SOLVING THE MOTOR PROBLEM

Since I began racing slot cars, over 50 years ago, virtually all my cars, (and there have been hundreds of them!) have been equipped with the motor that Scalextric introduced around 1970. It is called the E.9 Johnson small can motor and along with an almost identical version utilised by Airfix, these two have formed the basis of my racing. I should mention that when I was running 'current' F.1 cars, up to 1997 I did use Mabuchi motors as they are more suitable for the faster, modern cars. However, when I took the decision to build only older F.1 cars, I felt the Johnsons would be more suitable to use in cars running with such narrow tyres.

The problem of fitting the motor inside the bodyshell has arisen occasionally before, but I have always just about managed to overcome the problem, This time it became clear as soon as I began to construct the first of the E.R.As, pictured here,


there was absolutely NO WAY I was going to get a Johnson in there. After much searching and discussion on the Atlas F.1 Forum (Racing Simulators section) along with input from a friend, David Lawson, who produces magnificent scratch-built slot cars, I learned that modern Scalextric cars and the motor cycles, are fitted with an extremely slim motor. I was warned that these motors are indecently quick and would really disturb the delicate balance I try to achieve with my cars, whereby I try to get the relative performance levels of each type of car to something approaching how it was when the real ones were racing.

So, I ordered five of these motors, with the intention of installing one in each of the E.R.As. The information I had received regarding the performance of the slimline motor was not wrong! When the E.R.A was ready I built a small test track and tried it. The result was a car that would spin its wheels ALL the time under acceleration and was nigh on impossible to drive. More discussion required.....

When I was a teacher, I used to have to teach electronics to a very basic level, so I have a very rudimentary knowledge of that subject. I wondered if it would be feasible to reduce the current reaching the motor by an electronic means. My initial idea was resistors but eventually a very clever person from somewhere out there in Europe-land suggested diodes. Apparently, putting a diode into an electrical circuit absorbs about 0.6 volts. This four of them would reduce it by 4 x 0.6 volts - 2.4 volts. Once I had ascertained the most suitable diode to purchase, I bought 100 of them - at the princely sum of 2.50 - for the whole 100!

I started adding them to the wiring of the E.R.A and kept running the car to see the results. In the end, I settled for six of the things, three on each side of the motor.

The performance of this car is still rather high given its status in 1950, but I won't know for sure until I actually race it. In the meantime, I learned that Airfix, in whatever guise they now operate, are marketing an identically sized motor to the rapid Scalextric one, but with an upper rev figure of 10,000 rpm. This motor has a white can. I purchased half a dozen of those and they have gone straight into the other four E.R.As. The cars are much nicer to drive but are still pretty quick. Diodes may even be needed for those too.

These white can motors have been fitted to the three Gordinis pictured on the Index page. I have used two diodes on each of those little blue cars and their performance level seems about right in comparison with things like Alfa Romeos, Ferraris and Maseratis.

The remaining unused Scalextric motors will probably find their way into the works Alfa Romeos, although I will almost certainly 'diode them down' just a little in order to bring them into line with the other quick cars from the series.

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