The problem with this is insurance. Standard BMFA insurance, which anyone flying in the UK should get (about £21 per year, from memory), covers you for quite silly third-party liability costs (something like 5 megaquid), but specifically exempts commercial use of the model. Commercial use being anything that you profit from in any way, not necessarily being paid for in cash.

Helicopters particularly have the potential for truly spectacular damage claims

That said, I was reading an article about high-speed slope-soaring model gliders, the speed record for which currently stands at something like 225 mph! Get hit by one of those, and your problems would be over immediately

pca