guides:parachute_sizing_chart

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guides:parachute_sizing_chart [2008/07/19 23:33] 127.0.0.1 external edit |
guides:parachute_sizing_chart [2015/09/08 15:51] (current) edmoore |
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+ | ====== Quick video guide to parachute calculations ====== | ||

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+ | To understand how to calculate your descent rate under a parachute, watch [[https://youtu.be/S7KujrsUB1w?t=3h49m57s|this talk]] from the 2015 UKHAS conference. | ||

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====== Parachute Sizing Cart ====== | ====== Parachute Sizing Cart ====== | ||

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For streamers the value on the left represents the streamer length - the data assumes that the streamers will have a 10:1 length to width ratio (i.e. the width will be a 1/10th of this value). | For streamers the value on the left represents the streamer length - the data assumes that the streamers will have a 10:1 length to width ratio (i.e. the width will be a 1/10th of this value). | ||

- | For parachutes the value represents the parachute diameter. Of the group of four lines the two inner solid lines represent what is considered the normal range of decent speeds for an average parachute (a parachute with a Cd value of about 1). The upper of these represents a decent speed of 3.5m/sec (approx. 11.5ft/sec), the lower a decent speed of 4.5m/sec (approx. 15ft/sec). These two rates are normally considered to be the upper and lower bound of desirable decent speed - your experience may vary. | + | For parachutes the value represents the parachute diameter. Of the group of four lines the two inner solid lines represent what is considered the normal range of descent speeds for an average parachute (a parachute with a Cd value of about 1). The upper of these represents a descent speed of 3.5m/sec (approx. 11.5ft/sec), the lower a descent speed of 4.5m/sec (approx. 15ft/sec). These two rates are normally considered to be the upper and lower bound of desirable descent speed - your experience may vary. |

- | The upper dashed line in this group represents the slower decent rate for parachutes with a low coefficient of drag (a Cd of 0.75). An example of this type of chutes are those made from a single sheet of material (so called para-sheets) and are thus less efficient. The lower dashed line represents the faster decent rate for parachutes with a high coefficient of drag (a Cd of 1.5). An example of this type of chute are those made from many specially shaped segments of material sewn together. The PML "DuraChute" sizes fall approximately in this area of the chart. | + | The upper dashed line in this group represents the slower descent rate for parachutes with a low coefficient of drag (a Cd of 0.75). An example of this type of chutes are those made from a single sheet of material (so called para-sheets) and are thus less efficient. The lower dashed line represents the faster decent rate for parachutes with a high coefficient of drag (a Cd of 1.5). An example of this type of chute are those made from many specially shaped segments of material sewn together. The PML "DuraChute" sizes fall approximately in this area of the chart. |

{{guides:parach1.gif|}} | {{guides:parach1.gif|}} | ||

guides/parachute_sizing_chart.1216510403.txt.gz ยท Last modified: 2013/11/03 11:25 (external edit)