the spring ends being attached such that at low pitch the spring applies {HEAD ~ a moment} tending to decrease {TAIL ~ blade pitch}, at moderate pitch the spring exerts no significant moment, and at high pitch the spring applies a moment tending to increase blade pitch 
tending to decrease
the spring ends being attached such that at low pitch the spring applies { HEAD ~ a moment } tending to decrease { TAIL ~ blade pitch } , at moderate pitch the spring exerts no significant moment , and at high pitch the spring applies a moment tending to increase blade pitch
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH