For the love of CIMs (A question about CIMs and gearboxes)

[Marc S.]

While it unlikely that we will be able to use 6 cims next year consider this, a 6 motor drive train with 4 cims and 2 banebots(775's or 550's). 973 used them(3 in each gearbox) until the 775's started shorting out. There are quite a few teams that have used 6 motors in drive. 8 motor might require another stage of gearing.

148 has done this(6 motors in 1 gearbox).

[Billfred]

Originally Posted by EricH

1) YES. 2010 allowed 5 CIMs. Also, 2006 (and 2007?) had a motor type known as the Big CIM (bigger motor, but for the size not quite as much oomph as you might expect), of which type I remember 2 being allowed. (330 only used one big CIM--it powered our 2006 shooter wheel.)

They were legal in 2007--1618 used them in their drivetrain to free up a small CIM for the (horribly-overpowered-like-some-yutz-in-the-marketing-program-specced-it) arm. They were powerful and torquier than the small CIMs, but still had less available power. That was your six-CIM year (technically, anyway).

Originally Posted by Marc S.

While it unlikely that we will be able to use 6 cims next year consider this, a 6 motor drive train with 4 cims and 2 banebots(775's or 550's). 973 used them(3 in each gearbox) until the 775's started shorting out. There are quite a few teams that have used 6 motors in drive. 8 motor might require another stage of gearing.

148 has done this(6 motors in 1 gearbox).

Six-motor drive seems to be most popular when one of the smaller kit motors is made to act like a CIM. The overwhelming majority of teams that go this route seem to use the AndyMark AM Planetary, which takes a high-RPM motor like the Fisher-Price motor (originally) and gives you a speed and mounting interface that's close enough to the CIM that it'll work for our purposes. (Each motor has its spot on the curve where it's most beneficial, but all the motors will contribute one way or the other.) Indeed, that's what 148 did in 2008 to put the Fisher-Price motors in with their CIMS.

I don't have a picture, but what 2815 and 1398 did in 2010 with their six-motor drive (two CIMs and a planetaried F-P per side, shifted) was add another idler gear in between one of the CIMs and the F-P. You could plausibly squeeze all three together with a large enough input gear (and planning the rest of your drive system accordingly), but we went this route to make room for the shifter hardware. Even single-speed, I think we would've gone this route for packaging reasons--our robot that year was designed to go through tunnels on the field.