engine rated at "100 horsepower" might vary significantly from a reader's expectations. For this reason, various groups have attempted to standardize both the definition and measurement system, often leading to even more confusion. Although the SI watt is not subject to varying definitions, it can still vary based on the measurement conditions.

==Definition==

There have been many definitions for the term over the years since [[James Watt]] first coined the term in [[1782]]. The following metrics have been widely used:
* [[#Mechanical horsepower|Mechanical horsepower]] — 0.74569987158227022 [[watt|kW]] (33,000 ft·lbf per minute)
* [[#Metric horsepower|Metric horsepower]] — 0.73549875 kW
* [[#Electrical horsepower|Electrical horsepower]] — 0.746 kW
* [[#Boiler horsepower|Boiler horsepower]] — 9.8095 kW

Additionally, the term "horsepower" has been applied to calculated (rather than measured) metrics:
* [[#RAC horsepower|RAC horsepower]] is based solely on the dimensions of a piston engine

===Mechanical horsepower===
:''See [[#History of the term "horsepower"|History of the term "horsepower"]]''
The most-common definition of horsepower for engines is the one originally proposed by [[James Watt]] in 1782. Under this system, one horsepower is defined as:

: 1 hp = 33,000 [[foot (unit of length)|ft]]·[[pound-force|lbf]]·[[minute|min]]<sup>−1</sup> = exactly 0.74569987158227022 kW

A common memory aid is based on the fact that [[Christopher Columbus]] first sailed to [[the Americas]] in [[1492]]. The memory aid states that 1 hp = 1/2 Columbus or 746 W.

: ''In fourteen hundred and ninety-two''
: ''Columbus sailed the ocean blue''.
: ''Divide that [[son of a gun|son-of-a-gun]] by two''
: ''And that's the number of watts in a horsepower too''.

=== Metric horsepower ===

Metric horsepower began in Germany in the 19th century and became popular across Europe and Asia. The various units used to indicate this definition ("PS", "CV", "pk", and "ch") all translate to "horse power" in English, so it is common to see these values referred to as "horsepower" or "hp" in the press releases or media coverage of the German, French, Italian, and Japanese automobile companies. Companies of the United Kingdom often intermix metric horsepower and mechanical horsepower depending on the origin of the engine in question.

Metric horsepower, as a rule, is defined as 0.73549875 kW, or roughly 98.6% of mechanical horsepower. This was a minor issue in the days when measurement systems varied widely and engines produced less power, but has become a major sticking point today. Exotic cars from Europe like the [[McLaren F1]] and [[Bugatti Veyron]] are often quoted using the wrong definition, and their power output is sometimes even converted twice due to confusion over whether the original "horsepower" number was metric or mechanical.

==== PS ====
This unit (German: ''Pferdestärke'' = horse strength) is no longer a lawful unit, but is still commonly used in Europe, South America and Japan, especially by the automotive and motorcycle industry. It was adopted throughout continental Europe with designations equivalent to the English "horse power", but mathematically different from the British unit. It is defined by the ''Physikalisch-Technische Bundesanstalt'' (PTB)[http://www.ptb.de/] in [[Braunschweig (city)|Braunschweig]] as exactly:

: 1 PS = 75 [[kilopond|kp]]·m/s = 0.73549875 kW = 0.9863201652997627 hp (SAE)

The PS was adopted by the [[DIN|Deutsches Institut für Normung (DIN)]] and then by the automotive industry throughout most of Europe. But in the 19th century, the French did not use this German unit, but had their own, the [[Poncelet]]. In 1992, the PS was rendered obsolete by EEC directives, where it was replaced by the kilo[[watt]] as the official power measuring unit, but in situations where horsepower was used for commercial and advertising purposes, it continued to be used, as customers were not familiar with the use of kilowatts for combustion engines.

==== pk ====

A Dutch ''paardekracht'' equals the German ''Pferdestärke'' hence
: 1 pk = 0.73549875 kW

==== CV ====

Often the French name for the Pferdestärke. Also a French unit for [[tax horsepower]], short for ''chevaux vapeur'' ("steam horses") or ''cheval-vapeur''.

In Italian ("Cavalli"), Spanish ("Caballos"), and Portuguese ("Cavalos"), 'CV' is the equivalent to the German 'PS'.

==== ch ====

This is a French unit for automobile power. The symbol ch is short for ''chevaux'' ("horses"). Some sources give it as 0.7355 kW, but it is generally used interchangeably with the German 'PS'.

=== Boiler horsepower ===

A '''boiler horsepower''' is used for boilers in [[power station|power plants]]. It is equal to 33,475 [[Btu]]/h (9.8095 kW), which is the energy rate needed to evaporate 34.5 lb (15.65 kg) of water at 212 [[degree Fahrenheit|°F]] (100 [[degree Celsius|°C]]) in an hour.

=== Electrical horsepower===

The '''electrical horsepower''' is used by the electrical industry for electric motors and is defined to be exactly 746 W (at 100% efficiency).

=== Relationship with torque ===
For a given [[torque]], the equivalent power may be calculated. The standard equation relating torque in [[foot-pound]]s, rotational speed in [[RPM]] and horsepower is:
:<math>P / {\rm hp} = {[\tau / ({\rm ft \cdot lbf})] [\omega / ({\rm r/min})] \over 5252}</math>.
This is based on Watt's definition of the mechanical horsepower. The constant 5252 is rounded; the exact value is 16,500/π. See [[torque#Relationship between torque and power|torque]].

=== Drawbar horsepower (dbhp) ===
'''Drawbar horsepower''' is the power a [[railroad]] [[locomotive]] has available to haul a [[train]] or an agricultural tractor to pull an implement. This is a measured figure rather than a calculated one. A special [[railroad car]] called a [[dynamometer]] car coupled behind the locomotive keeps a continuous record of the [[drawbar]] pull exerted, and the speed. From these, the power generated can be calculated. To determine the maximum power available, a controllable load is required; this is normally a second locomotive with its brakes applied, in addition to a static load.

If the drawbar force is measured [[pounds-force]] (<math>F / {\rm lbf}</math>) and speed is measured in miles per hour (<math>v / ({\rm mi/h})</math>), then the drawbar power in horsepower (<math>P / {\rm hp}</math>) is:

:<math>P / {\rm hp} = {[F / {\rm lbf}] [v / ({\rm mi/h})] \over 375}</math>.

Example: How much drawbar power is needed to pull a cultivator load of 2025 pounds-force through medium soil at 5 miles per hour?

<math>P / {\rm hp} = {{2025 \times 5 } \over 375} = 27</math>.

The constant "375" is because 1 hp = 375 lbf·mi/h. If other units are used, the constant is different. When using a coherent system of units, such as [[SI]] (watts, newtons, and metres per second), no constant is needed, and the formula becomes <math>P = Fv</math>.

=== RAC horsepower (taxable horsepower) ===

This measure was instituted by the [[Royal Automobile Club]] in [[United Kingdom|Britain]] and used to denote the power of early [[20th century]] British [[automobile|cars]]. Many cars took their names from this figure (hence the [[Austin Motor Company|Austin]] Seven and [[Riley (automobile)|Riley]] Nine), while others had names such as "40/50hp", which indicated the RAC figure followed by the true measured power.

Taxable horsepower does not reflect developed horsepower; rather, it is a calculated figure based on the engine's bore size, number of cylinders, and a (now archaic) presumption of engine efficiency. As new engines were designed with ever-increasing efficiency, it was no longer a useful measure, but was kept in use by UK regulations which used the rating for [[tax horsepower|tax purposes]].

:<math>RAC h.p. = {D^2 * n}/2.5 \,</math>

:where

: ''D'' is the diameter (or bore) of the cylinder in inches
: ''n'' is the number of cylinders

This is equal to the displacement in cubic inches divided by 10π then divided again by the stroke in inches. [http://www.designchambers.com/wolfhound/wolfhoundRACHP.htm]

Since taxable horsepower was computed based on bore and number of cylinders, not based on actual displacement, it gave rise to engines with 'undersquare' dimensions, i.e. relatively narrow bore, but long stroke; this tended to impose an artificially low limit on rotational speed ([[rpm]]), hampering the true power output and efficiency of the engine.
The situation persisted for several generations of four- and six-cylinder British engines: for example, [[Jaguar (car)|Jaguar's]] 3.8-litre XK engine had six cylinders with a bore of 87 mm (3.43 inches) and a stroke of 106 mm (4.17 inches), where most American automakers had long since moved to oversquare (wide bore, short stroke) V-8s.

==Measurement==

The power of an engine may be measured or estimated at several points in the transmission of the power from its generation to its application. A number of names are used for the power developed at various stages in this process, but none is a clear indicator of both the measurement system and definition used.

In general:
:[[#Indicated horsepower (ihp)|Indicated]] or gross horsepower (theoretical capability of the engine)
::minus frictional losses within the engine (bearings, rods, etc), equals
:[[#Brake horsepower (bhp)|Brake]] or net horsepower (power delivered directly by the engine)
::minus frictional losses in the transmission (bearings, gears, etc.), equals
:[[#Shaft horsepower (shp)|Shaft]] horsepower (power delivered to the driveshaft)
::minus shaft losses (friction, slip, [[cavitation]], etc), equals
:[[#Effective horsepower (ehp)|Effective]] or wheel horsepower

=== Indicated horsepower (ihp) ===

'''Indicated horsepower''' is the theoretical power of a reciprocating engine assuming that it is completely efficient in converting the energy contained in the expanding gases in the cylinders. It is calculated from the pressures developed in the cylinders, measured by a device called an ''engine indicator'' - hence indicated horsepower. It was the figure normally used for [[steam engine]]s in the [[19th century]] but is misleading because the mechanical efficiency of an engine means that the actual power output may be only 70% to 90% of the indicated horsepower.

==== SAE gross horsepower ====

Prior to [[1972]] most American automakers rated their engines in terms of '''SAE gross horsepower''' (defined under SAE standards J245 and J1995). Gross hp was measured using a blueprinted test engine running on a stand without accessories, mufflers, or emissions control devices. It therefore reflected a maximum, theoretical value, not the power of an installed engine in a street car. Gross horsepower figures were also subject to considerable adjustment by carmakers: the power ratings of mass-market engines were often exaggerated, while those for the highest-performance [[muscle car]] engines were frequently underrated.

=== Brake horsepower (bhp) ===

'''Brake horsepower''' (bhp) is the measure of an engine's horsepower without the loss in power caused by the gearbox, generator, differential, water pump and other auxiliaries. The actual horsepower delivered to the driving wheels is less. An engine would have to be retested to obtain a rating in another system.

==== hp (SAE)====

In the United States the term "bhp" fell into disuse after the American [[Society of Automotive Engineers]] (SAE) recommended manufacturers use '''hp (SAE)''' to indicate the net power of the engine, given that particular car's complete engine installation. It measures engine power at the [[flywheel]], not counting drivetrain losses.

Starting in [[1971]] automakers began to quote power in terms of '''SAE net horsepower''' (as defined by standard J1349). This reflected the rated power of the engine in as-installed trim, with all accessories and standard intake and exhaust systems. By 1972 U.S. carmakers quoted power exclusively in SAE net hp. The change was meant to 'deflate' power ratings to assuage the [[auto insurance]] industry and environmental and safety lobbies, as well as to obfuscate the power losses caused by [[smog|emissions]]-control equipment.

SAE net ratings, while more accurate than gross ratings, still represent the engine's power at the flywheel. Contrary to some reports, it does ''not'' measure power at the drive wheels.

Because SAE gross ratings were applied liberally, at best, there is no precise conversion from gross to net. Comparison of gross and net ratings for unchanged engines show a variance of anywhere from 40 to 150 horsepower. The [[Chrysler]] [[426 Hemi]], for example, in 1971 carried a 425 hp gross rating (often considered to be underrated) and a net rating of 375 hp.

==== SAE-certified horsepower ====

In [[2005]], the [[Society of Automotive Engineers]] introduced a new test procedure ([http://www.sae.org/certifiedpower J2723]) for engine horsepower and [[torque]]. The procedure eliminates some of the areas of flexibility in power measurement, and requires an independent observer present when engines are measured. The test is voluntary, but engines completing it can be advertised as "SAE-certified".

Many manufacturers began switching to the new rating immediately, often with surprising results. The rated output of [[Cadillac]]'s [[supercharged|supercharger]] [[GM Premium V engine#Supercharged|Northstar]] V8 jumped from 440 hp (328 kW) to 469 hp (350 kW) under the new tests, while the rating for [[Toyota Motor Corporation|Toyota]]'s [[Toyota Camry|Camry]] 3.0 L ''[[Toyota MZ engine#1MZ-FE|1MZ-FE]]'' V6 fell from 210 hp (157 kW) to 190 hp (142 kW). The first engine certified under the new program was the 7.0 L [[GM LS engine#LS7|LS7]] used in the 2006 [[Chevrolet Corvette]] Z06. Certified power rose slightly from 500 hp (373 kW) to 505 hp (377 kW).

==== hp (DIN) ====

'''DIN horsepower''' is the power measured according to the German standard DIN 70020. It is measured at the flywheel, and is in practical terms equivalent to the SAE net figure. However, be aware that DIN "horsepower" is often expressed in [[#Metric horsepower|metric (Pferdestärke)]] rather than [[#Mechanical horsepower|mechanical]] horsepower.

==== hp (ECE) ====

'''ECE R24''' is another standard for measuring net horsepower. It is quite similar to the DIN 70020 standard, but the requirement for connecting an engine's fan during testing varies. ECE is seen as slightly more liberal than DIN, and ECE figures tend to be slightly higher than DIN. [[John Deere]] is one strong adherent to ECE testing.

==== 9768-EC ====

'''9768-EC''' is a standard from the [[European Union]]. Generally, ISO-14396 and 9768-EC metrics are very similar.

==== ISO 14396 ====

'''ISO 14396'''[http://webstore.ansi.org/ansidocstore/product.asp?sku=ISO+14396%3A2002] is a new method from the [[International Standards Organization]] for all engines not intended for on-road use. Generally, ISO-14396 and 9768-EC metrics are very similar. [[New Holland]] is an adherent of ISO-14396 testing.

=== Shaft horsepower (shp) ===
''Shaft horsepower'' is the power delivered to the [[propellor]] shaft of a [[ship]] or [[turboprop]] airplane. This may be measured, or estimated from the indicated horsepower given a standard figure for the losses in the transmission (typical figures are around 10%). This metric is uncommon in the automobile industry, through drivetrain losses can be significant.

=== Effective horsepower (ehp) ===

''Effective horsepower'' is the power converted to useful work. In the case of a vehicle this is the power actually turned into forward motion.

In automobiles, effective horsepower is often referred to as '''wheel horsepower'''. Most automotive [[dynamometer]]s measure wheel horsepower and then apply a conversion factor to calculate net or brake horsepower at the engine. Wheel horsepower will often be 5-15% lower than the bhp ratings due to a loss through the drivetrain.

== History of the term "horsepower" ==

The term "horsepower" was invented by [[James Watt]] to help market his improved [[steam engine]]. He had previously agreed to take royalties of one third of the savings in coal from the older [[Thomas Newcomen|Newcomen]] steam engines[http://www.pballew.net/arithm17.html]. This royalty scheme did not work with customers who did not have existing steam engines but used horses instead. Watt determined that a horse could turn a mill wheel 144 times in an hour (or 2.4 times a minute). The wheel was 12 feet in radius, thus in a minute the horse travelled 2.4 × 2π × 12 feet. Watt judged that the horse could pull with a [[force]] of 180 pounds (just assuming that the measurements of mass were equivalent to measurements of force in pounds-force, which were not well-defined units at the time). So:
:<math> power = \frac{work}{time} = \frac{force \times distance}{time} = \frac{(180 \mbox{ lbf})(2.4 \times 2 \pi \times 12 \mbox{ ft})}{1\ \mbox{min}}=32,572 \frac{\mbox{ft} \cdot \mbox{lbf}}{\mbox{min}}</math>
This was rounded to an even 33,000 ft·lbf/min[http://sections.asme.org/Philadelphia/sept02.htm].

Others recount that Watt determined that a pony could lift an average 220 pounds 100 feet (30 m) per minute over a four-hour working shift. Watt then judged a horse was 50% more powerful than a pony and thus arrived at the 33,000 ft·lbf/min figure[http://www.i5ive.com/article.cfm/history_bizarre_mysterious/114862].

''Engineering in History'' recounts that John Smeaton initially estimated that a horse could produce 22,916 foot-pounds per minute. John Desaguliers increased that to 27,500 foot-pounds per minute. "Watt found by experiment in 1782 that a 'brewery horse' was able to produce 32,400 foot-pounds per minute". James Watt and Matthew Boulton standardized that figure at 33,000 the next year[http://print.google.com/print?id=AVn_Sm56OCoC&pg=171&lpg=171&dq=smeaton&sig=6N_TJXrLqwQI-Fm7mU9ebKS1djA].

Put into perspective, a healthy human can sustain about 0.1 horsepower, and trained athletes can manage up to about 0.3 horsepower for a period of several hours. Most observers familiar with horses and their capabilities estimate that Watt was either a bit optimistic or intended to underpromise and overdeliver; few horses can maintain that effort for long. Regardless, comparison to a horse proved to be an enduring marketing tool.

===Conversion of historical definition to watts===
The historical value of 33,000 ft·lbf/min may be converted to the SI unit of watts by using the following [[conversion of units]] factors:
*1 ft = 0.3048m
* 1 lbf = ''[[acceleration due to gravity|g]]<sub>n</sub>'' × 1 lb = 9.80665 m/s<sup>2</sup> × 1 lb × 0.45359237 kg/lb = 4.44822 kg·m/s<sup>2</sup> = 4.44822 N
*60 seconds = 1 minute

:<math>33,000 \frac{\mbox{ft} \cdot \mbox{lbf}}{\mbox{min}} \times \frac{0.3048 \mbox{ m}}{\mbox{ft}} \times \frac{4.44822 \mbox{ N}}{\mbox{lbf}} \times \frac{\mbox{min}}{60 \mbox{ s}}=745.69987158227022 \ \frac{\mbox{N} \cdot \mbox{m}}{\mbox{s}}</math>

And the [[watt]] is defined as <math>1\ \mbox{W} = 1 \frac{\mbox{N} \cdot \mbox{m}}{\mbox{s}} </math> so the historical figure of 33,000 ft·lbf/min converts exactly to the modern definition.

==References==
*H.W.Dickenson, ''James Watt - Craftsman and Engineer'', Cambridge University Press, 1936, p 145.
*Richard Shelton Kirby, et al, ''Engineering in History'', Courier Dover Publications, 1990, p 171, ISBN 0486264122

==External links==
*"[http://www.straightdope.com/mailbag/mhorsepower.html What's the difference between horsepower and torque?]" at the [[Straight Dope]]
*"[http://www.web-cars.com/math/horsepower.html What is Horsepower?]" at [http://www.web-cars.com WebCars]

[[Category:Imperial units]]
[[Category:Units of power]]
[[Category:Customary units in the United States]]



[[bg:Конска сила]]
[[cs:Koňská síla]]
[[da:Hestekraft]]
[[de:Pferdestärke]]
[[et:Hobujõud]]
[[es:Caballo de vapor]]
[[eo:Ĉevalpovo]]
[[fr:Cheval-vapeur]]
[[it:Cavallo vapore]]
[[he:כוח סוס]]
[[lt:Arklio galia]]
[[nl:Paardenkracht]]
[[ja:馬力]]
[[no:Hestekraft]]
[[nn:Hestekraft]]
[[pl:Koń parowy]]
[[pt:Cavalo (unidade)]]
[[ru:Лошадиная сила]]
[[sl:Konjska moč]]
[[fi:Hevosvoima]]
[[sv:Hästkraft]]
[[vi:Mã lực]]
[[zh:馬力]]

Template:Infobox Automobile generation

2006-05-12T16:54:35Z

Jrosenblum: copied from wikipedia

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Template:Infobox Automobile

2006-05-12T16:52:14Z

Jrosenblum: Created the wikipedia infobox automobile template

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