Unusual options

Fuel Consumption Measurement Using the MUI-30 Sensor

To measure fuel consumption and the remaining fuel in the tank, mechanical flow sensors MFlow2 Gas (for piston engines) and MFlow2 Turbine (for turbine engines) are typically used. However, if the fuel is delivered by a pump, the MUI-30 telemetry sensor—originally designed for measuring voltage, current, and consumed capacity—can be used instead. This is common in turbine-powered models. The basic assumption is that the amount of transferred fuel correlates with the electrical energy consumed by the pump. The advantage of the MUI-30 is that it is small, lightweight, does not require any modification of the fuel system, and is accurate enough for practical use.

Sensor Wiring

• Fuel pumps usually have two (DC) or more wires. Cut the red (positive) wire and insert the MUI sensor in line so that its yellow wire with the arrow "from sensor" is connected toward the pump.
• Connect the MUI’s 3-wire cable to the Ext. port on the receiver, or to any other port configured for telemetry input.
• The 2-wire voltage-measurement cable from the sensor is not required for this setup.

 

 

Sensor Configuration

• Use a Jetibox or the virtual Jetibox in the Duplex transmitter to access the MUI sensor menu. Set the “Start Trigger” to 0 A.

 

Sensor Calibration

• In the transmitter menu: go to Menu > Timers - Sensors > Displayed Telemetry, and use button F3 (+) to add the telemetry value MUI-30: Capacity.
• The capacity value in mAh will now appear on the transmitter’s main screen.
• Fill the tank and run the model until the fuel is consumed.
• Note the recorded capacity value displayed at the end of the run.

 

 

Alarm Setup
Let’s assume the pump consumed 240 mAh to empty the tank. You want to be alerted when 30% of the fuel remains, and then warned again when only 10% is left.

• Go to Menu > Timers - Sensors > Alarms, and use F2 (+) to add an alarm for MUI-30: Capacity with the condition X > 160 mAh (240 - 30%).
• In the "File" row, select a suitable acoustic alert from the list.

 

• Similarly, create a second alarm for 216 mAh (240 - 10%) and choose a more urgent voice alert. Use the “Repeat” option if necessary.

 

Tip: "Sounds on Event" can be assigned to any control input. They enhance situational awareness and flying safety. If the desired announcement is not available in the transmitter’s sound library, you can record it using the transmitter’s microphone, download it from www.jetimodel.cz, or use a text-to-speech tool on a PC. Recommended audio format: *.wav; maximum filename length: 8 characters.

 

 

 

Automatic Gear Deployment on Pressure Loss

For single-acting pneumatic landing gear systems, the gear automatically deploys in the event of a pressure drop. However, with double-acting systems, a pressure loss typically results in an emergency landing with retracted or partially deployed gear and gear doors — a scenario that can lead to damage. This risk can be mitigated by using the MBar pressure telemetry sensor and configuring telemetry controls on your Duplex transmitter. The sensor monitors system pressure and, when it drops below a predefined safety threshold, automatically deploys the landing gear.

MBar EX is a Duplex system telemetry sensor designed for measuring gas or liquid pressure. It monitors and logs minimum and maximum pressure and temperature values and alerts the pilot via alarms and voice messages when preset limits are reached.

 

 

Setup Procedure:

• Connect the sensor to the pneumatic or hydraulic system in your model.
• Plug it into the receiver or CentralBox as a telemetry sensor.
• In Menu/Timers – Sensors/Data Logging, press F1 Auto to detect and load all connected sensors.
  Tip: In this menu, you can also change the unit format for certain sensor values.

 

 

Configuring Telemetry Controls:

• In Menu/Advanced Properties/Telemetry Controls, assign Mx1 to MBar, and enable it.
  • For Sensor, choose MBar: Pressure from the Telemetry list.
  • For Condition, select X < and enter the minimum safe pressure value at which the landing gear will still deploy reliably (e.g., 200 kPa).

 

 

Setting Up Logical Switch:

• Go to Menu/Advanced Properties/Logical Switches, enable L1, and name it (e.g., “Gear”).
  • For Control 1, press F1 + and select Mx1 MBar from Telemetry Controls.
  • For Control 2, assign the switch you use for manual gear operation (e.g., Sc), and set Condition to OR.

 

 

Assigning to Gear Function:

• In Menu/Model/Function Assignment, assign the newly created logical switch L1 to the Gear function.
  (Use Delete / + / Logical Switches / L1)

 

 

Resulting Gear Behavior:

• If the system pressure is above 2 bar, you can control gear operation manually using the assigned switch (e.g., Sc).
• If the pressure drops below 2 bar, logical switch L1 will automatically deploy the gear using the telemetry control and block any attempt to retract the gear until pressure is restored above the threshold.

 

 

 

 

Automatic Deployment of Flaps

One of the many possible uses of telemetry controls is the ability to automatically deploy flaps based on airspeed. Flight speed is measured by the MSPEED EX sensor and its pitot tube.

 

Function Description:

• The model’s flaps are always fully and manually controlled by the pilot using a selected control.
• When the automatic flap function is activated, they extend proportionally within a selected range starting from a defined minimum speed.
• The maximum deflection of the automatic deployment is always less than the maximum deflection available through manual control.
• Manual flap control is always available. Automatic control only works when this function is enabled and the defined minimum airspeed is reached.

Procedure:

• Install the pitot tube (included with the MSPEED EX telemetry sensor) in the model according to the manual and connect it to the MSPEED sensor electronics.
• In Menu/Timers – Sensors/Sensors – Data Logging, press the F1 Auto button to detect connected sensors.

 

• In Menu/Advanced Properties/Telemetry Controls, define Mx1 with the label “Flaps” and activate it. Set the control type to Prop. control, and set the Default Value to 100%.

 

• In the Range field, enter the desired airspeed values at which the automatic flaps will be active. Units correspond to those in the Sensors – Data Logging menu (here m/s). The minimum value can be 0, the midpoint should lie between the two extremes, and the higher value should reflect the safe flight speed with retracted flaps. This value can be identified from previous flight data in Menu/Applications/Data Analysis.

 

In this example, the flaps begin to deploy at 40 m/s, reach half deflection at 20 m/s, and are fully deployed at 5 m/s.

 

 

In Menu/Advanced Properties/Logical Switches, define L1 with the label Mix and activate it:

• Set Control 1 to the control that operates the flaps (here P5) and use the function IXI>
• Set Control 2 to the switch that will enable/disable automatic flaps and choose AND as the condition

 

• In Menu/Model/Function Assignment, press F3 + to create a new function, e.g., named Speed, and assign telemetry control Mx1 to it.

 

• In Menu/Fine Tuning/Free Mixes, press F2 + to create a new mix. Set Master to the function Speed, Slave to the function Flaps, and set Value to 100%.

 

• Press F4 Edit to open the mix menu and set Switch to L1.

 

 

 

Duplex transmitters offer advanced and comprehensive model setup options directly from the base menu. By using logical functions, telemetry controls, and telemetry sensor data, pilots can configure model behavior in new and previously unavailable ways.