Vertical Speed Indicator
Physical Vertical Speed Indicator (VSI) for the Cessna 172SP Six-Pack panel — bezel, needle mechanism, and X-Plane dataref mapping.
4 min read Updated 2026-06
Overview
The Vertical Speed Indicator (VSI) sits bottom-right in the six-pack "T" arrangement, showing rate of climb or descent in feet per minute via a needle sweeping a scale centred at zero, typically ±2,000 fpm.
Construction
Like the other six-pack instruments, this gauge is built as a self-contained module:
- Bezel / Face Plate — 3D-printed bezel with a printed VSI scale, zero at the 9 o'clock position
- Dial / Needle — single needle centred at zero, deflecting up for climb and down for descent
- Internal Mechanics — stepper motor driving the needle, centred at the zero-fpm rest position
- Back Housing — 3D-printed enclosure mounting to the MIP frame's instrument cutout
- PCB & Controller — ESP32 driving the stepper from the X-Plane vertical speed dataref
- Lighting — backlighting for night/IFR panel illumination
X-Plane Integration
sim/cockpit2/gauges/indicators/vvi_fpm_pilot
Status
Planning — design not yet started.