Comments on breaks and tires and aerodynamic breaking:
Brakes on helos are not exactly like those on cars, but they are powerful. The friction of a tire is large, about 75% of the weight that it supports. For an S76, this means that the two mains can put about 5000 pounds of deceleration on the aircraft, probably about .4 G
The brakes on an S-76 will certainly lock the wheels with full bottom collective, I have left dark black stripes and blue smoke during Cat A and Cat B landings, and the tires made a thumping feel as they rotated after that!
Tires make the most stopping force when they are at 95% of the ground speed, ie just slipping, not stopped. That is how ABS and "pumping the brakes" works. Skidding tires are quite a bit poorer at stopping.
Aerodynamic breaking is a very poor way to slow a helicopter. With normal attitudes, about .1 g is all that is available. Even with ridiculous nose up attitudes, like 20 degrees, the thrust of the main rotor that is actually decelerating you is about 25%, or about .25G, a lot less than the brakes can provide.
If you are on the ground, nose wheel off, mains on, the rotor is even less effective, because it is producing less thrust, and therefore has less decel capability. This situation, (mains on, nose off) is also bad for aft stick on most helos, because of the possibility of making a blade tailcone contact. The 76 has a control limiter to keep this from happening, but many helos do not(including original 76A's that have not had the control system mod - ask maintenance if the limiter SB has been installed!) , and it could be a bit more expensive to replace the blades then to replace the brakes!