just to be clear my c/a hinges were installed correctly
the fact is they began to fail from the control horn area
and began to move outward one hinge at a time
Dick Pettit of R/C report performed a test on robart hinges
he glued one into balsa blocks and using a fish scale
exceeded 90 pounds of pulling force before tearout
i have never sanded the robarts that would radius the sharp
edges and reduce their holding power
i have had no issues on .60 or smaller aircraft but had them fail on giant scale
heres how to improve an arf that comes pre slotted for c/a hinges
start by installing the c/a hinges and control surfaces with c/a glue
then seperatethem with an exato knife this both fills and bonds the wood that was removed for the c/a hinges
and after trimming the hinge flush
drill new holes and install the robarts
i have used robarts for at least thirty years now and they are by far the
easiest to drill ,align,and install