New to the forum with a UH1-D 800 series

[Helikapoter]

On my 212 600, with the same tail drive (slightly smaller)
The drive shafts to the tail rotor I have both aligned in a lathe and both were not perfectly straight
I also placed a ball bearing on the short shaft and 2 bearings on the long shaft. I also secured the bearings of the 45 degree teeth on the gears, tail had no vibrations on 1st flight. See video made in my backyard , tail doesnt shake at all

https://youtu.be/-qHvv6QN4Uo

[Astronome]

Hi PawPaw,

Effectively, my motor is the "TURNADO serie" A50-12L V4 look HERE but not a "Standard" A50-12L V4 here which is a 14 poles for 6/8S battery.
Thanks for clarifying that.

Daniel

[PawPaw]

I see that. I also see 14 poles listed for another A50-12L V4. My suggestion would be to count the poles in your motor to be certain, due to the very strong possibility your vibration issue is due to an incorrect ESC pole number entry. I got that number wrong on a 600 heli build several years ago and the vibrations were dramatic.

[Astronome]

I have this model Turnado V4

[PawPaw]

I see 2 different specs for the same A50-12L V4. One shows 10 and the other shows 14. I suspect yours is 14 poles and the source of the vibration.

[PawPaw]

The Hacker A50-12L V4 shows to be a 14 pole motor. Is yours an older version? Also lists timing at 20-25.

[Astronome]

Hi PawPaw,

My motor is an Hacker A50-12L
My ESC: Jeti Mezon 130 lite
PWM: 8khz
Timing 17°

[PawPaw]

Ok. What motor are you using? Also, what are your PWM and timing settings?

[Astronome]

Hi PawPaw,

Here some JetiBox screen:

Number of pole



Rotor gear


RPM max


RPM min


Current data motor running without blades

Battery voltage
R: motor power
Temperature ECS in C°
Current
RPM



Bests flights

Daniel

[PawPaw]

Ok, I have no experience with Jeti…only Castle Creations, Hobbywing, and now Scorpion Tribunus which all require poles/2. I do know that setting up the wrong number in that category will induce heavy vibrations as I have experienced on one occasion.

[Astronome]

If it’s a 10 pole motor, did you enter 5? It’s poles / 2 = factor.

PawPaw,
No in the Jeti ESC, it is the number of real poles that must be indicated, I ask JETI for validation.
I also checked with a tachymeter.
I'll give you a picture tomorrow (it is 9:30 pm in France)

[PawPaw]

Also, is you drive belt too tight or loose? YouTube has a good video on proper adjustment of the belt.

[PawPaw]

If it’s a 10 pole motor, did you enter 5? It’s poles / 2 = factor.

[Astronome]

Just thinking out loud…..are you sure your motor pole count is entered correctly in the ESC/FBL governor?

Yes PawPAw

The Jeti Box allows you to read the parameters in clear:
- Rotor/motor ratio 1:13.8
- Rotor rpm mini/max: 1160/1240rpm
- Number of poles: 10 for the Hacker engine

[Astronome]

Personally, I’d try a set of tests slowly removing components from the mechanics. First try removing the blades and running it up. If it’s still present, you can eliminate the blades as a possibility. Next, remove the head and run it up. If vibrations are still present, you can eliminate the heads as a cause. That should help narrow down the options.

Beautiful Vario choppers by the way, that’s some excellent craftsmanship!

Hello F106DeltaDart
That's exactly what I did.
Balanced blades
Verified Center of Gravity: Vibrations still present blades removed.
Head removed: ditto

[PawPaw]

Just thinking out loud…..are you sure your motor pole count is entered correctly in the ESC/FBL governor?

[F106DeltaDart]

Hi sfc,

Maybe, but I have the latest version of mechanics HSM800 (with the helicoid gears)

Personally, I’d try a set of tests slowly removing components from the mechanics. First try removing the blades and running it up. If it’s still present, you can eliminate the blades as a possibility. Next, remove the head and run it up. If vibrations are still present, you can eliminate the heads as a cause. That should help narrow down the options.

Beautiful Vario choppers by the way, that’s some excellent craftsmanship!

[Astronome]

I know in there older mechanics sets, the main shaft bearings were suspect as well, but that probably seems to have been mostly corrected. Perhaps just a bent main shaft?

Hi sfc,

Maybe, but I have the latest version of mechanics HSM800 (with the helicoid gears)

[Astronome]

Astronome Is there a certain RPM range where the vibrations begin, or end?

Hi Alpha,

Vibrations start gradually from 1000rpm

[sfcfury]

Astronome Is there a certain RPM range where the vibrations begin, or end?

Hey Alpha! Long time no see!