The app doesn't look half bad. Kinda limited, and only looks like it supports Novak's motors, but it's a start.
Someone here (can't remember who) made an R/C calc as well. But I think it was for the Android IIRC.
I personally hate making something for one platform, whether it's for Apple, Android, Blackberry, Windows, Mac, Linux, etc. This is where web-apps shine; they are cross-platform, provided the programmer does it right.