pic: 2012 frc971 transmission

[Nuttyman54]

Originally Posted by Nate Laverdure

I love the space savings with this "inverted" setup, but in order to place the CIMs outboard of the gearbox, you risk a higher moment of inertia.
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Takeaway: for a snappy turning response, mount your heaviest items as close to the center of rotation as possible.

This is a good point, and 5% is something that will be noticeable to most drivers. There are a few other factors as well that go into the decision for us:

1) With most 6wd dropped center setups, turning is usually really really snappy already, sometimes too much. Especially with a robot geared above 15fps, turning response can be almost uncontrollable without a lot of practice.

2) The drive code that 971 uses (along with 254 and maybe some other teams) is set up to do controlled radius turns in normal operation, rather than controlled turn rate, which mitigates the "snap" turn response characteristic of 6wd. This makes the robot much more controllable at high speeds (the 971 2012 robot was geared to 17fps no load). Further discussion on this style found here. Because of this, we try to avoid needing to turn in place when we drive, so the moment of inertia aspect isn't really an issue for us.