Root Cavitation on Small Commercial
A HydroComp Technical Report
Product link: NavCad,
cavitation is generally uncommon. It is most often found in high
speed, highly loaded propellers. It is generally indicated by a
pitting on the suction side (back) of the blade root area near the
point of maximum thickness.
One cure for root cavitation is based
on relieving some of the suction side lift by drilling a small hole
through the root to the pressure (face) side. This hole typically
is located at the mid-chord of the blade, just outside of the root.
One 10 mm (3/8 inch) hole is typical for propellers of about 800
to 1000 mm (32 to 38 inch) diameter.
Careful matching of the location of
the holes between blades must be observed, and the edges of the
holes should be softened with a chamfer. According to one respected
source, the key to successfully curing root cavitation is to be
sure to drill the holes parallel to the shaft line, not perpendicular
to the blade.