Quote:
Originally Posted by renault_megane_dci
But I wonder : up to 45 mph, is the SCx this influential ?
I'm thinking weight, weight distribution and rolling resistance are of paramount importance.
Also, as I understood, the potential for your top speed / acceleration is to be seeked in the controller / batteries area, right ?
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I agree - I don't think any minor improvements in aero will be noticeable at our speeds. Min sustained speed is probably around 30, max around 60, average is about 40
(EDIT: My son said the GPS registered 45 MPH average for 2 laps from a standing start), and it's not at the max for that long - less than 20% of the time (maybe more like 10%). Those would be more "speed-run" numbers. To get more endurance you'd need to drop it down from there. The more we drop it down the less of a factor the aero will be.
I think rolling resistance is the major mechanical factor limiting our endurance. Coasting is the key in that area. From what we learned, the biggest gains are in battery capacity. We probably had only 60-70% of the capacity of the top teams even with higher voltage overall. We needed to up our voltage to get more RPMs out of the motor due to our small dia tires and gearing limitations.
The weight is about where it has to be, and we are lighter than most because we didn't add 40 pounds of ballast needed to compete in-class.
Our controller is top-notch and completely programmable via laptop. Motor is also pretty good and commonly used by top teams.
To really be competitive we would need to build a chassis specifically around the rules with low-drag (rolling resistance mostly) being the major goal. Overall, what made us fast held us back in endurance - and the driver has a heavy foot...
Jay