Futaba 8SSAP - Manual (Page 15)

OPERATING INSTRUCTIONS
the tachometer mode is selected. Hold the sensor
about 20 to 30 cm from the rotating propeller
(two blade). The propeller speed is displayed on
the LCD.
Sensor
indicates that the propeller is r o t a t i n g at
12,300 rpm. For propeller speeds up to 30,000
rpm, set the REVOLUTION RANGE switch at the
upper left-hand corner to LOW and for propeller
speeds above 30,000 rpm, set the REVOLUTION
RANGE switch to HIGH.
The speed of a three blade propeller is displayed
value d i v i d e d b y 3 x 2.
The speed of a four blade propeller is 1/2 the dis-
played value.
——Measure the speed of the
\ rotating propeller at this
point
Connect the accessory tachometer
sensor to the sensor connector
as shown above.
Fig. 11
Make all speed measurements outdoors under
natural lighting. Accurate speed measurements
cannot be made indoors under artificial lighting
because of the affect of the 50 or 60 Hz power.
Make all
measurements
under natural
lighting.
20 30cm
Sensor
Fig. 12 13
The speed of model boat
and car engines can also be
measured in this fashion.
Warning: Use extreme cau-
tion. There is danger of
serious injury or death.
Draw two lines
on the flywheel
with magic ink.
Holding the sensor too close
to a spinning propeller is
dangerous.
1.Tachometer
Set the tachometer/times POWER switch to ON.
appears on the display. Next, press the
MODE SEL key switch at the upper-right corner
three times. The display changes to
and
To measure the speed of the main rotor of a
model helicopter, measure the speed of the tail
rotor as shown in Fig.13. and calculate the exact
speed from the equation.
Main rotor speed =
Tail rotor speed
Main rotor and tail rotor gear ratio
Sensor
Helicopter tail rotor
Fig. 13