Brushless Slot cars

21938 Views 199 Replies 24 Participants Last post by Dr_C, Feb 1, 2020

Damo

Discussion Starter · May 4, 2011

Hi All,

I have been looking into other hobbies recently as I saw an RC plane and thought I'd better give that a go too! Anyhow, these days all the electric motors in RC planes seem to be brushless. Is that something that we'll see with Slot Cars in the future? Are there any already?

Obviously they are more efficient and probably more reliable and have less wear, surely that'd be a good thing?

Cheers,
Damo.

41 - 60 of 200 Posts

injectorman

· #41 · Dec 24, 2018

Hi Dr C.
Ill need a 3D printed cradle over the new motor to fit into existing motor pods. Or a new pod or perhaps a new chassis. Anything is possible.
Am i going to upgrade 100 plus cars?
Just playing devils advocate to open the discussion right up.

Rick

Dr_C

· #42 · Dec 24, 2018 (Edited by Moderator)

I think the idea would be to have a few cars withn your collection which outperform everything brushed... take these along to your raceway and race against friends with similar brushless motored high spec racers... a new race category... why not? ... and we all love mixed portfolios/collections...

C

injectorman

· #43 · Dec 24, 2018 (Edited by Moderator)

Im a big fan of brushless in fact I just renewed and expanded my entire Makita battery tools to brushless.
Like any new concept getting everyone on board without upsetting the apple cart is the problem, the transition period, example a club scenario.
From a manufacturers view getting your cars banned at clubs and comps because they are too fast.
Looking forward to the firmware results I must say looks promising.
Lets ask Tesla can they do a slot motor😊
Im guessing in 15-20 years brushless will be standard in all forms of motors as prices drop and technology improves.

UDoKuoio

· #44 · Dec 24, 2018

Slotcars with battery inside, like RC cars.
This is the primary reason to switch to a brushless motor.

Tracks without metal rails, no power drops... but lot of weight inside the car...

Kevan

· #45 · Dec 25, 2018

UDoKuoio said:
Slotcars with battery inside, like RC cars.
This is the primary reason to switch to a brushless motor.

Tracks without metal rails, no power drops... but lot of weight inside the car...

They're not slot cars then, that'll be another hobby but this is slotforum for cars that run in slots and have done for nearly 60 years and will continue to do so.

Dr_C

· #46 · Dec 25, 2018

Not for today... but this looks quite a useful starting point...

http://ww1.microchip.com/downloads/en/appnotes/00970a.pdf

C

UDoKuoio

· #47 · Dec 25, 2018

Kevan said:
They're not slot cars then, that'll be another hobby but this is slotforum for cars that run in slots and have done for nearly 60 years and will continue to do so.

I said "track without rails", not "track without slot", so we DO talk about the same hobby.

Some time ago I ask to my friend (RC car driver) how difficult was ran a RC car on a slot track:

Technically, not that much. And we can achieve the same result with chip like Oxigen.

The advangage of brushless motor (just to remain in topic) is the efficency; it's a MUST if we run with battery.

The real question is: why we need something like this?

Only to avoid to take the power from the rails

Maybe for kids slot tracks?

Maybe for mount/dismount tracks where the elettrical connection is a pain everytime?

And.. for digital tracks.. does it worth?

Pros: the chips are constantly feeded also during a lane change.
Cons: We still need to feed che lane changers..

Sorry for my poor english

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Kevan

· #48 · Dec 25, 2018

3

UDoKuoio said:
I said "track without rails", not "track without slot", so we DO talk about the same hobby.

.....

Sorry for my poor english

You're right

...and your English is great!

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Dr_C

· #49 · Dec 26, 2018 (Edited by Moderator)

If we put max power/torque/speed and the thought of batteries to one side for a moment... how about the brushless motor and decoder board together provide an identical drive system for each driver... no variation between motor performance whatsoever... this would be achievable because the brushless controller could be designed to even out motor performance differences by eliminating any observable manufacturing variability between our motors. Then, racing would come down to driver skills, layout awarenss/practice, car weight distribution, downforce, gearing, tyres, driver adjusted throttle/braking profiles... and some racing good fortune (and collision avoidance)... does this sound familiar?

C

Reactions: 2

300SLR

· #50 · Dec 27, 2018

Dr_C said:
What about more cars per amp and smaller voltage drops along the track (I.e. more cars and more consistent power)?

Agreed increased efficiency gives you that.

However, is the fluctuation of track voltage a problem in digital racing? Many digital experts seem to be of the opinion that IF the track wiring, connectivity between sections and power supply are up to the job , fluctuation of track voltage aren't big enough to be a problem. For sure there are many posts on how to get good enough track wiring, connectivity between sections and power supplies.

How much of an advantage is less amps for the same power (aka increased efficiency) in digital slot racing? The current needed for a couple of dozen digital cars with brushed motors can be supplied by readily available power supplies, indeed substantially higher current power supplies are in use on some non-digital slot car tracks.

Just supposing fluctuating motor power is the real concern, is there another way of solving it?
While the lower current of brushless motors would somewhat reduce the fluctuations in track voltage, it cannot eliminate it. Some electronics in the car could deliver pretty consistent motor power even though the track voltage was fluctuating. So although we are still stuck with a fluctuating track voltage that doesn't necessarily mean we are stuck with fluctuating motor power. The simplistic approach would be to put an off the shelf linear voltage regulator in the car, but that would add mass and produce heating in the car. Redesigning the control chip to adjust the PWM so the motor delivered consistent power should add very little mass or heat in the car.

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Dr_C

· #51 · Dec 27, 2018 (Edited by Moderator)

300SLR said:
Agreed increased efficiency gives you that.

Just supposing fluctuating motor power is the real concern, is there another way of solving it?
While the lower current of brushless motors would somewhat reduce the fluctuations in track voltage, it cannot eliminate it. Some electronics in the car could deliver pretty consistent motor power even though the track voltage was fluctuating. So although we are still stuck with a fluctuating track voltage that doesn't necessarily mean we are stuck with fluctuating motor power. The simplistic approach would be to put an off the shelf linear voltage regulator in the car, but that would add mass and produce heating in the car. Redesigning the control chip to adjust the PWM so the motor delivered consistent power should add very little mass or heat in the car.

The regulator idea sounds cool. And, there are switching regulators which are far more efficient than simple linear regulators. If needed these would work nicely... they are light and they dissipate very little power so stay cool. Also, agree we could use the PWM function in the decoder to adjust for voltage fluctuations.

With my 130 sized brushless motors on route from China to Scotland, slot.it motor mounts at the ready, and compact brushless ESCs borrowed from another hobby... the fun may start soon...

C

Flag Slot Racer

· #52 · Dec 29, 2018

Couldnt you pack more power into a smaller engine package? Might be great for more modern LMP cars.

Dr_C

· #53 · Dec 29, 2018

I think in due course that will happen, smaller motors with higher power output. However, as a stepping stone I think motors that fit in standard motor mounts and match standard pinion shaft diameters are a useful starting point. If the 130 sized (off-the-shelf) brushless function well then I can see a case for designing something bespoke... and with the arrival of Industry 4.0 (and mass customisation) I can see the brushless motor requirements of our hobby could be met by low volume production at mass volume prices...

C

Reactions: 1

300SLR

· #54 · Dec 30, 2018

Flag Slot Racer said:
Couldnt you pack more power into a smaller engine package? Might be great for more modern LMP cars.

Much more power in a smaller package than 130 size motors are already available in off the shelf brushed slot car motors.

A major reason nobody uses them in plastic chassis LMPs is that they produce very much more power than those chassis can handle.

Dr_C

· #55 · Dec 30, 2018

Based on this discussion I can see that we can take almost any aspect of how brushless motors are known to outperforms brushed motors... we can then construct a highly plausible counter argument with respect to slotcar racing... thats what makes this subject so interesting... but it is time for a few data points on a graph...

C

Dr_C

· #56 · Dec 30, 2018 (Edited by Moderator)

Since I have volunteered to do some trials wth brushless configurations... a question... which should be faster...? a 911 RSR (991) with an in-line brushless motor or a 911 RSR (991) with a sidewider blushless configuration? Competition results to follow in Q1/ 2019...

C

Ade

· #57 · Dec 30, 2018

Hi

depends on track configuration

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Dr_C

· #58 · Dec 30, 2018 (Edited by Moderator)

So just to check... if there are long straights with gentle turns the in-line would likely be faster? While if there are lots of winds and sharper turns the sidewider would be faster and less likely to exit the track? Right?

(@Ade... it that your alto saxophone?)

C

Ade

· #59 · Dec 30, 2018

Dr_C said:
(@Ade... it that your alto saxophone?)

C

Hi

err no, that particular model belongs to Zoot

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300SLR

· #60 · Dec 31, 2018 (Edited by Moderator)

Wouldn't it be better to compare the same car with bruhsed and brushless motors in the same position? Changing the motor orientation introduces more variable that might confuse the comparison.

Dr_C said:
So just to check... if there are long straights with gentle turns the in-line would likely be faster? While if there are lots of winds and sharper turns the sidewider would be faster and less likely to exit the track? Right?

Are you talking about a Scalex 911 RSR slot car or some other make? Perhaps those with experience of that specific car could answer the question.

There's a whole bunch of reasons why the motor orientation might make a difference to performance - for example the motor's position changes the magnetic attraction to the rails: weight distribution: gear ratio: tyre diameter: the efficiency of the gears that will fit : the stiffness of the back end. There is no general answer to which is best for all sorts of slot car or for all sorts of track.

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