Requires a working version of X-Plane 10.40 or newer
Compatible with X Plane 11.
Connect your computer running X-Plane and your Android device to the same network.
That's all that is required - the app will auto-configure and connect to X-Plane without any intervention from you.
This free demo contains airspeed indicator and altitude indicator.
The demo never expires.
If you like this app but would like more instruments, try X Plane Steam Gauges Pro
for a full six-pack with not just airspeed indicator and altimeter, but also attitude indicator, heading indicator, vertical speed indicator, and turn coordinator. The pro version also lets you configure the airspeed indicator to match your plane.
Available here: https://play.google.com/store/apps/details?id=com.xplanesteamgaugespro
Graphics by Sébastien Matton (https://github.com/sebmatton/jQuery-Flight-Indicators)