Please excuse if a duplicate. . I never got a copy.
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I'm now hearing word about the use of the all-internal RDS in F3B and
F3J ships in highest level international competition. Some modelers are
installing servos and mechanics in the process of molding their wings.
Absolutely nothing is then evident on the wing surfaces to indicate that
servos or linkages are present.
One moldie, the Evolution, includes the designer's version of the RDS
for installation. It's good to see that one manufacturer is breaking
away from external hardware. However, there is a flaw in it. The sleeve
at the hingeline prevents normal, vertical float of the drive shaft at
that point that naturally wants to occur when the surface deflects. The
sleeve it not needed because the pocket itself supports the bent end of
the shaft. Lateral restraint is required at that point but should not be
provided with a snug fitting tube.
Builder-designer Mark Drela has developed the use of stainless steel
hypo tubing for the increased torsional rigidity provided for
applications more extreme than typical thermal flying. This torsional
rigidity can be obtained using such tubes with a simple, machined
aluminum sleeve pressed into the bottom section of the versatile,
injection-molded Kimbrough coupler. Using the coupler greatly simplifies
an RDS installation since it comes comes with a tree of splined adapters
of which one or the other fits most popular servos.
Details on this coupler/aluminum sleeve/hypo tubing arrangement have
been added at the end of File 6, the authoritative RDS file, at
http://genie.rchomepage.com. Modeler-machinist Walt Dimick of IRF
Machine Works is now set up to produce the sleeves. I jeep a supply of
the couplers on hand.
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