Misplaced Pages

#479520

77-414: A parachute is a device used to slow the motion of an object through an atmosphere by creating drag or aerodynamic lift . A major application is to support people, for recreation or as a safety device for aviators, who can exit from an aircraft at height and descend safely to earth. A parachute is usually made of a light, strong fabric. Early parachutes were made of silk . The most common fabric today

154-400: A balloon. At 900 meters she detached the gondola from the balloon and descended in the gondola by parachute. In doing so, she became the first woman to parachute. She went on to complete many ascents and parachute descents in towns across France and Europe. Subsequent development of the parachute focused on it becoming more compact. While the early parachutes were made of linen stretched over

231-404: A conical canopy. As a safety measure, four straps ran from the ends of the rods to a waist belt. Although the surface area of the parachute design appears to be too small to offer effective air resistance and the wooden base-frame is superfluous and potentially harmful, the basic concept of a working parachute is apparent. The design is a marked improvement over another folio (189v), which depicts

308-505: A considerably faster forward speed than, say, a modified military canopy. And due to controllable rear-facing vents in the canopy's sides, they also have much snappier turning capabilities, though they are decidedly low-performance compared to today's ram-air rigs. From about the mid-1960s to the late-1970s, this was the most popular parachute design type for sport parachuting (prior to this period, modified military 'rounds' were generally used and after, ram-air 'squares' became common). Note that

385-407: A controlled descent to collapse on impact with the ground. Round parachutes are purely a drag device (that is, unlike the ram-air types, they provide no lift ) and are used in military, emergency and cargo applications (e.g. airdrops ). Most have large dome-shaped canopies made from a single layer of triangular cloth gores . Some skydivers call them "jellyfish 'chutes" because of the resemblance to

462-547: A large scale for their observation balloon crews by the Germans, and then later by the British and French. While this type of unit worked well from balloons, it had mixed results when used on fixed-wing aircraft by the Germans, where the bag was stored in a compartment directly behind the pilot. In many instances where it did not work the shroud lines became entangled with the spinning aircraft. Although this type of parachute saved

539-461: A lower glide ratio . Atmosphere The atmosphere of Earth is composed of nitrogen (78%), oxygen (21%), argon (0.9%), carbon dioxide (0.04%) and trace gases. Most organisms use oxygen for respiration ; lightning and bacteria perform nitrogen fixation which produces ammonia that is used to make nucleotides and amino acids ; plants , algae , and cyanobacteria use carbon dioxide for photosynthesis . The layered composition of

616-428: A man trying to break the force of his fall using two long cloth streamers fastened to two bars, which he grips with his hands. Shortly after, a more sophisticated parachute was sketched by the polymath Leonardo da Vinci in his Codex Atlanticus (fol. 381v) dated to c.  1485 . Here, the scale of the parachute is in a more favorable proportion to the weight of the jumper. A square wooden frame, which alters

693-417: A means of safely disembarking from a hot-air balloon . While Blanchard's first parachute demonstrations were conducted with a dog as the passenger, he later claimed to have had the opportunity to try it himself in 1793 when his hot air balloon ruptured, and he used a parachute to descend. (This event was not witnessed by others.) On 12 October 1799, Jeanne Geneviève Garnerin ascended in a gondola attached to

770-709: A moon of Saturn, and Triton , a moon of Neptune, have atmospheres mainly of nitrogen . When in the part of its orbit closest to the Sun, Pluto has an atmosphere of nitrogen and methane similar to Triton's, but these gases are frozen when it is farther from the Sun. Other bodies within the Solar System have extremely thin atmospheres not in equilibrium. These include the Moon ( sodium gas), Mercury (sodium gas), Europa (oxygen), Io ( sulfur ), and Enceladus ( water vapor ). The first exoplanet whose atmospheric composition

847-490: A number of experimental military mass jumps starting from 2 August 1930. Earlier the same year, the first Soviet mass jumps led to the development of the parachuting sport in the Soviet Union . By the time of World War II , large airborne forces were trained and used in surprise attacks, as in the battles for Fort Eben-Emael and The Hague , the first large-scale, opposed landings of paratroopers in military history, by

SECTION 10

#1732779778480

924-585: A number of famous German fighter pilots, including Hermann Göring , no parachutes were issued to the crews of Allied " heavier-than-air " aircraft. It has been claimed that the reason was to avoid pilots jumping from the plane when hit rather than trying to save the aircraft, but Air Vice Marshall Arthur Gould Lee , himself a pilot during the war, examined the British War Office files after the war and found no evidence of such claim. Airplane cockpits at that time also were not large enough to accommodate

1001-554: A patent for a backpack style parachute – the Aviatory Life Buoy. His self-contained device featured a revolutionary quick-release mechanism – the ripcord – that allowed a falling aviator to expand the canopy only when safely away from the disabled aircraft. Otto Heinecke, a German airship ground crewman, designed a parachute which the German air service introduced in 1918, becoming the world's first air service to introduce

1078-418: A pilot and a parachute, since a seat that would fit a pilot wearing a parachute would be too large for a pilot not wearing one. This is why the German type was stowed in the fuselage, rather than being of the "backpack" type. Weight was – at the very beginning – also a consideration since planes had limited load capacity. Carrying a parachute impeded performance and reduced the useful offensive and fuel load. In

1155-508: A planet from atmospheric escape and that for some magnetizations the presence of a magnetic field works to increase the escape rate. Other mechanisms that can cause atmosphere depletion are solar wind -induced sputtering, impact erosion, weathering , and sequestration—sometimes referred to as "freezing out"—into the regolith and polar caps . Atmospheres have dramatic effects on the surfaces of rocky bodies. Objects that have no atmosphere, or that have only an exosphere, have terrain that

1232-532: A ring-shaped canopy, often with a large hole in the centre to release the pressure. Sometimes the ring is broken into ribbons connected by ropes to leak air even more. These large leaks lower the stress on the parachute so it does not burst or shred when it opens. Ribbon parachutes made of Kevlar are used on nuclear bombs, such as the B61 and B83 . The principle of the Ram-Air Multicell Airfoil

1309-448: A slightly tapered shape to their leading and/or trailing edges when viewed in plan form, and are known as ellipticals. Sometimes all the taper is on the leading edge (front), and sometimes in the trailing edge (tail). Ellipticals are usually used only by sport parachutists. They often have smaller, more numerous fabric cells and are shallower in profile. Their canopies can be anywhere from slightly elliptical to highly elliptical, indicating

1386-460: A standard parachute. Schroeder company of Berlin manufactured Heinecke's design. The first successful use of this parachute was by Leutnant Helmut Steinbrecher of Jagdstaffel 46 , who bailed on 27 June 1918 from his stricken fighter airplane to become the first pilot in history to successfully do so. Although many pilots were saved by the Heinecke design, their efficacy was relatively poor. Out of

1463-451: A variable amount of water vapor is also present, on average about 1% at sea level. The low temperatures and higher gravity of the Solar System's giant planets — Jupiter , Saturn , Uranus and Neptune —allow them more readily to retain gases with low molecular masses . These planets have hydrogen–helium atmospheres, with trace amounts of more complex compounds. Two satellites of the outer planets possess significant atmospheres. Titan ,

1540-464: A wide range of velocities, there will always be some fast enough to produce a slow leakage of gas into space. Lighter molecules move faster than heavier ones with the same thermal kinetic energy , and so gases of low molecular weight are lost more rapidly than those of high molecular weight. It is thought that Venus and Mars may have lost much of their water when, after being photodissociated into hydrogen and oxygen by solar ultraviolet radiation,

1617-518: A wooden frame, in the late 1790s, Blanchard began making parachutes from folded silk , taking advantage of silk's strength and light weight . In 1797, André Garnerin made the first descent of a "frameless" parachute covered in silk. In 1804, Jérôme Lalande introduced a vent in the canopy to eliminate violent oscillations. In 1887, Park Van Tassel and Thomas Scott Baldwin invented a parachute in San Francisco, California, with Baldwin making

SECTION 20

#1732779778480

1694-516: Is nylon . A parachute's canopy is typically dome-shaped, but some are rectangles, inverted domes, and other shapes. A variety of loads are attached to parachutes, including people, food, equipment, space capsules , and bombs . In 852, in Córdoba, Spain , the Moorish man Armen Firman attempted unsuccessfully to fly by jumping from a tower while wearing a large cloak. It was recorded that "there

1771-423: Is covered in craters . Without an atmosphere, the planet has no protection from meteoroids , and all of them collide with the surface as meteorites and create craters. For planets with a significant atmosphere, most meteoroids burn up as meteors before hitting a planet's surface. When meteoroids do impact, the effects are often erased by the action of wind. Wind erosion is a significant factor in shaping

1848-464: Is designed to have an average rate of descent 14% slower than the T-10D, thus resulting in lower landing injury rates for jumpers. The decline in the rate of descent will reduce the impact energy by almost 25% to lessen the potential for injury. A variation on the round parachute is the pull-down apex parachute, invented by a Frenchman named Pierre-Marcel Lemoigne. The first widely used canopy of this type

1925-401: Is the lowest layer of the atmosphere. This extends from the planetary surface to the bottom of the stratosphere . The troposphere contains 75–80% of the mass of the atmosphere, and is the atmospheric layer wherein the weather occurs; the height of the troposphere varies between 17 km at the equator and 7.0 km at the poles. The stratosphere extends from the top of the troposphere to

2002-697: The Rogallo wing , among other shapes and forms. These were usually an attempt to increase the forward speed and reduce the landing speed offered by the other options at the time. The ram-air parachute's development and the subsequent introduction of the sail slider to slow deployment reduced the level of experimentation in the sport parachuting community. The parachutes are also hard to build. Ribbon and ring parachutes have similarities to annular designs. They are frequently designed to deploy at supersonic speeds. A conventional parachute would instantly burst upon opening and be shredded at such speeds. Ribbon parachutes have

2079-675: The U.S. Army , Broadwick deployed her chute manually, thus becoming the first person to jump free-fall . The first military use of the parachute was by artillery observers on tethered observation balloons in World War I . These were tempting targets for enemy fighter aircraft , though difficult to destroy, due to their heavy anti-aircraft defenses. Because it was difficult to escape from them, and dangerous when on fire due to their hydrogen inflation, observers would abandon them and descend by parachute as soon as enemy aircraft were seen. The ground crew would then attempt to retrieve and deflate

2156-531: The Germans. This was followed later in the war by airborne assaults on a larger scale, such as the Battle of Crete and Operation Market Garden , the latter being the largest airborne military operation ever. Aircraft crew were routinely equipped with parachutes for emergencies as well. In 1937, drag chutes were used in aviation for the first time, by Soviet airplanes in the Arctic that were providing support for

2233-522: The Swiss skydiver Olivier Vietti-Teppa. According to historian of technology Lynn White , these conical and pyramidal designs, much more elaborate than early artistic jumps with rigid parasols in Asia, mark the origin of "the parachute as we know it." The Croatian polymath and inventor Fausto Veranzio , or Faust Vrančić (1551–1617), examined da Vinci's parachute sketch and kept the square frame but replaced

2310-489: The UK, Everard Calthrop , a railway engineer and breeder of Arab horses, invented and marketed through his Aerial Patents Company a "British Parachute" and the "Guardian Angel" parachute. As part of an investigation into Calthrop's design, on 13 January 1917, test pilot Clive Franklyn Collett successfully jumped from a Royal Aircraft Factory BE.2c flying over Orford Ness Experimental Station at 180 metres (590 ft). He repeated

2387-484: The United States Army T-10 static-line parachute. A round parachute with no holes in it is more prone to oscillate and is not considered to be steerable. Some parachutes have inverted dome-shaped canopies. These are primarily used for dropping non-human payloads due to their faster rate of descent. Forward speed (5–13  km/h) and steering can be achieved by cuts in various sections (gores) across

Parachute - Misplaced Pages Continue

2464-478: The United States Army as it replaces its older T-10 parachutes with T-11 parachutes under a program called Advanced Tactical Parachute System (ATPS). The ATPS canopy is a highly modified version of a cross/ cruciform platform and is square in appearance. The ATPS system will reduce the rate of descent by 30 percent from 21 feet per second (6.4 m/s) to 15.75 feet per second (4.80 m/s). The T-11

2541-480: The United States military, which later modified his design, resulting in the first military parachute. Banič had been the first person to patent the parachute, and his design was the first to properly function in the 20th century. On June 21, 1913, Georgia Broadwick became the first woman to parachute-jump from a moving aircraft, doing so over Los Angeles, California . In 1914, while doing demonstrations for

2618-629: The Wonders that may be Performed by Mechanical Geometry , published in London in 1648. However, Wilkins wrote about flying, not parachutes, and does not mention Veranzio, a parachute jump, or any event in 1617. Doubts about this test, which include a lack of written evidence, suggest it never occurred, and was instead a misreading of historical notes. The modern parachute was invented in the late 18th century by Louis-Sébastien Lenormand in France , who made

2695-567: The aircraft was spinning. After the war, Major Edward L. Hoffman of the United States Army led an effort to develop an improved parachute by bringing together the best elements of multiple parachute designs. Participants in the effort included Leslie Irvin and James Floyd Smith . The team eventually created the Airplane Parachute Type-A. This incorporated three key elements: In 1919, Irvin successfully tested

2772-565: The amount of taper in the canopy design, which is often an indicator of the responsiveness of the canopy to control input for a given wing loading, and of the level of experience required to pilot the canopy safely. The rectangular parachute designs tend to look like square, inflatable air mattresses with open front ends. They are generally safer to operate because they are less prone to dive rapidly with relatively small control inputs, they are usually flown with lower wing loadings per square foot of area, and they glide more slowly. They typically have

2849-453: The apex closer to the load, distorting the round shape into a somewhat flattened or lenticular shape when viewed from the side. And while called rounds , they generally have an elliptical shape when viewed from above or below, with the sides bulging out more than the for'd-and-aft dimension, the chord (see the lower photo to the right and you likely can ascertain the difference). Due to their lenticular shape and appropriate venting, they have

2926-438: The atmosphere can transport thermal energy from the higher temperature interior up to the surface. From the perspective of a planetary geologist , the atmosphere acts to shape a planetary surface. Wind picks up dust and other particles which, when they collide with the terrain, erode the relief and leave deposits ( eolian processes). Frost and precipitations , which depend on the atmospheric composition, also influence

3003-585: The atmosphere minimises the harmful effects of sunlight , ultraviolet radiation, solar wind , and cosmic rays and thus protects the organisms from genetic damage. The current composition of the atmosphere of the Earth is the product of billions of years of biochemical modification of the paleoatmosphere by living organisms. Atmospheres are clouds of gas bound to and engulfing an astronomical focal point of sufficiently dominating mass , adding to its mass, possibly escaping from it or collapsing into it. Because of

3080-405: The back, or by cutting four lines in the back, thereby modifying the canopy shape to allow air to escape from the back of the canopy, providing limited forward speed. Other modifications sometimes used are cuts in various gores to cause some of the skirt to bow out. Turning is accomplished by forming the edges of the modifications, giving the parachute more speed from one side of the modification than

3157-399: The balloon as quickly as possible. The main part of the parachute was in a bag suspended from the balloon with the pilot wearing only a simple waist harness attached to the main parachute. When the balloon crew jumped the main part of the parachute was pulled from the bag by the crew's waist harness, first the shroud lines, followed by the main canopy. This type of parachute was first adopted on

Parachute - Misplaced Pages Continue

3234-411: The base of the exosphere at 690 km and contains the ionosphere , where solar radiation ionizes the atmosphere. The density of the ionosphere is greater at short distances from the planetary surface in the daytime and decreases as the ionosphere rises at night-time, thereby allowing a greater range of radio frequencies to travel greater distances. The exosphere begins at 690 to 1,000 km from

3311-428: The bottom of the mesosphere , and contains the ozone layer , at an altitude between 15 km and 35 km. It is the atmospheric layer that absorbs most of the ultraviolet radiation that Earth receives from the Sun. The mesosphere ranges from 50 km to 85 km and is the layer wherein most meteors are incinerated before reaching the surface. The thermosphere extends from an altitude of 85 km to

3388-431: The canopy an annular geometry. This hole can be very pronounced in some designs, taking up more 'space' than the parachute. They also have decreased horizontal drag due to their flatter shape and, when combined with rear-facing vents, can have considerable forward speed. Truly annular designs - with a hole large enough that the canopy can be classified as ring-shaped - are uncommon. Sport parachuting has experimented with

3465-492: The canopy with a bulging sail-like piece of cloth that he came to realize decelerates a fall more effectively. A now-famous depiction of a parachute that he dubbed Homo Volans (Flying Man), showing a man parachuting from a tower, presumably St Mark's Campanile in Venice , appeared in his book on mechanics, Machinae Novae ("New Machines", published in 1615 or 1616), alongside a number of other devices and technical concepts. It

3542-426: The diminishing mass of the gas above the point of barometric measurement. The units of air pressure are based upon the standard atmosphere (atm), which is 101,325  Pa (equivalent to 760  Torr or 14.696  psi ). The height at which the atmospheric pressure declines by a factor of e (an irrational number equal to 2.71828) is called the scale height ( H ). For an atmosphere of uniform temperature,

3619-431: The distance from the Sun determines the energy available to heat atmospheric gas to the point where some fraction of its molecules' thermal motion exceed the planet's escape velocity , allowing those to escape a planet's gravitational grasp. Thus, distant and cold Titan , Triton , and Pluto are able to retain their atmospheres despite their relatively low gravities. Since a collection of gas molecules may be moving at

3696-534: The experiment several days later. Following on from Collett, balloon officer Thomas Orde-Lees , known as the "Mad Major", successfully jumped from Tower Bridge in London, which led to the balloonists of the Royal Flying Corps using parachutes, though they were issued for use in aircraft. In 1911, Solomon Lee Van Meter, Jr. of Lexington, Kentucky, submitted an application for, and in July 1916 received,

3773-472: The first (attached-type) parachute jump in the United States from a fixed-wing aircraft , a Benoist pusher, while flying above Jefferson Barracks , St. Louis, Missouri . The jump utilized a parachute stored or housed in a cone-shaped casing under the airplane and attached to a harness on the jumper's body. Štefan Banič patented an umbrella-like design in 1914, and sold (or donated) the patent to

3850-426: The first 70 German airmen to bail out, around a third died, These fatalities were mostly due to the chute or ripcord becoming entangled in the airframe of their spinning aircraft or because of harness failure, a problem fixed in later versions. The French, British, American and Italian air services later based their first parachute designs on the Heinecke parachute to varying extents. In the UK, Sir Frank Mears , who

3927-476: The first parachute jump from an airplane , a Wright Model B piloted by Phil Parmalee , at Venice Beach , California . Morton's device was of the "throw-out" type where he held the parachute in his arms as he left the aircraft. In the same year (1911), Russian Gleb Kotelnikov invented the first knapsack parachute, although Hermann Lattemann and his wife Käthe Paulus had been jumping with bagged parachutes in

SECTION 50

#1732779778480

4004-583: The first person to be saved by an Irvin parachute. Test pilot Lt. Harold R. Harris made another life-saving jump at McCook Field on 20 October 1922. Shortly after Harris' jump, two Dayton newspaper reporters suggested the creation of the Caterpillar Club for successful parachute jumps from disabled aircraft. Beginning with Italy in 1927, several countries experimented with using parachutes to drop soldiers behind enemy lines . The regular Soviet Airborne Troops were established as early as 1931 after

4081-507: The first recorded public jump in 1783. Lenormand also sketched his device beforehand. Two years later, in 1785, Lenormand coined the word "parachute" by hybridizing an Italian prefix para , an imperative form of parare = to avert, defend, resist, guard, shield or shroud, from paro = to parry, and chute , the French word for fall , to describe the aeronautical device's real function. Also in 1785, Jean-Pierre Blanchard demonstrated it as

4158-400: The first successful parachute jump in the western United States. In 1907 Charles Broadwick demonstrated two key advances in the parachute he used to jump from hot air balloons at fairs : he folded his parachute into a backpack , and the parachute was pulled from the pack by a static line attached to the balloon. When Broadwick jumped from the balloon, the static line became taut, pulled

4235-442: The hydrogen escaped. Earth's magnetic field helps to prevent this, as, normally, the solar wind would greatly enhance the escape of hydrogen. However, over the past 3 billion years Earth may have lost gases through the magnetic polar regions due to auroral activity, including a net 2% of its atmospheric oxygen. The net effect, taking the most important escape processes into account, is that an intrinsic magnetic field does not protect

4312-479: The last decade of the 19th century. In 1912, on a road near Tsarskoye Selo , years before it became part of St. Petersburg , Kotelnikov successfully demonstrated the braking effects of a parachute by accelerating a Russo-Balt automobile to its top speed and then opening a parachute attached to the back seat, thus also inventing the drogue parachute . On 1 March 1912, U.S. Army Captain Albert Berry made

4389-431: The latter, such planetary nucleus can develop from interstellar molecular clouds or protoplanetary disks into rocky astronomical objects with varyingly thick atmospheres, gas giants or fusors . Composition and thickness is originally determined by the stellar nebula's chemistry and temperature, but can also by a product processes within the astronomical body outgasing a different atmosphere. The atmospheres of

4466-690: The leading edge of the airfoil. The fabric is shaped and the parachute lines trimmed under load such that the ballooning fabric inflates into an airfoil shape. This airfoil is sometimes maintained by use of fabric one-way valves called airlocks . "The first jump of this canopy (a Jalbert Parafoil) was made by International Skydiving Hall of Fame member Paul 'Pop' Poppenhager." Personal ram-air parachutes are loosely divided into two varieties – rectangular or tapered – commonly called "squares" or "ellipticals", respectively. Medium-performance canopies (reserve-, BASE -, canopy formation-, and accuracy-type) are usually rectangular. High-performance, ram-air parachutes have

4543-411: The marine organisms. Modern sports parachutists rarely use this type. The first round parachutes were simple, flat circulars. These early parachutes suffered from instability caused by oscillations. A hole in the apex helped to vent some air and reduce the oscillations. Many military applications adopted conical, i.e., cone-shaped, or parabolic (a flat circular canopy with an extended skirt) shapes, such as

4620-480: The other. This gives the jumpers the ability to steer the parachute (such as the United States Army MC series parachutes), enabling them to avoid obstacles and to turn into the wind to minimize horizontal speed at landing . The unique design characteristics of cruciform parachutes decrease oscillation (its user swinging back and forth) and violent turns during descent. This technology will be used by

4697-614: The parachute by jumping from an airplane. The Type-A parachute was put into production and over time saved a number of lives. The effort was recognized by the awarding of the Robert J. Collier Trophy to Major Edward L. Hoffman in 1926. Irvin became the first person to make a premeditated free-fall parachute jump from an airplane. An early brochure of the Irvin Air Chute Company credits William O'Connor as having become, on 24 August 1920, at McCook Field near Dayton, Ohio ,

SECTION 60

#1732779778480

4774-587: The parachute from the pack, and then snapped. In 1911 a successful test took place with a dummy at the Eiffel Tower in Paris . The puppet's weight was 75 kg (165 lb); the parachute's weight was 21 kg (46 lb). The cables between the puppet and the parachute were 9 m (30 ft) long. On February 4, 1912, Franz Reichelt jumped to his death from the tower during initial testing of his wearable parachute. Also in 1911, Grant Morton made

4851-406: The past. The circulation of the atmosphere occurs due to thermal differences when convection becomes a more efficient transporter of heat than thermal radiation . On planets where the primary heat source is solar radiation, excess heat in the tropics is transported to higher latitudes. When a planet generates a significant amount of heat internally, such as is the case for Jupiter , convection in

4928-429: The planets Venus and Mars are principally composed of carbon dioxide and nitrogen , argon and oxygen . The composition of Earth's atmosphere is determined by the by-products of the life that it sustains. Dry air (mixture of gases) from Earth's atmosphere contains 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and traces of hydrogen, helium, and other "noble" gases (by volume), but generally

5005-826: The polar expeditions of the era, such as the first drifting ice station , North Pole-1 . The drag chute allowed airplanes to land safely on smaller ice floes . Most parachutes were made of silk until World War II cut off supplies from Japan. After Adeline Gray made the first jump using a nylon parachute in June 1942, the industry switched to nylon. Today's modern parachutes are classified into two categories – ascending and descending canopies. All ascending canopies refer to paragliders , built specifically to ascend and stay aloft as long as possible. Other parachutes, including ram-air non-elliptical, are classified as descending canopies by manufacturers. Some modern parachutes are classified as semi-rigid wings, which are maneuverable and can make

5082-416: The relief. Climate changes can influence a planet's geological history. Conversely, studying the surface of the Earth leads to an understanding of the atmosphere and climate of other planets. For a meteorologist , the composition of the Earth's atmosphere is a factor affecting the climate and its variations. For a biologist or paleontologist , the Earth's atmospheric composition is closely dependent on

5159-468: The scale height is proportional to the atmospheric temperature and is inversely proportional to the product of the mean molecular mass of dry air, and the local acceleration of gravity at the point of barometric measurement. Surface gravity differs significantly among the planets. For example, the large gravitational force of the giant planet Jupiter retains light gases such as hydrogen and helium that escape from objects with lower gravity. Secondly,

5236-468: The shape of the parachute from conical to pyramidal, held open Leonardo's canopy. It is not known whether the Italian inventor was influenced by the earlier design, but he may have learned about the idea through the intensive oral communication among artist-engineers of the time . The feasibility of Leonardo's pyramidal design was successfully tested in 2000 by Briton Adrian Nicholas and again in 2008 by

5313-413: The surface, and extends to roughly 10,000 km, where it interacts with the magnetosphere of Earth. Atmospheric pressure is the force (per unit-area) perpendicular to a unit-area of planetary surface, as determined by the weight of the vertical column of atmospheric gases. In said atmospheric model, the atmospheric pressure , the weight of the mass of the gas, decreases at high altitude because of

5390-417: The terrain of rocky planets with atmospheres, and over time can erase the effects of both craters and volcanoes . In addition, since liquids cannot exist without pressure, an atmosphere allows liquid to be present at the surface, resulting in lakes , rivers and oceans . Earth and Titan are known to have liquids at their surface and terrain on the planet suggests that Mars had liquid on its surface in

5467-436: The use of the word elliptical for these 'round' parachutes is somewhat dated and may cause slight confusion, since some 'squares' (i.e. ram-airs) are elliptical nowadays, too. Some designs with a pull-down apex have the fabric removed from the apex to open a hole through which air can exit (most, if not all, round canopies have at least a small hole to allow easier tie-down for packing - these aren't considered annular), giving

5544-535: Was called the Para-Commander (made by the Pioneer Parachute Co.), although there are many other canopies with a pull-down apex produced in the years thereafter - these had minor differences in attempts to make a higher performance rig, such as different venting configurations. They are all considered 'round' parachutes, but with suspension lines to the canopy apex that apply load there and pull

5621-431: Was conceived in 1963 by Canadian Domina "Dom" C. Jalbert, but serious problems had to be solved before a ram-air canopy could be marketed to the sport parachuting community. Ram-air parafoils are steerable (as are most canopies used for sport parachuting), and have two layers of fabric—top and bottom—connected by airfoil-shaped fabric ribs to form "cells". The cells fill with higher-pressure air from vents that face forward on

5698-461: Was determined is HD 209458b , a gas giant with a close orbit around a star in the constellation Pegasus . Its atmosphere is heated to temperatures over 1,000 K, and is steadily escaping into space. Hydrogen, oxygen, carbon and sulfur have been detected in the planet's inflated atmosphere. The atmosphere of Earth is composed of layers with different properties, such as specific gaseous composition, temperature, and pressure. The troposphere

5775-461: Was enough air in the folds of his cloak to prevent great injury when he reached the ground." The earliest evidence for the true parachute dates back to the Renaissance period. The oldest parachute design appears in a manuscript from the 1470s attributed to Francesco di Giorgio Martini (British Library, Add MS 34113, fol. 200v), showing a free-hanging man clutching a crossbar frame attached to

5852-630: Was once widely believed that in 1617, Veranzio, then aged 65 and seriously ill, implemented his design and tested the parachute by jumping from St Mark's Campanile, from a bridge nearby, or from St Martin's Cathedral in Bratislava . Various publications incorrectly claimed the event was documented some thirty years later by John Wilkins , one of the founders of, and secretary of, the Royal Society in London , in his book Mathematical Magick or,

5929-493: Was serving as a Major in the Royal Flying Corps in France (Kite Balloon section), registered a patent in July 1918 for a parachute with a quick release buckle, known as the "Mears parachute", which was in common use from then onwards. The experience with parachutes during the war highlighted the need to develop a design that could be reliably used to exit a disabled airplane. For instance, tethered parachutes did not work well when

#479520