Model Boat Mayhem

Technical, Techniques, Hints, and Tips => BRUSHLESS Motors and Speed Controllers => Topic started by: phillnjack2 on May 04, 2021, 04:57:27 pm

Title: Glow 90 to brushless ?
Post by: phillnjack2 on May 04, 2021, 04:57:27 pm
Hi folks. im thinking of going electric  ( its just a thought at the moment).
Boat is 60 inch long spirit of the south and I run a cmb 90 Direct drive with conventional prop underneath the boat (many reasons for this)
Now if I was to convert to electric and want the same sort of performance. what motor and batteries would this need ?
I run this on the sea a fair bit so need the power as this is a big boat...

I also have a pipedream mk1 that I run with 60 Irvine or a sc91 and again pretty large boat  and same sort of thing for that in electric.
I have run the pipedream before with a petrol 2 stroke 30cc and that was not enough performance compared to the 90 glow but about the same as the Irvine 61 set up.

only reason im thinking of changing is the cost of fuel nowdays , plus could use it on more lakes where ic is banned.

any info would be good, but ive never ran fast electrics and the lipo stuff before.. been thinking about an electric scooter motor as
they have a decent run time and pretty strong motors..... weight is not realy too much of an issue as both boats can take a good bit of weight.

cheers phill
Title: Re: Glow 90 to brushless ?
Post by: Andyn on May 04, 2021, 06:16:22 pm
I know nothing of electricity but if you want to shift on your CMB 90 give me a shout  :-))
Title: Re: Glow 90 to brushless ?
Post by: JimG on May 04, 2021, 08:36:22 pm
There are brushless motors sold as the equivalent to glow motor sizes, these are intended for aircraft. (
Title: Re: Glow 90 to brushless ?
Post by: Andyn on May 05, 2021, 09:01:39 am
Bear in mind that that is equivalent brushless to a sports glow engine, and their range will nowhere near compare to that of a CMB...
That motor is quoting 325kv at 22.2v - 7215rpm maximum, outputting 1150w. Even older CMB 90's are turning around 6kw at 25,000 rpm.
Title: Re: Glow 90 to brushless ?
Post by: JimG on May 05, 2021, 11:05:00 am
If you are needing more wattage then you can go to a larger engine equivalent, although outrunners tend to have a lower kV rating. ( at almost 8kW, but needs a 12 cell pack.Fast boats tend to use watercooled inrunners capable of higher revs. ( has a max voltage of 11 cells.In both cases they need a high voltage and current esc and would need proper no spark connecters between the battery and esc. (otherwise there will be a rather large spark when connecting up running the risk of welding connecters together. I have used 6S packs on normal connecters and have had pitting of the connecter surface due to the arc on connecting.)Note I have used Hobbyking motors as examples as it they are easy to find, there are other high power motor suppliers but I have never dealt with them.