At my school, at weekends when it's particular busy we have volunteers who help us by refuelling aircraft, manning the phones.... and also briefing trial lessons for us.
Last year, there was a lot of debate about the contents of the trial lessons - and therefore the contents of the trial lesson briefings that our volunteers gave. There were several heated discussions in instructor meetings, during which the only conclusion we came to is that it varies from instructor to instructor, day to day, student to student.
The only advice we could give our volunteers is to describe the primary effect of rudder and then explain that it's perfectly possible to fly a modern aircraft without using the rudder at all, and that your instructor may well prefer you to not use it. Or he may show you what it does on its own, or alternatively ask you to combine it with aileron, in which case he will explain it in more detail.
Personally, I don't bother with it, unless my student is interested in doing a PPL. In this case, I generally try to first of all show the primary effect of rudder, and then elicit from the student that it doesn't feel right using it on its own. Then I demonstrate adverse yaw, explain how to use rudder to counteract adverse yaw, and get them to do coordinated turns for the rest of the trial flight.
But there are exceptions to the rule - some people know they don't have the money or time for lessons, but want to learn as much as they can on their trial lesson. And others may want to take up lessons, but clearly don't have the coordination or aptitude to make balanced turns on their first ever time at the controls. So being flexible is the rule.
FFF
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