Is there any study on landscape/ vertical orientation of Apps?

I am working on the UX part of an App to interact with hardware. You would first design graphic and text images, and then the hardware would personalize your "view". (Sorry I am vague, not able to disclose much more)

Bottom line is: The app has been designed exclusively for Landscape orientation, but I have not used any landscape app in... forever. I am worried it is not going to be well received. Therefore I was wondering:

 Is there any study on customer preference of Landscape over Portrait orientation?