BASE jumping

BASE jump at Majlis Al Jinn, Oman, 2013

BASE jumping, also sometimes written as B.A.S.E. jumping, is parachuting or wingsuit flying from a fixed structure or cliff. "BASE" is an acronym that stands for four categories of fixed objects from which one can jump:building, antenna, span, and Earth (cliff).[1][2] Due to the lower altitudes of the jumps, BASE jumping is significantly more dangerous than skydiving from a plane. In the U.S., BASE jumping is currently regarded by many as a fringe extreme sport or stunt.[3] In some jurisdictions or locations, BASE jumping is prohibited or illegal; in some places, however, it is permitted. BASE jumping became known to the wider public by depictions of BASE jumping in a number of action movies.

History[edit] The acronym "B.A.S.E." (now more commonly "BASE") was coined by filmmaker Carl Boenish, his wife Jean Boenish, Phil Smith, and Phil Mayfield.[4] Carl Boenish was the catalyst behind modern BASE jumping, and in 1978, he filmed the first BASE jumps to be made using ram-air parachutes and the freefall tracking technique (from El Capitan, in Yosemite National Park).[5] While BASE jumps had been made prior to that time, the El Capitan activity was the effective birth of what is now called BASE jumping. BASE numbers are awarded to those who have made at least one jump from each of the four categories (buildings, antennas, spans and earth). When Phil Smith and Phil Mayfield jumped together from a Houston skyscraper on 18 January 1981, they became the first to attain the exclusive BASE numbers (BASE #1 and #2, respectively), having already jumped from an antenna, spans, and earthen objects. Jean and Carl Boenish qualified for BASE numbers 3 and 4 soon after. A separate "award" was soon enacted for Night BASE jumping when Mayfield completed each category at night, becoming Night BASE #1, with Smith qualifying a few weeks later. Faust Vrancic is widely believed to have performed a parachute jumping experiment for real[6] and, therefore, to be the first man to build and test a parachute: according to the story passed on, Veranzio, in 1617, then over sixty-five years old, implemented his design and tested the parachute by jumping from St Mark's Campanile in Venice.[7] It is generally added that this event were documented some 30 years later in a book Mathematical Magick or, the Wonders that may be Performed by Mechanical Geometry (London, 1648) written by John Wilkins, the secretary of the Royal Society in London. However, these and other sporadic incidents were one-time experiments, not the systematic pursuit of a new form of parachuting. After 1978, the filmed jumps from El Capitan were repeated, not as a publicity exercise or as a movie stunt, but as a true recreational activity. It was this that popularised BASE jumping more widely among parachutists.[citation needed] Carl Boenish continued to publish films and informational magazines on BASE jumping until his death in 1984 after a BASE-jump off of the Troll Wall. By this time, the concept had spread among skydivers worldwide, with hundreds of participants making fixed-object jumps. During the early eighties, nearly all BASE jumps were made using standard skydiving equipment, including two parachutes (main and reserve), and deployment components. Later on, specialized equipment and techniques were developed specifically for the unique needs of BASE jumping.

Jumpers from a cliff Upon completing a jump from all of the four object categories, a jumper may choose to apply for a "BASE number", which are awarded sequentially.[8] BASE #1 was awarded to Phil Smith of Houston, Texas in 1981. The 1000th application for a BASE number was filed in March 2005 and BASE #1000 was awarded to Matt "Harley" Moilanen of Grand Rapids, Michigan. As of December 2014, over 1,850 BASE numbers have been issued.[9] BASE jumping is often featured in action movies. The 2002 Vin Diesel film xXx includes a scene where Diesel's character catapults himself off the Foresthill Bridge in an open-topped car, landing safely as the car crashes on the ground. In the movie Lara Croft Tomb Raider: The Cradle of Life, includes the scene in which the main characters jump with wing suits from the IFC Tower in Hong Kong and fly over the Bank of China, finally opening their parachutes to land on a moving freighter. The stunt was done live, with no special effects, by base jumpers Martin Rosén and Per Eriksson, members of the Swedish "Team Bautasten". The scene was filmed by air-to-air camera man Mikael Nordqvist from the same team. Since the 1976 Mount Asgard jump featured in the pre- credits sequence to The Spy Who Loved Me, James Bond movies have featured several BASE jumps, including one from the Eiffel Tower in 1985's A View to a Kill, the Rock of Gibraltar in 1987's The Living Daylights, and in Die Another Day, 2002, Pierce Brosnan as James Bond jumps from a melting iceberg. Of the James Bond jumps only the Mt Asgard and Eiffel Tower jumps were filmed live; the rest were special effects. And in 2005's "Batman Begins", Bruce Wayne uses BASE jumping as inspiration for his memory cloth cape. A series of BASE jumps are featured in the video for a remix of M83's "Lower Your Eyelids to Die With the Sun".[10] Guinness World Records first listed a BASE jumping record with Carl Boenish's 1984 leap from Trollveggen (Troll Wall) in Norway. It was described as the highest BASE jump.[11] (The jump was made two days before Boenish's death at the same site.) This record category is still in the Guinness book and is currently held by Australians Glenn Singleman and Heather Swan with a jump from Meru Peak in northern India at a starting elevation of 6,604 metres (21,667 ft).[12] On July 8, 2006 Captain Daniel G. Schilling set the Guinness World Record for the most BASE jumps in a twenty-four hour period. Schilling jumped off the Perrine Bridge in Twin Falls, Idaho a record 201 times. BASE competitions have been held since the early 1980s, with accurate landings or free fall aerobatics used as the judging criteria. Recent years have seen a formal competition held at the 452 metres (1,483 ft) high Petronas Towers in Kuala Lumpur, Malaysia, judged on landing accuracy.[citation needed] In 2010 North west Norway celebrated with a world record with 53 Base jumpers jumping from a cliff.[citation needed]

Notable jumps[edit]

 In 1912, Franz Reichelt, tailor, jumped from the first deck of the Eiffel Tower testing his invention, the coat parachute. He died by hitting the ground. It was his first ever attempt with the parachute and both the authorities and the spectators believed he intended to test it using a dummy.[13]

 In 1913, Štefan Banič jumped from a 12 m building in order to demonstrate his new parachute to the U. S. Patent Office and military. Subsequently this design became standard equipment for U.S. pilots during the World War I.[citation needed]

 In 1913, a Russian student Vladimir Ossovski (Владимир Оссовский), from the Saint-Petersburg Conservatory, jumped from the 53-meter high bridge over the river Seine in Rouen (France), using the parachute RK-1, invented a year before that by Gleb Kotelnikov (1872–1944). Ossovski planned to jump from the Eiffel Tower too, but the Parisian authorities did not allow it.[14]

 In 1965, Erich Felbermayr from Wels jumped from the Kleine Zinne / Cima piccola di Lavaredo in the Dolomites.[15]

 In 1966, Michael Pelkey and Brian Schubert jumped from the cliff "El Capitan" in Yosemite Valley.[16]

 On January 31, 1972, Rick Sylvester skied off Yosemite Valley's El Capitan cliff, making the first skiBASE jump (he termed it a "ski/parachute jump" since the acronym BASE had yet to be coined), falling approximately halfway down, about 1500', before deploying his Thunderbow chute. He did this twice more, approximately two weeks later and a year later.[citation needed]

 On 9 November 1975, the first person to parachute off the CN Tower in Toronto, Canada, was Bill Eustace, a member of the tower's construction crew. He was fired.[17]  In 1975, Owen J. Quinn, a jobless man, parachuted from the south tower of the World Trade Center to publicize the plight of the unemployed.[18]

 In 1976 Rick Sylvester skied off Canada's Mount Asgard for the ski chase sequence of the James Bond movie The Spy Who Loved Me, giving the wider world its first look at BASE jumping.[19]

 On February 22, 1982, Wayne Allwood, an Australian skydiving accuracy champion, parachuted from a helicopter over the Sydney CBD and landed on the small top area of Sydney's Centrepoint Tower, approximately 300 metres (980 ft) above the ground. Upon landing, Allwood discarded and secured his parachute, then used a full-sized reserve parachute to BASE jump into Hyde Park below.[20] Video footage is also included in the Australian Base Associations' 2001 video compilation, Fistful of F-111.

 In 1986, Welshman Eric Jones became the first person to BASE jump from the Eiger.

 In 1987 Steve Dines (Australian) BASE 157 Made the first jump from the top of the Sydney Harbour Bridge.

 In 1990 Russell Powell (British) BASE 230 illegally jumped from the Whispering Gallery inside St Paul's Cathedral London. It was the lowest indoor BASE Jump in the world at 31.1 m.[21]

 In 1990 Australian Mark Scott BASE# 165 / OZ BASE # 13 / SA BASE #1 made the first BASE Jump off London's One Canada Square tower, four days before the topping out ceremony.[21]

 On August 26, 1992 Nic Feteris and Glenn Singleman (two Australians) made a BASE jump from an altitude of 20,600 feet (6286 meters) jump off Great Trango Towers Pakistan. It was the world's highest BASE jump off the earth at the time.[citation needed]

 In 1996, one jumper was injured and three landed safely in the only authorized BASE jump from Seattle's Space Needle.[22]

 In 2000, Hannes Arch and Ueli Gegenschatz were the first to dare a BASE jump from the imposing 1800-metre high north face of the Eiger.[citation needed]

 In 2005, Karina Hollekim became the first woman to perform a ski-BASE.

 In April 2008, Hervé Le Gallou and David McDonnell infiltrated Burj Khalifa, and jumped off a balcony on the 155th floor. They evaded arrest following their successful jump. However, on a second attempt two days later, Le Gallou was caught and subsequently detained in Dubai for three months.[23][24][25]

 In 2009, three women—29-year-old Australian Livia Dickie, 28-year-old Venezuelan Ana Isabel Dao, and 32-year-old Norwegian Anniken Binz[26]—base jumped from Angel Falls, the highest waterfall in the world. Ana Isabel Dao was the first Venezuelan woman to jump off Angel Falls.[27]

 On 8 January 2010, Nasr Al Niyadi and Omar Al Hegelan broke the then current world record for the highest building BASE jump after they leapt from a crane suspended platform attached to the Burj Khalifa's 160th floor at 672 metres (2,205 ft).[28]

 On 5 May 2013, Russian Valery Rozov, 48, jumped off Changtse’s north face from a height of 7,220 metres (23,690 ft). Using a specially-developed wing suit, he flew to the Rongbuk glacier breaking the world record for highest base jump.[29]

 In September 2013, 3 men jumped off the then-under-construction One World Trade Center in New York City. Footage of their jump was recorded using headcams and can be seen on YouTube.[30] In March 2014 the 3 jumpers and one accomplice on the ground were arrested after turning themselves in.[31][32]

 On April 21, 2014, Fred Fugen and Vince Reffet (both from France) broke the Guinness World Record for Highest BASE Jump From A Building with a jump of 828 m (2,716 ft 6 in). They performed the jump off the Burj Khalifa tower in Dubai, UAE.[33][34]  On May 27, 2014, Whisper became the world's first Wingsuit BASE jumping dog.[35]

 On August 21, 2014, Ramón Rojas of Chile broke the record for highest Earth-based wingsuit ski jump, 4,100 metres (13,500 ft) off of Cerro El Plomo.[36]

Comparison with skydiving[edit]

BASE jumping from antenna tower

BASE Jumping from Sapphire Tower, Istanbul. BASE jumping grew out of skydiving. BASE jumps are generally made from much lower altitudes than skydives, and a BASE jump takes place close to the object serving as the jump platform. Because BASE jumps generally entail slower airspeeds than typical skydives (due to the limited altitude), a BASE jumper does not always reach terminal velocity. Because higher airspeeds enable jumpers more aerodynamic control of their bodies, as well as more positive and quick parachute openings, the longer the delay, the better. BASE jumping is significantly more dangerous than similar sports such as skydiving from aircraft.[3] Skydivers use the air flow to stabilize their position, allowing the parachute to deploy cleanly. BASE jumpers, falling at lower speeds, have less aerodynamic control, and may tumble. The attitude of the body at the moment of jumping determines the stability of flight in the first few seconds, before sufficient airspeed has built up to enable aerodynamic stability. On low BASE jumps, parachute deployment takes place during this early phase of flight, so if a poor "launch" leads into a tumble, the jumper may not be able to correct this before the opening. If the parachute is deployed while the jumper is tumbling, there is a high risk of entanglement or malfunction. The jumper may also not be facing the right direction. Such an off-heading opening is not as problematic in skydiving, but an off-heading opening that results in object strike has caused many serious injuries and deaths in BASE jumping. At an altitude of 600 metres (2,000 ft), having been in free-fall for at least 300 metres (980 ft), the jumper is falling at approximately 55 metres per second (120 mph), and is approximately 10.9 seconds from the ground. Most BASE jumps are made from less than 600 metres (2,000 ft). For example, a BASE jump from a 150 metres (490 ft) object is about 5.6 seconds from the ground if the jumper remains in free fall. On a BASE jump, the parachute must open at about half the airspeed of a similar skydive, and more quickly (in a shorter distance fallen). Standard skydiving parachute systems are not designed for this situation, so BASE jumpers often use specially designed harnesses and parachute containers, with extra large pilot chutes, and many jump with only one parachute, since there would be little time to utilize a reserve parachute. If modified, by removing the bag and slider, stowing the lines in a tail pocket, and fitting a large pilot chute, standard skydiving gear can be used for lower BASE jumps, but is then prone to kinds of malfunction that are rare in normal skydiving (such as "line- overs" and broken lines). Another risk is that most BASE jumping venues have very small areas in which to land. A beginner skydiver, after parachute deployment, may have a three minute or more parachute ride to the ground. A BASE jump from 150 metres (490 ft) will have a parachute ride of only 10 to 15 seconds. One way to make a parachute open very quickly is to use a static line or direct bag. These devices form an attachment between the parachute and the jump platform, which stretches out the parachute and suspension lines as the jumper falls, before separating and allowing the parachute to inflate. This method enables the very lowest jumps — below 60 metres (200 ft) — to be made, although most BASE jumpers are more motivated to make higher jumps involving free fall. This method is similar to the paratrooper's deployment system, also called a PCA (Pilot Chute Assist).

PARACHUTE

A parachute is a device used to slow the motion of an object through an atmosphere by creating drag, or in the case of ram-air parachutes, aerodynamic lift. Parachutes are usually made out of light, strong cloth, originally silk, now most commonly nylon. Depending on the situation, parachutes are used with a variety of loads, including people, food, equipment, space capsules, and bombs.

Early Renaissance[edit]

The oldest known depiction of a parachute, by an anonymous author (Italy, 1470s)

The earliest evidence for the parachute dates back to the Renaissance period.[3] The oldest parachute design appears in an anonymous manuscript from 1470s Renaissance Italy (British Museum Add. MSS 34,113, fol. 200v), showing a free-hanging man clutching a cross bar frame attached to a conical canopy.[4] As a safety measure, four straps run from the ends of the rods to a waist belt. The design is a marked improvement over another folio (189v), which depicts a man trying to break the force of his fall by the means of two long cloth streamers fastened to two bars which he grips with his hands.[5] Although the surface area of the parachute design appears to be too small to offer effective resistance to the friction of the air and the wooden base-frame is superfluous and potentially harmful, the revolutionary character of the new concept is obvious.[5]

Shortly after, a more sophisticated parachute was sketched by the polymath Leonardo da Vinci in his Codex Atlanticus (fol. 381v) dated to ca. 1485.[4] Here, the scale of the parachute is in a more favorable proportion to the weight of the jumper. Leonardo's canopy was held open by a square wooden frame, which alters the shape of the parachute from conical to pyramidal.[5] 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.[6] The feasibility of Leonardo's pyramidal design was successfully tested in 2000 by Briton Adrian Nicholas and again in 2008 by Luigi Cani.[7] According to the 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."[3]

Fausto Veranzio's 1595 parachute design titled "Flying Man" or "the Man with an Angel's Blessing"

The Croatian inventor Faust Vrančić (1551–1617) examined da Vinci's parachute sketch, and set out to implement one of his own. He kept the square frame, but replaced the canopy with a bulging sail-like piece of cloth that he came to realize decelerates the fall more effectively.[5] 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 (1615 or 1616), alongside a number of other devices and technical concepts.[8] It was widely believed that in 1617, Vrančić, then aged 65 and seriously ill, implemented his design and tested the parachute by jumping from St Mark's Campanile,[9] from a bridge nearby,[10] or from St Martin's Cathedral in Bratislava.[11][12] In various publications it was falsely claimed that the event was documented some thirty years later by John Wilkins, founder and secretary of the Royal Society in London in his book Mathematical Magick or, the Wonders that may be Performed by Mechanical Geometry, published in London in 1648.[10] However, in this book, John Wilkins wrote about flying, not about parachutes. He neither mentions Faust Vrančić nor a parachute jump nor any event in 1617, and doubts about this test along with no written evidence of its occurrence, lead to the conclusion that it never occurred, and was caused by a misreading of historical notes.[13]

Modern times[edit] This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and

removed. (January 2009)

Louis-Sébastien Lenormand jumps from the tower of the Montpellier observatory, 1783. Illustration from the late 19th century

First use of a frameless parachute, by André Garnerinin 1797

Schematic depiction of Garnerin's parachute, from an early nineteenth century illustration Picture published in a Dutch magazine De Prins der Geïllustreerde Bladen(February 18, 1911)[14]

Gleb Kotelnikov and his invention, the knapsack parachute 18th and 19th centuries[edit]

The modern parachute was invented in the late 18th century by Louis-Sébastien Lenormand in France, who made 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 the French prefix paracete, meaning to protect against, and chute, the French word for fall, to describe the aeronautical device's real function.[citation needed]

Also in 1785, Jean-Pierre Blanchard demonstrated it as 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).

Subsequent development of the parachute focused on it becoming more coact. While the early parachutes were made of linen stretched over 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 using such a parachute. Garnerin also invented the vented parachute, which improved the stability of the fall. Eve of World War I[edit]

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 pack he wore on his back. 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 the parachute from the pack, and then snapped.[15]

In 1911 a successful test took place with a dummy at the Eiffel tower in Paris. The puppet's weight was 75 kg; the parachute's weight was 21 kg. The cables between puppet and the parachute were 9 m long.[14] 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 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, a Russian inventor Gleb Kotelnikov invented the first knapsack parachute,[16] although Hermann Lattemann and his wife Käthe Paulus had been jumping with bagged parachutes in the last decade of the 19th century.

Albert Berry collapses his parachute on Kinloch Field at Jefferson Barracks,Missouri, after his jump on March 1, 1912.

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.[16]

On March 1, 1912, U.S. Army Captain Albert Berry made 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 "pack" style parachute stored or housed in a casing on the jumper's body.

Štefan Banič from Slovakia built the first parachutes to see use beyond the experimental stage, patenting his design in 1914.[17] He tested his umbrella-like device by jumping from an airplane with it, and sold (or donated) the patent to the United States military, receiving very little money or fame for it.[18] On June 21, 1913, Georgia Broadwick became the first woman to parachute-jump from a moving aircraft, doing so over Los Angeles, California.[19] In 1914, while doing demonstrations for the U.S. Army, Broadwick deployed her chute manually, thus becoming the first person to jump free-fall.

Kite balloon observers preparing to descend by parachute. 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 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 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 a number of famous German fighter pilots were saved by this type of parachute, includingHermann Göring,[20] no parachutes were issued to Allied "heavier-than-air" aircrew, since it was thought at the time that if a pilot had a parachute he would jump from the plane when hit rather than trying to save the aircraft.[21]

Airplane cockpits at that time also were not large enough to accommodate 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 the U.K., 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. Thomas Orde-Lees, known as the "Mad Major," demonstrated that parachutes could be used successfully from a low height (he jumped from Tower Bridge in London) which led to parachutes being used by the balloonists of the Royal Flying Corps, though they were not available for aircraft.

In 1911, Solomon Lee Van Meter, Jr. of Lexington Kentucky, submitted for and in July 1916 received a patent for a backpack style parachute – the Aviatory Life Buoy.[22] 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.[23]

In 1918 the German air service introduced a parachute designed by Unteroffizier Otto Heinecke, an airship ground crewman, and thus became the world's first, and at the time only, air service to introduce a standard parachute. Despite Germany equipping their pilots with parachutes, their efficacy was relatively poor. As a result, many pilots died while using them, including aces such as Oberleutnant Erich Löwenhardt (who fell from 3,600 metres (11,800 ft) after being accidentally rammed by another German aircraft) and Fritz Rumey who tested it in 1918, only to have it fail at a little over 900 m (3,000 ft). Out of the first 70 German airmen to bail out, around a third died.[24] 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 of the Heinecke parachute. [24] High as the failure rate was, carrying a Heinecke parachute certainly beat the alternative and the general effectiveness of the Heinecke parachute can be gauged by the fact that the French, British, American and Italian air services later based their first parachute designs on the Heinecke parachute to varying extents.[25]

In the UK Sir Frank Mears who 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.[26] Post-World War I[edit]

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 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,

 storing the parachute in a soft pack worn on the back, as demonstrated by Charles Broadwick in 1906;

 a ripcord for manually deploying the parachute at a safe distance from the airplane, from a design by Albert Leo Stevens; and

 a pilot chute that draws the main canopy from the pack.

In 1919, Irvin successfully tested the parachute by jumping from an airplane. The Type-A parachute was put into production and over time saved a number of lives.[15] The effort was recognized by the awarding of the Robert J. Collier Trophy to Major Edward L. Hoffman in 1926.[27]

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 August 24, 1920 at McCook Field near Dayton, Ohio, the first person to be saved by an Irvin parachute.[28] Another life-saving jump was made at McCook Field by test pilot Lt. Harold H. Harris on October 20, 1922. Shortly after Harris' jump, two Dayton newspaper reporters suggested the creation of the Caterpillar Club for successful parachute jumps from disabled aircraft.

In 1924 Gleb Kotelnikov of Russia became the first parachutist to apply the soft packing of a parachute instead of a hard casing.[29]

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 a number of experimental military mass jumps starting from August 2, 1930.[16] Earlier the same year, the first Soviet mass jumps led to the development of the parachuting sport in the Soviet Union.[16] By the time of World War II, large airborne forces were trained and used in surprise attacks, as in the battles for Fort Eben-Emaeland The Hague, the first large-scale, opposed landings of paratroopers in military history, by the Germans.[30] 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.[31] Aircraft crew were routinely equipped with parachutes for emergencies as well.[citation needed]

In 1937, drag chutes were used in aviation for the first time, by Soviet airplanes in the Arctic that were providing support for the polar expeditions of the era, such as the first manned drifting ice station North Pole-1. The drag chute allowed airplanes to land safely on smaller ice-floes.[16]

Types[edit]

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 a controlled descent to collapse on impact with the ground. Round[edit]

An American paratrooperusing an MC1-1C series "round" parachute

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. These 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 the marine organisms. Modern sport 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 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.

Forward speed (5–13 km/h) and steering can be achieved by cuts in various sections (gores) across 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 sections (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 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. Cruciform (square)[edit]

The unique design characteristics of cruciform parachutes decreases oscillation (its user swinging back and forth) and violent turns during descent. This technology will be used by 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 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 rate of descent will reduce the impact energy by almost 25% to lessen the potential for injury. Annular and pull down apex[edit] The Mars Science Laboratorydescending under a ring parachute.

RAF Typhoon using a parachute for braking after landing

A variation on the round parachute is the pull down apex parachute. Invented by a Frenchman named Pierre- Marcel Lemoigne,[32][33][34] it is called a Para-Commander canopy in some circles, after the first model of the type. It is a round parachute, but with suspension lines to the canopy apex that apply load there and pull the apex closer to the load, distorting the round shape into a somewhat flattened or lenticular shape.

Some designs have the fabric removed from the apex to open a hole through which air can exit, giving the canopy an annular geometry. They also have decreased horizontal drag due to their flatter shape and, when combined with rear-facing vents, can have considerable forward speed. Rogallo wing[edit]

Sport parachuting has experimented with 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[edit]

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 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.[35] Ram-air[edit]

Most modern parachutes are self-inflating "ram-air" airfoils known as a parafoil that provide control of speed and direction similar to paragliders. Paragliders have much greater lift and range, but parachutes are designed to handle, spread and mitigate the stresses of deployment at terminal velocity. All ram-air parafoils have two layers of fabric; top and bottom, connected by airfoil-shaped fabric ribs to form "cells." The cells fill with high pressure air from vents that face forward on 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 ram-air test jump was performed by United States Navy test jumper Joe Crotwell.

Varieties[edit]

A United States NavyParachute Team "Leap Frogs" jumper landing a "square" ram-air parachute

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 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 in 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 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 a lower glide ratio.

Wing loading of parachutes is measured similarly to that of aircraft, comparing exit weight to area of parachute fabric. Typical wing loading for students, accuracy competitors, and BASE jumpers is less than 5 kg per square meter – often 0.3 kilograms per square meter or less. Most student skydivers fly with wing loading below 5 kg per square meter. Most sport jumpers fly with wing loading between 5 and 7 kg per square meter, but many interested in performance landings exceed this wing loading. Professional Canopy pilots compete with wing loading of 10 to over 15 kilograms per square meter. While ram-air parachutes with wing loading higher than 20 kilograms per square meter have been landed, this is strictly the realm of professional test jumpers.

Smaller parachutes tend to fly faster for the same load, and ellipticals respond faster to control input. Therefore, small, elliptical designs are often chosen by experienced canopy pilots for the thrilling flying they provide. Flying a fast elliptical requires much more skill and experience. Fast ellipticals are also considerably more dangerous to land. With high-performance elliptical canopies, nuisance malfunctions can be much more serious than with a square design, and may quickly escalate into emergencies. Flying highly loaded, elliptical canopies is a major contributing factor in many skydiving accidents, although advanced training programs are helping to reduce this danger.

High-speed, cross-braced parachutes, such as the Velocity, VX, XAOS and Sensei, have given birth to a new branch of sport parachuting called "swooping." A race course is set up in the landing area for expert pilots to measure the distance they are able to fly past the 1.5-metre (4.9 ft) tall entry gate. Current world records exceed 180 metres (590 ft).

Aspect ratio is another way to measure ram-air parachutes. Aspect ratios of parachutes are measured the same way as aircraft wings, by comparing span with chord. Low aspect ratio parachutes, i.e., span 1.8 times the chord, are now limited to precision landing competitions. Popular precision landing parachutes include Jalbert (now NAA) Para-Foils and John Eiff's series of Challenger Classics. While low aspect ratio parachutes tend to be extremely stable, with gentle stall characteristics, they suffer from steep glide ratios and a small tolerance, or "sweet spot", for timing the landing flare.

Because of their predictable opening characteristics, parachutes with a medium aspect ratio around 2.1 are widely used for reserves, BASE, and canopy formation competition. Most medium aspect ratio parachutes have seven cells.

High aspect ratio parachutes have the flattest glide and the largest tolerance for timing the landing flare, but the least predictable openings. An aspect ratio of 2.7 is about the upper limit for parachutes. High aspect ratio canopies typically have nine or more cells. All reserve ram-air parachutes are of the square variety, because of the greater reliability, and the less-demanding handling characteristics.

General characteristics[edit]

Roadside chai shop made of old parachute in Ladkah, India

Main parachutes used by skydivers today are designed to open softly. Overly rapid deployment was an early problem with ram-air designs. The primary innovation that slows the deployment of a ram-air canopy is the slider; a small rectangular piece of fabric with a grommet near each corner. Four collections of lines go through the grommets to the risers (risers are strips of webbing joining the harness and the rigging lines of a parachute). During deployment, the slider slides down from the canopy to just above the risers. The slider is slowed by air resistance as it descends and reduces the rate at which the lines can spread. This reduces the speed at which the canopy can open and inflate.

At the same time, the overall design of a parachute still has a significant influence on the deployment speed. Modern sport parachutes' deployment speeds vary considerably. Most modern parachutes open comfortably, but individual skydivers may prefer harsher deployment. The deployment process is inherently chaotic. Rapid deployments can still occur even with well-behaved canopies. On rare occasions deployment can even be so rapid that the jumper suffers bruising, injury, or death. Reducing the amount of fabric decreases the air resistance. This can be done by making the slider smaller, inserting a mesh panel, or cutting a hole in the slider.

Deployment[edit]

Animation showing a parachute release system

Reserve parachutes usually have a ripcord deployment system, which was first designed by Theodore Moscicki, but most modern main parachutes used by sports parachutists use a form of hand-deployed pilot chute. A ripcord system pulls a closing pin (sometimes multiple pins), which releases a spring-loaded pilot chute, and opens the container; the pilot chute is then propelled into the air stream by its spring, then uses the force generated by passing air to extract a deployment bag containing the parachute canopy, to which it is attached via a bridle. A hand-deployed pilot chute, once thrown into the air stream, pulls a closing pin on the pilot chute bridle to open the container, then the same force extracts the deployment bag. There are variations on hand- deployed pilot chutes, but the system described is the more common throw-out system.

Only the hand-deployed pilot chute may be collapsed automatically after deployment—by a kill line reducing the in-flight drag of the pilot chute on the main canopy. Reserves, on the other hand, do not retain their pilot chutes after deployment. The reserve deployment bag and pilot chute are not connected to the canopy in a reserve system. This is known as a free-bag configuration, and the components are often lost during a reserve deployment.

Occasionally, a pilot chute does not generate enough force either to pull the pin or to extract the bag. Causes may be that the pilot chute is caught in the turbulent wake of the jumper (the "burble"), the closing loop holding the pin is too tight, or the pilot chute is generating insufficient force. This effect is known as "pilot chute hesitation," and, if it does not clear, it can lead to a total malfunction, requiring reserve deployment.

Paratroopers' main parachutes are usually deployed by static lines that release the parachute, yet retain the deployment bag that contains the parachute—without relying on a pilot chute for deployment. In this configuration the deployment bag is known as a direct-bag system, in which the deployment is rapid, consistent, and reliable. Safety[edit]

A parachute is carefully folded, or "packed" to ensure that it will open reliably. If a parachute is not packed properly it can result in a malfunction where the main parachute fails to deploy correctly or fully. In the United States and many developed countries, emergency and reserve parachutes are packed by "riggers" who must be trained and certified according to legal standards. Sport skydivers are always trained to pack their own primary "main" parachutes.

Exact numbers are difficult to estimate, but approximately one in a thousand sport main parachute openings malfunction, requiring the use of the reserve parachute, although some skydivers have many thousands of jumps and never needed to use their reserve parachute. Reserve parachutes are packed and deployed somewhat differently. They are also designed more conservatively, and are built and tested to more exacting standards, making them more reliable than main parachutes. However, the primary safety advantage of a reserve chute comes from the probability of an unlikely main malfunction being multiplied by the even less likely probability of a reserve malfunction. This yields an even smaller probability of a double malfunction, although the possibility of a main malfunction that cannot be cut away causing a reserve malfunction is a very real risk. In the United States, the average fatality rate is considered to be about 1 in 175,851 jumps.[36] Numerous injuries and fatalities in sport skydiving occur under a fully functional main parachute because the skydiver made an error in judgment while flying the canopy, resulting in high-speed impact with the ground or with a hazard on the ground that might otherwise have been avoided, or collision with another skydiver under canopy.[citation needed]

Malfunctions[edit]

The Apollo 15 spacecraft landed safely despite a parachute line failure in 1971.

Below are listed the malfunctions specific to round parachutes. For malfunctions specific to square parachutes, see Malfunction (parachuting).

 A "Mae West" or "blown periphery" is a type of round parachute malfunction that contorts the shape of the canopy into the outward appearance of a brassiere, presumably one suitable for a buxom woman having the proportions of the late actress Mae West. The column of nylon fabric, buffeted by the wind, rapidly heats from friction and opposite sides of the canopy fuse together in a narrow region, removing any chance of the canopy opening fully.

 An "inversion" occurs when one skirt of the canopy blows between the suspension lines on the opposite side of the parachute and then catches air. That portion then forms a secondary lobe with the canopy inverted. The secondary lobe grows until the canopy turns completely inside out.  A "barber's pole" describes having a tangle of lines "behind your head and you have to cut away your main chute and pull your reserve."[37]

 The "horseshoe" is an out-of-sequence deployment, when the parachute lines and bag are released before the bag drogue and bridle. This can cause the lines to become tangled or a situation where the parachute drogue is not released from the container.[37]

 "Jumper-In-Tow" involves a static line that does not disconnect and "you are being dragged along in the wild blue yonder."[37]

 The "Streamer" is "dreaded" when the main chute is whistling in the wind, the chutist cuts away, and attempts to open the reserve if there is time.[37]

Records[edit]

On August 16, 1960, Joseph Kittinger, in the Excelsior III test jump, set the previous world record for the highest parachute jump. He jumped from a balloon at an altitude of 102,800 feet (31,333 m) (which was also a manned balloon altitude record at the time). A small stabilizer chute deployed successfully, and Kittinger fell for 4 minutes and 36 seconds,[38] also setting a still-standing world record for the longest parachute free-fall, if falling with a stabilizer chute is counted as free-fall. At an altitude of 17,500 feet (5,300 m), Kittinger opened his main chute and landed safely in the New Mexico desert. The whole descent took 13 minutes and 45 seconds.[39] During the descent, Kittinger experienced temperatures as low as −94 °F (−70 °C). In the free-fall stage, he reached a top speed of 614 mph (988 km/h or 274 m/s).[40]

Felix Baumgartner broke Joseph Kittinger's record on October 14, 2012, with a jump from an altitude of 127,852 feet (38,969.3 m) and reaching speeds up to 833.9 mph (1,342.0 km/h or 372.8 m/s).

Alan Eustace made a jump from the stratosphere on October 24, 2014 from an altitude of 135,889.108 feet (41,419 m). However, because Eustace's jump involved a drogue parachute while Baumgartner's did not, their vertical speed and free fall distance records remain in different record categories

According to Guinness World Records, Yevgeni Nikolayevich Andreyev (Soviet Union) held the official FAI record for the longest free-fall parachute jump (without drogue chute) after falling for 24,500 m (80,380 ft) from an altitude of 25,457 m (83,523 ft) near the city of Saratov, Russia on November 1, 1962, until broken by Felix Baumgartner in 2012.

Free fall From Wikipedia, the free encyclopedia For other uses, see Free fall (disambiguation). Commander David Scott conducting an experiment during the Apollo 15moon landing. In Newtonian physics, free fall is any motion of a body where its weight is the only force acting upon it. In the context of general relativity, where gravitation is reduced to a space-time curvature, a body in free fall has no force acting on it and moves along a geodesic. The present article only concerns itself with free fall in the Newtonian domain. An object in the technical sense of free fall may not necessarily be falling down in the usual sense of the term. An object moving upwards would not normally be considered to be falling, but if it is subject to the force of gravity only, it is said to be in free fall. The moon is thus in free fall. In a uniform gravitational field, in the absence of any other forces, gravitation acts on each part of the body equally and this is weightlessness, a condition that also occurs when the gravitational field is zero (such as when far away from any gravitating body). A body in free fall experiences "0 g". The term "free fall" is often used more loosely than in the strict sense defined above. Thus, falling through an atmosphere without a deployed parachute, or lifting device, is also often referred to as free fall. The aerodynamicdrag forces in such situations prevent them from producing full weightlessness, and thus a skydiver's "free fall" after reaching terminal velocity produces the sensation of the body's weight being supported on a cushion of air.

Contents [hide]

 1 History

 2 Examples

 3 Free fall in Newtonian mechanics

o 3.1 Uniform gravitational field without air resistance

o 3.2 Uniform gravitational field with air resistance

o 3.3 Inverse-square law gravitational field

 4 Free fall in general relativity

 5 Record free fall parachute jumps

 6 Surviving falls

 7 See also

 8 References

 9 External links

History[edit] In the Western world prior to the Sixteenth Century, it was generally assumed that the speed of a falling body would be proportional to its weight—that is, a 10 kg object was expected to fall ten times faster than an otherwise identical 1 kg object through the same medium. The ancient Greek philosopher Aristotle (384–322 BC) discussed falling objects in what was perhaps the first book on mechanics. The Italian scientist Galileo Galilei (1564–1642) subjected the Aristotelian theories to experimentation and careful observation. He then combined the results of these experiments with mathematical analysis in an unprecedented way. In a tale that may be apocryphal, Galileo (or an assistant, more likely) dropped two objects of unequal mass from the Leaning Tower of Pisa. Given the speed at which such a fall would occur, it is doubtful that Galileo could have extracted much information from this experiment. Most of his observations of falling bodies were really of bodies rolling down ramps. This slowed things down enough to the point where he was able to measure the time intervals with water clocks and his own pulse (stopwatches having not yet been invented). This he repeated "a full hundred times" until he had achieved "an accuracy such that the deviation between two observations never exceeded one-tenth of a pulse beat."

Examples[edit] Examples of objects in free fall include:

 A spacecraft (in space) with propulsion off (e.g. in a continuous orbit, or on a suborbital trajectory (ballistics) going up for some minutes, and then down).

 An object dropped at the top of a drop tube.

 An object thrown upward or a person jumping off the ground at low speed (i.e. as long as air resistance is negligible in comparison to weight). Technically, an object is in free fall even when moving upwards or instantaneously at rest at the top of its motion. If gravity is the only influence acting, then the acceleration is always downward and has the same magnitude for all bodies, commonly denoted . Since all objects fall at the same rate in the absence of other forces, objects and people will experience weightlessness in these situations. Examples of objects not in free fall:

 Flying in an aircraft: there is also an additional force of lift.

 Standing on the ground: the gravitational force is counteracted by the normal force from the ground.

 Descending to the Earth using a parachute, which balances the force of gravity with an aerodynamic drag force (and with some parachutes, an additional lift force). The example of a falling skydiver who has not yet deployed a parachute is not considered free fall from a physics perspective, since he experiences a drag force that equals his weight once he has achieved terminal velocity (see below). However, the term "free fall skydiving" is commonly used to describe this case in everyday speech, and in the skydiving community. It is not clear, though, whether the more recent sport of wingsuit flying fits under the definition of free fall skydiving. Measured fall time of a small steel sphere falling from various heights. The data is in good agreement with the predicted fall time of , where h is the height and g is the free-fall acceleration due to gravity. Near the surface of the Earth, an object in free fall in a vacuum will accelerate at approximately 9.8 m/s², independent of its mass. With air resistance acting on an object that has been dropped, the object will eventually reach a terminal velocity, which is around 56 m/s (200 km/h or 120 mph) for a human body. The terminal velocity depends on many factors including mass, drag coefficient, and relative surface area and will only be achieved if the fall is from sufficient altitude. A typical skydiver in a spread-eagle position will reach terminal velocity after about 12 seconds, during which time he will have fallen around 450 m (approx. 1,500 ft).[1] Free fall was demonstrated on the moon by astronaut David Scott on August 2, 1971. He simultaneously released a hammer and a feather from the same height above the moon's surface. The hammer and the feather both fell at the same rate and hit the ground at the same time. This demonstrated Galileo's discovery that, in the absence of air resistance, all objects experience the same acceleration due to gravity. (On the Moon, the gravitational acceleration is much less than on Earth, approximately 1.6 m/s²).

Free fall in Newtonian mechanics[edit] Main article: Newtonian mechanics Uniform gravitational field without air resistance[edit] This is the "textbook" case of the vertical motion of an object falling a small distance close to the surface of a planet. It is a good approximation in air as long as the force of gravity on the object is much greater than the force of air resistance, or equivalently the object's velocity is always much less than the terminal velocity (see below).

where is the initial velocity (m/s). is the vertical velocity with respect to time (m/s). is the initial altitude (m). is the altitude with respect to time (m). is time elapsed (s). is the acceleration due to gravity (9.81 m/s2 near the surface of the earth). Uniform gravitational field with air resistance[edit] Acceleration of a small meteoroid when entering the Earth's atmosphere at different initial velocities. This case, which applies to skydivers, parachutists or any body of mass, , and cross-sectional area, , with Reynolds number well above the critical Reynolds number, so that the air resistance is proportional to the square of the fall velocity, , has an equation of motion

where is the air density and is the drag coefficient, assumed to be constant although in general it will depend on the Reynolds number. Assuming an object falling from rest and no change in air density with altitude, the solution is:

where the terminal speed is given by

The object's speed versus time can be integrated over time to find the vertical position as a function of time:

Using the figure of 450 metres to reach terminal speed, this equation implies a free-fall time to terminal velocity of around 12 seconds. However, when the air density cannot be assumed to be constant, such as for objects or skydivers falling from high altitude, the equation of motion becomes much more difficult to solve analytically and a numerical simulation of the motion is usually necessary. The figure shows the forces acting on meteoroids falling through the Earth's upper atmosphere. HALO jumps, including Joe Kittinger's and Felix Baumgartner's record jumps (see below), and the planned Le Grand Saut, also belong in this category.[2] Inverse-square law gravitational field[edit] It can be said that two objects in space orbiting each other in the absence of other forces are in free fall around each other, e.g. that the Moon or an artificial satellite "falls around" the Earth, or a planet "falls around" the Sun. Assuming spherical objects means that the equation of motion is governed by Newton's Law of Universal Gravitation, with solutions to the gravitational two-body problem being elliptic orbits obeying Kepler's laws of planetary motion. This connection between falling objects close to the Earth and orbiting objects is best illustrated by the thought experiment, Newton's cannonball. The motion of two objects moving radially towards each other with no angular momentum can be considered a special case of an elliptical orbit of eccentricity e = 1 (radial elliptic trajectory). This allows one to compute the free-fall time for two point objects on a radial path. The solution of this equation of motion yields time as a function of separation:

where t is the time after the start of the fall y is the distance between the centers of the bodies

y0 is the initial value of y

μ = G(m1 + m2) is the standard gravitational parameter. Substituting y = 0 we get the free-fall time. The separation as a function of time is given by the inverse of the equation. The inverse is represented exactly by the analytic power series:

Evaluating this yields:

where

For details of these solutions see "From Moon-fall to solutions under inverse square laws" by Foong, S. K., in European Journal of Physics, v29, 987-1003 (2008) and "Radial motion of Two mutually attracting particles", by Mungan, C. E., in The Physics Teacher, v47, 502–507 (2009).

Free fall in general relativity[edit] Main article: General relativity In general relativity, an object in free fall is subject to no force and is an inertial body moving along a geodesic. Far away from any sources of space time curvature, where spacetime is flat, the Newtonian theory of free fall agrees with general relativity but otherwise the two disagree. The experimental observation that all objects in free fall accelerate at the same rate, as noted by Galileo and then embodied in Newton's theory as the equality of gravitational and inertial masses, and later confirmed to high accuracy by modern forms of the Eötvös experiment, is the basis of the equivalence principle, from which basis Einstein's theory of general relativity initially took off.

Record free fall parachute jumps[edit] Joseph Kittinger starting his record-breaking skydive in 1960. His record was broken only in 2012. In 1914, while doing demonstrations for the U.S. Army, a parachute pioneer named Tiny Broadwick deployed her chute manually, thus becoming the first person to jump free-fall. According to the Guinness Book of Records, Eugene Andreev (USSR) holds the official FAI record for the longest free-fall parachute jump after falling for 24,500 metres (80,400 ft) from an altitude of 25,458 metres (83,524 ft) near the city of Saratov, Russia on November 1, 1962. Although later on jumpers would ascend higher altitudes, Andreev's record was set without the use of a drogue chute during the jump and therefore remains the longest genuine free fall record.[3] During the late 1950s, Captain Joseph Kittinger of the United States was assigned to the Aerospace Medical Research Laboratories at Wright-Patterson AFB in Dayton, Ohio. For Project Excelsior (meaning "ever upward", a name given to the project by Colonel John Stapp), as part of research into high altitude bailout, he made a series of three parachute jumps wearing a pressurized suit, from a helium balloon with an open gondola. The first, from 89,000 feet (23,290 m) in November 1959 was a near tragedy when an equipment malfunction caused him to lose consciousness, but the automatic parachute saved him (he went into a flat spin at a rotational velocity of 120 rpm; the g-force at his extremities was calculated to be over 22 times that of gravity, setting another record). Three weeks later he jumped again from 74,700 feet (22,770 m). For that return jump Kittinger was awarded the A. Leo Stevens parachute medal. On August 16, 1960 he made the final jump from the Excelsior III at 102,800 feet (31,330 m). Towing a small drogue chute for stabilization, he fell for 4 minutes and 36 seconds reaching a maximum speed of 614 mph (988 km/h)[4]before opening his parachute at 14,000 feet (4,270 m). Pressurization for his right glove malfunctioned during the ascent, and his right hand swelled to twice its normal size.[5] He set records for highest balloon ascent, highest parachute jump, longest drogue-fall (4 min), and fastest speed by a human through the atmosphere.[6] The jumps were made in a "rocking-chair" position, descending on his back, rather than the usual arch familiar to skydivers, because he was wearing a 60-lb "kit" on his behind and his pressure suit naturally formed that shape when inflated, a shape appropriate for sitting in an airplane cockpit. For the series of jumps, Kittinger was decorated with an oak leaf cluster to his Distinguished Flying Cross and awarded the Harmon Trophy by President Dwight Eisenhower. In 2012, the Red Bull Stratos mission took place. On October 14, 2012, Felix Baumgartner broke the records previously set by Kittinger for the highest free fall, the highest manned helium balloon flight, and the fastest free fall; he jumped from 128,100 feet (39,045 m), reaching 833.9 mph (1342 km/h) - Mach 1.24. Kittinger was a member of the mission control and helped design the capsule and suit that Baumgartner ascended and jumped in. On October 24, 2014, Alan Eustace broke the record previously set by Baumgartner for the highest free fall. He jumped from a height of 135,908 feet (41,425 m).[7]

Surviving falls[edit] The severity of injury increases with the height of a free fall, but also depends on body and surface features and the manner that the body impacts on to the surface.[8] The chance of surviving increases if landing on a surface of high deformity, such as snow.[8] Overall, the height at which 50% of children die from a fall is between four and five storey heights above the ground.[9] JAT stewardess Vesna Vulović survived a fall of 10,000 metres (33,000 ft)[10] on January 26, 1972 when she was aboard JAT Flight 367. The plane was brought down by explosives over Srbská Kamenice in the former Czechoslovakia (now the Czech Republic). TheSerbian stewardess suffered a broken skull, three broken vertebrae (one crushed completely), and was in a coma for 27 days. In an interview, she commented that, according to the man who found her, "…I was in the middle part of the plane. I was found with my head down and my colleague on top of me. One part of my body with my leg was in the plane and my head was out of the plane. A catering trolley was pinned against my spine and kept me in the plane. The man who found me, says I was very lucky. He was in the German Army as a medic during World War Two. He knew how to treat me at the site of the accident."[11] In World War II there were several reports of military aircrew surviving long falls: Nick Alkemade, Alan Magee, and Ivan Chisov all fell at least 5,500 metres (18,000 ft) and survived. It was reported that two of the victims of the Lockerbie bombing survived for a brief period after hitting the ground (with the forward nose section fuselage in freefall mode), but died from their injuries before help arrived.[12] Juliane Koepcke survived a long free fall resulting from the December 24, 1971, crash of LANSA Flight 508 (a LANSA Lockheed Electra OB-R-941 commercial airliner) in the Peruvian rainforest. The airplane was struck by lightning during a severe thunderstorm and exploded in mid air, disintegrating two miles up. Köpcke, who was 17 years old at the time, fell to earth still strapped into her seat. The German Peruvian teenager survived the fall with only a broken collarbone, a gash to her right arm, and her right eye swollen shut.[13] In October 1985, 11-year-old Cindy Mosey survived a free fall of between three and five hundred feet into the sea from an Air Albatross Cessna 402B, which disintegrated in mid-flight after hitting a high voltage electricity transmission line spanning the Tory Channel in New Zealand's Marlborough Sounds. She was the sole survivor of the accident, which killed eight people including all of her family. She went on to a successful career as an international kite-surfer.[14] As an example of 'freefall survival' that was not as extreme as sometimes reported in the press, a skydiver from Staffordshire was said to have plunged 6,000 metres without a parachute in Russia and survived. James Boole said that he was supposed to have been given a signal by another skydiver to open his parachute, but it came two seconds too late. Boole, who was filming the other skydiver for a television documentary, landed on snow-covered rocks and suffered a broken back and rib.[15] While he was lucky to survive, this was not a case of true freefall survival, because he was flying a wingsuit, greatly decreasing his vertical speed. This was over descending terrain with deep snow cover, and he impacted while his parachute was beginning to deploy. Over the years, other skydivers have survived accidents where the press has reported that no parachute was open, yet they were actually being slowed by a small area of tangled parachute. They might still be very lucky to survive, but an impact at 80 mph (about 129 kph) is much less severe than the 120 mph (about 193 kph) that might occur in normal freefall. A falling person will reach terminal velocity after about 12 seconds, falling some 450 m (about 1,500 ft) in that time. That person will not then fall any faster, so it makes no difference what distance they fall if it is more than 450 m—they will still reach the ground at the same speed.[16] The speeds reached by Kittinger, Baumgartner and Eustace were faster due to the thinner atmosphere at higher altitudes. Terminal velocity depends on air resistance, so terminal velocity increases as air resistance decreases.