JR X9303 2.4 Instruction And Programming Manual page 170

Note on installing flap servos: Typical flap geometry
requires that the servo arms be significantly offset to
provide adequate down flap throw. This issue exists
because flaps typically have a large travel down (80 to 90
degrees) but very little up travel (less than 15 degrees). To
achieve proper flap travel, it is necessary that the right flap
sub trim is set at 225 down and the left flap sub trim is set
at 225 up as a starting point. Then when installing the flap
servo arms, be sure the spoiler stick is in the up position
and camber lever is in the middle position. Install the
flap servo horns such that they are angled approximately
30 degrees toward the trailing edge (if the flaps have the
control horn on the bottom of the flap) or 30 degrees
toward the leading edge (if the flap control horn is on top
of the flap) then adjust the flap linkage such that the flaps
are level. See Sub Trim on Page S-20 for more details.
S-40
B OTTOM C ONTR OL HOR N
30°
TOP C ONTR OL HOR N
30°