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McCutchen Teeter Block Setup

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  • McCutchen Teeter Block Setup

    Hi,
    I recently purchased a Bensen style, single place gyro that came with a set of 23 foot McCutchen blades.
    I was looking for Jim McCutchen's current email address so I could contact him regarding the correct procedure for setting up the teeter block on the hub bar.
    I tried mccutc9123@aol.com but never recieved a reply.
    Does anyone have Jims current email address or the procedure for setting up the teeter block?
    Thanks.

    Regards Rowdy

  • #2
    The block is able to adjust center cord and tracking.
    To adjust center cord loosen the allen screw on the side of the block.and adjust the block right to left to center block within the towers.
    Once in the center you will most likely adjust again after flight to get the sweet spot.
    You will have to play with it, 1/16th turns right or left till you find the best spot.
    Remember to tighten the allen screw after each adjustment

    The tracking is done by the four nuts on top of the block.
    Let's start with some terms, I will call right to left the diameter and for and aft leading edge and trailing edge.
    If the block was removed, center the block using feeler gauges under the block to the hub.
    Check all four corners and torque to bolt specs.
    Again, fly the machine.
    If out of track you will loosen the nuts on the leading edge of the high blade and tighten the nuts on the trailing edge.
    Do this with a 1/16th of a turn on the nuts to start. Do not do this right to left, trailing and leading edge bolts only..
    Just for clarity, your center cord adjusting screw has a round side and a slotted side.
    You will loosen the nuts on the round side and tighten the nuts on the slotted side.
    That was an example.
    You want to find the high blade and loosen the leading edge and tighten trailing edge.
    You want to roll the high side down in 1/16th of a turn trials.
    You will have to fly the machine to load the blades properly to see how the rotor is tracking.
    Life,The leading cause of Death

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

    321.252.7705

    Comment


    • #3
      In 2013, Jims' number used to be 812-890-8681. I don't know if it is still current

      David McCutchen
      615-390-2228
      Bensen B7m, 90 hp Mac
      Dominator Tandem, 100 hp Hirth
      Kolb Mark III Classic, 80 hp Verner
      Certified - Advanced Master Beef Producer
      EAA Member #0511805
      PRA Member #28866
      PRA Chapter 16 Member
      Secretary & Treasure - PRA Chapter 16
      President / Sylvia - Yellow Creek Volunteer Fire Dept.
      Chairmen - Dickson County Veteran's Day Committee
      Volunteer - Dickson County Airport Aviation Day Committee
      2 busy 2 No!

      Comment


      • #4
        Thanks for that Jake.
        I was hoping it would be as easy as placing the assembled rotors on a flat surface ( not necessarily dead level, but so they don't move)
        measuring the angle of both blades by placing a digital clineometer, perpendicular across the top of each blade, 12 inches outboard of the hub bar,
        then adjusting the angle of the teeter block to be exactly half that of the blades.
        As an easy example, left blade is +10, right blade is -10, so you set the top flat surface of the teeter block to 0.

        What is the easiest and best method of tracking the blades in flight?
        Last edited by Rowdy; 10-08-2018, 04:37 PM.

        Comment


        • #5
          Thanks David.
          Do you have an email address. I'm not in the States.

          Comment


          • #6
            What is the easiest and best method of tracking the blades in flight?
            Tip targets with a strobe light OR a tracking camera. The best scenario is in flight at the airspeed and gross weight you would normally fly at and a tracking camera is ALOT easier with only 1 person. I always used to do my tack & balances at the customers normal flight environment as different weight and airspeed would affect the overall solution. If you or your buddies don't have the equipment available then go find a reputable helicopter service center and talk to them about what you're doing.
            I'm sure there a whole bunch of ways around this, but that is the only way if you want true precision with a data sheet documenting the changes made.
            Last edited by Hueychief; 10-07-2018, 07:05 AM. Reason: Added more info.
            Jeff Brenhaug
            S-64 Captain Erickson Aircrane

            WATERBOARDING WORKS

            Comment


            • #7
              Originally posted by Hueychief View Post
              Tip targets with a strobe light OR a tracking camera. The best scenario is in flight at the airspeed and gross weight you would normally fly at and a tracking camera is ALOT easier with only 1 person. I always used to do my tack & balances at the customers normal flight environment as different weight and airspeed would affect the overall solution. If you or your buddies don't have the equipment available then go find a reputable helicopter service center and talk to them about what you're doing.
              I'm sure there a whole bunch of ways around this, but that is the only way if you want true precision with a data sheet documenting the changes made.
              Most likely 99% of tracking done on gyroplanes is done visually, no fancy gadgets and paper work.
              Some use a reflective tape on the tips with different colors.
              My self, I look for the high blade and adjust on the ground.
              I fly after each adjustment till I am happy with results.
              In conclusion, when there is no hop caused by out of track blades, then I am happy.
              Time consuming, inexpensive and works like a charm.
              Life,The leading cause of Death

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

              321.252.7705

              Comment


              • #8
                Thanks fellas.
                Jake what do you mean by "hop"

                Comment


                • #9
                  Originally posted by Rowdy View Post
                  Thanks fellas.
                  Jake what do you mean by "hop"
                  When your rotor is out of track one blade has more lift than the other because of the difference in pitch, which will cause an up and down hop in the air frame.
                  Tracking will smooth this out.
                  Life,The leading cause of Death

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

                  321.252.7705

                  Comment


                  • #10
                    Everything Jake has said matches my experience with my Air Command.

                    Look for out-of-track by flying and watching the tips out at 10 o'clock/2 o'clock. (Don't do this in traffic.) Hold the stick still. Once I spotted an out-of-track condition, I'd detect the high blade on the ground by letting the rotor wind down to perhaps 50 RPM. I had previously marked one blade near the root with a strip of black tape.

                    The chordwise balance adjustment (the threaded teeter barrel) OTOH is pure trial and error. Be sure the teeter bolt is tight so the rotor doesn't slide back and forth along the teeter bolt randomly.

                    Once you've dialed in both of these adjustments, be sure to mark the rotor head so that you always put the rotor on with the same blade on the same side of the head. The adjustments exist partly to compensate for slight asymmetries in the head. If you change heads, expect to re-do the adjustments.

                    The adjustable hub does ignore an elephant on the room: spanwise (tip-to-tip) balance. McCutchens were handmade, so there are minor inconsistencies in the distribution of the various liquid "goops" that harden into a composite structure. And, again, the machining of the head may be off a bit. Chordwise Imbalance will show up as a tendency for the stick to "circle" one per rev. The blades in their drooped position don't necessarily "seesaw" to the heavier side. Sometimes you can spot the heavier blade by putting a small weight (a coin, a nut) on each blade in turn and watching how far down it seesaws. Another trick is to use string to truss the blades up out of their drooped position; this makes them more likely to drop the heavier blade. Adding paint or gelcoat to the light blade's tip is one way to adjust spanwise balance.

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                    • #11
                      If you put the rotor upside down and let it pivot with the 3/8 bolt, you can use a water level to get a pretty accurate balance.
                      Make sure it is level right to left. Cordwise
                      I used powdered lead mixed with epoxy and injected through the breather hole.
                      Took about 700 milligrams for dead nuts balance.
                      Was installed right side up.
                      Do not plug up the hole.
                      Life,The leading cause of Death

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

                      321.252.7705

                      Comment


                      • #12
                        Thanks for all the help.
                        Very much appreciated.

                        Comment


                        • #13
                          Rowdy:
                          All I have is his old email address
                          David McCutchen
                          615-390-2228
                          Bensen B7m, 90 hp Mac
                          Dominator Tandem, 100 hp Hirth
                          Kolb Mark III Classic, 80 hp Verner
                          Certified - Advanced Master Beef Producer
                          EAA Member #0511805
                          PRA Member #28866
                          PRA Chapter 16 Member
                          Secretary & Treasure - PRA Chapter 16
                          President / Sylvia - Yellow Creek Volunteer Fire Dept.
                          Chairmen - Dickson County Veteran's Day Committee
                          Volunteer - Dickson County Airport Aviation Day Committee
                          2 busy 2 No!

                          Comment


                          • #14
                            No worries David.
                            Thanks

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