RCBM electric motor article

[BoatDoc]

i've gone through the article in the DEC '04 issue of rcbm about electric motors several times now. basically what i'm looking for is a good electric motor. maybe i'm wrong here, but a pretty important spec would be the RPM/V rating. none of the motors had that. this is kind of a minor gripe. but at the same time...i've gone to the web sites of a few of the manufacturers and they don't list them there either. what gives? to me it would seem stupid to buy a motor and not know how many RPM it can turn. adjustable timing, heat sinks, and "flat wire technology" are all well and good, but if it doesn't make any friggin' RPM's it's useless. maybe next time RCBM does an article like this, they can get those numbers. not complaining here, just making the suggestion.

[Pagemaster]

I agree, It seemed like a multi page motor advertisement to me.

Steven Vaccaro
www.OffshoreElectrics.com

[MattHiggins]

Hi, guys. Just so you know, our goal with this guide was to feature as many motors as possible. If we were to include complete performance evaluations for each motor, the number of motors we could feature would be dramatically lower. In my opinion, there's more to picking a motor than how many rpms it turns, so by the time we tested for rpm, amp draw, torque, efficiency, etc, we would have been down to two or three motors which is more of a shootout than a guide. Maybe in the future, we'll do an article like that, but I stand by the article we presented and feel it is much more than a multi-page advertisement and I firmly believe it will be valuable to many of our readers.
MH

[Pagemaster]

Matt maybe I was to harsh. I take that comment back. It was nice to see all the motors available in one central place. But It would be very cool to see a head to head motor test in the future. With all the different brush and magnet technologies out there we are all buying on a hunch and not fact or real numbers.

Steven Vaccaro
www.OffshoreElectrics.com

[MattHiggins]

We'll do a head-to-head or a shootout soon. But which two or three motors? I do have some shootouts between some boats set for the near future.

[Pagemaster]

For boat motors in the 500 size range a shootout between some roar stock motors would be helpful to many people.

Steven Vaccaro
www.OffshoreElectrics.com

[BoatDoc]

i thought it was a helpful article, but what i was getting at was that some basic specs were missing. i'm not saying that the staff of RCBM needs to sit down and test each motor. mainly what i'm saying is that the manufactures could have provided them to you or something. but then again, like i said above...most of them don't even list the specs on their web sites. i'm pretty new to FE boats myself, only have one...working on number two. so a lot of this stuff is greek to me.

[Doc]

FWIW

One of the problems with testing an electric motor is determining a 'standard' load to test with. The 'unloaded' speed of a motor means nothing without knowing how much torque the motor will produce, which depends on the strength of the magnets/field, which depends on the current capacity and resistance of the wire used in winding the motor, which depends... Well, you get the idea, it's sort of complicated. And since a particular motor may be used in a number of different sized hulls (which will also affect the motor's output), there ~is~ no 'standard' reference, or simple formula to 'rate' a motor. There are some sort of standard 'guesses' you can make about them according to size and weight (very 'broad' guesses based on prior usage). Which doesn't tell you anything about a 'new' motor.
Developing a 'standard' for model boats would take a lot of time and te$ting. First, getting your hands on the motor$. Then several dozen different prop$ of varying diameter and pitch. Not to mention the time to develope a fixture for the te$ting. I can't see anyone doing (affording) it. At least not for such a limited market as modeling (any kind of modeling, not just boats!), can you? But! It would sure be nice...
- 'Doc

[Chris LaPanse]

What I like is the RCCA method of testing motors - they describe all of its features in detail, and then actually show a dyno graph. The dyno #'s are really helpful (but they never test more than 2 or 3 in one issue because all the detail takes up a lot of room).