Thread Tools
Old Oct 13, 2015, 05:25 AM
Skystreak is offline
Find More Posts by Skystreak
Registered User
United Kingdom, Outwell
Joined Sep 2013
98 Posts
Discussion
Considerations when going brushless...

Hi, Everybody tells me how brushless is best, so I have been looking into what's available for boats.
Well, not much seems to be available, but a link from the Fireboat forum led me to Hobbyking offering a huge range of mainly Turnigy brushless boat motors. Most seem to be inrunners. I assume because they're easier to water cool. BUT, we're told the Kv of inrunners is too high for boats.
THEN, I find a few water cooled outrunners. How does that work??
Then I read that most of these Turnigy water cooled motors leak like baskets for want of some decent sealers in manufacture.
I also wonder why a low Kv motor is so much more expensive than a high Kv.
Also HK seem to offer such cheap high amperage ESCs. Can they really be any good?

I find the whole boat brushless thing to be a nightmare to trawl through.

Is there a single thread or article that presents this subject as a simple explanation of what's what?

Cheers,
Martin
Skystreak is offline Find More Posts by Skystreak
Reply With Quote
Sign up now
to remove ads between posts
Old Oct 13, 2015, 12:56 PM
boater_dave is offline
Find More Posts by boater_dave
Big Boats Rule!
boater_dave's Avatar
Wisconsin
Joined Jun 2007
2,436 Posts
One thing to consider is that most of the 'boat' brushless are go fast types. If going scale, air cooled outrunner is possible. The next line of questions is always the same...
What boat? What size? What type of battery are you using? What kind of speed do you want?

Dave
boater_dave is offline Find More Posts by boater_dave
Reply With Quote
Old Oct 13, 2015, 04:26 PM
nick_75au is offline
Find More Posts by nick_75au
NeverAgainVolunteerYourse lf
nick_75au's Avatar
Australia, QLD, Regents Park
Joined Mar 2007
3,913 Posts
I wrote an article for my club magazine , click on my name to go to my blog, there's a link to the article there. It answers basic questions

As to the ESCs, for 90% of scale boats a 40 amp ESC is sufficient, I have had little trouble with the Hobby King ESC,s for a lot of stuff the Quik 30 amp car is also suitable without needing to watercool the ESC as well.

Watercooled outrunners use water flowing through the mounting plate.

If the motor is suitably matched to the propeller watercooling is rarely needed.
nick_75au is offline Find More Posts by nick_75au
Reply With Quote
Old Oct 13, 2015, 05:20 PM
ZZ56 is offline
Find More Posts by ZZ56
Nickel Belter
ZZ56's Avatar
Canada, MB, Winnipeg
Joined Jun 2009
1,025 Posts
Quote:
Originally Posted by Skystreak View Post
Hi, Everybody tells me how brushless is best, so I have been looking into what's available for boats.
Well, not much seems to be available, but a link from the Fireboat forum led me to Hobbyking offering a huge range of mainly Turnigy brushless boat motors. Most seem to be inrunners. I assume because they're easier to water cool. BUT, we're told the Kv of inrunners is too high for boats.
THEN, I find a few water cooled outrunners. How does that work??
Then I read that most of these Turnigy water cooled motors leak like baskets for want of some decent sealers in manufacture.
I also wonder why a low Kv motor is so much more expensive than a high Kv.
Also HK seem to offer such cheap high amperage ESCs. Can they really be any good?

I find the whole boat brushless thing to be a nightmare to trawl through.

Is there a single thread or article that presents this subject as a simple explanation of what's what?

Cheers,
Martin
All the low-KV motors i looked at were YUUUUGE, physically and in terms of power output.
ZZ56 is offline Find More Posts by ZZ56
Reply With Quote
Old Oct 13, 2015, 07:45 PM
nick_75au is offline
Find More Posts by nick_75au
NeverAgainVolunteerYourse lf
nick_75au's Avatar
Australia, QLD, Regents Park
Joined Mar 2007
3,913 Posts
Quote:
Originally Posted by ZZ56 View Post
All the low-KV motors i looked at were YUUUUGE, physically and in terms of power output.
Have a look at some of the new multirotor 300kv lowest ive seen and brushless gimbal motors. Small package and as low as 80 kv
nick_75au is offline Find More Posts by nick_75au
Reply With Quote
Old Oct 13, 2015, 10:13 PM
Umi_Ryuzuki is offline
Find More Posts by Umi_Ryuzuki
Sea Dragon-Lover
Umi_Ryuzuki's Avatar
PDX, OR
Joined Dec 2002
11,537 Posts
Nick, I like your little article on brushless motors.
It almost seems too simple. Using your outline, instead of finding
the lowest KV rating, the outline seems to indicate that 500 kv might be a better choice.

Very nice
Umi_Ryuzuki is offline Find More Posts by Umi_Ryuzuki
Reply With Quote
Old Oct 14, 2015, 01:30 AM
nick_75au is offline
Find More Posts by nick_75au
NeverAgainVolunteerYourse lf
nick_75au's Avatar
Australia, QLD, Regents Park
Joined Mar 2007
3,913 Posts
Quote:
Originally Posted by Umi_Ryuzuki View Post
Nick, I like your little article on brushless motors.
It almost seems too simple. Using your outline, instead of finding
the lowest KV rating, the outline seems to indicate that 500 kv might be a better choice.

Very nice
Thanks Umi,

At the power we need for our scale stuff most outrunners will have more than enough power to spin the props, when you get into the higher speed or really big props then you need to pay a little more attention to the wattage the motor can handle

Nick
nick_75au is offline Find More Posts by nick_75au
Reply With Quote
Old Oct 14, 2015, 05:25 AM
mfr02 is online now
Find More Posts by mfr02
Registered User
Blackpool, Lancs
Joined Feb 2006
3,413 Posts
Quote:
THEN, I find a few water cooled outrunners. How does that work??
Consider how brushless motors work. The rotating part is the magnet. The part that does not rotate carries the coils, which is where the electric goes and produces the heat. So since the coils on an outrunner are attached to the base plate, that is where the cooling goes.
mfr02 is online now Find More Posts by mfr02
Reply With Quote


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
For Sale 3.3 Jato and Brushless E- Revo 5000Mah Lipo's with Will consider trades for nice qu quadracer678 Aircraft - Electric - Multirotor (FS/W) 5 Mar 03, 2016 09:49 PM
Cool When you've got to go, you've got to go DrFragnasty Scale Sailplanes 2 Aug 17, 2014 09:27 AM
Question When to go Brushless SlimBreaky Electric Power Cars 19 Apr 30, 2014 11:37 AM
Question Considering going long range for FPV, need advice robodeath Radios 2 Mar 20, 2014 11:16 AM
Discussion When things go wrong? When things go right? Kimber The Builders Workshop 1 Apr 10, 2010 04:54 AM