Futaba 8SGAP - Manual (Page 29)

•AIRCRAFT WITH VARIABLE PITCH PROP
ADVANTAGES OF VARIABLE PITCH PROPELLER
The variable pitch propeller offers such advantages as:
1. The desired speed and p u l l can be adjusted.
Fig. 50 Linkage
2. Speed matched to the engine is obtained.
3. Low noise.
4. Air braking effect by zero pitch.
5. Idling is unnecessary.
Pitch control
servo
High pitch-
Matching of the variable pitch propeller to the digital proportional RC set is essential. Improper use is ex-
tremely dangerous. Therefore, read this section carefully.
Low pitch High pitch Low pitch
Connect the pitch control servo to channel 8. A variable pitch propeller can be adequately controlled by a
common servo. Handle the servo the same as any other servo.
Install the servo and linkage as specified by the manufacturer. (Note) This section explains how to use a
MK variable pitch propeller.
Set switch [7] to the ACT
position. Turn trimmers[4]
and [5] fully counterclock-
wise.
Since trimmer 6 is adjusted
after making a test flight, set
it to about the center.
Switch II is the mixing ON-
OFF switch. When it is set to
the OFF position, monitor
lamp 22 B comes on. When
it is set to the ON position,
the lamp goes out. Set the
switch to the ON position
and check the pitch control
(channel 8) servo stroke and
direction. Set the servo so
the propeller is pitched when
the throttle stick is set to
HIGH and is zero pitch when
the throttle stick is set to
LOW. If the servo turns in
the wrong direction, reverse
the setting of servo reversing
switch 57 .
Fig. 51
Next, adjust the servo stroke. First set the trans-
mitter pitch control lever 8 to the HIGH posi-
tion. Then adjust the pitch control servo stroke
with the ATV trimmers 48 and 49 so a load is not
applied to the linkage. Set the mixing throttle po-
sition is 1 stop from the SLOW position (Fig. 52)
with the THROT POSIT trimmer [8], and check
if:
* The pitch is zero (minimum) when the throttle
lever is set to minimum slow.
* The pitch becomes 11 (maximum) when the
throttle lever is raised one stop.
Next, adjust the transmitter upper side pitch con-
trol HIGH side trim lever 8 throw. Set the throt-
tle lever to the HIGH side before making this
adjustment. Since lever 8 should be linked with
pitch 11 (maximum) the propeller pitch when this
lever is set to the lowest position must be checked.
A variable pitch propeller is difficult to measure
with a pitch gauge. Therefore, adjust trimmer [6]
for a pitch somewhat lower than the maximum
pitch 11 .
Pitch 11 (maximum)
at one stop
HIGH
Fig. 52
Pitch 0 (minimum) in slow