As you rightly state the R22 is a no go but you can safely demonstrate a small ammount of low g in the 300CB. The best results are obtained by a gentle pushover after a climb at about 40 knots.
Excessive pushovers can result in droop stop pounding and will cause considerable damage to the rotor head. Therefore try a little at a time, it won't take much of a push to feel light in the seat and that's all you need to demonstrate the effect, you're not looking for a few seconds NASA weightlessness training.
It is a worthwhile demo especially to a student who also flies R22 so they are familiar with the feeling allowing them to recognise low g and react to it in the correct way.
[This message has been edited by The Governor (edited 24 April 2001).]
[This message has been edited by The Governor (edited 24 April 2001).]