Young Engineers: March Update

We started the year by fitting a PWM (Pulse Width Modulation) controller to Silver Slug. This is intended to give us some speed control to help preserve battery life when in traffic or on tracks where there are inclines. In the first image the boys are modifying the new steering wheel to accommodate the speed control knob, in the second image they are preparing to wire up the PWM controller module.

Work was also done diagnosing the cause of the issue with Bullet's chain where it kept falling off whenever the drivers slowed down.  It was found to be due to a misalignment of the motor relative to the sprocket on the axle. This was corrected with shims and the fix was proved with on track testing.

We welcomed two of the other North East F24 teams, Banchory Academy and Albyn School, to the Grampian Transport Museum track on the 21st of March for on track testing.  Banchory and Albyn brought three cars each and this gave us the opportunity to test the two cars, Merlin and Silver Slug, we are racing at East Fortune in April against some of the fastest Scottish cars.

With eight cars on track at times it was great experience for the drivers before the qualification event in East Fortune. Merlin is by far our fastest car and showed excellent pace against the visiting vehicles and we are hopeful of a successful race next month.

Unfortunately there were issues with the PWM (Pulse Width Modulation) controller upgrade to Silver Slug. We found we were running over one second a lap slower than expected and both the PWM controller and our motor were overheating. The reasons for this will be investigated over the next few weeks but we are running out of time before the first race towards the end of April!

The overheating problems with Silver Slug at the track day with Banchory Academy and Albyn School raised the priority of fitting better motor cooling. At last year's International Final in Goodwood we were speaking to the team in the next door workbay about the heatsink they were using as it looked like it was designed specifically for the F24 motors. It turned out they had just made it from aluminium channel but reckoned they got a 10deg drop in motor temperatures. We decided to copy them as imitation is the sincerest form of flattery and their design was a really good idea even though it took quite a lot of hands to hold all the pieces together while they were secured!

We also disconnected the PWM (Pulse Width Modulation) controller and went out on track to test the results. We were faster without the PWM controller but temperature measurements were inconclusive as it was very cold and we didn't have time to do another 90 minute test run.

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