GEN-2 Fuel Gauges

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The RADIANT RFGA GEN-2 Fuel Gauge shows the current fuel level for one or two tanks using a bright, sunlight-readable color display. The screen combines an analog-style dial, large digital percent, fuel quantity, and a small trend/history graph so the pilot can see both the current fuel level and recent sender behavior.

The RFGA calibration system adapts the instrument to the sender and tank actually installed in the aircraft. Calibration may be performed with 2, 3, or 5 points per tank. A 5-point calibration is recommended for new installations because it better matches tank shape and sender nonlinearity.

The Resistive Fuel Gauge version works with passive resistive senders connected to ground, including conventional and reverse-acting sender curves within the measurable range of the instrument. It displays sender resistance in real time and can show sender OPEN or SHORT fault conditions.

The 0–5V Capacitive Fuel Gauge version works with analog sender systems that provide a 0 to 5 volt output. It displays sender voltage in real time and supports voltage curves that rise or fall with fuel level, as long as the calibration points form a valid monotonic curve.

Display units may be set to US gallons, liters, or imperial gallons. Each tank may have its own capacity setting, and fuel remaining is shown for each tank in the selected units.

The 2026 version of the GEN2 Fuel Gauges have these features:

• Single-tank or dual-tank display mode

• Analog-style dial with large digital fuel percent

• Fuel quantity displayed in US gallons, liters, or imperial gallons

• Individual capacity setting for each tank

• 2, 3, or 5-point calibration per tank

• Supports normal or reverse-acting sender curves when calibrated correctly

• Resistive version shows sender resistance in real time

• Resistive version can show OPEN or SHORT sender fault indications

• 0–5V Voltage version shows sender voltage in real time

• Fuel-level trend/history graph for each tank

• Internal 8-step brightness control adjusted from the front buttons

• 2-1/4" and 3-1/8" case versions available

• Sunlight-readable, high-contrast color display

• Single-tank or dual-tank display modes

• Fuel level shown as analog-style dial, large percent, quantity in selected units, and trend/history display

• Resistive version input: passive resistive sender to ground, user-calibrated, supports rising or falling resistance polarities

• 0–5V Capacitive version input: analog voltage sender output, nominal 0 to 5 V, user-calibrated, supports rising or falling voltage curves

• Calibration: 2, 3, or 5 points per tank

• Units: US gallons, liters, or imperial gallons

• Brightness: internal 8-step control from the front buttons

• Power: +9 to +16 VDC; use a 1 amp fuse or circuit breaker

• Harness: four wires — red power, black ground, white left/single tank sender, orange right tank sender

• Case: black nylon with chopped carbon fiber, 3D printed

• Mounting: 2-1/4" rectangular installation or 3-1/8" round panel installation, depending on model

• Operating temperature: -20 to +60 C

Sender Compatibility

The RFGA Resistive Fuel Gauge is for passive resistance senders connected to ground. The RFGA 0–5V Capacitive Fuel Gauge is for analog voltage-output senders in the 0 to 5 volt range. Digital, CAN, PWM, frequency, current-loop, or capacitive probes that require a separate excitation or conditioning module are not covered unless they provide a compatible analog output to the RFGA input.

Installation Basics

The RFGA uses a four-wire harness. Connect black to aircraft ground and red to +9 to +16 VDC aircraft power through a 1 amp fuse or circuit breaker. The white wire is the left tank sender input, or the single tank sender input. The orange wire is the right tank sender input. In single-tank mode, use the white sender wire and leave the orange wire insulated and unconnected.

For resistive senders, the sender body or sender ground terminal must be connected to aircraft ground. For 0–5V voltage senders, sender ground and RFGA ground should share a common aircraft ground reference. Do not connect aircraft bus voltage directly to the sender input.

Fuel-Level Trend and Computed Fuel Flow

The RFGA includes a fuel-level trend/history display, allowing the pilot to see recent fuel-level behavior. Fuel flow is computed from recent operating history and is advisory only. It is not calculated from a dedicated fuel-flow sender and should not be used for flight planning.

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Click to go to Radiant General Instruments Manual for setup, installation, operation, and configuration details for RFGA.