Here is an iOS/Android compatible HD camera designed with RC fans in mind. RunCam 2 offers 1080p at 60fps and 720p at 120ps video quality. It comes with built-in WiFi to connect to your smart devices. The app lets you see a live preview and change settings easily.
RunCam 2 comes with a 850 mAh replaceable battery that lets you record 90 minutes of HD video. It can also work as a power bank for your phone. More information is available here.