Trim Tuning

Paraglider Trim Tuning

Line trimming is necessary for all paraglider pilots looking to maximise performance, and in avoiding the inherent degradation of performance, handling and safety over time. There are various line materials in use each of which has their own characteristics. The length of the lines changes depending on the material, loading, temperature, humidity, dust ingress and UV exposure.

WHAT IS TRIM TUNING?

Trimming is a basic requirement for a good and safe flying wing, so we regard this as especially important. Trim Tuning is the adjustment of line lengths, based on millimetre-accurate measurement of all the lines between harness and wing. To do this we use laser equipment. The lines are re-trimmed based on the results of these line measurements. Virtual trim adjustment is simulated on the PC and finally corrected on the wing itself. The existing condition is adjusted to as near as possible the manufacturer’s original status, by means of varying the looping on the quick links.

HOW DOES TRIM AFFECT MY PARAGLIDER?

As your paraglider falls out of trim, certain performance characteristics important for safe flight are diminished. As the A’s & B’s stretch and the C’s & D’s shrink, your glider takes on a higher angle of attack. If you can picture how your speed bar decreases the AoA of your wing to increase its airspeed, an out of trim glider causes essentially the exact opposite effect. So the glider won’t inflate or kite like it should. It will also have diminished performance in the air as it flies at a slower airspeed close to the stall point. The most common reason for poor handling and performance is that lines go out of trim. This can affect safety by making spins and stalls more likely. A full measure of all the lines by the laser can determine if a retrim is needed. Bringing a paraglider back into trim allows it to fly as it was intended to.

WHEN TO TRIM?

Paragliders with as little as 20 hours of flight time will benefit from being trimmed. It’s recommended to get a paraglider trimmed after 100 hrs of flight time or two years, whichever comes first.

THE PROCESS.
Changes of a couple of centimeters can affect the trim of a paraglider. Therefore, it’s crucial to be able to measure lines with accuracy down to the millimetre. All of the lines on your paraglider are measured using a laser device with a 5 kg load for the most precise measurements possible. After measuring all of the lines, the results are analyzed in a spreadsheet. Any necessary adjustments are then made using the quick links on the risers. Paragliders are trimmed to within 10 mm of factory specifications with a +/- 50 mm offset considered acceptable.

BENEFITS OF TRIMMING

Correcting the profile and trim of the glider, so that it flies as it was intended in relation to handling and speed. For safety, A better handling glider which handles turbulence has better pitch stability, turns, collapse recovery and normal stall speed. It is necessary in order to be competitive at a high-level competition. In order to compete in PWC and Cat 1 glider must pass line length verification tests. The psychological benefit of knowing that your glider is at its optimum.

*Many pilots at the top-level change the relative trim for the purpose of increasing the intended speed of the glider.