High Quality Plan Sets and Laser Cut Partial Kits for Radio Control
Aircraft
Page 22
Henry Struck's 1937 Benny Boxcar in 108 inch span
6-32 screws with self locking nuts retain
the mount to the firewall and add strength to the mount.
The Boxcar was assembled and weighed at
both main gear legs and at the tail post. A before covering CG point
was calculated. It weighed 70.3 ounces at this point. The CG
is at 12.01. As usual all positionable components will
need to be mounted as far forward as possible, and ballast will be
required.
Control surface arms were made from 1/16
G10/FR4,
circuit board material. Carbon fiber would be good but it is much
harder to machine.
The arms should be installed centered on
the pivot points and with the holes aligned with the pivot points.
That will insure that the attach points describe equal arcs
around the pivot and are
diametrically opposite. The tension on the cords then should remain
very nearly constant at any control deflection.
Some time was spent determining the best
routings for the control runs. 64 pound bonded Kevlar cord is
used. I buy the cord from The Thread Exchange. Here is the page for
this cord: Thread
Exchange 207 Kevlar 64 pound cordOnce
the locations were determined the servos were installed.
