For a rotor in vertical autorotation, what is the relation between pitch, vertical speed and rpms? In other words, what happens to vertical speed and rpms in vertical autorotation if I change the pitch of the blades of the gyro I use to fly...?
Unless I am misinterpreting your question, if you add pitch [pulling collective in a helicopter] your RRPM [rotor RPM] will decrease, as it is being used to accelerate air down decent, if in a vertical decent the aerodynamics are screwy. Now if you have some forward speed increase Pitch trades RRPM for lowering vertical speed. Decreasing Pitch, allows you to trade altitude for RRPM giving you higher VS and higher RRPM.