Prop Advice - 22.5" Arowana Build

[slappy]

Im hoping someone can help me find a better prop option for my Arowana.

I'm currently running a 2s 7.4v 5000mah battery, 120A ESC and KD36-60-07L 3500kv brushless inrunner.

The prop I have on there is a Prather 220 (1.72" Diameter - 2.6" pitch) on a supervee27r flex shaft.

On my first run, just as my battery was going, the whole prop shaft ripped out of the collet and I lost it.

Today I installed the beefiest collet that would fit and this time the flex shaft broke where the flex meets the rod of the shaft.

I also get a bit of torque roll on the boat. Good news is the engine and ESC are running nice and cool.

I understand that a larger pitch and smaller diameter may be the solution, I just dont know enough about props to know whether to go for a 3 or 2 blade or what the fastest prop I can run is without breaking shafts!

Sorry for the long post.

[NativePaul]

You may see a small improvement switching props to an X640 on your current setup, but that motor is a lot bigger and lower KV than we typically use for Mono1 on 2s, you could try a 3s 3300mAh pack for the same weight and energy on an X435 prop which should net you about 5 mins runtime and limit the torque effects that you are seeing at the moment as much as possible without changing the motor to a 28mm. Changing the motor to a 28x50-60mm of around 4500kv on an X435 on your existing 2s 5000mAh pack would work too, for approx 5 min runs and much less torque effects from both prop and motor inertia.

[slappy]

Thanks mate, I'll try that motor/prop setup on one of my builds as I have two with the exact same setup.

I bought some better shafts so hopefully I can keep them for a while!

[martin]

The Arrowana is a Mono 1 size hull, The motor & prop size is to much for that size hull & will torque roll it as their narrow hulls.

[electric]

I ran my Arrowana with a x437 3blade with nice results yesterday. There is also small diameter grim prop that works well. I will see if I still have it out in the garage and report back later.

[martin]

Yes the 220 prop at 2.6" pitch is to much compared with the x435 at 1.93"pitch + the smaller diameter.

[slappy]

Ok I'll Try the x435 first and see how it goes.

I already ordered some upgraded shafts so hopefully they will be stronger.

Thanks again.