Thanks, all, for the advice. I didn't want to say too much about the application as we haven't announced the details to our students yet, but, on the other hand... if I've got them surfing CD often enough to catch this, then I'm happy.
A bit of background... after 13 years teaching high school "shop" classes, I took a job at the British Columbia Institute of Technology, teaching shop teachers on the technical aspects of what they will be teaching. Our students come in with a variety of backgrounds in trades and technologies, and at least one year of general post-secondary studies. They spend two years with us studying woodwork, metalwork, mechanics, drafting/design, electronics (that's me), and a few other support courses. I speak from experience when I say that the program is pretty much as fun as it sounds... I was a student in it 15 years ago (and my Dad was a student in it about 40 years ago, we've got more than a few second-generation shop teachers in BC!). After spending two years with us, the students spend a year at the University of British Columbia, where they do their practicum and complete their B.Ed.
As a capstone course in our program we do a major design project called the "Vehicle in a Box". The challenge is announced just before Christmas Break, and the competition takes place at the end of May. The students are doing other courses at the same time, and evening access to the shops is very limited, and they work in groups of three or four, but aside from that, it isn't entirely dissimilar from FRC... well, with the exception that the students who are driving the machines are actually in the machines. The vehicles have to dissassemble to fit in a fixed-size storage box, and the competition begins by unpacking and assembling the vehicles, with bonus points for the best time.
We've done various challenges and used various power sources in the past, ranging from human power to 1hp "electrathon" style motors and, most recently, brushless hub motors from electric bicycles. Normally the challenges are outdoors, but this year we are taking things indoors and playing a game somewhat similar to Breakaway (the soccer game, but without the bumps) but using a giant earth ball like the one from the "around the track" racing game of 2008.
We usually get decent media coverage and try to ensure a good design/build challenge for our students while coming up with an entertaining, media friendly presentation to help promote our program.
So given that the mass of the vehicles has to include a driver, I'm expecting vehicle masses in the range of 200-300lbs. Two CIMs would have to be geared pretty low in order to provide decent maneuverability, but I don't think I can justify going to four motors/controllers per vehicle. I'd rather have the students look into building a shifting gearbox if they wanted top speed, or we could double up the batteries to run at 24v. Yeah, the motors might not be rated for it, but they'll take it for as long as we need them to. The extra "kick" from starter motors would be nice, but it comes with the added "cost" of having to build high-current controllers and connections, as well as some massive battery drain.... not to mention characterizing the performance of essentially a random collection of motors pulled from a scrapyard.
We are working on developing the final details, including the motor specifications over the next week or two. We know we can use CIMs as a fallback, if the starters don't work, but I'm trying to work out right now just how much "hassle factor" is going to be involved. There will definitely be some... and we want the students to learn about motors... but we also want their learning to be in a positive sense of "what works well".
So that's what we've got planned. If any of my students are reading this, I hereby offer up a BEvERage bribe to keep quiet about this until the game is fully announced.
Thanks,
Jason
P.S. Yep, you can do that in post-secondary. The average age of students in our program is 28.