
.
Receiver
The receiver should also be wrapped in foam rubber and stowed as far forward as possible. Make certain that it is
somehow fastened in place so it will not move around during flight. A 36" long piece of large (3/16" o.d. approx.) nylon
tubing is provided for making an internal antenna mount. Glue the tube in a bottom corner of the fuselage, from the cabin
area back to the tail, and slide the antenna wire into it.
Switch
The receiver on/off switch may be mounted wherever it is convenient. Some servo trays have a slot along the front for
holding the switch. Then run a short length of music wire (*) from the switch to the outside of the model.
Aileron Hookup
One heavy-duty servo, such as recommended for the elevator and rudder, can
safely operate both ailerons at the same time from the center of the wing through
the use of 90° aileron bellcranks. The full size wing plan shows the servo
mounting, bellcranks, and pushrods in place in the wing. The importance of
making the installation operate perfectly smooth and friction free can't be over
emphasized. A heavy-duty 1/4-scale servo is more than strong enough to handle
the flight loads of both ailerons if its power isn't being robbed by a balky bellcrank
installation. There is no room for sloppiness or mismatched assembly. With a little
patience and forethought, your installation can be dependable and trouble free.
Two pieces of 3/32"x2-1/2"x4-1/8" plywood are provided for the bellcrank mounts.
Do not glue them into the wing at this time! First assemble the bellcranks onto the
ply mounts as shown here. Locate the holes for the music wire pivots according
to the wing plan drawing.
Be sure to make a right and a left bellcrank assembly. Sand the balsa spacer blocks down until the bellcranks and
washers just fit between the ply pieces with a minimum of clearance. Do not sand the blocks too small and put a bind in
the bellcrank movement. Epoxy the spacer blocks and top ply supports to the ply mounts. Slip the bellcranks and washers
in place and epoxy the music wire pivots to the ply pieces. Make sure the bellcranks operate freely up to this point.
A 36" long piece of small (1/8" o.d. approx.) nylon tubing is provided. Cut it into two 18" long pieces and slide these into
the holes you drilled into the wing ribs during the wing panel construction. Slide the 1/16" dia. music wire pushrods inside
the.nylon tubes. Check for any binding that may be caused by slight misalignment of the holes. Then epoxy the nylon tube
to all the ribs except for the W1s and WAs in the center section.
Pull the 1/16" pushrod wires out and make a "Z" bend in the end of each. Trial fit them and the bellcrank assemblies in the
wing to check that the "Z" bends don't bind on the bellcranks.
Bend the 4-40 x 8" threaded rods to the shape shown in the wing cross-section
drawing. Trial fit them into the control system and check again for binding. Fasten
the enthreaded ends of the rods to the bellcranks with a "Z" bend, or by bending
90· and soldering on a small washer (*). Only after you've got the entire aileron
control linkage assembled and operating freely should you glue the ply bellcrank
mount platforms to the wing ribs.
The aileron servo can be mounted in the center section and linked to the 1/16"
pushrod wires several ways. You may have your own favorite method. The
following two photos show different installations which vary only in the brand of
servo used and the positioning of it in the center section window.
The first photo shows a Kraft KPS-20H servo mounted vertically into the window from the bottom of the wing. The photo
was taken looking through the top window and is the same installation that is drawn on Plate 3 of the full size plans. The
second photo shows an Airtronics 94554 servo flat mounted onto a piece of plywood that was glued into the window
opening. In both installations, the right and left 1/16" pushrod wires have been spliced together with a piece of 1/16" i.d.
brass tubing (*). Then a 1/16" spur wire (*) must be bent to link the pushrods to the servo arm. Wrap and solder the spur
wire onto the pushrods. You'll probably find that the holes in the two center WA wing ribs will need to be oblonged slightly
to allow the pushrods to flex with the rotary motion of the servo without binding.