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
