Originally Posted by
triskele
Er, what happens with those long slim blades, for the rotorhead pulls them round and the tips follow a teeny bit later; with the jets surely now the tips are pulling the rotorhead?
As you state, the rotor thrust is proportional to the steady blade lag angle. To produce more thrust, the collective pitch angle is increased, which demands more torque at the rotorhead, up to the limits of the engine.
To allow more rotor thrust at a constant rotor RPM, the tip rockets allow additional pitch angle by compensating for the associated increased aero drag. The steady lag angle can be held at the previous value, hence the engine is providing the same power to the rotor as the baseline aircraft.
Essentially, the engine and rocket share the increased power requirement, with the engine operating within previously established limits. However, the differences in blade weight distribution (due to the plumbing), rotor dynamics (including transient loads due to rocket "ignition" and shutdown), static and fatigue loads, etc., must be considered before the system could be certified.