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| {{Image|SR-71 over mtns.jpg|right|300px| SR-71B loaned from the U.S. Air Force for use in high-speed, high-altitude research at the NASA Dryden Flight Research Center, Edwards, California.}} | | {{:{{FeaturedArticleTitle}}}} |
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| The '''[[Lockheed SR-71]]''' (known unofficially as the '''Blackbird''', and by its crews as the '''Habu''' or the '''sled''') was an advanced, long-range, Mach 3 strategic reconnaissance aircraft developed from the Lockheed YF-12A and A-12 aircraft by the Lockheed Skunk Works. The SR-71 line was in service from 1964 to 1998, and it was the world's fastest and highest-flying operational manned aircraft throughout that entire period, an unparalleled achievement in aviation history. The aircraft flew so fast and so high that if the crew detected a surface-to-air missile launch, the standard evasive action was simply to accelerate. Thirteen aircraft are known to have been lost, all from non-combat related reasons.
| | ==Footnotes== |
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| | {{reflist|2}} |
| The SR-71 included many novel and advanced technologies in order to achieve that performance; in particular, due to extensive frictional heating from its high speed, almost everything in the aircraft had to be specially produced; the airframe was built almost entirely of titanium, as operating temperatures were too high for aluminum. It was also one of the first aircraft to be have been built with a reduced radar cross section; however, the aircraft was not completely stealthy, and still had a fairly large radar signature. The chief designer, Kelly Johnson, was the man behind many of its advanced concepts. After his retirement, Ben Rich ran the program.
| | </small> |
| ====History====
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| While the U-2 Dragon Lady reconnaissance aircraft produced immense value when it began to overfly the Soviet Union in 1956, it was accepted that this subsonic, nonstealthy aircraft eventually would be vulnerable to the Soviet air defense network. Indeed, one was shot down in May 1960, ending manned reconnaissance overflights of the Russian landmass. Overhead reconnaissance of the Soviet Union was taken over by satellites, but the SR-71 was already in development.
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| =====Predecessor models=====
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| The A-12 Oxcart, designed for the CIA by Kelly Johnson at the Lockheed Skunk Works, was the precursor of the SR-71. Lockheed used the name "Archangel" for this design, but many documents use Johnson's preferred name for the plane, "the Article." As the design evolved, the internal Lockheed designation went from A-1 to A-12 as configuration changes occurred, such as substantial design changes to reduce the radar cross-section. The first flight took place at Groom Lake, Nevada, on April 25, 1962. It was 'Article 121,' an A-12, but it was equipped with less powerful Pratt & Whitney J75s due to protracted development of the intended Pratt & Whitney J58. The J58s were retrofitted as they became available. The J58s became the standard power plant for all subsequent aircraft in the series (A-12, YF-12, MD-21) as well as the follow-on SR-71 aircraft. Eighteen A-12 aircraft were built in four variations, of which three were YF-12As, prototypes of the planned F-12B interceptor version, and two were the M-21 variant (see below).
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| The Air Force reconnaissance version was originally called the R-12 (see the opening fly page in Paul Crickmore's book ''SR-71, Secret Missions Exposed'', which contains a copy of the original R-12 labeled plan view drawing of the vehicle). However, during the 1964 presidential campaign, Senator Barry Goldwater continually criticized President Lyndon B. Johnson and his administration for falling behind the Soviet Union in the research and development of new weapon systems. Johnson decided to counter this criticism with the public release of the highly classified A-12 program and later the existence of the reconnaissance version.
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| ===== Name and designation =====
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| The USAF had planned to redesignate the A-12 aircraft as the B-71 as the successor to the B-70 Valkyrie, whichhad two test Valkyries flying at Edwards Air Force Base, California. The B-71 would have a nuclear capability of 3 first-generation SRAM's (Short-Range Attack Missiles). The next designation was RS-71 (Reconnaissance-Strike) when the strike capability became an option. However, then USAF Chief of Staff Curtis LeMay preferred the SR designation and wanted the RS-71 to be named SR-71. Before the Blackbird was to be announced by President Johnson on February 29, 1964, LeMay lobbied to modify Johnson's speech to read SR-71 instead of RS-71. The media transcript given to the press at the time still had the earlier RS-71 designation in places, creating the myth that the president had misread the plane's designation.
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| ''[[Lockheed SR-71|.... (read more)]]''
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Latest revision as of 10:19, 11 September 2020
1901 photograph of a stentor (announcer) at the Budapest
Telefon Hirmondó.
Telephone newspaper is a general term for the telephone-based news and entertainment services which were introduced beginning in the 1890s, and primarily located in large European cities. These systems were the first example of electronic broadcasting, and offered a wide variety of programming, however, only a relative few were ever established. Although these systems predated the invention of radio, they were supplanted by radio broadcasting stations beginning in the 1920s, primarily because radio signals were able to cover much wider areas with higher quality audio.
History
After the electric telephone was introduced in the mid-1870s, it was mainly used for personal communication. But the idea of distributing entertainment and news appeared soon thereafter, and many early demonstrations included the transmission of musical concerts. In one particularly advanced example, Clément Ader, at the 1881 Paris Electrical Exhibition, prepared a listening room where participants could hear, in stereo, performances from the Paris Grand Opera. Also, in 1888, Edward Bellamy's influential novel Looking Backward: 2000-1887 foresaw the establishment of entertainment transmitted by telephone lines to individual homes.
The scattered demonstrations were eventually followed by the establishment of more organized services, which were generally called Telephone Newspapers, although all of these systems also included entertainment programming. However, the technical capabilities of the time meant that there were limited means for amplifying and transmitting telephone signals over long distances, so listeners had to wear headphones to receive the programs, and service areas were generally limited to a single city. While some of the systems, including the Telefon Hirmondó, built their own one-way transmission lines, others, including the Electrophone, used standard commercial telephone lines, which allowed subscribers to talk to operators in order to select programming. The Telephone Newspapers drew upon a mixture of outside sources for their programs, including local live theaters and church services, whose programs were picked up by special telephone lines, and then retransmitted to the subscribers. Other programs were transmitted directly from the system's own studios. In later years, retransmitted radio programs were added.
During this era telephones were expensive luxury items, so the subscribers tended to be the wealthy elite of society. Financing was normally done by charging fees, including monthly subscriptions for home users, and, in locations such as hotel lobbies, through the use of coin-operated receivers, which provided short periods of listening for a set payment. Some systems also accepted paid advertising.
