(same thread in rookie zone) Setting up a car for vehicle dynamics research
Hi, everyone. Sorry to repost, but this forum seems to get more traffic than the rookie zone.
I am a mechanical engineering student and am specing some components for a car to be used in research at my university. I am totally new to RC cars and would like some advice. I know what I want to achieve, but having no experience with these motors, I do not know how much of a difference in performance I could expect to receive from different motors.
The car we are using is an HPI Super RS4. It's big, but it has to be because it will be loaded with some sensors (and an extra battery pack to power them) as well as a relatively large weight which may be adjusted to give us control of the location of the vehicle's center of gravity. The guys who used the old car last year complained that it accelerated too slowly. The new car will be just as big and heavy, so I need to improve its acceleration performance. Here's the old setup:
Trinity Midnight 2 27-turn motor (can't find torque numbers or dyno charts for it anywhere)
Sanyo 2400 6-cell Ni-Cad battery packs (2)
Futaba MC230CR ESC
I'm not sure what the output gear ratio is. I didn't have time to count the pinion teeth, although I imagine the spur gear is an 81 since that seems to be the most common size.
From what I have read, more turns means better acceleration. 27 is already a lot of turns, so should I bother trying to find anything higher? Would moving to a 36 offer a noticeable improvement in acceleration, given the huge (by racing standards)weight of my car? How about if I go to an 8.4V battery pack (or even 9.6 for that matter)? How quickly will the extra voltage damage the motor and ESC? How much can I gear down the motor before I burn it out? We don't need the car to run for long in our experiments, and it won't be used in all that many tests, either. Better still, we're on a pretty good budget, so if I need to replace a cheap stock motor, that's no big deal.
I know there were a lot of question marks in there. Sorry for that, but I have never dealt with this equipment before and don't have time to learn by trial and error. Thanks in advance for your help.