Overspin Problems with Tienly

Discussion in 'Gun Building, Modifications & Repairs' started by Squad144, Jun 7, 2021 at 10:24 AM.

  1. Squad144

    Squad144 Member

    Ocean Springs
    Does anyone else have overspin problems with a Tienly? If so how did you fix it?

    Cause I have a 35k that will not stop overspinning until 100% Active Brake is applied.

    This is the setup...
    Tienly 35k
    PDI 170% spring (about equal to an m115)
    2200 mAh 35c 70c 11.1 (1200 mAh 25c 50c 7.4 heats up)

    I believe the problem with all my motor heat up and wire heat issues are coming from the 35k overspinning, which it corrects using the active brake, pulling a lot of amps and heating the wires and motor. Would I be correct in thinking this?
    Last edited: Jun 8, 2021 at 2:46 PM
  2. Ben3721

    Ben3721 Well-Known Member

    This isn't technically the motors fault.

    You have a few options to fight overspin, some are not ideal alone.

    - use a lower voltage
    - short stroke and use a stronger spring
    - use a high speed gearset
    - use a slower motor

    Mixing above methods to get whatever outcome is what it takes, or use AB.

    I basically only use 13:1 gears in my builds with a m130 spring and short stroked by 3. Paired with a 25k motor on a 3 cell lipo. This gives about 400fps with .20 at 30rps, but with an extremely snappy semi that will work great with a hair trigger.

    One should also check to see if their cutoff lever is actually cutting off, sometimes the cutoff lever or the trigger contact shuttle/trolley is worn out, resulting in either a delayed cutoff, multiple cycles to cutoff or even full auto in semi.

    A lot of newer players try to throw in a high speed motor into a stock gun with a m120 spring and discover what overspin is the hard way, typically they end up damaging the trigger shuttle from crunching the trigger while the cutoff lever is resting at the same level as the shuttle, which is a rare thing in a normal aeg as it rarely lands the cycle there, but in overspin weird things can happen.
    Last edited: Jun 7, 2021 at 10:33 PM
    wetpee, Squad144 and hawkchief like this.

  3. Squad144

    Squad144 Member

    Ocean Springs
    I forgot to mention that my gears are G&P 18:1 and my moseft is a gate titan. I ordered a m125 spring hoping that it will fix the problem. How many teeth would you suggest I short stroke if I need to and off the pickup or release side?
  4. Ben3721

    Ben3721 Well-Known Member

    The logic is the motor is spinning faster and so is the bevel with a high speed motor on stock 18:1 gears, so it takes longer to slow down.

    If you have a quick change spring id test that spring out of the box for the fps before you even consider short stroking. If you have a very long wide bore barrel you may need every bit of volume for the best joule creep, which in that case short stroking can be problematic. I'm talking taking like 4 teeth off when using a 400mm+ barrel being an issue with heavier bbs.

    Short stroking on the release side too much can cause two issues with a standard cutoff lever system, if using a optical cutoff that senses the sector gears rotation then #1 can be ignored.
    1- the piston will drop way before the cutoff happens, resulting in more overspin since its basically free spinning without load for a moment. This becomes more of an issue after removing 3 or more on the release side. It also becomes more of a issue with a worn out trigger contact trolley and cutoff lever.

    2- if your using a sector chip, and take more than 2 or 3 teeth off the release side (or like 4 to 5 teeth without use of a sector chip), the piston will drop before the tappet is all the way forward resulting in no air seal, cutting the bottom of the tappet in a angle backwards or shortening it can avoid this drawback up to a point. But cutting it dsg style can cause the tappet to kick the pellet partly past the hop up rubber in some builds.

    The big pro of short stroking on the release side is more time for the piston to go forward before the tappet is pulled back again, which would be tappet PME if it happens, it causes fps drop in full auto. Many techs do not understand this and just preach "never short stroke on the release side!" Because they do not understand what other factors pop up when doing so. And exploiting those factors can result in some really fast ssg builds with perfect fps consistency in auto, if you know what your doing with the timing of everything.

    The max id recommend taking off the release side is 2, and the max off the pickup side is 4, which can be 6 teeth removed, any more and a dsg build is more viable to go with, and lower stress on the piston rack on pickup since the rpm of the gear will be half that of a equal rps/fps short stroked ssg build

    I'm not sure how the titan does cutoff.

    Another question is what is your rps goal? Or just trigger response? It gets much more complicated after 35rps on a ssg. Especially when trying to have a working semi auto without active braking.
    wetpee and Squad144 like this.
  5. Squad144

    Squad144 Member

    Ocean Springs
    I want anywhere from 25-30 rps. But my true goal is just trigger response. I already get 31 rps with it currently. I would like to stay away from buying a new gearset or motor if I can.

    When you mentioned that you short stroked by 3 teeth, I am assuming that you went with 2 of the pickup and 1 off the release to sorta balance the timing?

    How many teeth would you recommend me ss if the m125 does not fix the problem?

    Do you think that making the 18:1 gearset slower by adding a 9 tooth bevel would help if ss and a heavier spring do not fix the problem?
    Last edited: Jun 8, 2021 at 7:53 PM
  6. Ben3721

    Ben3721 Well-Known Member

    A 9 tooth bevel wouldn't help.

    I take off 2 on release and 1 on pickup for most my builds.

    For your setup you could try 2, one off each side.
  7. Cothonian

    Cothonian Member

    A high speed gear set would probably eat up more of the motor's excess energy and help with trigger response. Would also be a relatively easy first step.