Thanks HB 999
I thought that I was probably being over protective towards the machinery. It's just that I'd never noticed it before during fifty plus years of observation, but I guess that rotor brakes are a fairly recent addition and I don't get to see as many helicopters as I used to (on the ground that is)!
I have always been in awe of rotor head design and I appreciate the tremendous loads they have to handle. I assume, now that I know that they are indeed intended to stop the rotor, that they are suitably sized so that at optimum condition they cannot overstress anything. Are they inhibited above certain power levels or in flight and of a fail-safe design?