Making Plywood Boomerangs

MAKING PLYWOOD BOOMERANGS ... starts with selecting quality grade 1 and grade 2 aircraft plywood in 6mm thickness. Because of the weight and density aircraft plywood thicker than 6mm will be just too heavy to perform properly. Russian Birch plywood is considerably less in weight and for some boomerangs is appropriate, but is never used by us due to it's inferior quality.

Precut patterns ( 180 various designs) are traced onto the plywood and cut to shape on the band saw as shown. Nearly every sheet of plywood (aircraft plywood manufactured in sheets 152 cm square) has a warp to it, however slight it may be. The warp is very important to use to your advantage. When tracing your boomerang pattern it is important the side warped upward is the side the pattern is traced on. A boomerang generally flies better if the wings are slightly warped upward as opposed to downward. Each plywood shape has the wings contoured identical to an airplane wing. Each wing must be contoured in the opposite direction. Contouring is best done on special pneumatic drum sanders (as shown left).

Once the boomerang is cut out and the wings contoured a palm sander is used to further contour and to remove any sharp edges ( airflow requires smooth surfaces without forcing air around sharp edges) as featured. Some plywood shapes just like the strip laminated boomerangs require tuning. Tuning is where each wing is held over steam for a period of time to soften the wood ply's as shown in the slide show.  Each boomerang wing is then twisted upwards and held over an air dryer for about one minute while the wing cools. This tuning process adds the much needed permanent upward twist (dihedral) that gives the Cryderman's boomerangs their exceptional flight characteristics. See slide show photograph  demonstrating the hand twisting of each wing. After each wing has completely cooled the boomerang is placed on a flat granite surface to check for the right positive dihedral ( wing lift just like an aircraft).