StatusBarHidden - ParkinT/RubyMotion_Life GitHub Wiki
You can set the StatusBar (the black bar at the top) to be hidden, while your application is running, with this command
UIApplication.sharedApplication.setStatusBarHidden true, animated:false
But suppose you want the app to load with no visible StatusBar initially? That requires a PList entry.
Add this to your Rakefile in the Motion::Project::App.setup block
app.info_plist['UIStatusBarHidden'] = true
Thanks to Dylan Markow for answering this in the Google Groups