The solution is painfully obvious, but it doesn't seem to work.
<img src="http://i.imgur.com/DuKc2wP.png" border="0" />
Whenever I test it, the turnRate never goes above 1.1:
<img src="http://i.imgur.com/2jvd2Qw.jpg" border="0" />
Anyone know how the keyboard input works for 'on key down' and can explain how this would be done?