The documentation in FSX states the 'R' key changes the simulation rate.I've hit this key numerous times with no success and cannot therefore change the sim rate.Is anyone else having this problem?

At the risk of insulting your intelligence.....you have to follow the pressing the 'R' key with '+' or '-' to increase or decrease the sim rate.CalCYXX

Thanks. I never thought of that and don't remember reading it anywhere.I assumed hitting the 'R' key would cycle through the different rates.

You can also just go up to the menu bar and hit Options, Sim Rate and change it there.