This is the Futaba RPM Sensor (Optical type) For Futaba telemetry systems

Features:

This sensor, when used in conjunction with a telemetry-enabled radio system, is used to indicate the rotation speed of a propeller, rotor, or other component. Nothing needs to be attached to the component since the sensor uses available light reflected off that component.

Includes:

• One RPM sensor with attached cable
• One plastic mounting bracket
• Two pieces of double-sided foam tape
• One instruction sheet
• One warranty sheet

Requires:

Connection to S.BUS 2 system

Specifications:

• Weight: 4.9g (0.173oz)
• Voltage: 3.7 to 7.4 VDC
• Range: 360 to 300,000 RPM/Fin(s)

• Length: 6-1/4" (160mm)
• Width: 28mm   (1-1/8")
• Height: 13mm   (1/2")

• length: 34mm   (1-3/8")
• Width:  26mm   (1")
• height: 12mm   (1/2")
• Foam tape
• Length:  22mm   (7/8")
• Thickness:  1.3mm  (1/8")

Comments:

This sensor will only work with S.BUS 2-compatible devices.

Helicopters: Because of the large rotor diameter, use of this sensor on a helicopter is not recommended. A magnetic sensor, such as the Futaba Magnetic RPM Sensor is suggested.

Brightness: Adequate light is needed for this sensor to operate properly. Conditions such as dusk, dawn, clouds, indoor operation, poor angle-of-reflection off of propellor or fin, etc., will result in a measurement of 0 RPM.

Installation: It is recommended that the sensor be mounted at or less than 150mm (6") from the object whose rotation speed is being measured. The closer to the object the sensor is mounted, the more reliable the measurements will be.