Question - Why is it required (again) with these 2 separate tuning arrangements below when a USD rule is one of the main functions ..?
MOTOR: 23.5K RPM or lower, based on manufacturer's specifications.
20K RPM or lower if any installed magnet is positioned rearward of the front of rear tyres.
MAGNETS: USD rule ... If motor is 20K RPM or less, magnets may be positioned anywhere.
If motor is greater than 20K RPM, magnets must be positioned ahead of the rear tyres when viewed from the bottom or top of the chassis.
I believe the USD rule and one motor RPM rating are sufficient settings for any type slot-car in this racing competition.
Early morning thoughts with ... while tuning (days earlier) my own slotcar for this class
Luke
Last edited by Luke on Sun Nov 11, 2018 12:33 pm, edited 1 time in total.
Luke, the reason is because magnet location can vary the strength of magnets that can be used while still obeying the USD rule. The further back from the front/rear centerline of the car that the magnet is, the stronger the magnet can be while still obeying the USD rule. To attempt to slow cars somewhat, we introduced this rule to differentiate cars running motors up to and cars running over 20K. It seems to be working quite well so far.
Of course an alternative would be to require that all cars in the class regardless of motor RPM (up to the present limit) have heir magnets ahead of the rear tyres.
The original rule for this class had all magnets ahead of rear wheels. There was no ground clearance or USD rule then. The class allowed motors up to 30 k rpm. There was a differentiation in chips however. Cars with motors above 25 k rpm were allowed free chips while those above had to use Scalextric chips. The feeling was that downforce would be regulated based on the chip's ability to handle high rpm motors and high downforce at the same time and that a car running 25 k motor , using a Slot.it chip could run more downforce than a car running a 30 k motor and using a Scalextric chip. The overall performance of both setups proved to be quite similar which was the objective.
Sometime later, it was felt that these cars were getting too fast and a suggestion was made to lower average speeds by having a 20 k rpm limit. This suggestion was resisted by some and a compromise position was reached by retaining cars up to 25 k rpm but now to allow cars with 20 k rpm motors but for these cars to have free magnet location, giving a potential handling advantage to compensate for their slower motors. Of course now there was no chip restriction anymore. I believe that the ground clearance and USD rules were introduced at a later date but can't be sure. The ground clearance and USD rules, when introduced, applied to all cars, regardless of motor and similarly, the recent removal of the ground clearance rule applies to all cars.
The reason for this post is to give a short historical perspective to the evolution of this class and to show that there was always some difference allowed in set-up of cars, based on motor rpm rating. I think that the current regulations for this class are fine and should remain as they are.
Sorry, in post above , I erroneously wrote that cars above 25 k rpm were allowed free chips. This should be that cars below 25 k rpm were allowed free chips.
