I am trying to sus out what is required in the heli so I can make a better choice for my next heli.

I understand: Pilot 75%, heli 25% and that there is a range of power/wt that is OK for 3D.

What about disc loading? Main Blade area/weight (AUW).

Do the blades and mounting to the head need to be quite stiff (non-flexible) to cope with the loads generated on the disc during sudden changes in direction OR does the head speed mean this is not required so much.

I read somewhere about "coning" of the blades during a loop.
Is there a rule of thumb for Tail rotor size in relation to MR size or blade stiffness?

Thanks Jeff

Wow! you could get some really long replies with that question. I don't really think you need to know the answers to all of those questions to choose a good 3D helicopter, the market is full of good choices. Just remember you really do get what you pay for, this doesn't mean that the cheapest helicopter on the market isn't any good its just affordable.

If you have money to spare then go with a Fury Extreme, if the budget is tight get a Raptor 60, I know Guys that have plenty of money but fly Raptors any way just because they don't like the idea spending $300 and a whole weekend to repair a Fury.

The rappy 50 is very 3D capable and so is the Caliber 30. It is just not as powerful. 3D is a term that is way to overused. When you can fly backwards both inverted and straight up then you can fly 3D. The questions you asked do not determine the 3Dness of a heli but may influence the overall flight charicteristics

60's with beefed up engines are about the optimal as far as 3D machines go. Main blade area isn't very important, unless it dramatically changes lift. Weight of course you want to keep low because the less rotating mass you have the more agile the craft will be. I doubt stiffness means anything at all in the real world. Overall material density is probably more important (the more uniform it is the better) That's why 'serious' pilots tend to eventually switch to carbon blades, because even well balanced wood blades can have the mass of each blade in slightly different spots which causes centrifugal 'drag' on the blades when they change speeds and orientation. Some degree of flexibility at the head is required because of the shock loads applied when an engine goes full/no load quickly as in 3D. If the blade union to the head was totally rigid the energy wouldn't be dissipated as in a slightly articulated head. The rotor disc on a helli will cone at any point in time where there's an aerodynamic load, it's just most sustained in a hard loop.