[Monochron]

Just as an example of what we have tried, we often do small projects in the off-season that are completely open to student failure, and then offer more guidance and try to deflect failure more during the season or in "large scale" off-season projects.

For instance, last year we did a t-shirt cannon competition where we built 3 teams and had them compete to build the strongest / fastest cannon. The teams were entirely student led with mentors only helping when specifically asked. Rather than mentors constantly offering guidance or trying to foster ideas, we made our involvement entirely up to the students. As a result very few groups came to us for help and only one group was ultimately able to build a cannon that shot more than 10 feet.
Afterwards we had a debrief on what went right with that one team and what went wrong with the others. It was mostly due to one or two students putting in a lot of work researching build techniques and making their mistakes early in the process.

We don't think that the massive 2+ month FRC season is a useful place to let the students fail if we can prevent it. But a short small scale project lets them fail in a more low-key environment and a good post-analysis helps them uncover what caused that failure and how they could prevent it.