Feb 18, 2002, 3:14 PM
Post #1 of 2
Steering Line lengths
The length of the steering lines can drastically affect how a canopy flies. High performance canopies are affected much more than lower performance canopies. All canopies should have some slack or a slight bow in the steering lines. If the steering lines are too short and pull down the tail of the canopy during full flight, even slightly, the canopy is flying in brakes. If the canopy is flying in brakes, it will not have as much speed to trade for lift during the landing flare. Over time the steering lines shrink as a result of friction from the slider during opening, as much as 6 inches in extreme cases. New canopies or line sets adjusted to have no slack in the steering lines will begin to fly in brakes as the control lines shrink.
To maximize the performance of your canopy it is necessary to understand the construction of the steering lines. The steering lines on a canopy are made of several parts. The upper control lines, usually four or five lines cascade or split at the top of the central control line and attach to the tail. The central control line attaches the upper control lines to the lower control line. The lower control line attaches from the finger-trapped loop (for setting the brakes) at the bottom of the central control line to the toggle. The lower control line is where your rigger can make adjustments.
If you do not use your front risers, adjusting steering line length is a fairly simple process. To check your control lines, pull one toggle down an inch or two while watching the tail of the canopy in flight. The tail should not move and the canopy should not turn. If it does, your lower steering lines need to be lengthened. Make small adjustments, no more than an inch at a time. This may require several adjustments. It is better to be an inch too long than an inch too short. Once you find the correct length, have your rigger finger-trap and bar-tack the lower steering line to eliminate the knot next to the toggle which can hang up on the guide ring. Periodically check the steering lines to see if they have shrunk and need to be lengthened again. Micro-line can shrink 4 to 6 inches or more over its life span. Vectran tends not to shrink with wear but is not as durable as Micro-line.
If you use your front risers, adjusting steering line length is more complicated. Having enough slack in the lower steering lines on a high performance canopy is more critical to how the canopy will fly. In a front riser turn you are pulling the toggle down a little with the riser and there has to be some slack to prevent pulling down the tail. If the tail of a high performance canopy is pulled down even a little when front risering, the riser pressure will be much higher and the recovery arc (the amount of altitude required to get back under the canopy) will be shortened. To check if the steering line is long enough, clear your airspace, do a full 360 degree front riser turn (keeping the toggles in your hands), and watch the tail of the canopy. As the speed increases, the drag on the control line increases and if there isn’t enough slack, the tail will be pulled down. You need enough slack so that the tail won’t be pulled down while pulling the toggle and the riser down at the maximum speed of the canopy. you can also pull one front riser down, with out the toggles in your hands and compare the riser pressure. If the pressure is the same as having the toggles in your hands, then the steering lines are not affecting front riser performance. Again, make small adjustments no more than an inch at a time and have your rigger finger-trap and bar-tack the lower control line once you have them adjusted correctly.
With the steering lines correctly set you can get the most out of your canopy.