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I know many of you don’t really like/use “Slimcan” motors, feeling that they don’t provide the torque (acceleration/braking) that you want, but, in certain circumstance, the handling advantages of these motors may well provide lower lap times.
On tracks with long (15ft+) straights, and wide radius corners, the “grunt” of the “S” can/FK etc. motors, will still rule, but on tracks that place a premium on handling, as opposed to outright speed (shorter straights/tighter corners), the handling advantages of the “Slim” motors, may well prove beneficial.

While the relatively weak magnets ordered by and used (so far at least) in most manufacturers “Slim” motors have limited their performance, they do have benefits as far as weight and physical size,… they are 2 to 3 gms. lighter than a typical “S’ can (much lighter than a “longcan”) and have a considerably lower cg. ……….both of which are good attributes for a slotcar motor.

As far as how these attributes actually affect handling,…..well,……a few hundred years ago, Galileo, and a certain Mr. Newton, discovered and detailed the principles of “moment of inertia”, and, the “pendulum effect”, which in very simple car/slotcar terms (simple is all I can manage ;) ) state that, the bigger the hunk of weight you hang at the back of a car, the more likely it is to swap ends (slide/oversteer) when lateral forces (cornering) are applied.
Anyone who knows the Porsche 911 evolution knows the lengths Porsche went to in order to lighten the motor, and , to move it forward to minimize these effects, creating a more balanced, and , quicker cornering car.
From a slot perspective, “longcan” anglewinders tend to “tail wag” exiting corners as a result of these principles.

So, with this in mind, I have been playing for several years with various “slim” motors in various configurations, for use in Sports/GT type cars……and while all have handled very well indeed, the slow ones (14/20K) are rather anemic no matter how they are geared. (These slower "Slim" motors are however well suited to the light Scaley Classic/Legends F1 type cars) The quicker ones, (25/40K) while very quick, need to be geared 4 to 1 + in order to provide worthwhile braking, and with those ratios, are very “peaky”, and difficult to drive.

Recently, I have been impressed with the performance of the Policar “Slim” motors in their F1 cars, and when the SCCA proxy (on this forum) was announced, it allowed either the Policar “Slim” motor or an 18K “S” can motor to be used, so, the “Slim” motor was my choice. This motor has a 25K arm wind, with seemingly somewhat stronger magnets, or perhaps a smaller air gap, and therefore, has a bit more grunt than the average “skinny” motor. (Although only less than half way through, the top three cars in the SCCA proxy are Policar powered, and only Policar powered cars have won a race.....so far at least ).
Before going on, I should add that I have no association with Policar whatsoever.

So,…..back at the bench, I installed one in a Devis 3d anglewinder pod, and stuffed it into a Slot-it Porsche 956. I used the anglewinder version as it gave me the most leeway in selecting different gear diameters that allowed me to, ….achieve the ratios I wanted/needed....let me use gears with close to “true” pitch, and, to use a spur small enough to use 18/19mm tires with plenty of gear/track clearance. For those interested, I used a 9T 5.5 mm MrSlotcar steel pinion, with a 30T 16.5mm MRSlotcar spur. (3.3 to 1)

On my track (wood with 10ft straights), the car turned lap times virtually identical to my similarly tuned Slot-it cars with “orange”/”Piranha” motors…….a touch slower on the straights, but, quicker, into/through/and, out of corners……more importantly, it was better balanced, and more consistent/easier to drive.

So for anyone with a moderate sized track, this set-up may well prove worthwhile……equal lap times, better balance, and a car that is easier to drive will most certainly lead to less “offs” and higher placings at your local club.............Priceless !! :dance:

Cheers
Chris Walker

PS Galileo, and Mr. Newton were clearly not your average students !! ;)


Policar motor, Devis 3d pod, in a Slot-it Porsche 956

Chris, if you run these in an inline setup, are they are short enough that the pinion axis is below the axle centerline and you need hypoid gears? That would seem to take advantage of the smaller height and lower cog. Is that a consideration?

I'm way behind with the slim cans. I have a few I picked up from Mark, plus there are some RTR cars I have with them. I have to say, the reason I never did much with them has always been that I didn't want the bother of a new form of motor mount. I need to build up my fleet of 1960s-1970s vintage F-1 cars, so I guess I'll be remotoring a bunch of Scales to make them manageable for wood track. I'll mark this post to come back to when I face that task. Thank you.

There certainly is a place for FF motors and at one stage I had a Scaley '18k' ??? version in a FLY Capri Grp5 car that could keep up with a lot of the cars, including Sideways, in our open Group 5 class. But one thing that did surprise me is that most FF motors we use in the slot world are pretty much the same weight or marginally heavier than a regular 'black stripe' Scaley motor.

my only gripe with the policar ff motor is the mount screw holes are vertically placed above and below the bearing....plus the holes are smaller than the m2 threaded ones we are used to....once that is solved you do have a great drive unit.

Is Devis 3D Designs still making slot car pods, adapters, etc.? There are no products currently showing on their website.

Allan

No...Devis3d Designs doesn't make pods any more. I saved that picture of the Slimline pod.....I don't have one of those. It's going to take some time to get one set up for printing....

What happened to them?

Allan

Great info and nice write up...thanks CW!!

So Chris,

If I stay with in-line configuration on my Ninco Gulf McLaren on a moderate sized track, which replacement of the stock long can do about the you think will give better results: 1) a slim low long can or 2) a Mabuchi? i know I'll need an adapter for the Mabuchi, but what about the a slim can? I can see how the slim can will lower CG and due to less mass move the CG forward a bit. But I'm wondering if the Mabuchi sitting further aft is light enough to keep the fore/aft CG for remaining roughly equal to the stock long can.

From the last few lines of your post, the piranha orange gave you good results. But you were in the angle winder set-up and I'll be in-line, so maybe your results don't translate to the in-line configuration and 'll need to do my own trial and error. (Or weigh the motors and do the newton calcs.) ;) :think:

Thanks,
david