This large 26cc gas engine-powered RC helicopter is used as a camera platform for taking still and video pictures of events such as the motorcycle racing that was happening at the racetrack next to our flying field.
You won't find this at Hobby King.
It has an onboard alternator (a brushless motor actually) which keeps the batteries charged. In fact, the batteries haven't needed charging for about 6 months, thanks to this system.
It is incredibly stable and he gets over 20 minutes flying out of a tank of gas. Not cheap though -- about NZ$12,000 (US$10K). But, it is an alternative to those quadcopters and tricopters people are using.