Over-Talk Posted March 7, 2005 Report Share Posted March 7, 2005 I've read through all the replies......all excellent, but I still had my own thoughts....then Skids Up pretty much mirrored my ideas........ Is this a strong, increasing-amplitude vertical bounce, (collective bounce) or more of a fore and aft shuffle that seems to whip from the masthead to the bottom of the long-line (pylon rock) ??????? For collective bounce, tighten the pre-set friction etc. etc. (very scary stuff, often resulting in punching-off the load to save the ship). Pylon rock.....here's what I know. It usually happens in a heavily loaded ship on a slow approach (or possibly departure), the disc is fully-loaded and the pilot moves the cyclic forward or back to slightly change airspeed, then a fore/aft rock or whip starts. It can happen with just a heavy passenger load, but is more commonly seen with a sling load, more so on a long-line. Tests....is the collective bouncing from floor to ceiling ?? If yes, see above. If not, continue... next....if it's a rock/slow-hump/shuffle/whip, try not to punch-off, fly around a bit, gain airspeed, change power settings etc. If it goes away.....it is probably pylon rock. Causes....many factors as mentioned above....but usually xmsn mounts/rubbers/dampers/stuff getting worn. I believe they are an on-condition article and are hard to check (other than sending them to Lord for factory testing). One of the best ways the engineers access their 'condition' is whether several pilots complain of pylon rock ! Some pilot's personal techniques may show this problem before others, but something worth noting is still going on up there. Remedies....Tighten the pilot's cyclic friction a little......**** hard to do from the left seat !! Depending on the ship and mounts, this may be all that's needed. Depending on location and job, try a different approach, i.e. steeper, flatter, out-of-wind/more left pedal, etc. This sounds like a tough job Vibe, especially to try something new. Good luck. Fly safe. Climb on the roof and shake the mast HARD while your engineer checks the mounts/dampers etc........as mentioned above. Hope that helps with the diagnosis. OT Quote Link to comment Share on other sites More sharing options...
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