How do I build a DIY dual-engine throttle quadrant?

To build a DIY dual-engine throttle quadrant for flight simulation, use two mechanically independent levers, one linear potentiometer or Hall-effect sensor per lever, and a USB joystick controller with at least two analogue inputs. Mount the parts, wire each axis separately, calibrate the USB device, then bind and test both engines in your simulator.

This is a general PC flight-simulation design that can work with Microsoft Flight Simulator, X-Plane, FSX, Prepar3D and similar simulators. Generic DIY USB devices are usually unsuitable for consoles, which generally require platform-authorised hardware. Confirm compatibility first if the target system is Xbox or PlayStation.

Parts for a twin-engine throttle quadrant

A dependable build needs an axis-capable USB controller, two position sensors and mechanics that prevent the levers from loading the sensors directly.

• Two independent levers: use plywood, aluminium, acrylic or printed parts, with a separate pivot for each engine.
• Two analogue sensors: choose linear-taper potentiometers or analogue Hall-effect position sensors. A 10 kΩ linear potentiometer is common, but the resistance and voltage must suit the controller.
• USB joystick controller: it must support at least two analogue axes and appear to the PC as a USB HID game controller. A button-only arcade encoder cannot read throttle position.
• Mechanical hardware: pivots, bushes, spacers, locknuts, friction washers, linkages and positive end stops.
• Electrical hardware: flexible wire, insulated connectors, a USB cable, strain relief and a secure board mount.
• Optional controls: detents, reverse-thrust switches, engine cut-off switches or additional propeller and mixture axes.

Do not substitute a rotary encoder for an analogue position sensor. An encoder reports movement pulses rather than the lever's absolute position, so the simulator cannot reliably know where the throttle is after startup.

Build sequence

1. Define the controls. Two levers provide engine-one and engine-two throttle. A complete twin-piston quadrant normally needs six axes: two throttles, two propeller controls and two mixture controls. Our guide to throttle, propeller and mixture lever layouts explains how those controls differ.
2. Test the electronics first. Connect both sensors temporarily and verify that the PC sees two independent axes before cutting the enclosure. If a microcontroller appears only as a serial device, it needs suitable USB joystick firmware.
3. Build separate pivots. Fit each lever with bushes or spacers so it moves without wobbling. Adjustable nylon, fibre or felt friction washers can provide resistance without coupling the two levers together.
4. Couple each sensor. Use a short linkage, gear, pulley or accurately aligned direct coupling. The sensor should measure movement, not support the lever or absorb the pilot's force.
5. Set the mechanical travel. Arrange the linkage so normal lever movement uses most of the sensor range. Fit physical stops that engage before a potentiometer reaches its internal end stop or a linkage binds.
6. Add friction and detents. Make both levers feel similar, but retain independent movement. Install aircraft-specific detents only after the raw axes work correctly.
7. Secure the enclosure. Mount the controller away from moving parts, insulate exposed terminals and provide strain relief where the USB cable exits.

A mistake we see repeatedly is attaching a long lever directly to a potentiometer shaft. That arrangement bends the shaft, loosens the mounting nut and produces unstable readings. Let a proper pivot carry the load and connect the sensor through a light linkage.

How do I wire two throttle axes to USB?

Each sensor needs its own signal input, while both can normally share the controller's reference supply and ground.

• Connect the controller's reference or sensor-supply terminal to the positive side of both sensors.
• Connect both sensor grounds to the controller ground.
• Connect the first sensor's signal or potentiometer wiper to analogue axis input one.
• Connect the second sensor's signal or wiper to analogue axis input two.

Use the voltage supplied by the controller rather than assuming every board or sensor uses 5 V. For a three-terminal potentiometer, the two outer terminals take reference and ground, while the centre wiper supplies the axis signal. Hall-sensor pin arrangements vary, so identify the supply, ground and analogue-output pins from the component documentation rather than guessing from their physical order.

Unplug USB power while changing connections. Keep analogue wiring short, maintain a common ground and route sensor wires away from illuminated switches or other powered accessories. If you need starter, fuel-pump or cut-off controls, our advice on adding a separate switch and button panel covers the cleaner approach.

How do I calibrate and bind each engine?

Calibrate the physical device before assigning simulator commands, then bind each lever to a separate engine axis rather than to a combined throttle.

1. Check the operating-system test display. Move one lever at a time. Each must operate a different axis smoothly from one end to the other.
2. Calibrate the controller. Use its configuration utility if supplied; otherwise use the operating system's game-controller calibration. Move each lever through its full physical range without forcing the stops.
3. Clear duplicate bindings. Remove automatic throttle assignments from other joysticks, yokes or gamepads. Two devices controlling one command cause jumping and unexplained power changes.
4. Assign engines separately. Bind the left lever to the engine-one throttle axis and the right lever to the engine-two throttle axis. Exact command names differ between simulators.
5. Correct direction in software. If advancing a lever reduces power, enable the axis-reverse or invert option. This is safer and easier to maintain than rewiring a working sensor.
6. Start with a linear response. Throttles do not need a centre dead zone. Add only enough endpoint dead zone to reach reliable idle and full power.
7. Test an aircraft. Compare idle, mid-travel and maximum power with both levers physically aligned. Calibrate axes individually if one engine consistently leads the other.

Our USB-axis calibration and binding checklist covers the simulator-side setup in more detail. X-Plane users can also follow the steps for mapping two physical levers to separate X-Plane engines.

Should I add detents, reverse thrust or more levers?

Add detents only for the aircraft family you intend to fly, because airliner, turboprop and piston-engine quadrants use different lever ranges and gates.

A generic quadrant usually works best with an idle stop and uninterrupted forward range. Reverse thrust can use a gated below-idle section if the simulator and aircraft support that axis arrangement, or a microswitch can activate a separate reverse command. Test the software logic before cutting a permanent reverse gate.

For a twin-piston aircraft, add separate propeller and mixture sensors rather than mechanically linking those controls to the throttles. Each lever needs its own analogue input. Switches for fuel, ignition and engine start use digital inputs and do not consume analogue axes.

Common throttle-quadrant faults and fixes

A finished dual-engine quadrant should present two stable, independent axes, reach idle and maximum power without forcing the levers, and hold any intermediate setting without creeping. Resolve noise and range problems in the operating-system test display before trying to correct them with simulator sensitivity curves.