Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length.

[wayne quigley]

I have been reading up for week now am ,I think nearer a final Brushless combo for a 47" fairy huntsman GRP hull.
the brushed motor every one seems to suggest (graupner 700BB turbo neadene motor) with a no load speed of 15750rpm. I have found a formular of taking the brushed motor rpm devide by the voltage to be used the give a KV rating of the brushless motor.
15750/12V = 1312 KV
does that sound ok
Next question is most suppiers only give li/po requirement for battery,,, can SLA or ni/cad be used
cheers in advance Wayne

[essex2visuvesi]

The is a chap one here called RED181 who did quite exhaustive research regarding the 47" Huntsman and brushless motors
see here:-
http://www.modelboatmayhem.co.uk/forum/index.php/topic,21584.0.html


I am building one as well but mine is only the 36" precident version....
http://www.modelboatmayhem.co.uk/forum/index.php/topic,36813.0.html


Currently stalled as Im working on my current shiny ball.... A Robbe seawolf lol

[pompebled]

Hi Wayne,

Welcome on this forum!

I'm sure that you'll find all the information in the link E2V provided.
Regarding SLA batteries in a fast moving, hich powered boat; most likely the motor selected will draw too much current for an SLA battery, next to the fact that the weight of an SLA battery isn't the best way to go.

Lipo's can handle the Ampdraw of a big brushless motor much easier and they pack more punch than an SLA battery.

If you don't want to use a reduction like Red181, take a look at large outrunners, these are very affordable these days and have gobs of torque.
For longer runs, a watercooled motormount is advisable, to reduce the heat build up.

Regards, Jan.

[wayne quigley]

thanks