What to do when mentors are leading the team in the wrong direction?

[The Doctor]

Last year our team was made up of a bunch of upperclassmen, and this year we lost almost all of them, leaving only 4 people who have been on the team more than 2 years. This has made it increasingly difficult to compete with two of our mentors (unnamed) who seem increasingly intent on running the team themselves. I mean, shouldn't the team be student-led?

Take for example the issue of robot add-ons. Our original design (we actually did it in cad this year!) called for a 6wd chassis short enough to go under the low bar with the ability to pick up balls with an attachment at the front end. However, these two mentors got the idea in their heads that we should have an arm on the front to open door and gate-based defenses, because going over 5 isn't enough apparently? They also decided it would be a good idea to prototype an arm to climb the tower. Neither of these were part of our original design and strategy.

The worst part is that these mentors are leading several students in prototyping these add-ons, which leaves us with no fabricators to build our frame. In my opinion, the frame is kinda important, don't you think?

Like I said, us upperclassmen have had a tough time standing up to them. Does anyone have any idea how to rectify this situation??