pic: 114 is thinking of what?!

[lukevanoort]

Originally Posted by 114ManualLabor

Actually, this is designed for a tank track. We're not really traction limited with around 60 inches square of red linatex on the ground. (I haven't really taken physics yet, so correct me if that's flawed. A discussion with a mentor yielded that answer). There's no middle wheel to be lowered. As for not pushing someone in high gear, you never really know when you're going to get defended against, and not be practiced enough to downshift before the pushing begins.

Your conjecture is, in fact, flawed. On an ideal surface, friction and surface area are unrelated. FIRST carpet is not an ideal surface; however, I have never seen any conclusive evidence to support the idea that surface area and friction on it are related. (Unless you have real rigid 'spiky' traction materials, like 71's 2002 file cards or the old Technokat tread designs, but those have been illegal since 2003?, so that isn't really relevant)

Since red linatex has a mu of 1.6 instead of the mu of 1.3 that I did my earlier calcs with, I need to revise what I said. Most definitely, do not use this design if you intend to push in high gear; the FP will be drawing a bit over 41A, which is 65% of a FP's stall current. I do not think that this will last too well. You may not get a sudden smoking of the FP (well, if you push a lot in high you will, but not if it is just a tad here and there), but I think you will probably slowly loose power as you melt insulation on the windings, which causes windings to short out, reducing power. In low gear, you are still fine; the FPs only draw 15A. If I intended to use a gear for pushing, I would feel comfortable with FPs drawing 16A at the traction limit, but not much more than that.

On a sidenote: when trying to do drivetrain calculations, has anyone else been getting 403 forbidden errors when trying to use Google calculator due to their query looking like something malware would produce.