Adjusting speed through rotation

Hello community,

I would like to make it so my object's speed is dependent on its X rotation.
For example: Its default speed is 10.
When tilting up, giving it a X rotation of -40, the speed should go down to 4
When tilting down, giving it a X rotation of 40, the speed should go up to 16.
I've been trying all kinds of ways, but I can't seem to get it working.
I hope someone can give me some directions!

Thanks!

 

Post the code you've tried and you'll probably get some feedback, comments & suggestions.

Please use code tags (there's a button in the reply section "Insert -> Code" and a pinned thread in the forums, for more details).