Gearing help

[Matty6901]

I installed a Tonic-X Z20 1470kv with stock gearing now my lipos are puffing like crazy. What is a good gear ratio to tame this beast?

[SQRT(-2)]

Here is a head speed calculator:

https://www.helifreak.com/showthread.php?t=233407

Don't quote me, but I think you want a 550 around 2K headspeed. Could be wrong though.

[PTcaflyer]

...Fill us in on what you have now....How old are your Batts?...what is their rating?

[dragonflyhkg]

Guys,

Just checking the head speed calculator for the GAUI Hurricane 550;

What is the "stock" gear set-up for the 850KV and 1100KV motor configurations?

Mark

[sp00fman]

Matty, i think with a 60T front gear and 13T or 14T pinion you should get close to 2000rpm. It also depends on if you run a governor or a throttlecurve, want a fast heli or docile.

[Matty6901]

I am running two 3300 mah nano tec 45-90c (new) batteries 13t pinion and stock gearing all around.

[PTcaflyer]

...Possibly 2 strikes against you with those batteries...I have never had any luck running 2-3s batts. on my Gaui's and Nano techs are kinda notorious from what I have read..
So, are you running 13T pinion on a 50T front main and swinging 550 blades?
If so, you are probably not hitting the power band for that motor and stressing your set up. Brushless motors are most happy running near max speed all the time and too high of head speed will cause you problems. As Spoofman said, try 13T and 60T main

[kavic5150]

Matty6901 how long are the blades on your Hurricane? 550mm?

[Matty6901]

Yes they are

[Jerrymac]

If it was a stock '550' kit it would have likely came with a 42T front gear, which would give you a head speed of between 2800 and 3200 (battery voltage 22.2 - 25.2) which is what I run on my short boomed Hurri running 430mm blades and the same exact motor.
As someone mentioned above, you would need to run a 60T front to get in the 2000 rpm range, but I don't think that motor is well suited for running 550mm blades. I use that motor on one of my Gaui 425's. Something in the 800kv to 1100kv range works much better when running the long boom and 550mm blades, plus, the larger Z30 motor, or something similar is better with the longer blades.

I run an old stock Gaui 850kv motor in my long boomed ship with 2 X 3s MegaPower 3300mah batteries in series and they are 5+ years old now, and just starting to get a little 'puffy'.

You could try a 60T front gear with a 13T pinion, but the smaller motor might suffer from a lack of power and bog with moderate collective inputs on the sticks.

[milliotseb]

I would also say that 1470 is high for a 550 blade heli. I would say less than 1100kv would be better. I run 1350kv with 475mm blade
yep try the 60 gear if you find one.

[milliotseb]

I know this topic is mainly on 500/550 blades but I have a question :
I have a mid boom 425 and I run CF 475mm blades. I use a Hacker 1350kv

My Castle logger indicate that on flight begin I am at around 2250rpm on normal mode (80% flat). My IDLE1 is around 2400 rpm in same conditions.
I finish my flights at around 2000rpm (I am translating low above ground when end of lipo is close)
My gearing is 14/50/20/61

Is it enough head speed? I am asking that because I also have quite some landing gear/tail fins vibrations in these conditions?

What would be your advice?