Originally Posted by
SASless
Memory serves me the 540 rotor system Charlie Model had accumulators too.....for the Collective system was it?
It was designed to allow for two full cycles of the Collective....meaning from full up to fully down twice.
As it was only fifty years ago I flew the B and C model Hueys......the recollection of those days is getting a bit dim.
The 540 system had an accumulator charged by the #1 system for the collective in the event of a dual system failure. On shutdown you would "bleed" the accumulator by making slow strokes of the collective. For this test you were supposed to get four full strokes (full up, down, up, down). In the event of an actual failure there was no guarantee of the movement allowed and I can tell you that without hydraulics the collective was not movable, you would bend the lever before the blades moved. The AH-1G and AH-1S(MOD)/(PROD) had the same system. The AH-1S(ECAS)/(MC) had an electric pump emergency hydraulic system for the collective.