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House of Cards (British TV series)

House of Cards is a 1990 British political thriller television serial in four episodes, set after the end of Margaret Thatcher's tenure as Prime Minister of the United Kingdom. It was televised by the BBC from 18 November to 9 December 1990. Released to critical and popular acclaim for its writing, direction, and performances, it is considered one of the greatest British television shows ever made.

The story is centred on the sudden and manipulative rise to power of the machiavellian Chief Whip of the Conservative Party, Francis Urquhart. Urquhart, on the party's right wing, is frustrated over his lack of promotion in the wake of Margaret Thatcher's resignation and the moderate government which succeeds it. He conceives a calculated and meticulous plan to bring down the new Prime Minister and replace him, on the same lines as Shakespeare's Richard III (which he often quotes). During this drawn-out and ruthless coup, his life is complicated by his relationship with young female reporter Mattie Storin, whom he uses to leak sensitive information in confidence. The question of whether the serial's ending is a tragedy (in the same vein as plays such as Macbeth) is left to the viewer.

Andrew Davies adapted the story from the 1989 novel of the same name by Michael Dobbs, a former chief of staff at Conservative Party headquarters. Neville Teller also dramatised Dobbs's novel for the BBC World Service in 1996, and it had two television sequels (To Play the King and The Final Cut). The opening and closing theme music for this TV series is entitled "Francis Urquhart's March", by Jim Parker.

House of Cards was ranked 84th in the British Film Institute list of the 100 Greatest British Television Programmes in 2000. In 2013, the serial and the Dobbs novel were the basis for a US adaptation set in Washington, D.C., commissioned and released by Netflix as the first ever major streaming service television show. This version was also entitled House of Cards, and starred Kevin Spacey and Robin Wright.

Overview
The antihero of House of Cards is Francis Urquhart, a fictional Chief Whip of the Conservative Party, played by Ian Richardson. The plot follows his amoral and manipulative scheme to become leader of the governing party and, thus, Prime Minister of the United Kingdom.

Michael Dobbs did not envisage writing the second and third books, as Urquhart dies at the end of the first novel. The screenplay of the BBC's dramatisation of House of Cards differs from the book, and hence allows future series. Dobbs wrote two following books, To Play the King and The Final Cut, which were televised in 1993 and 1995, respectively.

House of Cards was said to draw from Shakespeare's plays Macbeth and Richard III, both of which feature main characters who are corrupted by power and ambition. Richardson has a Shakespearean background and said he based his characterisation of Urquhart on Shakespeare's portrayal of Richard III.

Urquhart frequently talks through the camera to the audience, breaking the fourth wall.

Plot
The ruling Conservative Party is about to elect a new leader. Francis Urquhart, the Government Chief Whip in the House of Commons, introduces viewers to the contestants, before Henry Collingridge, the Secretary of State for the Environment, emerges victorious. Urquhart is contemptuous of Collingridge, who embodies the Thatcher-era rise of the lower-middle classes. Urquhart feigns respect and expects promotion to a senior position in the Cabinet. After the general election, the party narrowly retains power. Urquhart makes suggestions for a hard-right reshuffle, including his own desired promotion to Home Secretary. However, Collingridge effects no changes at all, relying entirely on the advice of his party chairman, Lord "Teddy" Billsborough. Urquhart resolves to oust Collingridge.

Urquhart begins an affair with Mattie Storin, a junior political reporter at a Conservative-leaning tabloid, The Chronicle. This allows Urquhart to manipulate Mattie and skew her coverage of events in his favour. Another pawn is Roger O'Neill, the party's cocaine-addicted public relations consultant, whom Urquhart blackmails into leaking planned budget cuts, thereby humiliating Collingridge during Prime Minister's Questions. Later, Urquhart blames Billsborough for leaking a poll showing the Conservatives' declining rate in voting intentions, leading Collingridge to sack Billsborough.

As Collingridge's image suffers, Urquhart encourages Patrick Woolton, the boorish and lecherous Foreign Secretary, and the equally unpleasant Chronicle owner Benjamin Landless to support his removal. He also impersonates Collingridge's alcoholic brother to trade shares and benefit from advance information confidential to the government. Collingridge becomes falsely accused of insider trading and resigns partly to save face, partly to care for his brother after he suffers a guilt-induced decline in his health.

In the ensuing leadership race, Urquhart feigns unwillingness to stand before announcing his candidacy. Urquhart makes sure his competitors drop out of the race: Health Secretary Peter MacKenzie accidentally runs his car over a protester at a demonstration staged by Urquhart and withdraws, while Education Secretary Harold Earle is blackmailed into withdrawing when Urquhart anonymously sends pictures of him in the company of a rent boy whom Earle had paid for sex.

The first ballot leaves Urquhart to face Woolton and Michael Samuels, the moderate Environment Secretary. Urquhart eliminates Woolton by a prolonged scheme: at the party conference, he pressures O'Neill into persuading his lover, Penny Guy, to sleep with Woolton in his suite, which Urquhart records via a bugged ministerial red box. The recording reveals Woolton ignoring Guy's pleas to stop, with Woolton ostensibly raping her. When the tape is sent to Woolton, he is led to assume that Samuels is behind the scheme and backs Urquhart in the contest. Urquhart also receives support from Collingridge, who is unaware of Urquhart's role in his own downfall. Samuels is forced out of the running when the tabloids reveal that he backed leftist causes as a student.

Seeing contradictions in the allegations against Collingridge and his brother, Mattie begins to dig deeper, while falling in love with Urquhart and blinding herself to his possible role. On Urquhart's orders, O'Neill vandalises her car and throws a brick with a threatening letter through her window. O'Neill becomes increasingly uneasy with what he is being asked to do, and his addiction adds to his instability. When he threatens to go to the police, Urquhart invites him to his home in Hampshire, promising O'Neill a knighthood. There, O'Neill becomes completely inebriated before passing out. Urquhart mixes O'Neill's cocaine with rat poison, causing him to die after he takes the cocaine in a toilet at a nearby motorway service station.

Mattie's colleague, John Krajewski, insists that Urquhart was the only one with the means, motive and opportunity. Knowing that Urquhart as Chief Whip was adroit at gaining information sensitive enough to blackmail almost anyone, Mattie realises that he is responsible for O'Neill's death and the downfall of his rivals. She confronts Urquhart on the roof garden of the Houses of Parliament, demanding to know if he killed Roger O’Neill. He admits to everything, then throws her off the roof to her death. She lands on the roof of a van parked below. An unseen person picks up Mattie's tape recorder, which she had been using to record her conversations with Urquhart. The series ends with Urquhart defeating Samuels in the second leadership ballot and being driven to Buckingham Palace to be invited to form a government.

Deviations from the novel in the series
In the first novel, but not in the television series:
 * Urquhart never speaks directly to the reader; the character is written solely in a third-person perspective.
 * When alone, Urquhart is much less self-assured and decisive.
 * Mattie Storin works for The Daily Telegraph. (In the television series she is a journalist with the fictional Chronicle newspaper.)
 * Mattie Storin does not have a relationship with Urquhart; she does not even talk to him frequently. She does, however, have a sexual relationship with John Krajewski.
 * Urquhart's wife is called Miranda and is a minor character, not sharing in his schemes. (In the later novels, To Play the King and The Final Cut, however, she is called "Elizabeth" and plays a larger role, as in the television series.)
 * The Conservative party conference is held in Bournemouth. (In the television series it is held in Brighton.)
 * The minor character Tim Stamper is introduced for the on-screen adaptation.
 * Earle's rent boy appears in person at an important speech of Earle's, distracting him; subsequently, Earle is harassed by reporters who have been told of his indiscretion.
 * In the final confrontation scene Urquhart throws himself from the roof terrace and Mattie survives.

Before the series was reissued in 2013 to coincide with the release of the US version of House of Cards, Dobbs rewrote portions of the novel to bring the series in line with the television series and restore continuity among the three novels. In the 2013 version:
 * Urquhart murders Mattie Storin, throwing her off the roof after she confronts Urquhart about his actions.
 * Mattie Storin does not scream "Daddy" as she falls.
 * Urquhart covers up his murder of Mattie Storin by claiming she was an obsessed stalker who was mentally ill and vows to make mental health amongst the young a priority.
 * Mattie Storin works for newspaper The Chronicle, per the TV series.
 * Urquhart's wife Miranda is changed to Mortima.
 * Tim Stamper, though present in the serial, does not appear in the revised version of the novel.
 * Urquhart makes asides to the audience in the form of epigraphs at the beginning of each chapter (the original novel has no chapters).

Reception
The first instalment of the TV series coincidentally aired two days before the Conservative Party leadership election. During a time of "disillusionment with politics", the series "caught the nation's mood".

Ian Richardson won the British Academy Television Award for Best Actor in 1991 for his role as Urquhart, and Andrew Davies won an Emmy for outstanding writing in a miniseries.

The series ranked 84th in the British Film Institute list of the 100 Greatest British Television Programmes.

American adaptation
The Urquhart trilogy has been adapted in the United States as House of Cards. The show stars Kevin Spacey as Francis "Frank" Underwood, the Majority Whip of the Democratic caucus in the U.S. House of Representatives, who schemes and murders his way to becoming President of the United States. It is produced by David Fincher and Spacey's Trigger Street Productions, with the initial episodes directed by Fincher.

The series, produced and financed by independent studio Media Rights Capital, was one of Netflix's first forays into original programming. Series one was made available online on 1 February 2013. The series was filmed in Baltimore, Maryland. The first series was critically acclaimed and earned four Golden Globe Nominations, including Best Drama, actor, actress and supporting actor, with Robin Wright winning best actress. It also earned nine Primetime Emmy Award nominations, winning three, and was the first show to earn nominations that was broadcast solely via an internet streaming service.

In popular culture
The drama introduced and popularised the phrase: "You might very well think that; I couldn't possibly comment". It was a non-confirmation confirmative statement, used by Urquhart whenever he could not be seen to agree with a leading statement, with the emphasis on either the "I" or the "possibly", depending on the situation. The phrase was even used in the House of Commons, House of Lords and Parliamentary Committees following the series. Prince Charles (as he was known at the time) himself said the phrase in response to a provocative question from a journalist in 2014.

A variation on the phrase was written into the TV adaptation of Terry Pratchett's Hogfather for the character Death, as an in-joke on the fact that he was voiced by Richardson.

During the first Gulf War, a British reporter speaking from Baghdad, conscious of the possibility of censorship, used the code phrase "You might very well think that; I couldn't possibly comment" to answer a BBC presenter's question.

A further variation was used by Nicola Murray, a fictional government minister, in the third series finale of The Thick of It.

In the US adaptation, the phrase is used by Frank Underwood in the first episode during his initial meeting with Zoe Barnes, the US counterpart of Mattie Storin.

title: House of Cards (British TV series)


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Helen Gandy

Helen Wilburforce Gandy (April 8, 1897 – July 7, 1988) was the American longtime secretary to Federal Bureau of Investigation director J. Edgar Hoover, who called her "indispensable". Serving in that role for 54 years she exercised great behind-the-scenes influence on Hoover and the operations of the Bureau. Following Hoover's death in 1972, she spent weeks destroying his "Personal File," thought to contain the most incriminating material Hoover used to manipulate or blackmail the most powerful figures in Washington.

Early life
Helen Gandy was born in Rockville, New Jersey, one of three children (two daughters and a son) born to Franklin Dallas and Annie (née Williams) Gandy. She grew up in New Jersey in Fairton or the Port Norris section of Commercial Township (sources differ) and graduated from Bridgeton High School in Bridgeton, New Jersey. In 1918, aged 21, she moved to Washington, D.C., where she later took classes at Strayer Business College and George Washington University Law School.

Career
Gandy briefly worked in a department store in Washington before finding a job as a file clerk at the Justice Department in 1918. Within weeks, she went to work as a typist for Hoover, effective March 25, 1918, having told Hoover in her interview she had "no immediate plans to marry". She, like Hoover, would never marry; both were completely devoted to the Bureau.

When Hoover went to the Bureau of Investigation (its original title; it became the FBI in 1935) as its assistant director on August 22, 1921, he specifically requested Gandy return from vacation to help him in the new post. Hoover became director of the Bureau in 1924, and Gandy continued in his service. She was promoted to "office assistant" on August 23, 1937, and "executive assistant" on October 1, 1939. Though she would receive promotions in her civil service grade subsequently, she retained her title as executive assistant until her retirement on May 2, 1972, the day Hoover died. Hoover said of her: "if there is anyone in this Bureau whose services are indispensable, I consider Miss Gandy to be that person." Despite this, Curt Gentry wrote:

"Theirs was a rigidly formal relationship. He always called her 'Miss Gandy' (when angry, barking it out as one word). In all those fifty-four years he never once called her by her first name."

Hoover biographers Theoharis and Cox would say "her stern face recalled Cerberus at the gate", a view echoed by Anthony Summers in his life of Hoover, who also pictured Gandy as Hoover's first line of defense against the outside world. When Attorney General Robert F. Kennedy, Hoover's superior, had a direct telephone line installed between their offices, Hoover refused to answer the phone. "Put that damn thing on Miss Gandy's desk where it belongs", Hoover would declare.

Gentry described Gandy's influence: Her genteel manner and pleasant voice contrasted sharply with this domineering presence. Yet behind the politeness was a resolute firmness not unlike his, and no small amount of influence. Many a career in the Bureau had been quietly manipulated by her. Even those who disliked him praised her, most often commenting on her remarkable ability to get along with all kinds of people. That she held her position for fifty-four years was the best evidence of this, for it was a Bureau tradition that the closer you were to him, the more demanding he was.

William C. Sullivan, an agent with the Bureau for three decades, reported in his memoir that when he worked in the public relations section answering mail from the public, he gave a correspondent the wrong measurements for Hoover's personal popover recipe, relying on memory rather than the files. Gandy, ever protective of her boss, caught the error and brought it to Hoover's attention. The director then placed an official letter of reprimand in Sullivan's file for the lapse. Mark Felt, deputy associate director of the FBI, wrote in his memoir that Gandy "was bright and alert and quick-tongued—and completely dedicated to her boss, whose interests she constantly protected".

Files
Hoover died during the night of May 1–2, 1972. According to Curt Gentry, who wrote the 1991 book J Edgar Hoover: The Man and the Secrets, Hoover's body was not discovered by his live-in cook and general housekeeper, Annie Fields; rather, it was discovered by James Crawford, who had been Hoover's chauffeur for 37 years. Crawford then yelled out to Fields and Tom Moton (Hoover's new chauffeur after Crawford had retired in January 1972). Fields first called Hoover's personal physician, Dr. Robert Choisser, then used another phone to call Clyde Tolson's private number. Tolson then called Gandy's private number with the news of Hoover's death along with orders to begin destroying the files. Within an hour, the "D List" ("d" standing for destruction) was being distributed, and the destruction of files began. However, The New York Times quoted an anonymous FBI source in spring 1975, who said: "Gandy had begun the destruction of files almost a year before Mr. Hoover's death and was instructed to purge the files that were presently in his office."

Anthony Summers reported that G. Gordon Liddy had said of his sources in the FBI: "by the time Gray went in to get the files, Miss Gandy had already got rid of them." The day after Hoover died, L. Patrick Gray, who had been named acting director by President Richard Nixon upon Tolson's resignation from that position, went to Hoover's office. Gandy paused from her work to give Gray a tour. He found file cabinets open and packing boxes being filled with papers. She informed him the boxes contained personal papers of Hoover's. Gandy stated Gray flipped through a few files and approved her work, but Gray was to deny he looked at any papers. Gandy also told Gray it would be a week before she could clear Hoover's effects out so Gray could move into the suite.

Gray reported to Nixon that he had secured Hoover's office and its contents. However, he had sealed only Hoover's personal inner office, where no files were stored, not the entire suite of offices. Since 1957, Hoover's "Official/Confidential" files, containing material too sensitive to include in the FBI's central files, had been kept in the outer office, where Gandy sat. Gentry reported that Gray would not have known where to look in Gandy's office for the files, as her office was lined floor to ceiling with filing cabinets; moreover, without her index to the files, he would not have been able to locate incriminating material, for files were deliberately mislabeled, e.g., President Nixon's file was labeled "Obscene Matters".

On May 4, Gandy transferred 12 boxes labelled "Official/Confidential", containing 167 files and 17,750 pages, to Mark Felt. Many of them contained inflammatory and derogatory information. Gray told the press that afternoon that "there are no dossiers or secret files. There are just general files, and I took steps to preserve their integrity." Yet, Gandy retained the "Personal File."

Gandy went through Hoover's "Personal File" in the office until May 12. She then transferred at least 32 file drawers of material to the basement recreation room of Hoover's Washington home at 4936 Thirtieth Place, NW, where she continued her work from May 13 to July 17. Gandy later testified in court that nothing official had been removed from the FBI's offices, "not even Mr. Hoover's badge." At Hoover's residence, the destruction was overseen by John P. Mohr, the third highest-ranking official in the FBI after Hoover and Tolson. They were aided by James Jesus Angleton, the Central Intelligence Agency's counterintelligence chief, whom Hoover's neighbors saw removing boxes from Hoover's home. Mohr would claim the boxes Angleton removed were cases of spoiled wine.

In 1975, when the House Committee on Government Oversight investigated the FBI's illegal COINTELPRO program of spying on and harassment of Martin Luther King Jr. and others, Gandy was summoned to testify regarding the "Personal Files." "I tore them up, put them in boxes, and they were taken away to be shredded," she told the congressmen about the papers. The FBI Washington field office had FBI drivers transport the material to Hoover's home, then once Gandy had gone through the material, the drivers transported it back to the field office in the Old Post Office Building on Pennsylvania Avenue, where it was shredded and burned.

Gandy stated that Hoover had left standing instructions to destroy his personal papers upon his death, and this instruction was confirmed by Tolson and Gray. She also stated that she destroyed no official papers; that everything was personal papers of Hoover's. The staff of the subcommittee did not believe her, but she told the committee: "I have no reason to lie." Representative Andrew Maguire (D-New Jersey), a freshman member of the 94th Congress, said "I find your testimony very difficult to believe." Gandy held her ground: "That is your privilege."

"I can give you my word. I know what there was—letters to and from friends, personal friends, a lot of letters," she testified. Gandy also said the files she took to Hoover's home included his financial papers, such as tax returns and investment statements, the deed to his home, and papers relating to his dogs' pedigrees.

Curt Gentry wrote:

Helen Gandy must have felt quite safe in testifying as she did, for who could contradict her? Only one other person knew exactly what the files contained, and he was dead.

In J. Edgar Hoover: The Man and His Secrets, Gentry describes the nature of the files: "their contents included blackmail material on the patriarch of an American political dynasty, his sons, their wives, and other women; allegations of two homosexual arrests which Hoover leaked to help defeat a witty, urbane Democratic presidential candidate; the surveillance reports on one of America's best-known first ladies and her alleged lovers, both male and female, white and black; the child molestation documentation the director used to control and manipulate one of the Red-baiting proteges; a list of the Bureau's spies in the White House during the eight administrations when Hoover was FBI director; the forbidden fruit of hundreds of illegal wiretaps and bugs, containing, for example, evidence that an attorney general, Tom C. Clark, who later became Supreme Court justice, had received payoffs from the Chicago syndicate; as well as celebrity files, with all the unsavory gossip Hoover could amass on some of the biggest names in show business."

Personal life
Gandy lived for decades with Margaret E. Morrow. Morrow died April 16, 1986.

Later years
Hoover left Gandy $5,000 in his will.

In 1961, she and her sister, Lucy G. Rodman, donated a portrait of their mother by Thomas Eakins to the Smithsonian American Art Museum. Gandy lived in Washington until 1986, when she moved to DeLand, Florida, in Volusia County, where a niece lived. Gandy was an avid trout fisher.

Death
Gandy died of a heart attack on July 7, 1988, either in DeLand (as indicated by her New York Times obituary) or in nearby Orange City, Florida, (as stated in her Washington Post obituary).

In popular culture
Gandy has been portrayed by actresses Lee Kessler in J. Edgar Hoover (1987), Naomi Watts in J. Edgar (2011), and Rebecca Toolan in Bad Times at the El Royale (2018).

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Helen Gandy


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Horsepower

Horsepower (hp) is a unit of measurement of power, or the rate at which work is done, usually in reference to the output of engines or motors. There are many different standards and types of horsepower. Two common definitions used today are the imperial horsepower, which is about 745.7 watts, and the metric horsepower, which is approximately 735.5 watts.

The term was adopted in the late 18th century by Scottish engineer James Watt to compare the output of steam engines with the power of draft horses. It was later expanded to include the output power of other types of piston engines, as well as turbines, electric motors and other machinery. The definition of the unit varied among geographical regions. Most countries now use the SI unit watt for measurement of power. With the implementation of the EU Directive 80/181/EEC on 1 January 2010, the use of horsepower in the EU is permitted only as a supplementary unit.

History

The development of the steam engine provided a reason to compare the output of horses with that of the engines that could replace them. In 1702, Thomas Savery wrote in The Miner's Friend:

 * So that an engine which will raise as much water as two horses, working together at one time in such a work, can do, and for which there must be constantly kept ten or twelve horses for doing the same. Then I say, such an engine may be made large enough to do the work required in employing eight, ten, fifteen, or twenty horses to be constantly maintained and kept for doing such a work...

The idea was later used 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 Newcomen steam engines. 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 ft in radius; therefore, the horse travelled 2.4 × 2π × 12 feet in one minute. Watt judged that the horse could pull with a force of 180 lbf. So:

Engineering in History recounts that John Smeaton initially estimated that a horse could produce 22,916 ftlb per minute. John Desaguliers had previously suggested 44,000 ftlb per minute, and Tredgold suggested 27,500 ftlb per minute. "Watt found by experiment in 1782 that a 'brewery horse' could produce 32,400 ftlb per minute." James Watt and Matthew Boulton standardized that figure at 33,000 ftlb per minute the next year.

A common legend states that the unit was created when one of Watt's first customers, a brewer, specifically demanded an engine that would match a horse, and chose the strongest horse he had and driving it to the limit. In that legend, Watt accepted the challenge and built a machine that was actually even stronger than the figure achieved by the brewer, and the output of that machine became the horsepower.

In 1993, R. D. Stevenson and R. J. Wassersug published correspondence in Nature summarizing measurements and calculations of peak and sustained work rates of a horse. Citing measurements made at the 1926 Iowa State Fair, they reported that the peak power over a few seconds has been measured to be as high as 14.88 hp and also observed that for sustained activity, a work rate of about 1 hp per horse is consistent with agricultural advice from both the 19th and 20th centuries and also consistent with a work rate of about four times the basal rate expended by other vertebrates for sustained activity.

When considering human-powered equipment, a healthy human can produce about 1.2 hp briefly (see orders of magnitude) and sustain about 0.1 hp indefinitely; trained athletes can manage up to about 2.5 hp briefly and 0.35 hp for a period of several hours. The Jamaican sprinter Usain Bolt produced a maximum of 3.5 hp 0.89 seconds into his 9.58 second 100 m sprint world record in 2009.

In 2023 a group of engineers modified a dynometer to be able to measure how much horsepower a horse can produce. This horse was measured to 5.7 hp.

Calculating power
When torque $2 1⁄2$ is in pound-foot units, rotational speed $T$ is in rpm, the resulting power in horsepower is

 * $$\{P\}_\mathrm{hp} = \frac{\{T\}_\mathrm{ft {\cdot} lbf} \{N\}_\mathrm{rpm}}{5252}.$$

The constant 5252 is the rounded value of (33,000 ft⋅lbf/min)/(2π rad/rev).

When torque $N$ is in inch-pounds,

 * $$\{P\}_\mathrm{hp} = \frac{\{T\}_\mathrm{in {\cdot} lbf} \{N\}_\mathrm{rpm}}{63{,}025}.$$

The constant 63,025 is the approximation of

 * $$33{,}000~\frac{\text{ft} {\cdot} \text{lbf}}{\text{min}} \times \frac{12~\frac{\text{in}}{\text{ft}}}{2\pi~\text{rad}} \approx 63{,}025 \frac{\text{in} {\cdot} \text{lbf}}{\text{min}}.$$

Imperial horsepower
Assuming the third CGPM (1901, CR 70) definition of standard gravity, gn = 9.80665 m/s2, is used to define the pound-force as well as the kilogram force, and the international avoirdupois pound (1959), one imperial horsepower is:

 * 1 hp
 * ≡ 33,000 ft·lbf/min
 * colspan="2" |by definition
 * = 550 ft⋅lbf/s
 * since
 * 1 min = 60 s
 * = 550 × 0.3048 × 0.45359237 m⋅kgf/s
 * since
 * 1 ft ≡ 0.3048 m and 1 lb ≡ 0.45359237 kg
 * = 76.0402249068 kgf⋅m/s
 * = 76.0402249068 × 9.80665 kg⋅m2/s3
 * since
 * g = 9.80665 m/s2
 * = 745.69987158227022 W ≈ 745.700 W
 * since
 * 1 W ≡ 1 J/s = 1 N⋅m/s = 1 (kg⋅m/s2)⋅(m/s)
 * }
 * = 76.0402249068 × 9.80665 kg⋅m2/s3
 * since
 * g = 9.80665 m/s2
 * = 745.69987158227022 W ≈ 745.700 W
 * since
 * 1 W ≡ 1 J/s = 1 N⋅m/s = 1 (kg⋅m/s2)⋅(m/s)
 * }
 * = 745.69987158227022 W ≈ 745.700 W
 * since
 * 1 W ≡ 1 J/s = 1 N⋅m/s = 1 (kg⋅m/s2)⋅(m/s)
 * }
 * 1 W ≡ 1 J/s = 1 N⋅m/s = 1 (kg⋅m/s2)⋅(m/s)
 * }

Or given that 1 hp = 550 ft⋅lbf/s, 1 ft = 0.3048 m, 1 lbf ≈ 4.448 N, 1 J = 1 N⋅m, 1 W = 1 J/s: 1 hp ≈ 745.7 W

Metric horsepower (PS, KM, cv, hk, pk, k, ks, ch)

The various units used to indicate this definition (PS,  KM, cv, hk, pk, k, ks and ch) all translate to horse power in English. British manufacturers often intermix metric horsepower and mechanical horsepower depending on the origin of the engine in question.

DIN 66036 defines one metric horsepower as the power to raise a mass of 75 kilograms against the Earth's gravitational force over a distance of one metre in one second: 75 kg × 9.80665 m/s2 × 1 m / 1 s = 75 kgf⋅m/s = 1 PS. This is equivalent to 735.49875 W, or 98.6% of an imperial horsepower. In 1972, the PS was replaced by the kilowatt as the official power-measuring unit in EEC directives.

Other names for the metric horsepower are the Italian cavallo vapore (cv), Dutch paardenkracht (pk), the French cheval-vapeur (ch), the Spanish caballo de vapor and Portuguese cavalo-vapor (cv), the Russian лошадиная сила (л. с.), the Swedish hästkraft (hk), the Finnish hevosvoima (hv), the Estonian hobujõud (hj), the Norwegian and Danish hestekraft (hk), the Hungarian lóerő (LE), the Czech koňská síla and Slovak konská sila (k or ks), the Serbo-Croatian konjska snaga (KS), the Bulgarian конска сила, the Macedonian коњска сила (KC), the Polish koń mechaniczny (KM) (lit. 'mechanical horse'), Slovenian konjska moč (KM), the Ukrainian кінська сила (к. с.), the Romanian cal-putere (CP), and the German Pferdestärke (PS).

In the 19th century, the French had their own unit, which they used instead of the CV or horsepower. Based on a 100 kgf⋅m/s standard, it was called the poncelet and was abbreviated p.

Tax horsepower
Tax or fiscal horsepower is a non-linear rating of a motor vehicle for tax purposes. Tax horsepower ratings were originally more or less directly related to the size of the engine; but as of 2000, many countries changed over to systems based on emissions, so are not directly comparable to older ratings. The Citroën 2CV is named for its French fiscal horsepower rating, "deux chevaux" (2CV).

Electrical horsepower
Nameplates on electrical motors show their power output, not the power input (the power delivered at the shaft, not the power consumed to drive the motor). This power output is ordinarily stated in watts or kilowatts. In the United States, the power output is stated in horsepower, which for this purpose is defined as exactly 746 W.

Hydraulic horsepower
Hydraulic horsepower can represent the power available within hydraulic machinery, power through the down-hole nozzle of a drilling rig, or can be used to estimate the mechanical power needed to generate a known hydraulic flow rate.

It may be calculated as
 * $$\text{hydraulic power} = \frac{\text{pressure} \times \text{volumetric flow rate}}{1714},$$

where pressure is in psi, and flow rate is in US gallons per minute.

Drilling rigs are powered mechanically by rotating the drill pipe from above. Hydraulic power is still needed though, as 1 500 to 5 000 W are required to push mud through the drill bit to clear waste rock. Additional hydraulic power may also be used to drive a down-hole mud motor to power directional drilling.

When using SI units, the equation becomes coherent and there is no dividing constant.

 * $$\text{hydraulic power} = \text{pressure} \times \text{volumetric flow rate}$$

where pressure is in pascals (Pa), and flow rate is in cubic metres per second (m3).

Boiler horsepower
Boiler horsepower is a boiler's capacity to deliver steam to a steam engine and is not the same unit of power as the 550 ft lb/s definition. One boiler horsepower is equal to the thermal energy rate required to evaporate 34.5 lb of fresh water at 212 °F in one hour. In the early days of steam use, the boiler horsepower was roughly comparable to the horsepower of engines fed by the boiler.

The term "boiler horsepower" was originally developed at the Philadelphia Centennial Exhibition in 1876, where the best steam engines of that period were tested. The average steam consumption of those engines (per output horsepower) was determined to be the evaporation of 30 lb of water per hour, based on feed water at 100 °F, and saturated steam generated at 70 psi. This original definition is equivalent to a boiler heat output of 33,485 Btu/h. A few years later in 1884, the ASME re-defined the boiler horsepower as the thermal output equal to the evaporation of 34.5 pounds per hour of water "from and at" 212 F. This considerably simplified boiler testing, and provided more accurate comparisons of the boilers at that time. This revised definition is equivalent to a boiler heat output of 33,469 Btu/h. Present industrial practice is to define "boiler horsepower" as a boiler thermal output equal to 33,475 Btu/h, which is very close to the original and revised definitions.

Boiler horsepower is still used to measure boiler output in industrial boiler engineering in the US. Boiler horsepower is abbreviated BHP, not to be confused with brake horsepower, below, which is also abbreviated bhp, in lower case.

Drawbar power
Drawbar power (dbp) is the power a railway 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 railway 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; it is normally a second locomotive with its brakes applied, in addition to a static load.

If the drawbar force ($T$) is measured in pounds-force (lbf) and speed ($F$) is measured in miles per hour (mph), then the drawbar power ($v$) in horsepower (hp) is

$$\{P\}_\mathrm{hp} = \frac{\{F\}_\mathrm{lbf} \{v\}_\mathrm{mph}}{375}.$$

Example: How much power is needed to pull a drawbar load of 2,025 pounds-force at 5 miles per hour?

$$\{P\}_\mathrm{hp} = \frac{2025 \times 5}{375} = 27.$$

The constant 375 is because 1 hp = 375 lbf⋅mph. If other units are used, the constant is different. When using coherent SI units (watts, newtons, and metres per second), no constant is needed, and the formula becomes $P = Fv$.

This formula may also be used to calculate the power of a jet engine, using the speed of the jet and the thrust required to maintain that speed.

Example: how much power is generated with a thrust of 4000 pounds at 400 miles per hour?

$$\{P\}_\mathrm{hp} = \frac{4000 \times 400}{375} = 4266.7.$$

RAC horsepower (taxable horsepower)
This measure was instituted by the Royal Automobile Club and was used to denote the power of early 20th-century British cars. Many cars took their names from this figure (hence the Austin Seven and Riley Nine), while others had names such as "40/50 hp", 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 purposes. The United Kingdom was not the only country that used the RAC rating; many states in Australia used RAC hp to determine taxation. The RAC formula was sometimes applied in British colonies as well, such as Kenya (British East Africa).

 * $$\text{RAC h.p.} = \frac{D \times D \times n}{2.5}$$

where

 * D is the diameter (or bore) of the cylinder in inches,
 * n is the number of cylinders.

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 (bore smaller than stroke), which tended to impose an artificially low limit on rotational speed, hampering the potential power output and efficiency of the engine.

The situation persisted for several generations of four- and six-cylinder British engines: For example, Jaguar's 3.4-litre XK engine of the 1950s had six cylinders with a bore of 83 mm and a stroke of 106 mm, where most American automakers had long since moved to oversquare (large bore, short stroke) V8 engines. See, for example, the early Chrysler Hemi engine.

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 either the measurement system or definition used.

In general:
 * nominal horsepower is derived from the size of the engine and the piston speed and is only accurate at a steam pressure of 48 kPa;
 * indicated or gross horsepower is the theoretical capability of the engine [PLAN/ 33000];
 * brake/net/crankshaft horsepower (power delivered directly to and measured at the engine's crankshaft) equals
 * indicated horsepower minus frictional losses within the engine (bearing drag, rod and crankshaft windage losses, oil film drag, etc.);
 * shaft horsepower (power delivered to and measured at the output shaft of the transmission, when present in the system) equals
 * crankshaft horsepower minus frictional losses in the transmission (bearings, gears, oil drag, windage, etc.);
 * effective, true (thp) or commonly referred to as wheel horsepower (whp) equals
 * shaft horsepower minus frictional losses in the universal joint/s, differential, wheel bearings, tire and chain, (if present).

All the above assumes that no power inflation factors have been applied to any of the readings.

Engine designers use expressions other than horsepower to denote objective targets or performance, such as brake mean effective pressure (BMEP). This is a coefficient of theoretical brake horsepower and cylinder pressures during combustion.

Nominal horsepower
Nominal horsepower (nhp) is an early 19th-century rule of thumb used to estimate the power of steam engines. It assumed a steam pressure of 7 psi.

Nominal horsepower = 7 × area of piston in square inches × equivalent piston speed in feet per minute/33,000.

For paddle ships, the Admiralty rule was that the piston speed in feet per minute was taken as 129.7 × (stroke)1/3.38. For screw steamers, the intended piston speed was used.

The stroke (or length of stroke) was the distance moved by the piston measured in feet.

For the nominal horsepower to equal the actual power it would be necessary for the mean steam pressure in the cylinder during the stroke to be 7 psi and for the piston speed to be that generated by the assumed relationship for paddle ships.

The French Navy used the same definition of nominal horse power as the Royal Navy.

Indicated horsepower
Indicated horsepower (ihp) is the theoretical power of a reciprocating engine if it is completely frictionless in converting the expanding gas energy (piston pressure × displacement) in the cylinders. It is calculated from the pressures developed in the cylinders, measured by a device called an engine indicator – hence indicated horsepower. As the piston advances throughout its stroke, the pressure against the piston generally decreases, and the indicator device usually generates a graph of pressure vs stroke within the working cylinder. From this graph the amount of work performed during the piston stroke may be calculated.

Indicated horsepower was a better measure of engine power than nominal horsepower (nhp) because it took account of steam pressure. But unlike later measures such as shaft horsepower (shp) and brake horsepower (bhp), it did not take into account power losses due to the machinery internal frictional losses, such as a piston sliding within the cylinder, plus bearing friction, transmission and gear box friction, etc.

Brake horsepower
Brake horsepower (bhp) is the power measured using a brake type (load) dynamometer at a specified location, such as the crankshaft, output shaft of the transmission, rear axle or rear wheels.

In Europe, the DIN 70020 standard tests the engine fitted with all ancillaries and the exhaust system as used in the car. The older American standard (SAE gross horsepower, referred to as bhp) used an engine without alternator, water pump, and other auxiliary components such as power steering pump, muffled exhaust system, etc., so the figures were higher than the European figures for the same engine. The newer American standard (referred to as SAE net horsepower) tests an engine with all the auxiliary components (see "Engine power test standards" below).

Brake refers to the device which is used to provide an equal braking force, load to balance, or equal an engine's output force and hold it at a desired rotational speed. During testing, the output torque and rotational speed are measured to determine the brake horsepower. Horsepower was originally measured and calculated by use of the "indicator diagram" (a James Watt invention of the late 18th century), and later by means of a Prony brake connected to the engine's output shaft. Modern dynamometers use any of several braking methods to measure the engine's brake horsepower, the actual output of the engine itself, before losses to the drivetrain.

Shaft horsepower
Shaft horsepower (shp) is the power delivered to a propeller shaft, a turbine shaft, or to an output shaft of an automotive transmission. Shaft horsepower is a common rating for turboshaft and turboprop engines, industrial turbines, and some marine applications.

Equivalent shaft horsepower (eshp) is sometimes used to rate turboprop engines. It includes the equivalent power derived from residual jet thrust from the turbine exhaust. 2.5 lbf of residual jet thrust is estimated to be produced from one unit of horsepower.

Engine power test standards
There exist a number of different standards determining how the power and torque of an automobile engine is measured and corrected. Correction factors are used to adjust power and torque measurements to standard atmospheric conditions, to provide a more accurate comparison between engines as they are affected by the pressure, humidity, and temperature of ambient air. Some standards are described below.

Early "SAE horsepower"
In the early twentieth century, a so-called "SAE horsepower" was sometimes quoted for U.S. automobiles. This long predates the Society of Automotive Engineers (SAE) horsepower measurement standards and was another name for the industry standard ALAM or NACC horsepower figure and the same as the British RAC horsepower also used for tax purposes. Alliance for Automotive Innovation is the current successor of ALAM and NACC.

SAE gross power
Prior to the 1972 model year, American automakers rated and advertised their engines in brake horsepower, bhp, which was a version of brake horsepower called SAE gross horsepower because it was measured according to Society of Automotive Engineers (SAE) standards (J245 and J1995) that call for a stock test engine without accessories (such as dynamo/alternator, radiator fan, water pump), and sometimes fitted with long tube test headers in lieu of the OEM exhaust manifolds. This contrasts with both SAE net power and DIN 70020 standards, which account for engine accessories (but not transmission losses). The atmospheric correction standards for barometric pressure, humidity and temperature for SAE gross power testing were relatively idealistic.

SAE net power
In the United States, the term bhp fell into disuse in 1971–1972, as automakers began to quote power in terms of SAE net horsepower in accord with SAE standard J1349. Like SAE gross and other brake horsepower protocols, SAE net hp is measured at the engine's crankshaft, and so does not account for transmission losses. However, similar to the DIN 70020 standard, SAE net power testing protocol calls for standard production-type belt-driven accessories, air cleaner, emission controls, exhaust system, and other power-consuming accessories. This produces ratings in closer alignment with the power produced by the engine as it is actually configured and sold.

SAE certified power
In 2005, the SAE introduced "SAE Certified Power" with SAE J2723. To attain certification the test must follow the SAE standard in question, take place in an ISO 9000/9002 certified facility and be witnessed by an SAE approved third party.

A few manufacturers such as Honda and Toyota switched to the new ratings immediately. The rating for Toyota's Camry 3.0 L 1MZ-FE V6 fell from 210 to 190 hp. The company's Lexus ES 330 and Camry SE V6 (3.3 L V6) were previously rated at 225 hp but the ES 330 dropped to 218 hp while the Camry declined to 210 hp. The first engine certified under the new program was the 7.0 L LS7 used in the 2006 Chevrolet Corvette Z06. Certified power rose slightly from 500 to 505 hp.

While Toyota and Honda are retesting their entire vehicle lineups, other automakers generally are retesting only those with updated powertrains. For example, the 2006 Ford Five Hundred is rated at 203 hp, the same as that of 2005 model. However, the 2006 rating does not reflect the new SAE testing procedure, as Ford is not going to incur the extra expense of retesting its existing engines. Over time, most automakers are expected to comply with the new guidelines.

SAE tightened its horsepower rules to eliminate the opportunity for engine manufacturers to manipulate factors affecting performance such as how much oil was in the crankcase, engine control system calibration, and whether an engine was tested with high octane fuel. In some cases, such can add up to a change in horsepower ratings.

Deutsches Institut für Normung 70020 (DIN 70020)
DIN 70020 is a German DIN standard for measuring road vehicle horsepower. DIN hp is measured at the engine's output shaft as a form of metric horsepower rather than mechanical horsepower. Similar to SAE net power rating, and unlike SAE gross power, DIN testing measures the engine as installed in the vehicle, with cooling system, charging system and stock exhaust system all connected. DIN hp is often abbreviated as "PS", derived from the German word Pferdestärke (literally, "horsepower").

CUNA
A test standard by Italian CUNA (Commissione Tecnica per l'Unificazione nell'Automobile, Technical Commission for Automobile Unification), a federated entity of standards organisation UNI, was formerly used in Italy. CUNA prescribed that the engine be tested with all accessories necessary to its running fitted (such as the water pump), while all others – such as alternator/dynamo, radiator fan, and exhaust manifold – could be omitted. All calibration and accessories had to be as on production engines.

Economic Commission for Europe R24
ECE R24 is a UN standard for the approval of compression ignition engine emissions, installation and measurement of engine power. It is similar to DIN 70020 standard, but with different requirements for connecting an engine's fan during testing causing it to absorb less power from the engine.

Economic Commission for Europe R85
ECE R85 is a UN standard for the approval of internal combustion engines with regard to the measurement of the net power.

80/1269/EEC
80/1269/EEC of 16 December 1980 is a European Union standard for road vehicle engine power.

International Organization for Standardization
The International Organization for Standardization (ISO) publishes several standards for measuring engine horsepower.
 * ISO 14396 specifies the additional and method requirement for determining the power of reciprocating internal combustion engines when presented for an ISO 8178 exhaust emission test. It applies to reciprocating internal combustion engines for land, rail and marine use excluding engines of motor vehicles primarily designed for road use.
 * ISO 1585 is an engine net power test code intended for road vehicles.
 * ISO 2534 is an engine gross power test code intended for road vehicles.
 * ISO 4164 is an engine net power test code intended for mopeds.
 * ISO 4106 is an engine net power test code intended for motorcycles.
 * ISO 9249 is an engine net power test code intended for earth moving machines.

Japanese Industrial Standard D 1001
JIS D 1001 is a Japanese net, and gross, engine power test code for automobiles or trucks having a spark ignition, diesel engine, or fuel injection engine.

title: Horsepower