Question:Determining equivalent brushed vs brushless motors for stock class.

[sam the man]

Hi guys

At our club we currently race a 23t stock class and are looking at introducing brushless to run alongside the brushed motors for the next year as a sort of integration period, thereafter we would like to make it a brushless only class.

Our dilemna comes in where what "stock" bl equipment to run now which will be on a par with it's brushed counterparts which can still be used the next year with "stock" settings switched off.

We currently run the tamiya 23t RZ/TZ motors and have been advised by one of the local importers to run any esc so long as it has "sprtsman" mode but to limit the kv of the motor as a tool to level out performance rather than going the "one make system" route, although he isn't against it. The other thing is, some of our racers already have esc's that have "sportsman" mode and don't want to spend extra cash on another esc.

Another question that keeps popping up is:
1. ""I would think a ESC locked would then limit the Kv rating to a certain value on the motor???

....so if someone has a fancy motor rated at 2600 compared to a 1900, under stock conditions the Kv value of 2600 is governed surely, the motor cant perform to its max. I mean its related to revs and that's what provides the performance???

If not....what then makes the sport mode equal across the board ??""

2. ""So...and I am sorry for a few dof Q's but I am doing some serious homework at the moment re Brushless....

If any set up is restricted to Sportsmode with light to indicate, does this mean is alters the Kv output of the motor??

If so...then does all, meaning different brands, have the same Kv rating when restricted.""

Any and all help will be greatly appreciated.

[sosidge]

First of all - you will never get equivalency between brushed and brushless motors. Even a brushless motor that has a similar amount of power delivers that power in a different way and a lot more consistently.

Secondly - although the ESCs in "blinky" mode are equal, the motors are not. There is no requirement (at present) for locked timing in the motors, so the motors with a larger amount of built-in advance will perform better in "blinky" class (not much in it, but enough to make the moneybags racers seek out the fastest "stock" motor).

It might be worth choosing a "spec" motor for everyone since your club hasn't gone brushless yet. You can let people keep use their old ESCs in "blinky" mode, there will be no advantage to any particular model.

Even if you have an open motor I suspect that the motor choices will even out quite quickly. Someone will turn up with a certain motor and be fast, then everyone will copy them!

13.5 blinky should be fairly close to your 23T brushed.

[Bigbaddave]

The sportsman mode tends to stop timing advance and turbo on brushless motors so you are better limiting it to 13.5 stock with standard timing, as others say eventually all will follow and also the costs are coming down now. E.g. Hobbywing justock (no timing advance) £36 delivered from giant Cod and the new HPI Flux pro 13.5 brushless motors are around £50 perfect starter brushless stock setup for £85!

[sam the man]

Thanks guys, very valuable info. Now to go find out the different manufacturers' built in timing. Is there anywhere easy to find this info or would we have to contact each manufacturer to get the info?

Another question has come up from one of our guys:
If there is not a one motor rule for this class, do you guys think the variation of a few 100Kv will make a difference at our club, with our style of racing?


Ok, I know you going to ask what is our style of racing, so here's a pic to show our parking lot setup. We typically change our track design from week to week, and our lap times are generally between 9.5sec to 12sec laps, so it's a pretty small and tight layout, if that helps with your answer.

http://i198.photobucket.com/albums/aa289/samjnr/IMAG0055.jpg

[sam the man]

Thanks guys, very valuable info. Now to go find out the different manufacturers' built in timing. Is there anywhere easy to find this info or would we have to contact each manufacturer to get the info?

Another question has come up from one of our guys:
If there is not a one motor rule for this class, do you guys think the variation of a few 100Kv will make a difference at our club, with our style of racing?

Anyone got the answer?

[sosidge]

You won't find any accurate manufacturer-published timing figures. You won't know if non-spec motors make a difference until you start running them. Depends on how high the standard of racers is and what kind of attitude they have to seeking an advantage.

[sam the man]

Thanks sosidge, pity though.

[Fast Eddie]

Thats a cool track:thumbsup:

[sam the man]

Thanks Eddie, we change the design every week, keeps us on our toes.