Brushless Slot cars

22004 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.

181 - 200 of 200 Posts

Dr_C

· #181 · Jan 24, 2020

300SLR said:
Comparisons between brushless motors with an NSR King46 motor would be interesting, I look forward to seeing the results. So would comparisons with superfast brushed slotcar motor
A King is an example of a "long can" (Mabuchi FK-180 size) motor, These are the largest and heaviest motors commonly used in slot cars these days. Superfast brushed slotcar motors are considerably smaller, around half the weight and rev to several times the speed.
Some while ago the average revs of a superfast brushed slotcar motor in the fastest sort of slot car ( a "wing car") were calculated from the lap time, gear ratio and tyre diameter, the result was.110k rpm. This was only average rpm for a lap, the maximum speed must surely have been higher.
The suppliers of high reving brushed motors warn against free running them at anywhere near full voltage. The problem is they will fail due to excessive revs. apparently the commutator is what usually goes first, figures in excess of 200k rpm are often quoted. Of course the revs in a car don't reach that so comm failures are rare.

Hi 300SLR, appreciate your insights, what would be a good example of a modern superfast brushed slotcar motor please?

C

Dr_C

· #182 · Jan 26, 2020

NSR King 50k ordered (180-sized).
NSR Evo Shark 46k ordered (130-sized).

130 size brushless motors with onboard Hall-effect sensors delivered.

The brushless sensored motors should run nicely with the latest DRV driver chips which also include brake function.

C

Flag Slot Racer

· #183 · Jan 27, 2020

Cant wait to see more!

Dr_C

· #184 · Jan 28, 2020

It aint over til its over...

Brushless motors with integral sensors... these are 130-size and should run nicely off a single-chip brushless driver IC... these include sensor input channels... and brake signal inputs... add a switching regulator and a decoder/receiver board...

C

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RikoRocket

· #185 · Jan 28, 2020

Trying not to be a damp squib, but my chatsworth channel 5 gadget show Guinness world record attempt car had a 38k motor, and that is undriveable on my local club track (which is a fast track). It would be OK for drag racing, which is what the event was, over a scale quarter mile...

At the event it came 6th at an average speed of 797 MPH

DRC you will need a very long track to test these properly....

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Dr_C

· #186 · Jan 28, 2020

Interesting question... where to draw the line between proper testing and improper testing... ?

Meanwhile I am going to stick with actual m/s rather than calculated scale speed... keep things simple strategy

Appreciating the input... this brushless stuff needs some further experimentation... IMO

C

NikS

· #187 · Jan 29, 2020

Dr_C said:
It aint over til its over...

Brushless motors with integral sensors... these are 130-size and should run nicely off a single-chip brushless driver IC... these include sensor input channels... and brake signal inputs... add a switching regulator and a decoder/receiver board...

C

C5451118-FB64-4874-9A7C-9942642C17F4.jpeg

Dr_C, you have probably mentioned this already, but if I can trouble you - what is the make and model of the 130 sized sensored motor?
Thanks,
Nik

Dr_C

· #188 · Jan 29, 2020

2

C

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NikS

· #189 · Jan 29, 2020 (Edited by Moderator)

Thanks Dr_C, much appreciated.

Kevan

· #190 · Jan 29, 2020

You can't scale speed so easily, if it was scale weight (top fuel dragster weighs 1000kg so scale that 1:32 and you have 31kg+) that would be impressive.

Dr_C

· #191 · Jan 29, 2020

I am going to stick firmly with real measured m/s for the brushless speed trials... should short circuit a lot of previously debated views

Meanwhile... when I apply 1/32 slot car scaling, mass goes from 1000kg down to 30.5 grammes... which sounds about right.

C

RikoRocket

· #192 · Jan 29, 2020 (Edited by Moderator)

Kevan said:
You can't scale speed so easily, if it was scale weight (top fuel dragster weighs 1000kg so scale that 1:32 and you have 31kg+) that would be impressive.

mass is 3 dimensional, speed is one dimensional.

To get equivalent mass you need to divide by 32x32x32 0r 32, 678. So an accurate model would be 30 grams

Speed is linear so equivalent to 100mph is 3mph or 1.3 metres per second

its all maths today....

RikoRocket

· #193 · Jan 29, 2020

Discussion on Chatsworth moved to the original thread

merkit the grof

· #194 · Jan 29, 2020

RikoRocket said:
mass is 3 dimensional, speed is one dimensional.

To get equivalent mass you need to divide by 32x32x32 0r 32, 678. So an accurate model would be 30 grams

Speed is linear so equivalent to 100mph is 3mph or 1.3 metres per second.

But but but, to me, 30 grams sounds nearly as wrong as 31Kg.

And isn't speed made up of 2 components, distance and time, shouldn't time be treated as a dimension? https://www.forbes.com/sites/startswithabang/2019/08/27/this-is-why-time-has-to-be-a-dimension/#7594bf223646

To my eyes, scale speed doesn't exist, scale is not a law of physics, it's a description like big or small.

Joel

PS: Apologies to Dr_C for high-jacking the thread.

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Dr_C

· #195 · Jan 30, 2020

In an attempt to bring us back to brushless motors...

If brushless motors can be shown to be faster than brushed motors then the time dilation effects (special relativity) will be greater... but only ever so slightly...

Does that help?

Meanwhile does anyone by chance know of a supplier of slot-it compatible aluminium in-line motor mounts for 180-size motors...please?

C

300SLR

· #196 · Jan 30, 2020 (Edited by Moderator)

Dr_C said:
Hi 300SLR, appreciate your insights, what would be a good example of a modern superfast brushed slotcar motor please?

C

The fastest motors are known a strap motors, this is a generic term rather than a specific model of motor. The armatures are normally specified by the wind, a typical example in the Eurosport class would be 19 turns of 25 AWG wound on a 7.6mm long 12.2mm diameter stack. The rest of the motor often comes from a different maker and would normally have multiple small magnets rather than just one each side.

It might be worth mentioning that these sorts of motor needs to be fitted in a spring steel chassis to provide good handling and cornering speeds with that sort of motor performance., Trying to put one in a proprietary plastic chassis is pretty much a non starter, as has been said these cars can easily be overpowered to the detriment of handling even with much slower motors so there's not a lot to be gained by making them even more overpowered!

Dr_C

· #197 · Jan 30, 2020

Many thanks 300SLR - very helpful info.

C

merkit the grof

· #198 · Jan 30, 2020

Dr_C said:
Meanwhile does anyone by chance know of a supplier of slot-it compatible aluminium in-line motor mounts for 180-size motors...please?

To the best of my knowledge, Scaleauto were the only people who made such a thing, that was a few years ago, you're unlikely to find one now.

Why does it need to be metal?

Joel

Dr_C

· #199 · Jan 30, 2020 (Edited by Moderator)

Many thanks merkit... i did a search of ScaleAuto but couldn't find the aluminium in-line mounts in stock anywhere... then another solution popped up... a metal F1 chassis with metal bracket to attach in-line motor... so problem solved thank you!

The issue I was struggling with is that the 130-sized sensored brushless motors are a couple of mm longer than standard s-can motors so they wont fit standard in-line mounts. Rather than make something up, I want to mount from the pinion end using a robust mount so that the other end can be left free standing. The F1 chassis achieves this (hopefull) perfectly... so two ordered up

Again many thanks for your suggestions which helped... and I will still keep a look out for the ScaleAuto mounts

C

Dr_C

· #200 · Feb 1, 2020

Another discovery... cg slotcars make some very nice adapters (CGMA001) that convert long can motor mounts for short can motors... these look idea for conversion of the new NSR F1 86/89 chassis for brushless trials...

C

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