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Scalextric 4×4 – how it’s done

Introduction
Take the cover off any traditional Scalextric car and you’ll find an electric motor and one driven axle, usually at the rear, connected together with a set of gears. The gear on the motor is generally small and is known as a pinion gear while the gear fitted to the driven axle is usually larger and is known as a contrate gear. The difference in gear size allows the speed of the motor to be reduced to give the Scalextric car the correct speed on the track. The gears also increase the torque produced by the motor as measured at the drive wheels.
This article explains how to go from two wheel drive to four wheel drive.
Scalextric 4×4
To make a Scalextric car have genuine four wheel drive there are 2 methods available. The first is to add a second driven axle with contrate gear, take the drive from the other end of the motor and fit a second pinion gear to the motor shaft. This method essentially copies the primary drive.

The picture above shows an SCX Subaru Impreza chassis with a second axle powered directly from the motor. This a strong and durable solution. The only real down side to this solution is cost, as two additional components (the gears) and a unique motor are needed.
On the other hand Scalextric have used a different method to achieve genuine four wheel drive. Take the cover off a Scalextric 4×4 model and you’ll see something quite different. Scalextric retain the primary drive gear system for the driven axle and connect together both axles with a rubber drive belt or drive band, see the picture below where the drive band can be seen just behind the set of wheels in the foreground:

This method uses unique wheels moulded with integrated pulleys, the wheels are usually usually model related and unique to the car anyway, so no extra parts. Also, this solution uses the standard motor. Overall this method of delivering a 4×4 drive uses only one additional component, the drive band.
So, I guess the real question is does a Scalextric 4×4 drive car work any better than the traditional two wheel drive model? The short answer is a definite yes. As long as there’s some weight on all four wheels through either mass or magnatraction there will be a benefit. Acceleration out of the corners is the main benefit but cornering is improved as the rear wheels are doing less work, just like a real car.
The only real downside to a 4×4 mechanism is the drag caused by the mechanical losses. With the geared mechanism there’s additional friction and noise and with the drive belt method there’s mostly just additional friction. This additional mechanical loss really only adds up to a reduced top speed which will not be noticed on small and medium sized layouts. The additional friction does give improved braking into corners too.
Applications
Over the years Scalextric have produced 4×4 models in only 2 periods; in the 1980’s with the Ford RS200 and the Audi Quattro, in the 2000’s with the Ford Focus, Subaru Impreza, Peugeot 307 and Skoda Fabia models. All of these cars use the drive band solution. In the 1960’s Scalextric used a small drive band to transfer the drive from the motor to the rear axle of the B1 Typhoon and B2 Hurricane motorcycle and side car models. This was to achieve two wheel drive and not four wheel drive.
Drive bands
The drive bands used by Scalextric are not too dissimilar to traditional small elastic bands. However they are not elastic bands as they are moulded from a high grade synthetic rubber material similar to the material used to mould the Scalextric tyres.

This material and shape gives the drive band a small amount of stretch and flexibility but more importantly good grip and a long service life. Just like the tyres on your Scalextric car the drive band will stiffen and crack with age reducing it’s effect. So, just like the tyres the drive band will need to be replaced from time to time to maintain performance.

Crimp Failure at Braid Contact on Scalextric cars from 2016 onwards

Introduction

For a scalextric car to operate the electrical current must flow into and out of the car. That’s two discrete electrical connections. To do this the slot rails in the track are the two conductors. The electric current connects to the car via the flexible woven braids fitted to the guide blade, then to the braid contact plates and then through wires to the motor. The rotation of the guide blade for corners and the like is managed through the use of the flexible wires.
The wires need to be securely fixed to the braid contact plate to make the electrical connection and to withstand the regular rotation of the guide blade.

Recently (we believe sometime in 2016) Scalextric introduced a change in the way the wire is crimped to the braid contact plate. This is the silver coloured plate that makes contact with the braid. There is a very serious problem with this new design of crimp.
There is insufficient length to the crimp fingers to fully secure the outer insulation of the wire. With the action of the guide rotating over time the wire pulls out of the crimp. This breaks the electrical connection between the wire and the braid contact plate.
Once the crimp has failed the Scalextric car stops on the track.

Scalextric G38 round guide blade
Damaged Scalextric crimp to wire

Here is a close-up picture showing the failed condition. As this is a design based problem the repair is not as simple as it might appear.
Option 1. Simply re-make the crimp. This will last for a short while until the crimp fails again.
Option 2. Just crimp onto the conductor wire strands. This will last for a short while until the wire strands break through the action of metal fatigue.
Option 3. Solder the wire to the braid contact plate. This doesn’t work as the latest braid contact plate is plated in a material that doesn’t take solder. There’d also be the strain relief problem.

As shown in this picture to make the electrical contact the insulation is removed and the end of the wire strands are tinned with solder and bent back over the insulation. That’s why the electrical contact fails once the crimp fails.
As this is a design based problem the solution must also be design based. That means a new design of connection.

Scalextric wire connection
Replacement Scalextric wire connection

The solution is to use a new braid contact plate made from a slightly stronger steel that is plated with a thin layer of brass. This will take solder.
To overcome the lack of strain relief with this soldered solution a short length of ultra-flexible silicon wire is used. This wire consists of 128 strands of 0.05mm diameter copper and a silicon insulating layer.
This is flexible enough to easily withstand all the movement of the guide blade.

Here is the repair complete in the Scalextric car. The original green and yellow wires are shortened to make the room for the silicon wire tails. The joints are soldered and a length of insulating tape covers the exposed joint.
We freely admit this isn’t pretty but it does use the right materials in the correct Engineering environment.
Stronger brass plated steel braid contact plates. Solder joints. Ultra-flexible wire where the wires are needed to move regularly.

Scalextric car repaired

About the author:

Gary Harding has been working with Scalextric cars for over 35 years and now operates Scalextric Car Restorations in the UK. Scalextric Car Restorations is a Worldwide internet based business that offers for sale high quality Scalextric cars and Scalextric parts from the 1960s to the present day. All the restoration work is carried out to the highest standards with the highest quality parts available. Only the best cars are selected and the final result is a car that is genuinely like new.
Further help and advice relating to this article or Scalextric cars in general can be found at:
http://www.scalextric-car.co.uk

Fried chips and smokin’ motors – Keeping the vital parts of a Scalextric car cool by understanding “duty cycle”

In order for your Scalextric car to give the best and ongoing performance it is necessary for the key components not to get too hot. The key components discussed in this article is the motor and the digital chip (if fitted). This article uses the notion of “duty cycle” to keep your Scalextric cars cool and running well.

Duty cycle
In this World not all machinery or equipment is capable of running or operating continuously. Some equipment needs to be serviced, some may wear out and some may get hotter and hotter in use. This would indicate that the equipment needs a period of rest between usage periods. This “on” verses “off” time is known as the duty cycle.

Scalextric duty cycle

For example one of our instant soldering guns can be used for 12 seconds but must then rest for 40 seconds to allow the transformer to cool down. After the 40 seconds cool down period it can be used again for 12 seconds, etc. This on / off period is known as the duty cycle for this soldering gun.
Duty cycle may be expressed in time as in the soldering gun example or as a percentage. For example a 75% duty cycle could mean the equipment can be operated for 3 minutes and then rested for 1 minute.

Smokin’ Scalextric motors
None of the motors used in any of the Scalextric cars is capable of continuous racing conditions. They are capable of long term use at slow speeds. As the race continues the motor is unable to dissipate the heat it generates and the motor just gets hotter and hotter. That is until the internal solder joints melt and the motor stops working with permanent damage.
Sometimes a tiny amount of oil contamination on the commutator will start to burn and the motor will emit smoke and smell of burning.
It therefore follows that a Scalextric motor has a duty cycle to let the motor cool down between races. All motors, cars and track layouts will be different but to be safe it is best to assume a duty cycle of 50%. That is race for 5 minutes and let the motor cool for 5 minutes, or race for 10 minutes and let the motor cool for 10 minutes. I’m sure you’ve got the idea by now.

Fried Scalextric digital chips
The Scalextric digital chip is nothing more than some basic electronics and a single micro chip computer to manage the communication side of things. The chip has 3 main sections; the power supply, the micro processor and the motor power drive. Even when operating in analogue the chip is still regulating the power to the motor. Note, there is no overcurrent protection on the Scalextric digital chips.
The power supply and micro processor are well enough designed to not usually cause a problem. The cause of failed digital chips is the motor power drive transistors. These drive transistor turn on and off many times a second to control the power to the motor. The transistor on time and off time is controlled by the micro processor based on the hand throttle position.
When the motor power transistors are switched on they effectively become low value resistors allowing the electrical current to flow through the motor. When the transistors are switched off they effectively become high value resistors stopping the electrical current from flowing through the motor.
When the motor power transistors are switched off there’s no current flow and therefore no heat generated within the transistors. Therefore off is no problem for heat generation.
When the transistors are switched on, the full motor current passes through the transistors and heat is generated within the transistors. So, the more on time the more heat generated per unit time. The more on time, the more power to the motor, the harder the motor is working, In this case full speed racing will generate more heat in the motor power transistors and as this heat builds up there comes a point where the internal silicon of the transistor effectively melts. This will destroy the transistor function – fried chip.
Again the Scalextric digital chip has a duty cycle depending on the chip installation, motor, car and track layout. In this case Silicon cools very quickly so a duty cycle of 75% would be OK. However, we should limit the race time to prevent the heat building in the first place. We recommend not racing for more than 5 minutes to prevent permanent damage to the Scalextric digital chips.

Article from Scalextric Car Restorations

New tyres for the Tri-ang Jump Jockey set

These new tyres are direct replacements for the original tyres fitted to the Tri-ang Jump Jockey sets, see above image. They are available in MAX Grip versions.
The new hand made MAX Grip tyres are unique to Scalextric Car Restorations and give the absolute maximum in performance at all times. Cornering and acceleration will all be at their maximum with these tyres. They give the very best performance possible on all track surfaces at all times. Simply put we have not yet discovered a better tyre for grip and race performance.
The MAX Grip tyres are hand moulded from 29 Shore A hardness rubber which is a very high grip material.

The tyres are smooth treaded and have a smooth tyre sidewall.

http://www.scalextric-car.co.uk/Parts/Tyres_Triang/Triang_Tyres_Jump_Jockey/Triang_Tyres_Jump_Jockey.htm
http://www.scalextric-car.co.uk/Parts/Tyres_Triang/Triang_Tyres_Jump_Jockey/Triang_Tyres_Jump_Jockey.htm
Dimension
Size (mm)
Outside Diameter
11.0
Inside Diameter
4.5
Overall Width
3.0

MAX Grip tyres from Scalextric Car Restorations

Fitting instructions for a Scalextric motor pinion gear – 9z

This process does not require specialist gear pullers or other tools

 

1. Place the gear on a hard surface
Warm the gear to at least 30 degrees centigrade which will allow the plastic to stretch over the motor shaft without splitting. Simply holding the gear in a warm, closed hand for a few minutes will be sufficient or soak the gear in a container of warm water for a few minutes.
Place the gear on a hard surface with the circular flange facing upwards.
2. Gently push the motor shaft into the gear
Gently push the motor shaft into the hole in the centre of the motor pinion gear. Use a constant gentle downward pressure.
Continue until the motor shaft is right through the gear and touching the hard surface.
3. Pinion gear partly fitted
Here the motor pinion gear is partly fitted. The shaft is flush with the face of the gear.
4. Pressing the gear into the final location
Position the motor shaft over a void or hole in the hard surface. In this picture a gap in the jaws of the pliers is used.
Again apply constant and gentle downward pressure to push the gear along the motor shaft and into the correct final position.
5. Motor pinion gear fitted
Here the motor pinion gear can be seen in the correct final location along the motor shaft.
The exact location may depend on your specific application.

Note:
This pinion gear is used to service several different types of motor pinion gears fitted to several different Scalextric motors used over the years (decades). With some motors, especially those with poor or missing spines it may be necessary to reduce the diameter of the internal hole of the pinion gear. This will ensure the pinion gear is a good tight fit onto the motor shaft.
To do this, use an opened up paper clip to smear a little superglue on the inside of the pinion gear. Allow the superglue 1 hour to set fully before a trail fitting the pinion gear to the the motor shaft. What you want is a good tight fit where the pinion gear will slide onto the motor shaft with a some effort. Add another smear of superglue onto the inside of the pinion gear if necessary. Allow this to dry fully for 1 hour before trail fitting again. Repeat as required.

Great ideas from Scalextric Car Restorations

Scalextric slot car Neodymium magnatraction magnet kit

Improved track performance with minimal effort.

These Scalextric spares Neodymium Iron Boron magnets have a gauss level which is typically 2 – 4 times higher than standard Alnico magnets. They are nickel-plated for improved corrosion resistance and appearance.

They are suitable for all slot cars; Artin, Ninco, SCX, Scalextric, SCX Scalextric, Tri-ang and many more.

This kit is great if you are not sure which Scalextric spares magnets would be best suited for your car.

http://www.scalextric-car.co.uk/Parts/Magnetraction/Magnet_Neodymium_Selection/Magnet_Neodymium_Selection.htm

This kit contains:

Quantity
Description
2
Bar magnet 12mm x 6mm x 1.5mm (1/2″ x 1/4″ x 1/16″ approx.)
2
Bar magnet 25mm x 6mm x 1.5mm (1″ x 1/4″ x 1/16″ approx.)
1
Bar magnet 25mm x 6mm x 3mm (1/2″ x 1/4″ x 1/8″ approx.)
2
Button magnet 8mm x 3mm (1/4″ x 1/8″ approx.)
2
Button magnet 8mm x 5mm (1/4″ x 3/16″ approx.)
1
Button magnet 10mm x 5mm (3/8″ x 3/16″ approx.)
Please see our Neodymium Magnet Safety Page for further information.
Our unique Magnet Downforce Calculator gives the magnetic attraction force for this magnet at given distances from the track. Ideal for locating the magnet.

Scalextroc spare parts from Scalextric Car Restorations.

Windscreen for the vintage Scalextric C69 Ferrari 250 GT

This windscreen is new and a direct replacement for the vintage Scalextric Ferrari 250 GT Berlinetta windscreen. This window moulding comprises all the windows, front, back and sides, for this Scalextric Ferrari Berlinetta model.
It is moulded in a fully clear material.

http://www.scalextric-car.co.uk/Parts/Windscreens/Windscreen_C69_Ferrari_250_GT/Windscreen_C69_Ferrari_250_GT.htm
http://www.scalextric-car.co.uk/Parts/Windscreens/Windscreen_C69_Ferrari_250_GT/Windscreen_C69_Ferrari_250_GT.htm
Ref.
Description
C69 Ferrari 250 GT Berlinetta
E4 Ferrari 250 GT Berlinetta

Scalextric spare parts from Scalextric Car Restorations.