|
Bob
Hoey explained his groups experiments with a variable geometry radio controlled
bird model. Bob was using the model of a Raven to accomplish the
testing since the wing was less complex than that of other bird models
types in his collection.
Bob noted
that the model was using a non-reflexed airfoil that required large trim
elevator deflection so a better airfoil is needed. The AC moved forward
½ inch with wing retraction but this was corrected with a minor
linkage adjustment. The wing structure is sort of awkward but strong,
which is amazing considering the spar breaks.
Above you can see
the wing in both the retracted and extended positions. Note the differences
in the sweep angles of both the inboard and outboard sections. The
picture at the left shows the center section pivot at the trailing edge.In-flight
wing movement required unloading the wing slightly to take the strain off
the control rods. Future models would use a jackscrew. Bob
noted that the concept worked with fast and fairly flat glides in both
configurations. However, there was NO obvious performance change
with wing position. More flight are needed before he would have a
definitive answer on whether or not there were significant gains to be
made for this reconfiguration system.
Below are shots
of the covered model with the wings in both positions. |
3/27/06
