As part of the FI course before things got “health and safety conscious” I would get the student to stop the prop “for the experience.” C152 with Lycoming.
To actually get the thing to stop rotating you’d have to slow to about 40kts before it would shudder to a halt. It was a good opportunity to compare the difference in ROD between idle/rotating and stopped. Not much in it.
To get the thing rotating again it would require about 110-115kts - which few students appreciated the pitch angle required to achieve.
We’d have a hard deck of 3,000’ which if we weren’t rotating by then then a quick flick of the starter would usually resolve the issue and we’d always be within gliding distance of an RLG/good sized field for a PFL. Never required that bit though.
In the Duchess the manual stated an air start would require 104 (?) before the blue lever forward but always found about 114 meant the accumulator worked so much better. Air starts without the accumulator were horrible - seemed to vibrate for hours until the blade settled down again.