[Cuog]

It also depends upon the dynamics f the students on your team, if they can build the robot themselves with a little guidance from mentors then they should do that. If the team doesn't have amny students with mechanical and electrical know-how then it is better if the mentors get more involved in teaching the students what to do and what would be the best way to do it.

When it comes to the actually building of the robot i beleive that the mentors should take a "hands-off" approach as much as possible and allow the students to learn through experience, but if there are time/capability reasons then the mentor/engineer should take on the building task.