Vacuum / ammeter

A round cluster gauge with suction (vacuum, in inches of mercury) on the left half-scale and a center-zero ammeter on the right, as on a C172's panel. A C152-style pair of small dials is the other variant.

Modeled on: Classic light-aircraft dual cluster gauge (suction and ammeter in one round case)
Category: Engine and systems
Size: 1 cell
Version: 1.0 · 2026-10-19
Plan: Pro
Simulators: MSFS 2020 · MSFS 2024 · X-Plane 11 · X-Plane 12

Variants

C172 stylev1.0

One round case, VAC and AMP half-scales

Picker, FACE: C172 style

C152 stylev1.0

Two small rectangular dials, SUCTION and AMPS (the vacAmpMini instrument)

Picker, FACE: C152 style

Features

VAC half-scale 3 to 7 in Hg with its green band
AMP half-scale -60 to +60, signed numbers, the needle level at zero
Red X when suction or amps is missing or stale
Realistic needles (Settings): spring and vibration
Night lighting: the face takes the panel's red flood light, the glareshield's warm light from above (stronger for instruments higher on the page) and its own light, a lamp hidden at the top of the case lighting the dial downward (Settings > Dimmers: Red flood light, Glareshield, Instruments (analog))

Your aircraft: The suction green band comes from the profile when it has one (e.g. PA-28 4.8-5.2); otherwise a default 3-7 in Hg with 4.5-5.5 green.

On the iPad

No knobs: a tap on the face asks to change the instrument

Settings

FACE: C172 style, C152 style
Global: Realistic needles

Simulator data

What the Hub reads from the simulator for this instrument, and what the instrument sends back. Names are the simulators' own: MSFS SimVars and events, X-Plane datarefs and commands.

Reads

Value	MSFS	X-Plane
Vacuum / suction (inHg)	`SUCTION PRESSURE (inHg)`	`sim/cockpit/misc/vacuum`
Ammeter, + charging (A)	`ELECTRICAL BATTERY LOAD:1 (amperes)`	`sim/cockpit2/electrical/battery_amps[0]`

Add-on aircraft with their own systems may use other variables; the Hub reads the standard ones.