High-g training: Difference between revisions
Updated link, corrected citation name to "Wingrove", removed sentence as I cannot find any evidence that 17 g eyeballs-in was tolerated (without blackout) for more than a minute in any study referenced. |
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{{Short description|Training done by aviators and astronauts}} |
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[[Image:20G centrifuge.jpg|thumb|upright=2|The 20 |
[[Image:20G centrifuge.jpg|thumb|upright=2|The 20 g centrifuge at the [[NASA Ames Research Center]]]] |
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| ⚫ | '''High- |
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| ⚫ | '''High-g training''' is done by [[Aircraft pilot|aviator]]s and [[astronaut]]s who are subject to high levels of [[acceleration]] ('[[g-force|g]]'). It is designed to prevent a [[G-LOC|g-induced loss of consciousness]] (g-LOC), a situation when [[g-force#Human g-force experience|the action of ''g''-forces]] moves the [[blood]] away from the [[brain]] to the extent that [[consciousness]] is lost. |
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Incidents of acceleration-induced loss of consciousness have caused fatal accidents in [[aircraft]] capable of sustaining high-''g'' for considerable periods. |
Incidents of acceleration-induced loss of consciousness have caused fatal accidents in [[aircraft]] capable of sustaining high-''g'' for considerable periods. |
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The value of training has been well established during the decades since the 1970s and has been the subject of much research and literature, and training has contributed to extending pilots' |
The value of training has been well established during the decades since the 1970s and has been the subject of much research and literature, and training has contributed to extending pilots' ''g'' tolerance in both magnitude and duration.<ref>{{cite web|url=http://www.amtiusa.com/frst_ed/digpg16.htm |title=Centrifuge Training |accessdate=2008-02-04 |url-status=dead |archiveurl=https://web.archive.org/web/20070802191447/http://www.amtiusa.com/frst_ed/digpg16.htm |archivedate=2007-08-02 }}</ref> Training includes centrifuge, Anti-g Straining Maneuvers (AGSM), and acceleration physiology. |
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==Overview== |
==Overview== |
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{{main| |
{{main|g-force}} |
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As ''g''-forces increase, visual effects include loss of colour vision ("[[Greyout (medical)| |
As ''g''-forces increase, visual effects include loss of colour vision ("[[Greyout (medical)|greyout]]"), followed by [[tunnel vision]] (where peripheral vision is lost, retaining only the centre vision). If ''g''-forces increase further, complete loss of vision will occur, while consciousness remains. These effects are due to a reduction of blood flow to the [[eyes]] before blood flow to the brain is lost, because the extra pressure within the eye ([[intraocular pressure]]) counters the [[blood pressure]]. The reverse effect is experienced in advanced [[aerobatic]] maneuvers under negative ''g''-forces, where excess blood moves towards the brain and eyes ("[[redout]]"). |
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The [[human body]] has different tolerances for g-forces depending on the acceleration direction. [[Humans]] can withstand a positive acceleration forward at higher g-forces than they can withstand a positive acceleration upwards. This is because when the body accelerates up at such high rates the blood rushes from the brain which causes loss of vision. |
The [[human body]] has different tolerances for g-forces depending on the acceleration direction. [[Humans]] can withstand a positive acceleration forward at higher g-forces than they can withstand a positive acceleration upwards. This is because when the body accelerates up at such high rates the blood rushes from the brain which causes loss of vision. |
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A further increase in g-forces will cause |
A further increase in g-forces will cause g-LOC where consciousness is lost. This is doubly dangerous because, on recovery as ''g'' is reduced, a period of several seconds of disorientation occurs, during which the aircraft can dive into the ground. [[Dreams]] are reported to follow g-LOC which are brief and vivid.<ref>{{cite report|title=A Database to Evaluate Acceleration (+Gz) Induced Loss of Consciousness (G-Loc) in the Human Centrifuge|first=Estrella M. |last=Forster|date=June 20, 1993|url=https://apps.dtic.mil/sti/pdfs/ADA278769.pdf|publisher=Defense Technical Information Center|access-date=December 3, 2022}}</ref> |
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The ''g'' thresholds at which these effects occur depend on the training, [[Ageing|age]] and [[Physical fitness|fitness]] of the individual. An untrained individual not used to the ''g''-straining maneuver can black out between 4 and 6 ''g'', particularly if this is pulled suddenly. [[Roller coaster]]s typically do not expose the occupants to much more than about 3 g. A hard [[Slapping (strike)|slap]] on the [[face]] may impose hundreds of g-s locally but may not produce any obvious damage; a constant 15 g-s for a minute, however, may be deadly. A trained, fit individual wearing a ''g'' suit and |
The ''g'' thresholds at which these effects occur depend on the training, [[Ageing|age]] and [[Physical fitness|fitness]] of the individual. An untrained individual not used to the ''g''-straining maneuver can black out between 4 and 6 ''g'', particularly if this is pulled suddenly. [[Roller coaster]]s typically do not expose the occupants to much more than about 3 g. A hard [[Slapping (strike)|slap]] on the [[face]] may impose hundreds of g-s locally but may not produce any obvious damage; a constant 15 g-s for a minute, however, may be deadly. A trained, fit individual wearing a ''g'' suit and practicing the straining maneuver can, with some difficulty, sustain up to 9 ''g'' without loss of consciousness. |
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The human body is considerably more able to survive g-forces that are [[perpendicular]] to the [[Vertebral column|spine]]. This is not true in |
The human body is considerably more able to survive g-forces that are [[perpendicular]] to the [[Vertebral column|spine]]. This is not true in 0 ''g'' when you strafe up; that is an eyeballs-down maneuver, which is the same force as a blackout where blood rushes to the feet, and this force is parallel to the spine. In general, when the g-force pushes the body forwards (colloquially known as 'eyeballs in'<ref>[http://roland.lerc.nasa.gov/~dglover/dictionary//tables/table11.html NASA Physiological Acceleration Systems] {{webarchive |url=https://web.archive.org/web/20080519185954/http://roland.lerc.nasa.gov/~dglover/dictionary/ |date=May 19, 2008 }}</ref>) a much higher tolerance is shown than when g-force is pushing the body backwards ('eyeballs out') since [[blood vessels]] in the [[retina]] appear more sensitive to that direction.<ref>[https://ntrs.nasa.gov/citations/19980223621 NASA Technical note D-337, Centrifuge Study of Pilot Tolerance to Acceleration and the Effects of Acceleration on Pilot Performance], by Brent Y. Creer, Captain Harald A. Smedal, USN (MC), and Rodney C. Wingrove</ref> |
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==G-suits== |
==G-suits== |
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{{main| |
{{main|g-suit}} |
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A |
A g-suit is worn by aviators and astronauts who are subject to high levels of acceleration and, hence, increasing positive ''g''. It is designed to prevent a blackout and g-LOC, due to the blood pooling in the lower part of the body when under high-''g'', thus depriving the brain of blood. |
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==Human centrifuge training== <!-- This section is linked from redirect [[Human centrifuge]] --> |
==Human centrifuge training== <!-- This section is linked from redirect [[Human centrifuge]] --> |
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'''Human centrifuges''' are exceptionally large [[centrifuge]]s that test the reactions and tolerance of [[aviator|pilots]] and [[astronaut]]s to acceleration above those experienced in the [[Earth]]'s [[gravity]]. |
'''Human centrifuges''' are exceptionally large [[centrifuge]]s that test the reactions and tolerance of [[aviator|pilots]] and [[astronaut]]s to acceleration above those experienced in the [[Earth]]'s [[gravity]]. |
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In the [[UK]] High-G training is provided at the High-G Training and Test Facility, [[RAF Cranwell]] using an AMST built human centrifuge. The facility trains [[Royal |
In the [[UK]] High-G training is provided at the [[RAF High G Training and Test Facility|High-G Training and Test Facility]], [[RAF Cranwell]] using an AMST built human centrifuge. The facility trains [[Royal Navy]], [[Royal Air Force]] and international students.<ref>{{cite web | url=https://www.thalesgroup.com/en/europe/united-kingdom/markets-we-operate/aerospace-uk/training-and-simulation/high-g-training-and | title=High G Training and Test Facility| date=6 June 2019|access-date=December 3, 2022|publisher=Thales Group}}</ref> |
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KBRwyle at [[Brooks City-Base]] in [[San Antonio]], [[Texas]], operates a human centrifuge. The centrifuge at Brooks is used to train [[USAF]] and [[USN]] aircrew for sustained high- |
KBRwyle at [[Brooks City-Base]] in [[San Antonio]], [[Texas]], operates a human centrifuge. The centrifuge at Brooks is used to train [[USAF]] and [[USN]] aircrew for sustained high-g flight.<ref>{{cite web|url=https://www.kbr.com/en/insights-news/stories/kbrwyle-provides-high-g-centrifuge-flight-training|title=KBRwyle Provides High-G Centrifuge Flight Training|date=March 7, 2019|publisher=KBRWyle|access-date=December 3, 2022}}</ref> |
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The use of large centrifuges to simulate a feeling of gravity has been proposed for future long-duration [[space mission]]s. Exposure to this simulated gravity would prevent or reduce the [[bone decalcification]] and [[muscle atrophy]] that affect individuals exposed to long periods of [[free fall]].<ref name=Hypergravity>{{cite web|title=The Pull of HyperGravity - A NASA researcher is studying the strange effects of artificial gravity on humans.|url=https://science.nasa.gov/science-news/science-at-nasa/2003/07feb_stronggravity/|publisher=[[NASA]]|accessdate=11 March 2012}}</ref><ref name=Space>{{cite web|last=Hsu|first=Jeremy|title=New Artificial Gravity Tests in Space Could Help Astronauts|url=http://www.space.com/8384-artificial-gravity-tests-space-astronauts.html|publisher=[[Space.com]]|accessdate=11 March 2012}}</ref> An example of this can be seen aboard the ''Discovery'' spacecraft in the film ''[[2001: A Space Odyssey (film)|2001: A Space Odyssey]]''. |
The use of large centrifuges to simulate a feeling of gravity has been proposed for future long-duration [[space mission]]s. Exposure to this simulated gravity would prevent or reduce the [[bone decalcification]] and [[muscle atrophy]] that affect individuals exposed to long periods of [[free fall]].<ref name=Hypergravity>{{cite web|title=The Pull of HyperGravity - A NASA researcher is studying the strange effects of artificial gravity on humans.|url=https://science.nasa.gov/science-news/science-at-nasa/2003/07feb_stronggravity/|publisher=[[NASA]]|accessdate=11 March 2012|archive-date=16 March 2012|archive-url=https://web.archive.org/web/20120316183032/http://science.nasa.gov/science-news/science-at-nasa/2003/07feb_stronggravity/|url-status=dead}}</ref><ref name=Space>{{cite web|last=Hsu|first=Jeremy|title=New Artificial Gravity Tests in Space Could Help Astronauts|date=12 May 2010|url=http://www.space.com/8384-artificial-gravity-tests-space-astronauts.html|publisher=[[Space.com]]|accessdate=11 March 2012}}</ref> An example of this can be seen aboard the ''Discovery'' spacecraft in the film ''[[2001: A Space Odyssey (film)|2001: A Space Odyssey]]''. |
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Human-rated centrifuges are made by AMST Systemtechnik in Austria (Austria Metall SystemTechnik), [[Groupe Latécoère|Latécoère]] in France, Wyle Laboratories and ETC in the US. |
Human-rated centrifuges are made by AMST Systemtechnik in Austria (Austria Metall SystemTechnik), [[Groupe Latécoère|Latécoère]] in France, Wyle Laboratories and ETC in the US. |
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==See also== |
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*[[Bárány chair]] |
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*[[Aerotrim]] |
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*[[Flight training]] |
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*[[G-seat]] |
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*[[Index of aviation articles]] |
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==References== |
==References== |
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{{reflist}} |
{{reflist}} |
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{{commonscat|High-g training}} |
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[[Category:Flight training]] |
[[Category:Flight training]] |
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[[Category:Effects of |
[[Category:Effects of gravity]] |
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[[Category:Acceleration]] |
[[Category:Acceleration]] |
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Latest revision as of 19:09, 18 July 2024
High-g training is done by aviators and astronauts who are subject to high levels of acceleration ('g'). It is designed to prevent a g-induced loss of consciousness (g-LOC), a situation when the action of g-forces moves the blood away from the brain to the extent that consciousness is lost. Incidents of acceleration-induced loss of consciousness have caused fatal accidents in aircraft capable of sustaining high-g for considerable periods.
The value of training has been well established during the decades since the 1970s and has been the subject of much research and literature, and training has contributed to extending pilots' g tolerance in both magnitude and duration.[1] Training includes centrifuge, Anti-g Straining Maneuvers (AGSM), and acceleration physiology.
Overview
[edit]As g-forces increase, visual effects include loss of colour vision ("greyout"), followed by tunnel vision (where peripheral vision is lost, retaining only the centre vision). If g-forces increase further, complete loss of vision will occur, while consciousness remains. These effects are due to a reduction of blood flow to the eyes before blood flow to the brain is lost, because the extra pressure within the eye (intraocular pressure) counters the blood pressure. The reverse effect is experienced in advanced aerobatic maneuvers under negative g-forces, where excess blood moves towards the brain and eyes ("redout").
The human body has different tolerances for g-forces depending on the acceleration direction. Humans can withstand a positive acceleration forward at higher g-forces than they can withstand a positive acceleration upwards. This is because when the body accelerates up at such high rates the blood rushes from the brain which causes loss of vision.
A further increase in g-forces will cause g-LOC where consciousness is lost. This is doubly dangerous because, on recovery as g is reduced, a period of several seconds of disorientation occurs, during which the aircraft can dive into the ground. Dreams are reported to follow g-LOC which are brief and vivid.[2]
The g thresholds at which these effects occur depend on the training, age and fitness of the individual. An untrained individual not used to the g-straining maneuver can black out between 4 and 6 g, particularly if this is pulled suddenly. Roller coasters typically do not expose the occupants to much more than about 3 g. A hard slap on the face may impose hundreds of g-s locally but may not produce any obvious damage; a constant 15 g-s for a minute, however, may be deadly. A trained, fit individual wearing a g suit and practicing the straining maneuver can, with some difficulty, sustain up to 9 g without loss of consciousness.
The human body is considerably more able to survive g-forces that are perpendicular to the spine. This is not true in 0 g when you strafe up; that is an eyeballs-down maneuver, which is the same force as a blackout where blood rushes to the feet, and this force is parallel to the spine. In general, when the g-force pushes the body forwards (colloquially known as 'eyeballs in'[3]) a much higher tolerance is shown than when g-force is pushing the body backwards ('eyeballs out') since blood vessels in the retina appear more sensitive to that direction.[4]
G-suits
[edit]A g-suit is worn by aviators and astronauts who are subject to high levels of acceleration and, hence, increasing positive g. It is designed to prevent a blackout and g-LOC, due to the blood pooling in the lower part of the body when under high-g, thus depriving the brain of blood.
Human centrifuge training
[edit]
Human centrifuges are exceptionally large centrifuges that test the reactions and tolerance of pilots and astronauts to acceleration above those experienced in the Earth's gravity.
In the UK High-G training is provided at the High-G Training and Test Facility, RAF Cranwell using an AMST built human centrifuge. The facility trains Royal Navy, Royal Air Force and international students.[5]
KBRwyle at Brooks City-Base in San Antonio, Texas, operates a human centrifuge. The centrifuge at Brooks is used to train USAF and USN aircrew for sustained high-g flight.[6]
The use of large centrifuges to simulate a feeling of gravity has been proposed for future long-duration space missions. Exposure to this simulated gravity would prevent or reduce the bone decalcification and muscle atrophy that affect individuals exposed to long periods of free fall.[7][8] An example of this can be seen aboard the Discovery spacecraft in the film 2001: A Space Odyssey.
Human-rated centrifuges are made by AMST Systemtechnik in Austria (Austria Metall SystemTechnik), Latécoère in France, Wyle Laboratories and ETC in the US.
See also
[edit]References
[edit]- ^ "Centrifuge Training". Archived from the original on 2007-08-02. Retrieved 2008-02-04.
- ^ Forster, Estrella M. (June 20, 1993). A Database to Evaluate Acceleration (+Gz) Induced Loss of Consciousness (G-Loc) in the Human Centrifuge (PDF) (Report). Defense Technical Information Center. Retrieved December 3, 2022.
- ^ NASA Physiological Acceleration Systems Archived May 19, 2008, at the Wayback Machine
- ^ NASA Technical note D-337, Centrifuge Study of Pilot Tolerance to Acceleration and the Effects of Acceleration on Pilot Performance, by Brent Y. Creer, Captain Harald A. Smedal, USN (MC), and Rodney C. Wingrove
- ^ "High G Training and Test Facility". Thales Group. 6 June 2019. Retrieved December 3, 2022.
- ^ "KBRwyle Provides High-G Centrifuge Flight Training". KBRWyle. March 7, 2019. Retrieved December 3, 2022.
- ^ "The Pull of HyperGravity - A NASA researcher is studying the strange effects of artificial gravity on humans". NASA. Archived from the original on 16 March 2012. Retrieved 11 March 2012.
- ^ Hsu, Jeremy (12 May 2010). "New Artificial Gravity Tests in Space Could Help Astronauts". Space.com. Retrieved 11 March 2012.
