Hands off thermalling

At 12:18 24 April 2004, Andreas Maurer wrote:
On Fri, 23 Apr 2004 20:14:02 GMT, 'Bill Daniels'
wrote:


A perfectly symmetrical glider with a perfectly smooth
polar and
frictionless controls SHOULD develop a spiral dive
from a hands off turn.

How does this explain the behaviour of non-radio-controlled
model
gloiders that return to level flight anytime? They
are built perfectly
symmetrical, have a smooth polar and no controls at
all...


Bye
Andreas


My hand-launced gliders are built with crossed controls,
which produces this effect. A slight amount of rudder
into the turn keeps it going. A slight amount of opposite
aileron keeps it from overbanking. A slight amount
of up elevator lifts the nose. Just enough weight on
the nose keeps it from making phugoids. Just enough
dihedral helps it right itself. It is not the most
effective climbing setup possible, but it produces
stability much like a sailboat with the tiller down,
the main sheet slack, and the jib tied across to the
opposite side.

It requires experimentation to get it right and they
have to be built for a left-handed or right-handed
person. It must turn to the left for a right-hander
and vice versa.