Throttle Quadrant
Cessna 172SP throttle quadrant — throttle, mixture, and carb heat push-pull controls with Hall-effect axis sensing.
Overview
The Cessna 172SP throttle quadrant consists of three push-pull controls mounted in the lower centre of the instrument panel:
- Throttle (black knob) — engine power
- Mixture (red knob) — fuel/air mixture
- Carb Heat (black knob with label) — carburettor heat
Unlike the 737 MAX throttle quadrant, there are no levers — the C172 uses friction-held push-pull cables with distinctive knob colours.
Design
The quadrant housing is laser-cut from 3mm MDF or aluminium sheet and mounts flush into the sub-panel. Each control uses a 10kΩ linear potentiometer (or Hall-effect sensor) attached to a sliding shaft inside a tube.
The knob caps are 3D-printed in PLA and painted/finished to match the real aircraft:
- Throttle: black knurled knob
- Mixture: red knurled knob
- Carb Heat: black flat knob
Axis Mapping
| Control | X-Plane Dataref |
|---|---|
| Throttle | sim/cockpit2/engine/actuators/throttle_ratio |
| Mixture | sim/cockpit2/engine/actuators/mixture_ratio |
| Carb Heat | sim/cockpit2/engine/actuators/carb_heat_ratio |
Each potentiometer connects to an analogue input on the ESP32. Values are read and sent to X-Plane via the CockpitConnect bridge.
Friction Mechanism
The real push-pull controls use cable friction. The replica uses an O-ring or felt pad friction fit on the sliding shaft to give a realistic resistance that holds position without snapping back.
Status
Planning — dimensional drawings in progress.