Model Boat Mayhem

Technical, Techniques, Hints, and Tips => BRUSHLESS Motors and Speed Controllers => Topic started by: sigfortunata on September 24, 2017, 10:43:34 pm

Title: Should I consider Torque vs KV
Post by: sigfortunata on September 24, 2017, 10:43:34 pm
Just general question really.


Through necessity I have a Turnigy D2826/6 motor rated at 2200kv  in an aerokits Sea Hornet. It was a temporary fit not planned. 


I run it on a 3S lipo.  The boat is quick but the motor gets really hot ( not smoking hot) just too hot to comfortably hold but I would expect this as its not really fit for purpose.
 
So I want to fit a more suitable motor. Originally it had a 3536  ???turns  1000kv on 14.8v but I've came to realise  that was TOO big. (I hit a buoy flat out, the boat took off, flipped and promptly sank which is what ruined the motor necessitating the temporary fit)


So I'm looking at a 3530/14  1100kv which will clearly develop more torque and enough speed but will it run cooler?   


I don't know, suggestions, view all welcome


 
Title: Re: Should I consider Torque vs KV
Post by: chas on September 24, 2017, 10:59:09 pm
Could you try a slightly smaller propeller? Less load = less amps= less heat.

Title: Re: Should I consider Torque vs KV
Post by: sigfortunata on September 24, 2017, 11:05:27 pm
Hi Chas


I have dropped the prop size from 35 to 30mm, forgot to mention I did that as a matter of course, sorry. 


The fitted motor is really just not suitable, it was intended for an airboat project and I wanted high KV, I need to change it out rather then compromise to make it work, smaller prop, dropping a battery cell etc
Title: Re: Should I consider Torque vs KV
Post by: canabus on September 25, 2017, 05:04:15 am
Hi sigfortunata
I am running a B28-57-15L 1900kv on 3S with a 45Amp car ESC and a 2 blade 32mm 1.4 pitch prop.
Also my mate is running the same setup, but with a B28-57-17L 1700kv.

Both are in Aerokits Sea Hornets.
My 1900kv has an air scoop on the engine hatch with an outlet under the rear dash.
No ware cooling!!!

Canabus
Title: Re: Should I consider Torque vs KV
Post by: unbuiltnautilus on September 25, 2017, 06:11:42 am
Try 1000kv at 7.4v, but the slightly bigger prop. I think torque is your friend in the thicker environment of water rather than air.
Title: Re: Should I consider Torque vs KV
Post by: sigfortunata on September 25, 2017, 06:41:50 am
Thank you gentlemen  :-))