On a personal level (not necessarily what the rest of my teammates would be looking for), I prefer mentors that are relatable and easy to approach, but who are also hands-off when it comes to student projects.
If I were more heavily involved in the robot's construction, my preference would probably be a bit different... But as a student leader and Chairman's Award presenter, I like it when our mentors trust me enough to give me an assignment and let me do it my own way. I seek mentors who are patient and willing to compromise, though I also appreciate those who aren't afraid to tell me when I'm overstepping my authority as a leader, or who give me the criticism I sometimes need to see the greater good of the team. I highly value a mentor who listens to my ideas and treats me as an equal, and gives me the encouragement I need to carry through with a large project. If I become completely overwhelmed, (s)he is willing to step in and help only when absolutely needed, or will assign other students to aid me.
Scheduling really wouldn't be too much of an issue with my ideal mentor, as his/her primary role would simply be to oversee us and give feedback or suggestions, or to teach relevant concepts. Most of that could even be done through email or phone calls.
I've had the honor of working with several of such mentors over the last three years. Especially our coaches, and our Chairman's mentor -- those three have taught me so much, and have built me up into the person I am today. I am eternally grateful for my experiences with them, and I hope that I can provide that kind of support/guidance to another team as I enter the role of mentor in the coming years.
