Futaba 8SGAP User Manual download pdf (Page 14)

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.

OPERATING INSTRUCTIONS

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

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-

3x2.

The speed of a four blade propeller is 1/2 the dis-

played value.

Connect the accessory tachometer

sensor to the sensor connector

as shown above.

Sensor

Sensor

connector

Fig. 14

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.

Measure the speed of the

rotating propeller at this

point.

Sensor

Make all

measurements

under natural

lighting.

Holding the sensor too close

to a spinning propeller is

dangerous.

Draw two lines

on the flywheel

with magic ink.

Fig.

15

To measure the speed of the main rotor of a

model helicopter, measure the speed of the tail

rotor as shown in Fig.16. and calculate the exact

speed from the equation.

Tail rotor speed

Main rotor speed = ——————--—--—————————

Main rotor and tail rotor gear ratio

Sensor

Helicopter tail rotor

Fig. 16

1 2 ... 9 10 11 12 13 14 15 16 17 18 19 ... 37 38

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