The aircraft climbs in the left pedal turn, and descends in a right pedal turn due to the applicable governor. when you make a right pedal turn, the reference point(we shall call it the nose) for RRPM is now moving against the rotation of the main rotor. This would seem to INDICATE that the rotor was trying to overspeed(when in fact the tip speed hasn't changed). the governor will adjust tip speed down to maintain an INDICATED 100% NR. This results in an actual decrease in the tip speed at the rotor. The faster the turn, the faster the descent(or climb in a left pedal turn). so when a right yaw is encountered during LTE the yaw will also have the secondary effect of lower the tip speed NR(although indicated still says 100%) and this results in a lower TR tip speed as well. Not something you need when a right yaw develops. for those that like math, one "normal" pedal turn generally takes about 15 seconds to complete a full revolution. that means the rate of turn is approximately 4 revolutions per minute. the main rotor is around 375RPM IIRC. so a "normal" turn results in a loss of just over 1% NR. a rapid yaw will cause a tip speed change proportional to the yaw rate.