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  • Stick shake

    I am trying to eliminate/reduce stick shake on my gyro.

  • #2
    Try a coke shim under one side of the center block and test fly. If it gets worse change sides. In doing that you are increasing the pitch on one blade and decreasing it on the other. It may seem primitive but that"s what we do.

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    • #3
      Rotors don"t know which way you turn, so no, it wouldn"t make a difference.A tight teeter hinge can do this, coz the teetering angle is slightly greater ina lh than a rh turn.

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      • #4
        Thanks guys, this is gold.My gyro had the same. I had nipped the teeter bolt up a bit tight and it made it shake. And another time I when I had mounted a new heavy prerotator on the head it made it shake real bad but if I flew it sideways the shake went away completely??johnc, does your machine have a worse shake when you do a verticle descent?I"ll try that when I next fly on saturday brownyRotors don"t know which way you turn, so no, it wouldn"t make a difference.A tight teeter hinge can do this, coz the teetering angle is slightly greater ina lh than a rh turn. G"day again birdy thanks again for them rotors, I"ll un nip the teeter bolt a fraction.

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        • #5
          Gd day John,This thread has been discussed before. You may want to follow the link; http://www.asra.org.au/smf/index.php...4586.0.htmlYou may find something or 2 that will be of interest....Lou

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          • #6
            G"day again birdy thanks again for them rotors, I"ll un nip the teeter bolt a fraction. Im assumin your the bloke i sent the 24"RR to.NEVER use bolt tension to adjust teeter free play. [ on any set of blades]The bolt should be tight, coz its designed to brace the tops of the towers wen its tight.You regulate teeter free play with shimms, either on the bearing bush or the thrust washers on the block."unnippn" the teeter bolt JUST FOR THIS TEST is ok, but its gota be shimmed and the bolt tight.

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            • #7
              Righto.
              ..........

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              • #8
                The less weight up the top of the mast makes for smoother rotors.The less pitch rotors have, the smoother they should be.Its possible your head is out of balance as well. A good example of this is years ago I sold a set of rotors to a bloke, he put them on & he reckons the shake was so bad his knuckles hit the dash. I gave the guy his money back & Nick Spehre flew those rotors & he claimed those rotors were the smoothest he had flown....which I already knew anyway. So it proved the rotors were excellent but the blokes head was out of whack, badly!

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                • #9
                  That is why blade manufacturers prefer to test each set of blades on a blue printed head. Then they know their end of the bargain is correct.

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                  • #10
                    So it proved the rotors were excellent but the blokes head was out of whack, badly! Looking back at earlier correspondence, Nick Spehr actually said that one blade of those AK28s was a different aerofoil from the other and that he also experienced stick shake when he flew them on my aircraft.He also thought I may have been over rotored for my light machine and you very kindly took them back again.Importantly for this thread however, is that when I picked up my new AK26 footers from Rosco at BH, he also stripped and thoroughly checked the rotor head. Apart from replacing the older design mushrooms with new ones, he found no other issues.As a novice pilot, in hindsight it would seem I had most likely overtightened the teeter bolt and caused myself some frightening moments with the cyclic oscillating 4-6in back and forth in flight.So your comment about the blokes head being out of whack should refer perhaps to my Head and stupid pilot error, as the Rotor head was not at fault.Thanks for your support at the time all the same Brian (and Nick too)

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                    • #11
                      So it proved the rotors were excellent but the blokes head was out of whack, badly! Looking back at earlier correspondence, Nick Spehr actually said that one blade of those AK28s was a different aerofoil from the other and that he also experienced stick shake when he flew them on my aircraft.He also thought I may have been over rotored for my light machine and you very kindly took them back again.Importantly for this thread however, is that when I picked up my new AK26 footers from Rosco at BH, he also stripped and thoroughly checked the rotor head. Apart from replacing the older design mushrooms with new ones, he found no other issues.As a novice pilot, in hindsight it would seem I had most likely overtightened the teeter bolt and caused myself some frightening moments with the cyclic oscillating 4-6in back and forth in flight.So your comment about the blokes head being out of whack should refer perhaps to my Head and stupid pilot error, as the Rotor head was not at fault.Thanks for your support at the time all the same Brian (and Nick too)Great to see you back on the forum !! Thanks for letting us know what the exact problem was and yes, overtightning the teeter bolt will emulate a head badly out of whack & that was my first thought that the head was the problem and in hindsight, I should have recognized the fact that the rotors were too big for your machine as well which wouldnt help the situation.One thing for certain, when Rosco gives a clear bill of health, there is no doubting that what he has checked is pretty close to perfect !!

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                      • #12
                        A good practice

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