Thanks for timely replies. Yes, in these Novenco fans all the blades are fixed pitch. They can be adjusted with the fan at rest. Each blade has six bolts through the blade base into a locking collar on the inside of the hub fairing. We're thinking these bolts have possibly loosened. And yes...
Does anyone know what affect, if any, having blades in a fan at different pitch/angles affects vibration in a fan? Any literature? Have a new customer with some 300hp 1200rpm vane-axial fans with 8 fixed-pitch blades each. Apparently some of the blades have 'un-pitched' themselves and there...
