I've been teaching a couple of beginners, starting with little 1/2-A sized all-slab planes.

I came up with a motor mount that's just strong enough to survive bad landings (usually), but breaks with a severe crash.  Given the crew I'm currently working with, there have been a lot of opportunities to test the mounts out -- we've got several weeks worth of flying on a Park 300 and a Park 370.  There's been a lot of airplane damage, including a couple of post-hole crashes, but so far the motors are just fine.

The one here -- shown broken in the second picture -- got put back together with a bit of CA and has flown again.