RE: Time - A question of safety?
Oddly enough this really is a serious issue. When in undergraduate school I took several education courses but did not get a teacher’s certificate because the department chair and I clashed. I was doing some substitute teaching and he was telling folks to do things that would not work in the class room.
However, there are several known things about teaching that most all the people in that industry (private, public schools, commercial instructor pilots-eg the FAA, and military educators) agree on.
First is that the average student has an attention span that is inverse to the complexity of the task. Once the student gets a ‘mindful’ the attention is gone and no more learning takes place. Flying model airplanes is a very complex task. That means shorter flight times work better.
The second thing I recall is that corrected repetition works in small amounts. This tends to encourage shorter training flight times to avoid boredom and insure ‘internalization’ of what has been learned on this flight so it can be demonstrated, and corrected if need be, on the next flight.
The third thing I learned from my flight training and looking into becoming a CFI and that is to have a lesson plan especially for aviation. It is hard work to have a preflight discussion that effectively covers all that is going to be accomplished in a long lesson. This is why most commercial flight schools charge for ‘ground school’. This difficulty is one of many things that encourages me to keep my students flight times in the 10 to 15 minute range, until they are almost ready to solo.
The shorter flight times allow better post flight discussions and pointers since fewer new subjects are touched on during the flight.