LeadingEdges

Leading Edges

Here is a simple stripper to cut some off some of the leading edge (LE) of a wing core while it is held in the top and bottom saddle. The flat edges of the saddles ride in the trough of the stripper and keep the blade at a constant angle (approximately perpendicular) relative to the chord line (line from the LE to the trailing edge or TE). The depth of the cut can be adjusted by putting different rails under the blade. Be sure to use a fresh, sharp blade and clamp it securely. If it shifts during the cut it will give an irregular edge which takes time to sand off. The deeper the jig blade is set to cut, the more material it will remove, and the more the effective camber of your airfoil will be removed. Eventually this defeats the purpose of trimming the LE to begin with, which is to allow the wing to reach a higher angle of attack before stalling, thus producing a greater maximum lift. This compromise of lift from camber vs. lift from angle of attack is different for every airfoil. Between 1/4 to 1/2" (6 to 13mm) was removed from many of the Trick RC Zagi-THL models shown on this site with good results.

Once the panels have been cut with the stripper, they are held together and marked with the desired curve, which can be seen in these two photos as the black marker outline at the bottom of each image. The corners of the LE outside of the marked curve are then sanded off, preferrably with a long rigid sanding bar or block. Be sure to support each panel over its entire span while sanding. Foam is flexable, and if you only push part of the panel against the sanding bar, the bar will only sand where you are pushing. Using the top and bottom of the saddles as a clamp works well for this, as do some extra hands. Do not breathe the dust while sanding foam, and vacuum the wing cores, saddles, and work surface after sanding each panel. These photos show the wing core set of a Trick RC Zagi-LE, not to complicate matters.

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