Dick, I’ll address both parts of your comments. First, your models are indeed in the lower extreme range of Reynolds number where up to now there is little actual data. That may be changing with the new military interest in very small remote controlled spy craft. There’s nothing like such interest to generate the money to do a lot of basic testing and research. Until such time as that data is made available, you are pretty much on your own in that range. As I suggested, if you could record results of your many experiments including measurements rather than relying on memory and gross impressions, that would be a great help in understanding what is happening in these rather unexplored flight regimes. On the other hand I know you are in this for fun and such notes would be too much like work.

I agree with the emphasis on engines and airframe construction. Aerodynamics is perhaps more significant for full scale machines since available power and weight reduction are somewhat limited. With our model-sized craft, power is almost unlimited. Modern model aircraft engines are a marvel of power to weight engineering and it’s almost a given that vertical flight is usually possible.

Weight reduction while retaining structural integrity is always a challenge. This is clearly one area where most models could achieve noticeable gains.

Your analogy of a three-legged stool is appropriate. And in such a stool, each leg is necessary if the stool is to stand.