I used to fly a Bonanza out of what was effectively graded cow pasture fairly often. Strong gear, and with the 3 blade prop very good prop clearance. The Bonanza has big, effective flaps so – especially when light, which will usually be the case with just student and instructor – the touchdown speed is very reasonable.
I think in reality there are very few light single retracts that won’t work well on grass.
This video provides some information on operating nosewheel (including many retracts) in the back country – generally far rougher strips than a proper grass airfield:
Another vote for the Arrow *non T-tail". I operate a newer Arrow in and out of grass fields without issues, but not that frequent. Our maintenance organisation also runs an Arrow out of a grass field, says something…
I think Achim is spot on at the beginning. It’s not that these aircraft have any difficulty with grass. I fly an Arrow II and have gone to plenty of grass strips without problem. The problem will come from operating a retractable off an uneven surface in a training situation.
