VS6075 lap times out-of-sync with other historic series

[steveaca]

Very interesting discussion.
Gordon, the placement of the red lines on the diagram show that in both cars, the magnets would need to be moved forward of your earlier suggested '40 mm ahead of the axle' , that of the GT40 slightly more than that of the 33/3. I wonder what, in practical terms, the performance difference would be by doing this as opposed to leaving both at the 40 mm mark. I'm just wondering about the practical aspects of mounting magnets where this new thinking suggests as it would certainly entail a lot more work (at least in the Slot.it cars) than just re-locating a Slot.it magnet.
Steve

[gordon]

Steve, there are times that when the chassis design makes it impossible to place the magnet at the precise location determined by the regulation. It sometimes has to be placed a bit further forward of the limit to still comply. I actually have one Sebring-chassis car set up this way because of the shape of the chassis. In the case of the Slot.It cars in my diagram, placing the magnet at the red line would mean modifying the pod, or using very slim magnets, or placing the magnets under the car.

We can come to some sort of agreement about all of this, but again, for the most equal set-up for different chassis designs and dimensions, the best way is to use the method in my diagram. Interestingly, once we're looking at magnets placed approximately in the middle of the chassis, in theory the further forward the magnet is, the stronger it can be yet still obey the USD rule. So a car with the magnet at its centreline will require a weaker magnet than one where the magnet is half an inch further forward. More food for thought.

Perhaps the fixed 40mm suggestion is the best compromise on this.

[gordon]

Guys,

I'd like a decision to be made on this. Here are the main points:

1. The Vintage Sports cars are too fast and I want to slow them down by at least 1 sec per lap.
2. The two primary proposed changes to accomplish this while having virtually any car with the appropriate body race competitively are:
   1. Move the magnet location forward and...
   2. Allow any chassis (which will help accomplish this for certain models and will allow a wider range of cars).

With regard to item "a", there are two suggestions:

1. Use the forward of midpoint between rear axle and guide flag pivot point option (see diagram on previous page). This will mean modifications to the chassis or motor pod on many cars.
2. To simplify things, use a standard 40mm forward of the rear axle position for all cars (the location of the forward-most magnet on Slot.It motor pods).

Once implemented, we can always fine-tune these if we see fit.

Gordon

[RameshB]

Hi guys the suggestion of leaving the slot it motor pod 40mm measure , can be used i am good with that , so we can start working on cars early. See you all on Thur . bye

[steveaca]

Hi all,
I agree with the points above. As far as the magnet location goes, I'd go with using the 40 mm ahead of the rear axle limit.
Steve

[gordon]

OK, the 2017 Vintage Sports '60-'75 class regulations have been amended based on this discussion. You can see the changed requirements in the updated FRC Classes 2017 page on the forum.