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Dragon wings are hitting my torque tube, why?

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  • #31
    You also have to look at the wear and tear of a single bearing in the ALUMINUM bearing block.
    Think of a lever pulling back and forth on the bearing.
    Two bearings have more surface than one and can withstand higher radial loads.
    Life,The leading cause of Death

    Live and Learn--OR--Die and be an example

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    • #32
      Originally posted by Gyro28866 View Post


      I will attempt to explain this in a manner for you to also visualize.
      On the Dragonwings, the only adjustment for the end user is just to adjust for lead/lag. Place the rotor onto 2 saw horses, several feet from where the blade attaches to the hubbar. One sawhorse for each blade. you will adjust the sawhorses closer or farther out, attempting to get the hubbar into a slightly lower position than the rotor blade tips. You will attach a string and pulled tight to the tip of each blade, I use the seam where the upper skin is attached. This position is exactly the same on each blade. With the string pulled
      This all sounds complicated, but it really is not. real easy, once you have done it.
      Meet me at Mentone, and I will be glade to show you.
      I hope to Fly into Mentone this year and look forward to the meeting.
      This is “stringing” though and not tracking, right?
      I did string the blades when I put them together, but I was unaware of this fuel line trick. At some point I did try and sling them also, but noticed no difference. Some speculated that the stringing was pointless claiming that the centrifugal forces were so strong that no matter how tight the bolts were the blades would essentially “sling” themselves anyway. Anyone have thoughts on that?
      Air Command CLT Tandem
      BROKE, SIEZED, NO GOOD, Subaru 2.2 FI- Stock
      68" Warp Drive
      28' Dragon Wings
      0 #'s Thrust

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      • #33
        If you have already strung your blades, and they are still out of track, lift them out of the teeter towers and spin the head 180º and put them back on to see if that make a difference.
        If that doesn't get them in track, it's time for shims.

        To track a set of Dragon Wings, you would need to use shims between the teeter block and the hub bar, but only on one side.
        You just have to loosen the two vertical bolts in the teeter block enough to slip a shim under it, then re-tighten. I don't recall the torque specs right off the top of my head though.

        I used shims made from Coke cans (~0.003" to 0.004" thickness).
        It's kind of a hit and miss process unless you can identify which blade is flying high, or low.
        Adding a shim under one side of the block adds pitch to one blade while removing pitch from the other.

        I just put a shim under one side, and if it tracked worse I took it out and put it under the other side and kept adding until they tracked together.
        Then I marked the hub bar and rotorhead so that if I took the blades off, I always put them back on the same way.
        Mike Gaspard
        Forum Administrator
        Kaplan, Louisiana
        Bensen B8MG, NX36MG

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        • #34
          Originally posted by gyromike View Post
          If you have already strung your blades, and they are still out of track, lift them out of the teeter towers and spin the head 180º and put them back on to see if that make a difference.
          If that doesn't get them in track, it's time for shim

          I just put a shim under one side, and if it tracked worse I took it out and put it under the other side and kept adding until they tracked together.
          Then I marked the hub bar and rotorhead so that if I took the blades off, I always put them back on the same way.
          Awesome, thank you. Can you really tell a definite difference in just one thin shim?
          I just landed from flipping the towers 180*. I should mention previous owner had the towers and teeter marked R.H & L.H. But out of diligence I did it anyway just to see. The stick felt about the same but I could notice my leg and instrument pod bouncing more. So now I’ll put it back and start with the shims.


          Last edited by N447MR; 05-28-2018, 05:55 PM.
          Air Command CLT Tandem
          BROKE, SIEZED, NO GOOD, Subaru 2.2 FI- Stock
          68" Warp Drive
          28' Dragon Wings
          0 #'s Thrust

          Comment


          • #35
            Originally posted by N447MR View Post

            Can you really tell a definite difference in just one thin shim?
            It just depends on how far out the blades are.
            Just pick a side and start shimming.

            For some reason the tracking of the tips was more noticable when I was in a bank with the clouds in the back ground.
            Mike Gaspard
            Forum Administrator
            Kaplan, Louisiana
            Bensen B8MG, NX36MG

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            • #36
              Originally posted by gyromike View Post

              It just depends on how far out the blades are.
              Just pick a side and start shimming.

              For some reason the tracking of the tips was more noticable when I was in a bank with the clouds in the back ground.
              Make sense. How many shims would you expect to use; 2,3.5? I know it probably depends, but I'm thinking if you put 5 in there and there's no difference, then it's probably not going to, right?

              And as for the size of the shim; I read earlier, but I don't see any in my teeter block at all as they sit now. They would have to begin at the edge, and run the length of the block, but would they go all the way to the halfway of the width? And you're putting a hole in it for the bolt to go through, yes?
              I drew this rudimentary picture with the red being the outline of the shim.

              Air Command CLT Tandem
              BROKE, SIEZED, NO GOOD, Subaru 2.2 FI- Stock
              68" Warp Drive
              28' Dragon Wings
              0 #'s Thrust

              Comment


              • #37
                I would start using one shim at a time so you can feel the change. Using five you may go past the ideal setting.
                Regards, Vance Breese Gyroplane CFI http://www.breeseaircraft.com/

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                • #38
                  Originally posted by Vance View Post
                  I would start using one shim at a time so you can feel the change. Using five you may go past the ideal setting.
                  Yes, agreed. I more meant that if I get to 5 without improvement then that’s the wrong direction.
                  Any thought on my crude drawing?
                  Air Command CLT Tandem
                  BROKE, SIEZED, NO GOOD, Subaru 2.2 FI- Stock
                  68" Warp Drive
                  28' Dragon Wings
                  0 #'s Thrust

                  Comment


                  • #39
                    One of the best things to use is buy a feeler gauge and use the gauges for the shims,I would only go about 0.002 at a time 0.005

                    will probably move the tips about 1/2 ",remember as one tip go's up the other side go's down.
                    Best Regards,
                    Eddie Sigman,Polvadera,nm
                    (575) 835-4921

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                    • #40
                      Originally posted by eddie View Post
                      One of the best things to use is buy a feeler gauge and use the gauges for the shims,I would only go about 0.002 at a time 0.005

                      will probably move the tips about 1/2 ",remember as one tip go's up the other side go's down.
                      Do you find any made of aluminum to eliminate rust potential? Also, those feeler gauges seem to be much thinner with a 0.5" width than what I put in that drawing, so I guess it doesn't have to have the bolt through it.
                      Air Command CLT Tandem
                      BROKE, SIEZED, NO GOOD, Subaru 2.2 FI- Stock
                      68" Warp Drive
                      28' Dragon Wings
                      0 #'s Thrust

                      Comment


                      • #41
                        I think I made mine about 3/4" wide and as long as the side of the block, and punched a hole for the bolt.

                        You will start noticing a difference from the first shim.
                        Stick a shim under one side and it will either get better or worse.
                        If it gets worse, move it to the other side and keep adding until the blades tips are in track.
                        I kept adding shims until it went out of track again slightly, then removed shims until it was back in track.
                        Mike Gaspard
                        Forum Administrator
                        Kaplan, Louisiana
                        Bensen B8MG, NX36MG

                        Comment


                        • #42
                          Hello Geoff:
                          Let me see if I can explain this in a way that makes sense and you can visualize.
                          The teeter bolt and Bushings/Majic hats and Teeter block are a rigid/solid component. If machined correctly, there will be several thousands clearance.; as much as 20 thousands clearance to the Teeter Towers. This will allow the teeter block and hub bar to move side to side within the tower. Between the bushings and tower there is a plastic washer inserted. The aluminum SHIMS are placed between the plastic washer/shim and bushing top. You are shimming to close the gap to 4 to 8 thousands total. You should be able to take a flathead screwdriver and move the teeter block back and forth between the towers and have a total of only 4 to 8 thousands play. And you are trying to get it shimmed to the exact rotational center.
                          If you shim out all the gap/play and the teeter block and tower are being pushed together, you will have a pronounced stick shake (two per rev vibration) and probable galling and heat buildup at the tower and bushing area.
                          Hope this helps and hope to see you at Mentone.
                          Start making a list of questions to ask while you are there.
                          David McCutchen
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                          • #43
                            Originally posted by gyromike View Post
                            I think I made mine about 3/4" wide and as long as the side of the block, and punched a hole for the bolt.

                            You will start noticing a difference from the first shim.
                            Stick a shim under one side and it will either get better or worse.
                            If it gets worse, move it to the other side and keep adding until the blades tips are in track.
                            I kept adding shims until it went out of track again slightly, then removed shims until it was back in track.

                            Perfect, I'll give it a try and report back. I thought I read someone saying they just loosened the teeter tower bolts and slipped shims in. Also, as note for future readers, Mr. Boyette emailed me back and told me that there are no torque specs of any consequence for the teeter block bolts that hold the tower to the hub. Just tighten it up real well.



                            Air Command CLT Tandem
                            BROKE, SIEZED, NO GOOD, Subaru 2.2 FI- Stock
                            68" Warp Drive
                            28' Dragon Wings
                            0 #'s Thrust

                            Comment


                            • #44
                              Originally posted by Gyro28866 View Post
                              Hello Geoff:
                              Between the bushings and tower there is a plastic washer inserted. The aluminum SHIMS are placed between the plastic washer/shim and bushing top. You are shimming to close the gap to 4 to 8 thousands total.
                              If you shim out all the gap/play and the teeter block and tower are being pushed together, you will have a pronounced stick shake (two per rev vibration) and probable galling and heat buildup at the tower and bushing area.
                              I took the rotors off a couple days ago to check balance (seem pretty darn good still) and everything looks good to me visually. I didn't notice any plastic washers. There's no galling or apparent heat build up or wear. The only washers are on the outside of the teeter towers between the bolt head and on the other side between the nut and tower. I attached another crude drawing.
                              Should the plastic washer you reference be on the inside of the teeter tower?
                              Does the plastic washer contact the teeter block, or is it between the bushing and the teeter tower somehow?

                              I numbered the options I tried to explain the second drawing, but I don't know if it is clear.


                              Air Command CLT Tandem
                              BROKE, SIEZED, NO GOOD, Subaru 2.2 FI- Stock
                              68" Warp Drive
                              28' Dragon Wings
                              0 #'s Thrust

                              Comment


                              • #45
                                The teeter bolt, teeter block, and hat bushing should all move as one piece. That block assy should move together back and forth within the tower with the 4-8 thousands tolerance.
                                Bobby Munroe
                                Private Pilot (SEL)
                                PRA Chapter 62 #42748
                                EAA #1160523

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