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129-635: The Kawasaki Ki-61 Hien (飛燕, "flying swallow ") is a Japanese World War II fighter aircraft . Used by the Imperial Japanese Army Air Service , it was designated the "Army Type 3 Fighter" (三式戦闘機). Allied intelligence initially believed Ki-61s were Messerschmitt Bf 109s and later an Italian Macchi C.202 , which led to the Allied reporting name of " Tony ", assigned by the United States War Department . The design originated as

258-466: A Parker truss or Pratt truss than a true arch . In the Brown truss all vertical elements are under tension, with exception of the end posts. This type of truss is particularly suited for timber structures that use iron rods as tension members. See Lenticular truss below. This combines an arch with a truss to form a structure both strong and rigid. Most trusses have the lower chord under tension and

387-667: A covered bridge to protect the structure. In 1820, a simple form of truss, Town's lattice truss , was patented, and had the advantage of requiring neither high labor skills nor much metal. Few iron truss bridges were built in the United States before 1850. Truss bridges became a common type of bridge built from the 1870s through the 1930s. Examples of these bridges still remain across the US, but their numbers are dropping rapidly as they are demolished and replaced with new structures. As metal slowly started to replace timber, wrought iron bridges in

516-416: A truss allows the analysis of its structure using a few assumptions and the application of Newton's laws of motion according to the branch of physics known as statics . For purposes of analysis, trusses are assumed to be pin jointed where the straight components meet, meaning that taken alone, every joint on the structure is functionally considered to be a flexible joint as opposed to a rigid joint with

645-430: A 1988 study on house martins . Swallows are excellent flyers and use these skills to feed and attract mates. Some species, such as the mangrove swallow , are territorial , whereas others are not and simply defend their nesting sites. In general, the male selects a nest site, and then attracts a female using song and flight and (dependent on the species) guards his territory. The size of the territory varies depending on

774-445: A B-29 raid; Shinomaya rammed one B-29, but was able to land his damaged Ki-61, which had lost most of the port outer wing, back at base. After attacking another B-29 Itagaki had to parachute from his damaged fighter, while Nakano rammed and damaged Long Distance of the 498th BG and crash-landed his stripped-down Ki-61 in a field. Shinomaya's damaged Ki-61 was later displayed inside Tokyo's Matsuya department store while Nakano's Ki-61

903-511: A Bf 109 by USAAF Capt. C. Ross Greening during the Doolittle Raid . In early reports, when it was thought to have been a German fighter, the Ki-61 had been code-named "Mike". The final, and better known code name adopted was "Tony", because the Ki-61 looked like an Italian aircraft. The new Ki-61 Hien fighters entered service with a special training unit, the 23rd Chutai , and entered combat for

1032-544: A Parker truss vary from near vertical in the center of the span to diagonal near each end, similar to a Warren truss. George H. Pegram , while the chief engineer of Edge Moor Iron Company in Wilmington, Delaware , patented this truss design in 1885. The Pegram truss consists of a Parker type design with the vertical posts leaning towards the center at an angle between 60 and 75°. The variable post angle and constant chord length allowed steel in existing bridges to be recycled into

1161-431: A bay just above and behind the engine. The breeches partly projected into the cockpit, above the instrument panel. The Ho-103 was a light weapon for its caliber (around 23 kg/51 lb) and fired a light shell, but this was compensated for by its rapid rate of fire. The ammunition capacity was limited, having only around 250 rounds for each weapon. A self-sealing fuel tank with a capacity of 165 L (44 US gal)

1290-594: A continuous truss functions as a single rigid structure over multiple supports. This means that the live load on one span is partially supported by the other spans, and consequently it is possible to use less material in the truss. Continuous truss bridges were not very common before the mid-20th century because they are statically indeterminate , which makes them difficult to design without the use of computers . A multi-span truss bridge may also be constructed using cantilever spans, which are supported at only one end rather than both ends like other types of trusses. Unlike

1419-516: A continuous truss, a cantilever truss does not need to be connected rigidly, or indeed at all, at the center. Many cantilever bridges, like the Quebec Bridge shown below, have two cantilever spans supporting a simple truss in the center. The bridge would remain standing if the simple truss section were removed. Bridges are the most widely known examples of truss use. There are many types, some of them dating back hundreds of years. Below are some of

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1548-435: A conventional truss into place or by building it in place using a "traveling support". In another method of construction, one outboard half of each balanced truss is built upon temporary falsework. When the outboard halves are completed and anchored the inboard halves may then be constructed and the center section completed as described above. The Fink truss was designed by Albert Fink of Germany in 1854. This type of bridge

1677-555: A family of passerine songbirds found around the world on all continents, including occasionally in Antarctica . Highly adapted to aerial feeding, they have a distinctive appearance. The term "swallow" is used as the common name for Hirundo rustica in the UK and Ireland . Around 90 species of Hirundinidae are known, divided into 21 genera , with the greatest diversity found in Africa, which

1806-422: A few days to begin to sprout, and the chicks are brooded by the parents until they are able to thermoregulate . On the whole, they develop slowly compared to other passerine birds. The parents do not usually feed the chicks individual insects, but instead feed a bolus of food comprising 10–100 insects. Regardless of whether the species has males that incubate or brood the chicks, the males of all hirundines help feed

1935-429: A gross area of 20 m (215.28 ft) and featured three spars; a Warren truss main spar and two auxiliary spars. The rear spar carried the split flaps and long, narrow- chord ailerons, while the front spar incorporated the undercarriage pivot points. The undercarriage track was relatively wide at 4 m (13 ft 1.5 in). Each wing had a partially self-sealing 190 L (50 US gal) fuel tank behind

2064-590: A lack of durability, and gave way to the Pratt truss design, which was stronger. Again, the bridge companies marketed their designs, with the Wrought Iron Bridge Company in the lead. As the 1880s and 1890s progressed, steel began to replace wrought iron as the preferred material. Other truss designs were used during this time, including the camel-back. By the 1910s, many states developed standard plan truss bridges, including steel Warren pony truss bridges. In

2193-712: A late 1939 tender by the Koku Hombu for two fighters, each to be built around the Daimler-Benz DB 601 Aa. Production aircraft would use a Kawasaki licensed DB 601, known as the Ha-40 , which was to be manufactured at its Akashi plant. The Ki-60 was to be a heavily armed specialised interceptor , with a high wing loading ; the Ki-61 was to be a more lightly loaded and armed general-purpose fighter, intended to be used mainly in an offensive, air superiority role at low to medium altitudes. Both single-seat, single-engine fighters used

2322-477: A lower chord (functioning as a suspension cable) that curves down and then up to meet at the same end points. Where the arches extend above and below the roadbed, it is called a lenticular pony truss bridge . The Pauli truss bridge is a specific variant of the lenticular truss, but the terms are not interchangeable. One type of lenticular truss consists of arcuate upper compression chords and lower eyebar chain tension links. Brunel 's Royal Albert Bridge over

2451-420: A mean body mass of 9.4 g (0.33 oz) while the purple martin and southern martin , which both weigh in excess of 50 g (1.8 oz) on average, rival one another as the heaviest swallows. The wings are long, pointed, and have nine primary feathers. The tail has 12 feathers and may be deeply forked, somewhat indented, or square-ended. A long tail increases maneuverability, and may also function as

2580-405: A moral lesson about greed and altruism through the mending of a swallow's broken leg. During the 19th century, Jean Desbouvrie attempted to tame swallows and train them for use as messenger birds, as an alternative to war pigeons . The swallows would have a light load of course, as a laden swallow could only travel about half as far as an unladen swallow in the same trip. He succeeded in curbing

2709-704: A new span using the Pegram truss design. This design also facilitated reassembly and permitted a bridge to be adjusted to fit different span lengths. There are twelve known remaining Pegram span bridges in the United States with seven in Idaho , two in Kansas , and one each in California , Washington , and Utah . The Pennsylvania (Petit) truss is a variation on the Pratt truss . The Pratt truss includes braced diagonal members in all panels;

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2838-482: A number of species occasionally consume fruits and other plant matter. Species in Africa have been recorded eating the seeds of Acacia trees, and these are even fed to the young of the greater striped swallow . The swallows generally forage for prey on the wing, but they on occasion snap prey off branches or on the ground. The flight may be fast and involve a rapid succession of turns and banks when actively chasing fast-moving prey; less agile prey may be caught with

2967-489: A ramming flight called " Hagakure -Tai " ("Special Attack Unit"), which was composed out of volunteers from the three Chutai (squadrons) of the 244th: the 1st Chutai " Soyokaze ", 2nd Chutai " Toppu ", and the 3rd Chutai known as " Mikazuki ". First Lieutenant Toru Shinomiya was selected to lead the Hagakure -Tai . On 3 December 1944, Shinomiya – along with Sergeant Masao Itagaki and Sergeant Matsumi Nakano – intercepted

3096-407: A sexual adornment, since the tail is frequently longer in males. In barn swallows, the tail of the male is 18% longer than those of the female, and females select mates on the basis of tail length. Their legs are short, and their feet are adapted for perching rather than walking, as the front toes are partially joined at the base. Swallows are capable of walking and even running, but they do so with

3225-400: A shuffling, waddling gait. The leg muscles of the river martins ( Pseudochelidon ) are stronger and more robust than those of other swallows. The river martins have other characteristics that separate them from the other swallows. The structure of the syrinx is substantially different between the two subfamilies; and in most swallows, the bill, legs, and feet are dark brown or black, but in

3354-408: A slower, more leisurely flight that includes flying in circles and bursts of flapping mixed with gliding. Where several species of swallows feed together, they separate into different niches based on height off the ground, some species feeding closer to the ground and others feeding at higher levels. Similar separation occurs where feeding overlaps with swifts . Niche separation may also occur with

3483-410: A state of torpor , or even that they withdrew for the winter under water. Aristotle ascribed hibernation not only to swallows, but also to storks and kites . Hibernation of swallows was considered a possibility even by as acute an observer as Rev. Gilbert White , in his The Natural History and Antiquities of Selborne (1789, based on decades of observations). This idea may have been supported by

3612-445: A strike; before the collapse, similar incidents had been common and had necessitated frequent repairs. Truss bridges consisting of more than one span may be either a continuous truss or a series of simple trusses. In the simple truss design, each span is supported only at the ends and is fully independent of any adjacent spans. Each span must fully support the weight of any vehicles traveling over it (the live load ). In contrast,

3741-545: A variant of the Kawasaki Ki-60 , which never entered production. The Ki-61 became the only mass-produced Japanese fighter of the war to use a liquid-cooled inverted V engine . Over 3,000 Ki-61s were produced. Initial prototypes saw action over Yokohama during the Doolittle Raid on 18 April 1942, and continued to fly combat missions throughout the war. The Ki-61 was designed by Takeo Doi and his deputy Shin Owada in response to

3870-532: A variant of the lenticular truss, "with the top chord carefully shaped so that it has a constant force along the entire length of the truss." It is named after Friedrich Augustus von Pauli  [ de ] , whose 1857 railway bridge (the Großhesseloher Brücke  [ de ] ) spanned the Isar near Munich . ( See also Grosshesselohe Isartal station .) The term Pauli truss is not interchangeable with

3999-434: A while after the breeding season. If a human being gets too close to their territory, swallows attack them within the perimeter of the nest. Colonial species may mob predators and humans that are too close to the colony. For the most part, swallows are insectivorous, taking flying insects on the wing. Across the whole family, a wide range of insects is taken from most insect groups, but the composition of any one prey type in

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4128-680: Is Miochelidon eschata from the Early Miocene of Siberia ; it is the only record of Hirundinidae from the Miocene . It is likely a basal member of the family. The Hirundinidae have an evolutionarily conservative body shape, which is similar across the clade , but is unlike that of other passerines . Swallows have adapted to hunting insects on the wing by developing a slender, streamlined body and long, pointed wings, which allow great maneuverability and endurance, as well as frequent periods of gliding. Their body shapes allow for very efficient flight ;

4257-677: Is a Pratt truss design with a polygonal upper chord. A "camelback" is a subset of the Parker type, where the upper chord consists of exactly five segments. An example of a Parker truss is the Traffic Bridge in Saskatoon , Canada. An example of a camelback truss is the Woolsey Bridge near Woolsey, Arkansas . Designed and patented in 1872 by Reuben Partridge , after local bridge designs proved ineffective against road traffic and heavy rains. It became

4386-507: Is a hybrid between a Warren truss and a double-intersection Pratt truss. Invented in 1863 by Simeon S. Post, it is occasionally referred to as a Post patent truss although he never received a patent for it. The Ponakin Bridge and the Bell Ford Bridge are two examples of this truss. A Pratt truss includes vertical members and diagonals that slope down towards the center, the opposite of

4515-482: Is also thought to be where they evolved as hole-nesters. They also occur on a number of oceanic islands. A number of European and North American species are long-distance migrants ; by contrast, the West and South African swallows are nonmigratory. This family comprises two subfamilies: Pseudochelidoninae (the river martins of the genus Pseudochelidon ) and Hirundininae (all other swallows, martins, and saw-wings). In

4644-798: Is named after the K formed in each panel by the vertical member and two oblique members. Examples include the Südbrücke rail bridge over the River Rhine, Mainz, Germany, the bridge on I-895 (Baltimore Harbor Tunnel Thruway) in Baltimore, Maryland, the Long–Allen Bridge in Morgan City, Louisiana (Morgan City Bridge) with three 600-foot-long spans, and the Wax Lake Outlet bridge in Calumet, Louisiana One of

4773-671: Is practical for use with spans up to 250 feet (76 m) and was a common configuration for railroad bridges as truss bridges moved from wood to metal. They are statically determinate bridges, which lend themselves well to long spans. They were common in the United States between 1844 and the early 20th century. Examples of Pratt truss bridges are the Governor's Bridge in Maryland ; the Hayden RR Bridge in Springfield, Oregon , built in 1882;

4902-772: Is presumed to be the reason behind the decline of the critically endangered white-eyed river martin , a species that is only known from a few specimens collected in Thailand . The species presumably breeds in riverbanks, a much diminished habitat in Southeast Asia. As the species has not been reliably seen since 1980, it may already be extinct. Two insular species, the Bahama swallow and golden swallow , have declined due to forest loss and also competition with introduced species such as starlings and sparrows, which compete with these swallows for nesting sites. The golden swallow formerly bred on

5031-513: Is the Victoria Bridge on Prince Street, Picton, New South Wales . Also constructed of ironbark, the bridge is still in use today for pedestrian and light traffic. The Bailey truss was designed by the British in 1940–1941 for military uses during World War II. A short selection of prefabricated modular components could be easily and speedily combined on land in various configurations to adapt to

5160-604: Is used in the teaching of statics, by the building of model bridges from spaghetti . Spaghetti is brittle and although it can carry a modest tension force, it breaks easily if bent. A model spaghetti bridge thus demonstrates the use of a truss structure to produce a usefully strong complete structure from individually weak elements. In the United States , because wood was in abundance, early truss bridges would typically use carefully fitted timbers for members taking compression and iron rods for tension members , usually constructed as

5289-597: The Dearborn River High Bridge near Augusta, Montana, built in 1897; and the Fair Oaks Bridge in Fair Oaks, California , built 1907–09. The Scenic Bridge near Tarkio, Montana , is an example of a Pratt deck truss bridge, where the roadway is on top of the truss. The queenpost truss , sometimes called "queen post" or queenspost, is similar to a king post truss in that the outer supports are angled towards

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5418-1224: The Fort Wayne Street Bridge in Goshen, Indiana , the Schell Bridge in Northfield, Massachusetts , the Inclined Plane Bridge in Johnstown, Pennsylvania , the Easton–Phillipsburg Toll Bridge in Easton, Pennsylvania , the Connecticut River Bridge in Brattleboro, Vermont , the Metropolis Bridge in Metropolis, Illinois , and the Healdsburg Memorial Bridge in Healdsburg, California . A Post truss

5547-491: The Howe truss . The interior diagonals are under tension under balanced loading and vertical elements under compression. If pure tension elements (such as eyebars ) are used in the diagonals, then crossing elements may be needed near the center to accept concentrated live loads as they traverse the span. It can be subdivided, creating Y- and K-shaped patterns. The Pratt truss was invented in 1844 by Thomas and Caleb Pratt. This truss

5676-1026: The Indian Ocean , and a number of migratory species are common vagrants to other isolated islands and even to some sub-Antarctic islands and Antarctica. Many species have enormous worldwide ranges, particularly the barn swallow, which breeds over most of the Northern Hemisphere and winters over most of the Southern Hemisphere. The family uses a wide range of habitats. They are dependent on flying insects, and as these are common over waterways and lakes, they frequently feed over these, but they can be found in any open habitat, including grasslands, open woodland, savanna, marshes, mangroves, and scrubland, from sea level to high alpine areas. Many species inhabit human-altered landscapes, including agricultural land and even urban areas. Land-use changes have also caused some species to expand their range, most impressively

5805-1177: The International Ornithological Committee (IOC). Pseudochelidon – river martins (2 species) Psalidoprocne – saw-wings (5 species) Ptyonoprogne – crag martins (5 species) Hirundo – swallows (16 species) Atronanus – forest swallow Delichon – house martins (4 species) Petrochelidon – includes cliff swallows (10 species) Cecropis – swallows (9 species) Pseudhirundo – grey-rumped swallow Cheramoeca – white-backed swallow Phedina – Mascarene martin Neophedina – banded martin Phedinopsis – Brazza's martin Riparia – martins (6 species) Tachycineta – swallows (9 species) Progne – martins (9 species) Stelgidopteryx – rough-winged swallows (2 species) Atticora – swallows (3 species) Pygochelidon – swallows (2 species) Alopochelidon – tawny-headed swallow Orochelidon – swallows (3 species) The oldest known fossil swallow

5934-612: The Japanese Army Air Force (JAAF), but when the Allies re-organized and enhanced the combat capabilities of their air forces, they gained the upper hand against the JAAF. High non-combat losses were also experienced by the Japanese during this campaign. For example, while in transit between Truk and Rabaul, the 78th lost 18 of its 30 Ki-61s. The finicky Ha-40 engine could not be overhauled in

6063-737: The Mitsubishi Ha-112 -II radial engine, resulting in the Ki-100 . While the Ha-112 solved the problems encountered with the Ha-140, the new engine still had a major weakness: a lack of power at altitude, which diminished its ability to intercept high-flying B-29 Superfortresses relative to the Ki-61-II. During testing, the Hien proved capable, but several shortcomings were subsequently revealed in operational service, namely

6192-475: The River Tamar between Devon and Cornwall uses a single tubular upper chord. As the horizontal tension and compression forces are balanced these horizontal forces are not transferred to the supporting pylons (as is the case with most arch types). This in turn enables the truss to be fabricated on the ground and then to be raised by jacking as supporting masonry pylons are constructed. This truss has been used in

6321-462: The cowling side panels being fixed. For servicing or replacement, only the top and bottom cowling panels could be removed. A tapered, rectangular supercharger air intake was located on the port-side cowling. Behind the engine bulkhead were the ammunition boxes feeding a pair of synchronized 12.7 mm (.50 in) Ho-103 machine guns which were set in a "staggered" configuration (the port weapon slightly further forward than that to starboard) in

6450-701: The cupwings in the family Pnoepygidae . The two families diverged in the early Miocene around 22 million years ago. Within the family, a clear division exists between the two subfamilies, the Pseudochelidoninae, which are composed of the two species of river martins, and the Hirundininae, into which the remaining species are placed. The division of the Hirundininae has been the source of much discussion, with various taxonomists variously splitting them into as many as 24 genera and lumping them into just 12. Some agreement exists that three core groups occur within

6579-466: The welcome swallow , which began to colonise New Zealand in the 1920s, started breeding in the 1950s, and is now a common landbird there. Species breeding in temperate regions migrate during the winter when their insect prey populations collapse. Species breeding in more tropical areas are often more sedentary, although several tropical species are partial migrants or make shorter migrations. In antiquity , swallows were thought to have hibernated in

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6708-412: The 1920s and 1930s, Pennsylvania and several states continued to build steel truss bridges, using massive steel through-truss bridges for long spans. Other states, such as Michigan , used standard plan concrete girder and beam bridges, and only a limited number of truss bridges were built. The truss may carry its roadbed on top, in the middle, or at the bottom of the truss. Bridges with the roadbed at

6837-411: The 244th Sentai, who was credited by some with a dozen victories mostly due to conventional attacks against B-29s. Note: Ko, Otsu, Hei and Tei are the Japanese equivalents to a, b, c, d. Kai ('modified' or 'improved') was also used for some models of the Ki-61. Not included: Note: Not included: Post War The Hiko Sentai , usually referred to as Sentai , was the basic operational unit of

6966-465: The 4th Sentai intentionally flew his Kawasaki Ki-45 into a B-29; debris from the explosion severely damaged another B-29, which also went down. Other attacks of this nature followed, as a result of which individual pilots determined it was a practicable way of destroying B-29s. On 7 November 1944, the officer commanding the 10th Hiko Shidan (Air division) made ramming attacks a matter of policy by forming ramming attack flights specifically to oppose

7095-525: The Allied air forces commander in the Southwest Pacific , found his Curtiss P-40s completely outclassed, and begged for more Lockheed P-38 Lightnings to counter the threat of the new enemy fighter. However, the increasing numerical strength of Allied bomber units, along with inadequate anti-aircraft systems, imposed crippling losses on Japanese units. Approximately 174 out of 200 Japanese aircraft based in

7224-550: The B-29s at high altitude. The aircraft were stripped of their fuselage armament and protective systems in order to attain the required altitudes. Although the term " kamikaze " is often used to refer to the pilots undertaking these attacks, the word was not used by the Japanese military. The units assigned to the 10th Hiko Shidan included the 244th Hiko Sentai (Fighter group), then commanded by Captain Takashi Fujita, who organised

7353-473: The Hirundininae: the saw-wings of the genus Psalidoprocne , the core martins, and the swallows of the genus Hirundo and their allies. The saw-wings are the most basal of the three, with the other two clades being sister to each other. The phylogeny of the swallows is closely related to evolution of nest construction; the more basal saw-wings use burrows as nest, the core martins have both burrowing (in

7482-583: The Imperial Japanese Army Air Force, composed of three or more Chutai (companies or squadrons). A Sentai had 27 to 49 aircraft, with each Chutai having 16 aircraft and pilots plus a maintenance and repair unit. Several sentai had other units under their operational control, most notably the Hagakure-Tai ("Special Attack Units") of the 244th Sentai . By 1944, with the depredations of Allied attacks on supply lines and airfields, as well as

7611-429: The JAAF. The aircraft was largely trouble-free in service except for the liquid-cooled engine which tended to overheat when idling on the ground and suffered from oil circulation and bearing problems. The tactic of using aircraft to ram American Boeing B-29 Superfortresses was first recorded in late August 1944, when B-29s from Chinese airfields attempted to bomb the steel factories at Yawata . Sergeant Shigeo Nobe of

7740-409: The Ki-61 was so new, and had been rushed into service, it inevitably suffered from teething problems. Almost all of the modern Japanese aircraft engines, especially the Ki-61's liquid-cooled engines, suffered a disastrous series of failures and ongoing problems, which resulted in the obsolescent Ki-43 still forming the bulk of the JAAF's fighter capability. Initially, this campaign went successfully for

7869-655: The Ki-61-I basic (4 × 12.7 mm/.50 in) 3,130 kg (6,900 lb); and for the Ki-61-KAI (2 × 12.7 mm/0.50 in + 2 × 20 mm), 2,630 kg (5,798 lb) and 3,470 kg (6,750 lb). A number of Ki-61s were also used in Tokkotai ( kamikaze ) missions launched toward the end of the war. The Ki-61 was delivered to 15th Sentai (group/wing), as well as some individual Chutaicho (Squadron Leaders) in other Sentai , and even to operational training units in

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7998-406: The New World.) The family Hirundinidae was introduced (as Hirundia) by the French polymath Constantine Samuel Rafinesque in 1815. The Hirundinidae are morphologically unique within the passerines, with molecular evidence placing them as a distinctive lineage within the Sylvioidea ( Old World warblers and relatives). Phylogenetic analysis has shown that the family Hirundinidae is sister to

8127-447: The Old World members) and cavity adoption (in New World members) as strategies, and the genus Hirundo and its allies use mud nests. The genus level cladogram shown below is based on a molecular phylogenetic study by Drew Schield and collaborators that was published in 2024. The choice of genera and the number of species is taken from the list of birds maintained by Frank Gill , Pamela C. Rasmussen and David Donsker on behalf of

8256-435: The Old World, particularly Africa, whereas cavity-nesters are more common in the New World. Mud-nesting species in particular are limited in areas of high humidity, which causes the mud nests to crumble. Many cave-, bank-, and cliff-dwelling species of swallows nest in large colonies. Mud nests are constructed by both males and females, and amongst the tunnel diggers, the excavation duties are shared, as well. In historical times,

8385-412: The Old World, the name "martin" tends to be used for the squarer-tailed species, and the name "swallow" for the more fork-tailed species; however, this distinction does not represent a real evolutionary separation. In the New World, "martin" is reserved for members of the genus Progne . (These two systems are responsible for the same species being called sand martin in the Old World and bank swallow in

8514-427: The Pennsylvania truss adds to this design half-length struts or ties in the top, bottom, or both parts of the panels. It is named after the Pennsylvania Railroad , which pioneered this design. It was once used for hundreds of bridges in the United States, but fell out of favor in the 1930s and very few examples of this design remain. Examples of this truss type include the Lower Trenton Bridge in Trenton, New Jersey ,

8643-399: The US started being built on a large scale in the 1870s. Bowstring truss bridges were a common truss design during this time, with their arched top chords. Companies like the Massillon Bridge Company of Massillon, Ohio , and the King Bridge Company of Cleveland , became well-known, as they marketed their designs to cities and townships. The bowstring truss design fell out of favor due to

8772-426: The Wewak area were lost during the attacks of August 17–21 1943 . By the end of the campaign, nearly 2,000 Japanese aircraft had been lost in air attacks from up to 200 Allied aircraft at a time, around half of which were Consolidated B-24 Liberators and North American B-25 Mitchells armed with fragmentation bombs. After the Japanese retreat, over 340 aircraft wrecks were later found at Hollandia . The Ki-61

8901-453: The adult male probably being the most common distinction. The chicks hatch naked and with closed eyes. Fledged juveniles usually appear as duller versions of the adult. The family has a worldwide cosmopolitan distribution , breeding on every continent except Antarctica. One species, the Pacific swallow , occurs as a breeding bird on a number of oceanic islands in the Pacific Ocean, the Mascarene martin breeds on Reunion and Mauritius in

9030-420: The armament of the early Hien was lighter, but still sufficient for most purposes. Some authors claim that the Lockheed P-38 Lightning was measurably superior. The Ki-61 carried a great deal of fuel, but due to having self-sealing fuel tanks it was not considered readily flammable, as many other Japanese aircraft were. Owing to the additional weight, the Ki-61's performance and agility suffered when its armament

9159-408: The armor protection that was insufficient against larger guns and a sub-standard engine that eventually led to a new engine being considered. The Ki-61 looked so different from the usual radial-engined Japanese fighters that the Allies at first believed it to be of German or Italian origin, possibly a license-built Messerschmitt Bf 109 . The first Ki-61 seen by Allied aircrew had been misidentified as

9288-454: The balance between labor, machinery, and material costs has certain favorable proportions. The inclusion of the elements shown is largely an engineering decision based upon economics, being a balance between the costs of raw materials, off-site fabrication, component transportation, on-site erection, the availability of machinery, and the cost of labor. In other cases, the appearance of the structure may take on greater importance and so influence

9417-400: The body condition of the bird and are presumably used by females to judge the physical condition and suitability for mating of males. Begging calls are used by the young when soliciting food from their parents. The typical song of swallows is a simple, sometimes musical twittering. Species of hirundine that are threatened with extinction are generally endangered due to habitat loss . This

9546-425: The bridge illustrated in the infobox at the top, vertical members are in tension, lower horizontal members in tension, shear , and bending, outer diagonal and top members are in compression, while the inner diagonals are in tension. The central vertical member stabilizes the upper compression member, preventing it from buckling . If the top member is sufficiently stiff then this vertical element may be eliminated. If

9675-707: The center, the opposite of the Pratt truss . In contrast to the Pratt truss, the diagonal web members are in compression and the vertical web members are in tension. Few of these bridges remain standing. Examples include Jay Bridge in Jay, New York ; McConnell's Mill Covered Bridge in Slippery Rock Township, Lawrence County, Pennsylvania ; Sandy Creek Covered Bridge in Jefferson County, Missouri ; and Westham Island Bridge in Delta, British Columbia , Canada. The K-truss

9804-433: The chicks. When the young fledge is difficult to determine, as they are enticed out of the nest after three weeks by parents, but frequently return to the nest afterwards to roost. Swallows are able to produce many different calls or songs, which are used to express excitement, to communicate with others of the same species, during courtship, or as an alarm when a predator is in the area. The songs of males are related to

9933-414: The compression members and to control deflection. It is mainly used for rail bridges, showing off a simple and very strong design. In the Pratt truss the intersection of the verticals and the lower horizontal tension members are used to anchor the supports for the short-span girders under the tracks (among other things). With the Baltimore truss, there are almost twice as many points for this to happen because

10062-576: The construction of a stadium, with the upper chords of parallel trusses supporting a roof that may be rolled back. The Smithfield Street Bridge in Pittsburgh, Pennsylvania , is another example of this type. An example of a lenticular pony truss bridge that uses regular spans of iron is the Turn-of-River Bridge designed and manufactured by the Berlin Iron Bridge Co. The Pauli truss is

10191-417: The contribution of male swallows towards parental care is the highest of any passerine bird. The eggs of swallows tend to be white, although those of some mud-nesters are speckled. The typical clutch size is around four to five eggs in temperate areas and two to three eggs in the tropics. The incubation duties are shared in some species, and in others the eggs are incubated solely by the females. Amongst

10320-429: The design decisions beyond mere matters of economics. Modern materials such as prestressed concrete and fabrication methods, such as automated welding , and the changing price of steel relative to that of labor have significantly influenced the design of modern bridges. A pure truss can be represented as a pin-jointed structure, one where the only forces on the truss members are tension or compression, not bending. This

10449-469: The diet varies by species and with the time of year. Individual species may be selective; they do not scoop up every insect around them, but instead select larger prey items than would be expected by random sampling. In addition, the ease of capture of different insect types affects their rate of predation by swallows. They also avoid certain prey types; in particular, stinging insects such as bees and wasps are generally avoided. In addition to insect prey,

10578-402: The disappointing flight characteristics of the earlier design. The all-metal, semi-monocoque fuselage was basically oval in cross-section, changing to a tapered, semi-triangular oval behind the cockpit canopy , with a maximum depth of 1.35 m (4 ft 5 in). An unusual feature of the Ki-61 was that the engine bearers were constructed as an integral part of the forward fuselage, with

10707-513: The earlier Ki-27). To address these concerns, Kawasaki staged a fly-off between two Ki-61 prototypes and the Nakajima Ki-43-I , a pre-production Nakajima Ki-44-I , a defector-flown Lavochkin-Gorbunov-Goudkov LaGG-3 , a Messerschmitt Bf 109E-7 , and a captured Curtiss P-40E Warhawk . The Ki-61 proved the fastest of all the aircraft and was inferior only to the Ki-43 in manoeuvrability. The Ki-61

10836-475: The earliest examples is the Old Blenheim Bridge , which with a span of 210 feet (64 m) and a total length of 232 feet (71 m) long was the second-longest covered bridge in the United States, until its destruction from flooding in 2011. The Busching bridge, often erroneously used as an example of a Long truss, is an example of a Howe truss, as the verticals are metal rods. A Parker truss bridge

10965-473: The female is away to reduce heat loss (this is different from incubation as that involves warming the eggs, not just stopping heat loss). Incubation stints last for 5–15 minutes and are followed by bursts of feeding activity. From laying, swallow eggs take 10–21 days to hatch, with 14–18 days being more typical. The chicks of swallows hatch naked, generally with only a few tufts of down. The eyes are closed and do not fully open for up to 10 days. The feathers take

11094-510: The first time in early 1943, during the New Guinea campaign. The first Sentai (Air Group/Wing) fully equipped with the Hien was the 68th in Wewak , New Guinea, followed by the 78th Sentai stationed at Rabaul . Both units were sent into a difficult theatre where jungles and adverse weather conditions, coupled with a lack of spares, quickly undermined the efficiency of both men and machines. Because

11223-453: The habit of some species to roost in some numbers in dovecotes, nests and other forms of shelter during harsh weather, and some species even entering torpor. There were several reports of suspected torpor in swallows from 1947, such as a 1970 report that white-backed swallows in Australia may conserve energy this way, but the first confirmed study that they or any passerine entered torpor was

11352-451: The head. The morphology of the eye in swallows is similar to that of a raptor. Like the unrelated swifts and nightjars , which hunt in a similar way, they have short bills, but strong jaws and a wide gape. Their body lengths range from about 10–24 cm (3.9–9.4 in) and their weight from about 10–60 g (0.35–2.12 oz). The smallest species by weight may be the Fanti sawwing , at

11481-652: The introduction of man-made stone structures such as barns and bridges, together with forest clearance, has led to an abundance of colony sites around the globe, significantly increasing the breeding ranges of some species. Birds living in large colonies typically have to contend with both ectoparasites and conspecific nest parasitism . In barn swallows, old mated males and young unmated males benefit from colonial behaviour, whereas females and mated young males likely benefit more from nesting by themselves. Pairs of mated swallows are monogamous, and pairs of nonmigratory species often stay near their breeding area all year, though

11610-516: The island of Jamaica , but was last seen there in 1989 and is now restricted to the island of Hispaniola . Swallows are tolerated by humans because of their beneficial role as insect eaters, and some species have readily adapted to nesting in and around human habitation. The barn swallow and house martin now rarely use natural sites. The purple martin is also actively encouraged by people to nest around humans and elaborate nest boxes are erected. Enough artificial nesting sites have been created that

11739-592: The loss of pilots and aircraft through combat attrition and accidents, few sentai were able to operate at full strength. Sgt. Susumu Kaijinami officially credited with eight victories plus 16 unofficially. Data from Japanese Aircraft of the Pacific War General characteristics Performance Armament Related development Aircraft of comparable role, configuration, and era Related lists Swallow 21, see text The swallows , martins , and saw-wings , or Hirundinidae are

11868-482: The lower chord (a horizontal member of a truss) is sufficiently resistant to bending and shear, the outer vertical elements may be eliminated, but with additional strength added to other members in compensation. The ability to distribute the forces in various ways has led to a large variety of truss bridge types. Some types may be more advantageous when the wood is employed for compression elements while other types may be easier to erect in particular site conditions, or when

11997-648: The main spar, just outboard of the fuselage. A single weapon (initially a 7.7 mm/0.303 in Type 89 machine gun ) was able to be carried in a weapons bay located behind the main spar. The first prototype of the San-shiki-Sentohki ichi gata ("Type 3 Fighter, Model 1", the official IJAAF designation) first flew in December 1941 at Kagamigahara Airfield . Although test pilots were enthusiastic about its self-sealing fuel tanks, upgraded armament, and good dive performance,

12126-744: The mass-production stage) to power the next generation of combat aircraft such as the Republic P-47 Thunderbolt . Moreover, the inline Ha-40 engine proved to be an unreliable powerplant, exacerbated in the South Pacific campaign, where high temperatures caused problems with the fuel pumps. The DB-601 engine required precise and sophisticated manufacturing; the Ha-40 was lighter by roughly 30 kg (70 lb) and required even higher manufacturing standards. Reaching these standards proved difficult for Japanese manufacturers, an issue further complicated by

12255-405: The metabolic rate of swallows in flight is 49–72% lower than equivalent passerines of the same size. Swallows have two foveae in each eye, giving them sharp lateral and frontal vision to help track prey. They also have relatively long eyes, with their length almost equaling their width. The long eyes allow for an increase in visual acuity without competing with the brain for space inside of

12384-457: The migratory instinct in young birds and persuaded the government of France to conduct initial testing, but further experimentation stalled. Subsequent attempts to train homing behaviour into swallows and other passerines had difficulty establishing a statistically significant success rate, although the birds have been known to trap themselves in a cage repeatedly to get to the bait. Truss bridge#Warren .28non-polar.29 truss The nature of

12513-504: The more common designs. The Allan truss , designed by Percy Allan , is partly based on the Howe truss . The first Allan truss was completed on 13 August 1894 over Glennies Creek at Camberwell, New South Wales and the last Allan truss bridge was built over Mill Creek near Wisemans Ferry in 1929. Completed in March 1895, the Tharwa Bridge located at Tharwa, Australian Capital Territory ,

12642-412: The needs at the site and allow rapid deployment of completed trusses. In the image, note the use of pairs of doubled trusses to adapt to the span and load requirements. In other applications the trusses may be stacked vertically, and doubled as necessary. The Baltimore truss is a subclass of the Pratt truss. A Baltimore truss has additional bracing in the lower section of the truss to prevent buckling in

12771-441: The nest site is defended most vigorously during the breeding season. Migratory species often return to the same breeding area each year, and may select the same nest site if they were previously successful in that location. First-year breeders generally select a nesting site close to where they were raised. The breeding of temperate species is seasonal, whereas that of subtropical or tropical species can either be continuous throughout

12900-545: The new interceptor reverted to the original wing and was put into service as the Ki-61-II-KAI. However, the Ha-140 engine had severe reliability problems that were never fully resolved, and around half of the first batch of engines delivered were returned to the factory to be re-built. A US bombing raid on 19 January 1945 destroyed the engine factory in Akashi, Hyōgo , and 275 Ki-61-II-KAI airframes without engines were converted to use

13029-551: The purple martin now seldom nests in natural cavities in the eastern part of its range. Because of the long human experience with these conspicuous species, many myths and legends have arisen as a consequence, particularly relating to the barn swallow. Roman historian Pliny the Elder described a use of painted swallows to deliver a report of the winning horses at a race. There is also the Korean folktale of Heungbu and Nolbu , which teaches

13158-503: The ramming unit had been kept confidential until then, but it was officially disclosed in the combat results announcement and officially named " Shinten Seiku Tai " ("Body Attack Detachment") by the Defense GHQ. On 27 January 1945, Itakagi survived another ramming attack on a B-29, again parachuting to safety, and received a second Bukosho ; he survived the war as only one of two known double- Bukosho recipients. Sergeant Shigeru Kuroishikawa

13287-415: The river martins, the bill is orange-red and the legs and feet are pink. The most common hirundine plumage is glossy dark blue or green above and plain or streaked underparts, often white or rufous. Species that burrow or live in dry or mountainous areas are often matte brown above (e.g. sand martin and crag martin ). The sexes show limited or no sexual dimorphism , with longer outer tail feathers in

13416-474: The roadbed but are not connected, a pony truss or half-through truss. Sometimes both the upper and lower chords support roadbeds, forming a double-decked truss . This can be used to separate rail from road traffic or to separate the two directions of road traffic. Since through truss bridges have supports located over the bridge deck, they are susceptible to being hit by overheight loads when used on highways. The I-5 Skagit River bridge collapsed after such

13545-522: The same basic construction: all-metal alloys with semi- monocoque fuselages and three- spar wings, with alloy-framed, fabric-covered ailerons , elevators and rudders . Priority was given to the Ki-60, which first flew in April 1941, while design work on the Ki-61 did not begin until December 1940. Although the Ki-61 was broadly similar to the Ki-60, it featured several refinements exploiting lessons learned from

13674-559: The short verticals will also be used to anchor the supports. Thus the short-span girders can be made lighter because their span is shorter. A good example of the Baltimore truss is the Amtrak Old Saybrook – Old Lyme Bridge in Connecticut , United States. The Bollman Truss Railroad Bridge at Savage, Maryland , United States is the only surviving example of a revolutionary design in the history of American bridge engineering. The type

13803-451: The simplest truss styles to implement, the king post consists of two angled supports leaning into a common vertical support. This type of bridge uses a substantial number of lightweight elements, easing the task of construction. Truss elements are usually of wood, iron, or steel. A lenticular truss bridge includes a lens-shape truss, with trusses between an upper chord functioning as an arch that curves up and then down to end points, and

13932-450: The size of prey chosen. The more primitive species nest in existing cavities, for example in an old woodpecker nest, while other species excavate burrows in soft substrate such as sand banks. Swallows in the genera Hirundo , Ptyonoprogne , Cecropis , Petrochelidon , Atronanus and Delichon build mud nests close to overhead shelter in locations that are protected from both the weather and predators. The mud-nesters are most common in

14061-595: The species of swallow; in colonial-nesting species, it tends to be small, but it may be much larger for solitary nesters. Outside the breeding season, some species may form large flocks, and species may also roost communally. This is thought to provide protection from predators, such as sparrowhawks and hobbies . These roosts can be enormous; one winter-roosting site of barn swallows in Nigeria attracted 1.5 million individuals. Nonsocial species do not form flocks, but recently fledged chicks may remain with their parents for

14190-529: The species where the males help with incubation, their contribution varies amongst species, with some species such as the cliff swallow sharing the duties equally and the female doing most of the work in others. Amongst the barn swallows, the male of the American subspecies helps (to a small extent), whereas the European subspecies does not. Even in species where the male does not incubate the eggs, he may sit on them when

14319-450: The standard for covered bridges built in central Ohio in the late 1800s and early 1900s. The Pegram truss is a hybrid between the Warren and Parker trusses where the upper chords are all of equal length and the lower chords are longer than the corresponding upper chord. Because of the difference in upper and lower chord length, each panel is not square. The members which would be vertical in

14448-414: The strength to maintain its shape, and the resulting shape and strength of the structure are only maintained by the interlocking of the components. This assumption means that members of the truss (chords, verticals, and diagonals) will act only in tension or compression. A more complex analysis is required where rigid joints impose significant bending loads upon the elements, as in a Vierendeel truss . In

14577-472: The term lenticular truss and, according to Thomas Boothby, the casual use of the term has clouded the literature. The Long truss was designed by Stephen H. Long in 1830. The design resembles a Howe truss , but is entirely made of wood instead of a combination of wood and metal. The longest surviving example is the Eldean Covered Bridge north of Troy, Ohio , spanning 224 feet (68 m). One of

14706-511: The theatre, instead they had to be shipped to the nearest service depot in Halmahera , in eastern Indonesia . Even with these problems, there was some concern in Allied aviation circles regarding the Hien. The new Japanese fighter caused some pain and consternation among Allied pilots, particularly when they found out the hard way that they could no longer go into a dive and escape as they had from lighter Japanese fighters. General George Kenney ,

14835-525: The top or the bottom are the most common as this allows both the top and bottom to be stiffened, forming a box truss . When the roadbed is atop the truss, it is a deck truss; an example of this was the I-35W Mississippi River bridge . When the truss members are both above and below the roadbed it is called a through truss; an example of this is the Pulaski Skyway , and where the sides extend above

14964-428: The upper chord under compression. In a cantilever truss the situation is reversed, at least over a portion of the span. The typical cantilever truss bridge is a "balanced cantilever", which enables the construction to proceed outward from a central vertical spar in each direction. Usually these are built in pairs until the outer sections may be anchored to footings. A central gap, if present, can then be filled by lifting

15093-678: The variable quality of materials, fuel, and the lubricants needed to run a sensitive, high-performance engine. The Japanese equivalent of the more powerful DB-605 engine was the Kawasaki Ha-140 , which was fitted onto the Type 3 to produce the Ki-61-II high-altitude interceptor. Compared to the Ki-61-I, the Ki-61-II had 10% greater wing area, used more armour and was powered by the Kawasaki Ha-140 engine generating 1,120 kW (1,500 hp). After overcoming initial fuselage and wing stability problems,

15222-423: The wing loading of 146.3 kg/m (30 lb/ft) at an all-up weight of 2,950 kg (6,500 lb) was viewed with scepticism by many of the senior officers of the Koku Hombu , who still believed in the light, highly manoeuvrable, lightly armed fighter epitomised by the then new Nakajima Ki-43-I- Hei which had a wing loading of 92.6 kg/m (19 lb/ft) (and even that was considered borderline compared to

15351-456: The year or seasonal. Seasonal species in the subtropics or tropics usually time their breeding to coincide with the peaks in insect activity, which is usually the wet season, but some species, such as the white-bibbed swallow , nest in the dry season to avoid flooding in their riverbank nesting habitat. All swallows defend their nests from egg predators, although solitary species are more aggressive towards predators than colonial species. Overall,

15480-414: Was also easy to assemble. Wells Creek Bollman Bridge is the only other bridge designed by Wendel Bollman still in existence, but it is a Warren truss configuration. The bowstring truss bridge was patented in 1841 by Squire Whipple . While similar in appearance to a tied-arch bridge , a bowstring truss has diagonal load-bearing members: these diagonals result in a structure that more closely matches

15609-557: Was also utilised in Southeast Asia , Okinawa , China and as an interceptor during US bombing raids over the Japanese home islands , including against Boeing B-29 Superfortresses . The Ki-61 was notable for many reasons: initially identified as of either German or Italian origin, these aircraft were capable of matching Allied aircraft such as the P-40 in speed, and as evaluation had already shown, were superior in almost every respect. However,

15738-498: Was another distinguished member of the unit. Despite their successful attacks, these pilots gained no reprieve, and were obliged to continue these deadly and dangerous ramming tactics until they were killed, or else wounded so badly that they could no longer fly. They were regarded as doomed men and were celebrated among the ranks of those who were going to certain death as Tokkotai ( kamikaze ) pilots. Some other Ki-61 pilots also achieved renown, among them Major Teruhiko Kobayashi of

15867-519: Was displayed outside, alongside of a life-size cut-away drawing of the forward fuselage of a B-29. These three pilots were the first recipients of the Bukosho , Japan's equivalent to the Victoria Cross or Medal of Honor , which had been inaugurated on 7 December 1944 as an Imperial Edict by Emperor Hirohito (there are 89 known recipients, most of whom fought and scored against B-29s). The existence of

15996-456: Was increased, but it still remained capable with a 580 km/h (313 kn) maximum speed. The cannon armament was needed to counter the Allied bombers, which proved to be difficult to shoot down with only 12.7 mm (.50 in) machine guns. The empty and maximum weights for the Ki-61 prototype (2 × 12.7 mm/0.50 in + 2 × 7.7 mm/0.303 in) were 2,238 kg (4,934 lb) and 2,950 kg (6,504 lb), respectively; for

16125-409: Was located behind the pilot's seat. The windshield was armored and there was a 13 mm (.51 in) armor plate behind the pilot. The radiator and oil cooler for the liquid-cooled engine were in a ventral location below the fuselage and wing trailing edge , covered by a rectangular section fairing with a large, adjustable exit flap. The evenly-tapered wings had an aspect ratio of 7.2 with

16254-405: Was named after its inventor, Wendel Bollman , a self-educated Baltimore engineer. It was the first successful all-metal bridge design (patented in 1852) to be adopted and consistently used on a railroad. The design employs wrought iron tension members and cast iron compression members. The use of multiple independent tension elements reduces the likelihood of catastrophic failure. The structure

16383-659: Was popular with the Baltimore and Ohio Railroad . The Appomattox High Bridge on the Norfolk and Western Railway included 21 Fink deck truss spans from 1869 until their replacement in 1886. There are also inverted Fink truss bridges such as the Moody Pedestrian Bridge in Austin, Texas. The Howe truss , patented in 1840 by Massachusetts millwright William Howe , includes vertical members and diagonals that slope up towards

16512-563: Was the last of the fighters powered by the DB-601 or its foreign derivatives, and it was soon overshadowed by fighters with more powerful engines. By the time it first flew in December 1941, one year after the Macchi C.202 's first flight and three years after the first Bf 109E, the engine was already underpowered compared to the new 1,120 kW (1,500 hp) inline or 1,491 kW (2,000 hp) radial engines being developed (and already nearing

16641-814: Was the second Allan truss bridge to be built, the oldest surviving bridge in the Australian Capital Territory and the oldest, longest continuously used Allan truss bridge. Completed in November 1895, the Hampden Bridge in Wagga Wagga, New South Wales , Australia, the first of the Allan truss bridges with overhead bracing, was originally designed as a steel bridge but was constructed with timber to reduce cost. In his design, Allan used Australian ironbark for its strength. A similar bridge also designed by Percy Allen

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