On Jun 4, 5:23*pm, ZL wrote:

Do you really know how much load is safe to apply to a control surface?
Is it in your operators manual? Airloads on modern tiny control surfaces
can be quite small in comparison to what an enthusiastic human hand can
apply...

Actually, it's not that hard to reverse-engineer estimated maximum
hinge moments from (rho*v^2)/2 and the suggested loading schedules in
the old FAA pub "Basic Glider Criteria." The total forces can be
pretty great, especially the accumulated torsion for something like a
c*.17, 2-drive full-span flaperon like yours.

As you observe, the maximum hinge moment and normal loading on
something like your LS6 elevator is pretty small. However, JAR22 and
FAR23 both require a fair bit of margin over the flight loads. They
also specify some pretty hefty minimum input loads between the control
stick and the stops, though by the looks of the European marques they
tend to weasel out of the default input forces with the "unless lower
can be rationally justified" clause.

Thanks, Bob K.