The Main Canopy has a variety of designs from 7 Cell to Cross Braced and Square to Fully Elliptical. The design of the Canopy influences its flying characteristics, pilot skill level and pack volume. In addition, canopies are made of different materials which influence the pack volume.
Many thanks to Tom Hill for writing this article and for taking the pics.
Manufacturers use different materials for their canopies from Zero Porosity to Low Pack Volume and F-111. Some materials are chosen over others for their performance and others to produce a lower pack volume.
This material does not let any air through and is found in many canopies. This material has a high pack volume
Low Pack Volume Material
Also known as Low Porosity. This material reduces the pack volume of the Canopy although has a higher porosity than Zero Porosity material. Some manufacturers have developed their own patented system for canopy materials. Low Pack Volume Material is used to manufacture Reserve Canopies.
Hybrid Canopies – This uses a combination of Low Pack Volume and Zero Porosity Material for example a Low Pack Volume Material bottom skin and Zero Porosity top skin.
F-111 Nylon is used on older Main Canopies although should be avoided due to its high porosity on old equipment.
Maximum Suspended Weight – Abbreviated to MSW. This is the maximum weight that can be suspended from the Canopy. This includes your body weight, clothes, helmet, altimeter and Rig. This weight must not be exceeded. If it is exceeded, serious injury or death is possible along with equipment damage. Furthermore, the suspended weight influences the flying characteristics of the Canopy.
Shape and Cells
The shape of the Canopy greatly influences the flying characteristics. Square canopies are docile whereas Fully Elliptical canopies are for high performance. Always speak to an Instructor before selecting a canopy and consider your experience level. In addition, check the operating procedures of a dropzone you are visiting, especially in a foreign country as they may be more restrictive than your home dropzone.
Used on student equipment and many sports canopies. The square shape provides a docile canopy.
Figure 36: An illustration of a Square canopy.
Also known as Slightly Tapered. Where the ends are tapered so they are narrower than the middle.
Figure 37: An illustration of a Semi Elliptical/Slightly Tapered Canopy. Note the rounded tips.
Also known as Highly Tapered. Where the ends of the Canopy are shorter than the centre. A characteristic of high performance canopies.
Found on high performance canopies used for swooping and piloted by very experienced jumpers. The cross bracing is reinforcement to increase the strength and rigidity of the canopy wing.
7 Cell Canopy
A Canopy with 7 cells. Used for Canopy Formation and for Reserves. Their use on Reserves is so the Canopy is docile and has a lower pack volume.
9 Cell Canopy
The most common configuration of Main Canopies and allow a range of performances and designs.
The Line Type used on a canopy varies with the performance of the Canopy. High Performance Canopies are likely to use Vectran® or HMA whereas normal sports Canopies are likely to use Microline also known as Spectra® however Vectran® is being used on normal sports canopies. Not all line types are available on every type of canopy. The strength of the line is determined by the preceding number for example 550 Microline states this is Microline with a 550 lb breaking strain.
Dacron® is the largest and most forgiving of the lines. While it is the bulkiest of the lines and will increase the pack volume, the lines stretch which give softer openings and is a popular choice on student equipment. Dacron® does not deform due to heat meaning the Canopy will retain its trim however it has a low abrasion resistance. When it wears, it turns a dull grey and has numerous frayed edges.
Also known as Spectra®. Microline is found on many sports canopies and has the highest abrasion resistance of any line type. However, it will shrink with usage meaning the canopy will become out of trim. When this happens, the line set will need replacing. Relative to size, Microline is stronger than Dacron®.
Often used on high performance canopies although is used on normal sports canopies. It has a slightly orange colour although do not confuse this with Orange Vectran® which is used on high performance canopies. Vectran® holds its trim as it does not shrink with heat however it susceptible to abrasion damage.
HMA (High Modulus Aramid)
Commonly known as HMA which is an acronym for High Modulus Aramid and sometimes known by the brand name Technora®. Similar to Vectran® however it has a slightly lower pack volume and less drag. HMA has poor resistance to Ultraviolet light unless it is treated.