Helicorsa App 0.5

Installation
Download the the zip file attached to this post. Extract/unzip the content to your assettocorsa directory, e.g. in Steam\SteamApps\common\assettocorsa
The content will extract itself to app\python\helicorsa (for the app) and content\gui\icons (for the icons).
You can overwrite older version without problem.

Now start assetto corsa and enable the 'helicorsa' app in the settings/general:

Then start a session. Once you sit in the cockpit, move the mouse to the right in order to show the app sidebar. Scroll down until you find this symbol

and click it. You will notice a window will show up, drag it wherever you want to start out. You will notice it will vanish after 5 seconds (you can still drag it). If you have problems to find it, just hide and re-show the app via the sidebar.
It will remain completly unvisible until you are moving, and there's a nearby car (also moving) - short: it will only be there if needed.

Hint: If it doesn't vanish after you moved the window around, re-open it again. It won't do this next time you start the game.

Advanced users
... may have a look at the heliSettings.py, here you can fiddle around and tweak some numbers - for example the gui scale. Increase this to get a bigger app for 4k and/or DSR.