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This
page takes a look at some of the airplane systems people
often ask about. Currently, the most frequent
questions involve the control mechanisms and radio
setup. As a result, we are posting a few sketches of
these particular systems, neglecting other areas of the Weed
Wacker's mechanics. If you would like to see a sketch
of something that is not included here, please let us know.
Better
renditions of the graphics shown below are available in
bitmap form on the downloads
page.
Above
is a depiction of the pull-pull linkage arrangement the Weed
Wacker uses. It consists of plasitic-coated cable,
nylon cable guide tubes, and Robart 1/4-scale control
horns. The cables have a clevis soldered at each
end. We used Robart Hinge Point hinges on all control
surfaces.
The
image above shows the general layout of the rudder,
elevator, and throttle control systems. Note that the
tail wheel servo is not included in this sketch. Also,
notice the clustered placement of the servos in the
mid-fuselage area. It was necessary to keep as many of
the servos as possible close to the receiver in order to
avoid radio interference.
As
shown above, the servos can be placed with alternating
orientations to accommodate a cramped installation
compartment. The Weed Wacker actually has a separate
servo for the tail wheel. This made it necessary for
us to install the servos in a double-decked arrangement.
Since
the ailerons are located on the outboard sections of the
wing, mounting the servos in the central bay with the others
was not practical. Instead, we put one 1/4-scale servo
in front of each aileron. The servo drives the aileron
with a simple music wire pushrod. Because of the
4-foot distance between each aileron servo and the receiver,
we had to install an interference trap on each servo
lead. Although we have flown the airplane without the
interference traps, we wouldn't recommend it The lines
just pick up to much interference for safe flight. |
