A look over the shoulder of our workshop expert
NOVA Trim Tuning - For an 'as new' flying feeling
Generally, the materials which make up every paraglider are elastic and flexible to a certain degree. Nowadays, the cloth lasts much better and longer than before, but the trim of the lines changes due to the material. This mainly happens at the beginning, in the initial 10 - 15 hours of flight, but can also occur later. The lines can stretch or shrink. When and why the line lengths change we will explain in a later article.
The changed trim in turn leads to a change in the flight behaviour of the glider. Therefore, if in doubt, the lines should be re-trimmed. The aim of trimming (i.e. a calculated change in line length in the millimetre range) is to restore the glider to its optimum angle of attack. Years ago we developed the NTT together with paragliding instructor and mathematician Ralf Antz to provide a simple service solution for this unavoidable problem. We are proud to be the first manufacturer to develop this service and we are happy to see others are following suit. The NTT just makes sense!
The NTT is then performed at one of our approved NOVA Check Centres. All our accredited and specially trained partner service centres follow a set inspection and trimming procedure and use the appropriate software for the NTT. This guarantees that the procedure is accurate and reliable.
Anyone buying a new NOVA wing in Germany or Austria is offered the first NTT free of charge. To be eligible, the wing must be registered at my NOVA within two weeks of purchase. At my NOVA the serial number of the glider and the contact details of the pilot for the return shipment are recorded.
How is an NTT performed? When the paraglider arrives at the NOVA Check Centre, the existing trim is first checked and entered in the corresponding trim record sheet. Based on the existing trim, the exact line lengths (down to the millimeter) are measured under load with a laser measuring device. Using the results, the lines are then newly trimmed. The line lengths are adjusted relative to each other (relative trim), so that the angle of attack is again optimised in all line areas. The line length is normally lengthened or shortened using a loop; line replacement is rarely necessary. Of course, if a line is damaged, it will be replaced.
When the pilot gets their wing back, they can be happy about the optimised flight characteristics once more! Another excellent advantage: if the NTT is carried out within the first year, the due date of the first NOVA Full Service (NFS) is postponed for year. Or put differently, the full inspection is due three years after purchase, not two years. During the NFS, the trim is also checked and the lines will be re-trimmed if necessary.
In conclusion: the lines of all paragliders, regardless which manufacturer they come from, are made of materials that change over time. This changes the trim which can have undesirable effects on the flight behaviour, handling and performance of the wing. So it makes sense, especially at the beginning but also later, to regularly check the trim of the lines. After the NTT the launch and landing characteristics, safety, agility and glide performance are again optimised.
Providing a free trim tuning in Austria and Germany makes NOVA unique. More information and the exact terms and conditions of the NTT can be seen here.
More exciting facts and terminology all about trimming:
NOVA uses a smart mix of Dyneema and Aramid (Kevlar) lines. For example, the more heavily used main A and B-lines are made from Dyneema. It has a higher breaking load and UV resistance but also changes more quickly. For the main C-lines Aramid is used, because it has to withstand a lower load and the trim stability of Aramid lines plays a major role.
NOVA paragliders are delivered with the lines looped, so that it is easier to change the loop them when re-trimming the wing. By using different types of loops (single loop, double loop, clove hitch, clove hitch plus loop) the line length can be adjusted relative to the others.
RELATIVE TRIM VS. ABSOLUTE TRIM
During the NTT, a relative trim is performed. This means the lines are adjusted to each other in order to optimise the angle of attack. This means the length of one line is oriented to the other lines. The entire wing is taken into consideration and the aim is not - as with the absolute trim - to adjust all lines back to the original length.
The NOVA Full Service (NFS) corresponds to the classic full inspection of a paraglider, where the trim of the lines (NTT), line strength, porosity and the condition of the cloth are thoroughly checked. After purchase of a new NOVA paraglider and registration on myNova within the first 14 days as well as an NTT within one year or 100 hours, the full service is only necessary in the third year. Without the NTT, as with paragliders from other manufacturers, the full inspection is due in the second year. Additionally the guarantee is extended from three years to a full four years!
Anyone who would like to have more information on this topic can view an in-depth talk (in German) by expert Ralf Antz at the Thermik Fair 2020 here.