davenport_95

combination for a scale boat with a 24" long hull.

I would like to go forward and reverse.

I would like excellent low-speed control for docking and tight maneuvers.

I am not concerned with top end.

Any suggestions which might be helpful, please?

mfr02

Mtronics Marine Viper, probably the 15, but that depends on your choice of motor. Scale on a 24" hull? Probably a basic generic 385 (15 volt type) running on about half that voltage. The other governing factor on speed if learning that the stick does not HAVE to go all the way to its limits every time it is used.

davenport_95

Thank you, sir.

I have contacted Mtronics to ask additional questions about this product. I asked them in an email if this Viper 15 controller is sensitive to the number of turns in a brushed motor. I have seen advertisements from various ESC companies stating that their controllers are only compatible with motors of a certain number of turns.

The Mtronics website literature states that there is a 15 Amp limit for motor under load with "prop under water".

With the CORRECT motor, this controller just might be the ticket.

mfr02

Just avoid "racing" motors where the advertising tells you that the motor has very few turns. Those few turns are invariably thick wire that causes huge current draw to give the power for the high RPM wanted in that type of boat. They usually cost a lot more as well.
I did use the words "basic" and "generic" with reference to the motor deliberately to point to a sensibly priced motor with the performance wanted.
The "correct" motor is just part of the package. It has to turn the prop in the water, so the loading caused by the prop has its part to play. Usual reckoning is "prop diameter not more than motor can diameter, prop should have fewer blades that the motor has poles"
There are cheaper ESCs, all have their disadvantages. Voltage limits, current limits, poor low speed control, poor quality control, no BEC, performance claims way beyond belief - take your pick. The only time I have ever had a problem with an Mtronics product was purely down to me.

davenport_95

I have this reply from Mtronics as a follow-up:

Hi,
Speed controllers that have a motor turn rating are designed to be used with RC model cars. RC Model car motors are rated by the number of turns they have.
RC Marine motors are rated by the amount of current they draw from the battery. The Viper Marine controller has a 15A limit which means it is suitable to be used with any motor that does NOT pull more than 15Amps.
I hope this helps,
Best regards,
Paul Kenningley
Mtroniks Ltd / Prism Audio Ltd.

mfr02

When you mention things like "amps" to many RC car people you can see their eyes glaze over. Since their bit of the hobby developed with a single battery size and largely a single motor size, "turns" was the simplest way to describe them to give an idea of likely performance. Boats are different.
As a general rule, if you know your likely amp draw, a good plan is to double that number and take the next available value up from that as a guide to the ESC rating. But not with Chinese products. They seem to regard numbers as being simple random marks on paper on existing evidence.

blizard05

Take a look at the Tugster, motor and esc from Zipp Kits

Stephen Vick

You want a 300 size motor w/ Mtronics speed control. I use a Mabuchi 300 can motor in a 1/96 Corvette. I get a good turn of speed, great low speed maneuvering and about 4 hours of run time on a 3 amp hour Nickle metal hydride battery (7.2 volts). Keep in mind also: if she is single screw, make it right hand turning. This will ensure she will back to port (which is standard). As per Crenshaw's Naval Ship Handling... High speed motors are un-necessary for scale applications and only serve to overdrive hulls and suck power.