Steve61

Anyone have one of these babies yet? Mean looking car and with the king motor (in the AW version) with 322 g.cm of torque must be a real rocket!!!!!

Hey DM....those decals from Pattos arrive yet?

I'm looking at the H & R racing chasis on the Professor Motor site and I'm tempted to get one. They're $43.50 US which seems like good value with a great set of racing wheels (21mm wide in Foam or 18 mm wide in Silicon). A lot of the other metal chassis (Plafit etc) are over $100 and you get standard thin wheels/tyres that would need to be upgraded for racing. One disadvantage is the height is not adjustable like a Plafit but is that a big drama? Anyone have one of these babies? H & R products

We single men on the forum don't have much choice some times!!!

I've just ordered the Ferrari Xlot from Chris. I've got the orange one and it's a great car...very smooth and a great buy for around $120....now I am feeling seriously broke after just buying the NSR P68 for a similar amount...no beer or wild women for me for the next month or so!!

Red Racer in Brisbane has a few Spirit cars so he may carry some spares

Got mine as well Matt....absolutely beautiful car with the usual hi quality NSR running gear underneath....luckily there's not too many releases of this quality or I'd be broke!!!!

Thanks for the kind words guys. It is a "slotfire inspired" track layout - with a few subtle differences here and there. Very reliable track lap counter, averaged 1 1/2 laps to every Pakistani batsman in the one day series!!!

Triggy, It's a liquid you put on the braids to give better electrical conduction and to provide lubrication on the rubbing surfaces. Parma, voodoo, Mura etc all make it and most hobby shops have it. I'm not even sure what it's made of these days, it used to be mostly Diesel fuel in the "old" days.

I had a couple of guys from the forum over for a friendly get together a few weeks ago, and both seemed unfamiliar with braid conditioner. I thought it was pretty common to use it, but maybe it's not such a big thing these days with the better materails used? 10 years ago (when I was last into slot cars) it was very common to use it. Do many people on the forum use it?

I'm amazed that the slot.it gears mesh so well with such a wide range of tooth pitches - pinions that go from 8 to 11 teeth can mesh with crown gears from 23 to 30 teeth -all without any variation to the diameter of either the gear or pinion. The tooth profile or shape must be so cleverly designed that it can pull in the mating tooth over a wide range of pitches and soak up the difference without accumulating errors and binding up the gears. The guys at slot.it REALLY know their stuff!!!

I'm no guru, but as an engineer I can't help but have a go. The most important thing is that the gear and pinion are a meshing pair - made by the same manufacturer so that both the pitch and the tooth profile match, otherwise the car will run rough and vibrate. As the gear gets more teeth the dimeter increases, so that can be a limiting factor itself - the gear must be smaller than the tire OD (obviously) and also clear the slot in the chassis if it's inboard of the bearings. It would say go for the largest diameter gear you can get because the forces on the gear teeth will be lower eg a torque of 600 g.cm on the rear shaft will have a gear force of 750 grams at a gear radius of 0.8cm, but only 600 grams at 1.0 cm radius (2cm gear diameter) With pinions when the no. teeth gets too low, the tooth profiles start to undercut each other - 8 seems to be about the min. you see and you can definitely see the undercut on them. This compromises the normal profile of the tooth and is required so the gear tooth can enter the pinion and rotate and clear itself out. For smother running I'd recommend the largest pinion you can get to get the ratio you need. These aren't big factors and lot's of cars run well with smaller gears, but if you have the choice - largest pinion and gear you can get in the car.

Dave, Use it as a good excuse to get another Slot.it controller!!

Thanks for the kind words Rick. Dave, For a heavy 1:24 car the answer is definitely yes....go for the higher torque motor to get the acceleration around the bends and into the staight. That's why the big heavy muscle cars have big grunty motors - to get that torque to the back wheels.

Dave, The torque is the "turning force" the motor has. It is the force avilable at the motor shaft at the voltage specified - that's what you need to know as well as the torque - what voltage is it referenced to. A lot of motor manufacturers quote it at 14.8 V. It's usually pretty linear down to zero volts so if it's quoted at 14.8V you can get a pretty good Idea what it will be at 12V (about 12/14.8 of the torque). For cars it's quoted in N-m, which is no good for slot cars because the scale is too high, so they use g.cm. Imagine putting a lever on the motor shaft 10cm long and putting 20g on the end that would be 200 g.cm torque (it's not grams per cm, this is wrong - it grams x cm's). When you go through a gear reduction, you multiply the torque by the gearing ratio, if it's 1:3, the torgue on the wheel shaft is 3 times higher and the speed three times lower. The final driving "force" then depends on the tyre outer diameter...a smaller wheel gives higher driving force.

Hi Paul, I thought you liked to run the front wheels just a fly's D*^K above the track, so they only came into play on a corner to support the car? If the car's running on four wheels the chassis setup must be perfect or it will rock on two of them (like nearly all tables at cafe's!!)

Look great Paul....make sure you get well out in front early in the races....don't want any collision damage to those bodies!!!

Slots, sorry to dredge this one back up...it was done to death last time.....I was more trying to find out if the PWM method of motor control really was technically better than the old resistors, and I completely forgot the major advantage of the adjustable sensitivity as being the main advantage. I did limited research, but came up with this: From this article PWM Atricle Doesn't make it true, but it's good to know if if is or not.

I was doing some research last night on pulse width modulation (PWM) to control DC electric motors verses using a series resistor (the typical Scalextrix and Parma controllers) and discovered some advantages I wasn't fully aware off. The first one is the PWM is more efficient in the amount of power consumed. A resistive controller in order to drop the motor speed by 50%, must soak up 21% of the power (about 71% of full power is consumed - 50% to the motor and 21% across the resister). Not that the cost of electricity is a major issue, but the power across the resistor leads to heat that must be dissipated, so over a long series of racing thats a lot of heat. PWM consumes much less energy to achieve the speed reduction. The second one suprised me even more. PWM drops the speed as required, but does not reduce the motor torque by the same amount. Resistive controllers reduce the voltage and the torque drops off substantially because the internal resistance of the motor windings is constant and so the lower voltage has to overcome this resistance before it generates torque. The PWM while it's in it's "on" part of the cycle is at full voltage and full torque, so the net effect is a higher average torque. High torque at low speeds is one of the holy grails of racing motors (acceleration out of bends) so this must be a good thing Now for disadvantages. The PWM I believe operates in the radio frequency range so can generate interference to radios. I use a TV in my slot car room and have no problems, although it is a digital TV. I do hear a distict high pitch ring in the cars using the Slot.it controller, but it doesn't seem to affect them in any way. Also it's a lot more complex and delicate with all the printed circuits, so if something goes wrong it's not an easy fix....a Parma is much more simple to understand and do something with. Interested to hear more views and experience with PWM verses resistance controllers.

Rick, I googled a couple of articles and measuring PWM voltage is problematic (see extract below). Some articles talk about using low pass filters etc, but it's beyond my electrical knowledge (I'm a mechanical engineer). Maybe there's an electrical expert lurking on the forum somewhere?

I had exactly the same trouble with my Slot.it M2 driver, and was annoyed because of what I payed for it. It then bought a couple of Wiha drivers (German made) and they are much much better and haven't lost their edge yet...recommend them. Thunderbird has them for under $10 ea. (marketed as PM drivers) Wiha Drivers

Rick, Another thing is that the Slot.it controller uses PWM (Pulse width modulation) to control the voltage to the motor so a conventional DC multimeter might not give accurate or reliable results with a square waveform? Not sure on that one, maybe one of the forum gurus can advise more than me?

Hi Rick, Let me say that this is all from the manual...I haven't tested or measured the actuals like you have but I know it works for me....I can drive any of my cars in a controllable way with the Slot.it........some of my cars are nearly impossible to drive controllably with my Parma 45 Ohm conventional controller. The red curve is the lower envelope of the curve mode....if you set the dip switches to off/off (0/0) and Cm to 0 and the Min speed to 0, that is the curve the controller would follow (according to the manual). The black curve is the upper envelope curve. If you set the dip switches to on/on (1/1) and the Cm knob to 100% and the Min speed to full (50%) that is the curve you'll get. If you drop the Min speed knob to 25% you'll get the dotted line. So you can choose almost anything inside that envelope. Like I said I like to have the point where the two lines meet high and wide and that suits all variations of the min speed knob, which is the most important setting on the controller and gives the flexibility to run almost any car with this controller (although I wish the current capacity of this controller was a bit higher...the 3.15 Amp fuses are just a bit stingy for my liking) It's complex to explain it in raw technical terms without experimenting with it.

One issue I'm having that might be a racing issue is that I'm blowing a few fuses now that I have a routed track and run 1:24 cars that draw more current. If you want it for racing I'd suggest you get the high current version....I've upped the fuses to 4 amp and they are still blowing.

Hi Dave, I set mine up for curve mode.........which is actually just two straight lines not a curve. I like to think of this as giving the car 2 gears to operate with.......a low gear for the bendy parts and a high gear for the straights. The curve I use is on the picture below (the blue line in the middle). I like to get the point where the two lines meet as high as possible (both dip switches set to 1 - on/on) and over to the right as much as possible (Cm set to zero - equals about 70% of full throttle). This gives a nice long lower gear with good control, and a short burst of speed and the end of the trigger for the straights. The flat part of the "curve" is good for bends because you get more control with the flatter response to the trigger. I like to keep the end of this curve high (65% of total power) so I can adjust the min speed to suit the car and motor (adjustable sensitivity up to a max 50% of total power) and still keep the line sloping upwards. You really need to test each car with the min speed settings until the trigger action feels right. Magnet cars require it a bit higher because of the extra drag. You want have the trigger mid range most of the time and not near one extreme. Likewise the brakes are a "suck it and see" thing. Hit the straight full speed and jam them on until you get the response you need. I really like the sweep brakes because you don't have to be precise about the release - it does that for you. The power trim is also car dependant - if the motor is really powerful and spins the car out too much it can take the edge of the accceleration (F1 cars have this)