One of the trees in the back yard is a black Oak.  After the peak color in the fall, as the leaves curl before dropping, they sometimes form into an aero-dynamical shape that glides instead of falling.  Of course many just swirl or dive straight down but the “gliders” stand out for their flight performance.

This pattern is suitable for gliders or Oak leaves for fall decorations.

Printing

I used a 0.15mm Z-step to get two cross layers in the 0.25mm thick leaf, and 20% hexagonal fill (for the launcher).  The stem printed solid since the area was so small.   Support will be needed for the rubber band notch in the leaf stem.

I've not printed the glider with PLA, but printing issues with the hook breaking loose from the bed have been reported.  In this case, print with the alternate STL file with the added “hook brim” and trim it off after printing.

Flight Adjustments

Bend the tips of the leaf up using a light touch.  If you print with PLA, hot water can be used to soften the plastic for bending.  I printed with ABS and used a lighter flame about 3” (7cm) below the surface to soften the leaf ends (they’re thin and heat up fast, plus you don’t need much of a bend).  If the flame is too close you can get black carbon soot deposited on the leaf.  The bent leaf ends produce the dihedral wing effect that birds and airplanes use for stability.  They also serve as rudders so keep the bend lines parallel to the main stem. 

The stem is a weight that tends to pull that end of the leaf down.  The leaf tip opposite the stem acts as an airplane elevator flap.  Don’t bend that tip up very much or the glider will loop and stall.  The different airflow velocities over that surface lifts the stem up for loops, for climbing in elevation, and for a gliding flight. 

Loop a rubber band through the eye in the launcher.  Connect to the notch in the oak leaf glider stem, pull back and let it go.  Note: just as you release the glider pull the launcher quickly down a couple inches (cm) so the glider passes over the launcher without colliding. The glider shown in the photo climbs quickly in elevation, slows down, turns, and switches into a gliding flight.

Bending the leaf tips up takes some experimentation.  Post a comment on your successes and glider performance.