120 SR bad vibes

[Scook]

After going through 3 tail motors on my 120 and countless more on my msr, I've had enough.
I took apart each 'burnt out' tail motor and found that each one was contrarily in good health, the hair-like leads however were not. All of my failed tail motors were caused by a broken connection to the brushes.

I clamped down my 120 and powered up the tail rotor. I observed this motors self destruction brought on by high freq vibrations and the resulting heat it produced.
Since hot glue has a pseudo-rubber like quality, i tacked some on evenly around the tail rotor side and also where the leads come out of the motor.
It reduced the vibrations greatly
The motor no longer makes a zip sound, more of a solid hum now.
No jittery yawing
No TBE


If you look at the tail motor you'll see a black line of rubbery sealant

this is where Horizon attempts to soak up these bad vibrations, but obviously isn't enough.
I went bonkers with hot glue and slapped some around the creases of where the main motor meets the black frame, worlds better...
I recomend you guys try this, if its no good then just peel it off.
After all, its just a lil hot glue!

[SplashN'Crash]

I guess I will have to take a chip off one of my tail rotor blades to make it vibrate to see if this will work.

I have not seen a tail vibration issue. My motor is smooth and has lasted a couple years.

Glad this solved your problem.

[Scook]

Thats spectacular its lasted this long for you. Balancing that tail rotor is a must, but the vibrations are mostly coming from the motor rocking in the plastic mount.
Also the motor design is absolutely terrible imo. But im sure it was all done on purpose, as you all know, replacement parts are how these companies bank

[Bigsmitty]

You say, "no TBE" Did you HAVE it and this solved it? Def gonna give this a shot anyhow. Thanks for the tip man.

[Scook]

Yes, TBE used to be so bad that I couldn't fly it worth a damn indoors.
After I applied the hot glue in various spots, I'm able to fly in my small bedroom.

the avg temperature of the tail motor dropped significantly as well.
It used to be too hot to touch after 5 mins of flying. Now ill run 3 batteries through her and it still wont be as hot as it was before the glue.

The main point of applying this holy hot glue was just to keep her wires from vibrating out of contact. I'm hoping to confirm this 'fix' by others trying it, so let me know!

[Scook]

It's been a couple months and about 50+ flights in. the tail motor is still fine and still no serious TBE. Vibrations are absolutely the problem with these Blade motors.

Standard Blade motors are not made with close tolerances, specifically the shaft-bearing gap that exists. This gap causes the shaft to rock latterly, and at high RPM's it produces fast vibrations that eventually shake the motor apart somewhere (usually the motor leads go first, then the winding's seize the shaft.).

I'm not saying that Hot glue is the best fix for this, but vibrations are most definitely the problem.

Happy tinkering,
Steve.

[airshot]

Thanks for the tip....makes a lot of sense, you thought it out well!!