Futaba 8SSHP - Manual (Page 11)

OPERATING INSTRUCTIONS
1. Tachometer
Set the tachometer/times POWER switch to ON.
appears on the display. Next, press the
MODE SEL key s w i t c h a t the upper-right corner
three times. The display changes to
and
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.
indicates that the propeller is rotating 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 divided b y 3x2.
The speed of a four blade propeller is 1/2 the dis-
played value.
Connect the accessory tachometer
sensor to the sensor connector 28
as shown above.
Fig. 20
Make all speed measurements outdoors under natural
lighting. Accurate speed measurements cannot be made indoors under artificial lighting becau se of the affect
of the 50 or 60 Hz power.
9
To measure the speed of the main rotor of a
model helicopter, measure the speed of the tail
rotor as shown in Fig. 22 and calculate the exact
speed from the equation.
Main rotor speed =
Tail rotor speed
Main rotor and tail rotor gear ratio
Fig. 22