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  1. #1
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    Excess Vibration running.187 cable without liner

    Just curious if this is normal? On my static run up using one of jeff wholts cables, I am getting what seems like excess vibration in the drive train. The stock setup (with telfon liner) seemed much smoother. I am contemplating just not running it without liner and going with the 9/32 stuffing tube and teflon liner setup. Any help is appreciated, I dont want to run the driveline apart with the vibration....

  2. #2
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    ...an update...so I went ahead and did the modification to use a 9/32'' stuffing tube and teflon liner instead of running without the liner and using a 1/4'' stuffing tube. It seems the vibrations have gone down some, but they are still there at certain RPM ranges. I cant pinpoint exactly where they are coming from. I have checked the obvious stuff like strut alignment and tightening everything down, but it just doesnt seem as smooth as the stock setup was when new. Is it because I am running a bigger shaft versus stock? How are other folks setups using .187 shafts, any vibrations?

  3. #3
    RC Competitor
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    May 2012
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    Having a teflon liner is very important. As long as you have the right size tube and teflon, vibration shouldn't be too bad. However you have to remember that water acts as a damper for vibration, so when the boat is in the water it won't be so bad. Also, maybe you forgot to put marine grease in the new tubes. Be sure to do that. Also put it in the strut.

    Also try turning the prop with your hand, if you can hear it scraping and it has what seems to be alot of resistence, this can be 2 things:
    No lube/grease in the teflon and strut
    Your tube isn't properly angled so the flex cable is hitting the teflon more then it needs to, as in the shape of the tube doesn't match the shape of the flex cable. You want it to not have curves if possible.

    Also how much flex cable is in between the collet and the TEFLON tube? It should be about 1/4 inch. Also be sure that the teflon tube sticks out from the copper tube, so the flex cable comes in contact with only teflon tube for a 1/8 or so inch.

  4. #4
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    67mustang, thanks for your points to ponder....I agree, I would prefer to run with the teflon liner, and glad I did the modified setup with it, versus running without it!

    As for the other items you mentioned, the cable and strut are well greased, so thats not of concern, and the tube is angled the same as stock so that couldnt be it either. Also, the shaft turns smoothly by hand with no rubbing so I think at this point I need to run it in the water to see what happens. Jeff Wholt also mentioned that bench running will produce artifical vibration that is dampened when in the water.

    The one thing you mention might be a contributor and that is the space between the teflon liner exit and the coupler. I have barely any! That is because I am running an aeromarine three piece coupler that takes up all the space with no extra. I am not sure if I should go with a smaller coupler? but this one was reccomended, and I know other folks on here are running it, so they also have reduced space between the liner and collet. Do you think thats a big deal or not?

    The only other thing I can think of is that it could be the strut bushing? Mine seems in great shape and only has around 25 runs on it, but I guess this could be the source of vibration too?

  5. #5
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    I run the aeromarine coupler and even though it is a close fit there is still room. Some other things to look at is the cable going in to deep and possibly hitting the end of the motor shaft? The strut has some play in it to adjust this. Are you running a thrust washer behind the drive dog? I adjust my strut so when the flex cable is installed the thrust washer is not tight but there is no gap. I also look very carefully at the height of the strut to make sure the flex cable enters the tube dead center. Just some things to consider.

  6. #6
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    Good news! The run seemed to go really well, it didnt seem like there was as much vibration as I thought. It ran well, and there was no abnormal signs of wear on the cable, strut, collet, or anything else at first glance. Also, the 9/32'' stuffing tube held in place very well, the inside of the hull was dry as the sahara! Hopefully, it hold for the next few runs, then I will take it all apart and inspect the stuffing tube and liner in more detail.

    One thing I still cant figure out is why my stock castle ESC still gets up over 190 degrees ( measuring the capacitors). Motor is still right around 110 and batteries were about 120 degrees. I guess, I will mess around more with the trim and batt placement.

    Overall I am very happy with the .187 flex cable and 9/32'' stuffing tube mod, I am glad I went with this....Thanks to all on the board here who helped answer questions and posting their experiences.

  7. #7
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    A bit late to the party but here are a couple comments.

    In your original post you mention a "static run up". If you are referring to hi rpm operation of the system while on the stand, I would like to mention that it is not recommended to run brushless motors at high rpm without a load on them. A quick bump check to confirm operation and rotation is generally all that is recommended.

    I was going to suggest trying a actual run to see if the results were better with the system under load. You have already done so and it appears the mod is working fine.

    The stock castle components are, in my opinion, running over loaded, or very close to it, when running 6S. Very high operating temps will continue to be an issue on 6S with the stock electrics.

    hog

  8. #8
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    Good inputs, thanks Hog. I learned my lesson, and for the record when I was doing the run ups they were never to wide open throttle, more like 75%, but this is definitely a good lesson learned!

    Second run tonight, and so far so good. I did reach an all time high on the capacitors on the ESC, 270 degrees! Crazy hot!

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