stuffing tube EXPLOSION

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • kevinpratt823
    Fast Electric Addict!
    • Aug 2012
    • 1361

    #16
    Did you have a sufficient gap between the drive dog and the strut to allow the shaft to shorten when it tightens up under load?
    My private off road rc track
    https://www.youtube.com/watch?v=XC3H...yaNZNA&index=8

    Comment

    • sundog
      Platinum Card Member
      • Feb 2009
      • 878

      #17
      You can see that the motor is at one angle, and the flex is another - causing a bend at the support area. That will build up a lot of heat fast. Adjust your motor to be at the same incline as your flex or it may happen again.
      Last edited by sundog; 05-20-2013, 12:12 PM. Reason: fixed typo
      Legend 36 sailboat, KMB Powerjet Ed Hardy Viper, ABC jet pwrd BBY Oval Master, ABC Hobby Jetski, NQD Tear Into's, HK Discovery 500, MickieBeez pwrd Jet Rigger!, Davette/Gravtix jet sprint, KMB Powerjet Pursuit, NQD pwrd Jet Catamaran!,Steam pwrd African Queen, Sidewinder airboat, Graupner Eco Power

      Comment

      • Ken Haines
        Racer
        • Jul 2007
        • 647

        #18
        Stuffing Tubes

        A couple of questions...
        Your set-up Kv / cell count ie; what RPM ?

        I would suggest if you exceed 40,000.
        or set-up a bigger higher amp boat
        you may want to ditch the teflon.
        Otherwise the teflon is fine.
        Increasing the shaft diameter does help.
        The .187 shafts as previously suggested are great.
        Odd thing, but an S-bend actually gives you
        a smoother cooler stuffing tube due to less vibration.
        That may be hard to believe but is definetely true.
        A very slight bend is where I have had most of my
        troubles....actually on a Q-Mono. Tried everything,
        Then Paul Pachmeyer suggested an outer stuffing tube
        of stainless tubing, this fits right over the brass, just
        1 additional ID. It has worked perfect and after blowing
        that stuffing tube no less that 5 times at various nationals
        it has never been a problem since. I have also added a zerk
        fitted aluminum block so that it makes it easier to grease
        every single heat.
        Hope one of these ideas help,
        Ken
        TenShock Brushless / Pro Marine
        INSANE Boats / Rico Racing/ Castle Creations
        2023, 2024 NAMBA & 2018 IMPBA FE High Points "National Champion"

        Comment

        • martin
          Fast Electric Addict!
          • Aug 2010
          • 2887

          #19
          Deff looks like in the pic theirs something strange going on re the angle of the motor/couping is at & the angle the stuffing tube has.

          Comment

          • lv_reefer
            Member
            • Jul 2009
            • 33

            #20
            Ok my support was a 3d printed support and the flex shaft went straight into the collet (no deflection at all). The pic made it look like things were not aligned because the flex is wrapped around the short piece of stuffing tube and it is cocked at an angle but they were aligned very well. There is one bend in the stuffing tube and it starts 1" (25.4mm martin this is for you ;-)) out side the hull and it is 3" long, nice and easy. The setup is a DF 22 3655 1850kv on 6s = 41,070rpm ~85%~ 34910rpm turning a 3517 cnc prop with ALL UL1hardware.
            Attached Files

            Comment

            • martin
              Fast Electric Addict!
              • Aug 2010
              • 2887

              #21
              A .130" flex on a 36mm size motor is to small in my opinion even more so on 6s at those rpm.

              Comment

              • lv_reefer
                Member
                • Jul 2009
                • 33

                #22
                I guess inexperienced... I have never seen a flex shaft shread like this lots of other stuff but never a flex give out. I was trying to keep the rotating mass down to a min i.e. the cnc prop...

                Comment

                • martin
                  Fast Electric Addict!
                  • Aug 2010
                  • 2887

                  #23
                  I have a few times, the problem is the damage that is caused after it breaks. This is one of the reasons some prefer not to run teflon liners as it grabs the broken flex & makes things worse, it can also be that some times the teflon causes flex failures ecspesially at those revs where the teflon melts & grabs the flex causing failures.

                  Comment

                  • lv_reefer
                    Member
                    • Jul 2009
                    • 33

                    #24
                    HUH!!! Never even considered.

                    Comment

                    Working...