Applying Gap Seal on a Discus Launch Glider (DLG)

Applying Gap Seal on a Discus Launch Glider (DLG)

Applying Gap Seal on a Discus Launch Glider (DLG)

Gap seals on RC gliders, and specifically discus launch gliders, are typically made with tape over the hinge for light weight. The top cavity of the hinge line can occasionally trip the airflow too early, usually in the launch and high speed flight envelope, meaning less launch height and less penetration. It is essential to apply gap seal on a hollow-wing DLG, but on the other hand, the cavity on a solid core model might be beneficial in slower flight regimes.

To get the most performance out of your model, you will need to test whether the gap seal is an improvement or not for your particular model and setup. To do so is easy:

  1. Without gap seals on your model, set it up for straight and true launches, and straight level hands-off flying,
  2. Apply gap seal to one side of your wing (in this example, let us say we have applied it to the right wing panel).
  3. Now do some launch testing: if it veers to the left slightly, it means the gap seal is decreasing the drag on the right wing panel... GOOD! If it veers to the right, it means the gap seal is increasing the drag on the right wing panel... BAD! *don't use your trims to adjust any steering, your model should already be trimmed straight in step 2*
  4. Now do some flight testing: let your model fly hands off, just like it was trimmed to do in step 2. Does it hold the line? Or does it start veering? If it holds the line, the tape is not affecting its flight behavior... not bad (especially if noted that it is increasing launch performance). If it veers left... even better! That means not only is it increasing your launch performance, but also your flight performance. If it veers right... that means it is decreasing it's flight performance.
  5. Now, with data from steps 3 and 4 on hand, you can decide whether to take off the gap seal, or to finish application on the other side!

You can buy the Kapton and colored tapes on Amazon here:

ProTapes Pro 950 Polyimide Film Tape Kapton tape

Fodattm 6 Rolls Graphic Art Thin Tape Colored tape



I hope you find that useful! Just so you know, ArmSoar may collect a small share of sales from the links on this page. It does not change your price.


  • Thank you very much! Theses articles and videos help people like me that’s beginning at F3K and trying to improve the knowledge

    Jefferson A. Galves on

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