Fei Bao MiG-21 Fishbed Instruction Manual (Draft Rev 0)
Page 8 of 24
Aileron Servo and Control Horn Installation
Like the rudder servo, the aileron servo plywood mounts are set up for a mid-mount style servo
(eg JR DS3301) which can be quickly and easily screwed directly to the plywood. A couple of
strips of ply or hardwood should be glued to the back side of the ply mounts to increase the
thickness and give the servo screws a bit more grip.
A JR DS3421sa servo which has a bit more torque can also be used but will require the servo
cutout to be modified to accept the servo mounts. Trim the pre-installed ply mounts, glue two
pieces of 3/16" plywood (1-1/4" x 3/4" ) to the inside surface of the lower wing skin, add some
hardwood blocks to support the new mounts and tie them to the pre-installed ply and the inner
surface of the upper wing skin. Trim the kit-supplied CF angles and drill new holes drilled to
match the servos. 1/16" pilot holes were drilled into the mounts and the angles screwed in
place. If the servo cover contact the head of the screws, countersink the holes in the CF angles
and substitute the stock screws with countersunk screws.
The control horn was trimmed at the front (like the rudder and flap horns) and Hysol'd in place.
Connect the aileron control horn to the servo arm using the provided hardware or the builder’s
preferred hardware. Final adjustment of the pushrod, centering the aileron, and installation of
the servo cover will be done when setting up the control throws.
