Line twists are something all static line students are intimately familiar with. However once we start using a pilot chute to extract the D-Bag away from our bodies the frequency of line twists is reduced.
Once we add a wingsuit to the deployment equation, a few things happen that increase the chance of line twists:
- A larger burble can slow the deployment sequence down and allow the d-bag to spin up before line stretch
- An asymmetrical body position during deployment is amplified by the wingsuit resulting in the risers loading unevenly
- Containers without dynamic corners can cause the d-bag to be extracted in a tumbling motion
These are just a few examples of why wingsuiters experience more line twists than other free fall skydivers. So is this just something you have to accept once you zip your arms into a flying nylon suit?
Thankfully the answer is NO. A lot can be done to reduce the frequency of line twists.
Containers
- It is recommended that a 8-9ft bridle is used with all wingsuits and this should be considered mandatory on larger suits.
- A large 28 or 30 inch pilot chute with a light weight handle helps to speed up deployment
- Dynamic corners are recommended as they allow the d-bag to be extracted more easily
- Semi-stowless d-bags are popular with wingsuiters as the lines feed out in the centre rather than in the rocking side to side motion of a regular d-bag
Canopies
The past 2 years have seen all major manufacturers working on wingsuit specific canopies.
These 7-cell canopies have low aspect ratios which are less likely to spin up if things don't go to plan with your deployment.
The canopies are also designed to pack smaller than your standard ZP canopy to allow you to fit a larger canopy into your existing rig. A larger canopy gives you a lower wingloading which is again more forgiving of poor deployments. PASA recommends a square or semi-elliptical canopy with a maximum wingloading of 1.3:1 for wingsuiting. Wingsuit specific canopies are aimed at skydivers flying larger intermediate and open class suits but can be used by all wingsuiters.
Some of the wingsuit canopies on the market are:
- Pilot 7 (Aerodyne)
- Horizon (PD)
- Epicene (Squirrel)
- Winx (Atair)
Wingsuit
A larger wingsuit is more more likely to cause line twists than a smaller one, as small errors are amplified in the deployment process.
More fabric also makes it more difficult to get out of line twists once you have them. If you are regularly getting line twists on a small suit it is highly recommended to get your openings dialed in before zipping into a larger wingsuit.
Angle of attack (AOA) at deployment also influences the chance of line twists. A low AOA results in d-bag extraction towards the feet. This deployment method requires dynamic corners or the d-bag is easily spun up during extraction from the container. A high angle of attack or a stalled suit results in lower airspeeds and a large burble which slows deployment down and gives more time for the d-bag and skydiver to rotate relative to each other.
For these reasons it is important to be current and have sufficient experience before jumping a large wingsuit.
In summary choosing the right gear and flying a suit that matches your experience level are the best ways to prevent line twists during deployment.
Dylan Hemer, D965, SSA WS
Disclaimer: This is in no way related to videos posted by the author
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