One thing I have noticed here is the assumption among some modelers that the "professional" aerodynamicists posting here, those working with aerodynamics in their daily lives, have a knowledge limited to the study of books and theory taught in the classroom. I have spent 11 years in total at university for my degrees in mechanical and aeronautical engineering, and I do admit that what is taught in the classroom is quite theoretical, although it is based on centuries of research in the fields of physics, mathematics and aerodynamics. However, I am also a modeler, and I built my first flying balsa model when I was only six years old. I have never stopped modeling and I have designed, built and flown models that range from very simple free-flight gliders, rubber powered models, control line, etc, all the way through to warbirds. I also fly full-scale sailplanes and I have some full-scale powered flying experience. (just as an aside: when it comes to graduate work, you spend very little time in the classroom.)

I do not post the above to boast about my own experience, because despite my studies and long experience with model airplanes, I admit that I learn new things about aerodynamics and flight mechanics every day. I do not regard myself as an "expert" in aerodynamics, even on the specific topic on which I focused my PhD research, because I don't think it is possible to ever know everything there is to know. What I did want to show is that my own interests go far beyond the technical jargon I have learnt in the classroom at university or the small library of books that I surround myself with. I also know I am not the exception, since almost all fellow aerodynamicists I have met during my work and graduate studies had similar interests - many of them are modelers, or fly full-scale sailplanes, some are military or commercial pilots, and some of them even spend their spare time sailing, which, by the way, have many similarities to aircraft.

In the thread on Bernoulli there is a poster who posted some very technical stuff on control volumes and momentum transfer. From that post you would think that this person is purely a theoretician - however I happen to know that he is one of the most knowledgeable and experienced people there are on handlaunched and discus-launched model gliders, which include designing, building and flying.

Dick, you mention 'wind tunnel extrapolations', referring, I assume, to some of the more technical posts in this and the other threads. I have tested airfoils in wind tunnels down to Reynolds numbers of 20,000 - in case you are suggesting that aerodynamicists don't know what is going on at that low Reynolds numbers. Much work is going on at even lower "insect-size" Reynolds numbers; Micro UAV research is currently very active all around the world. You often mention that the answer to most airplane design problems is low wing loading and more power. That may work for the planes we fly for pleasure, but what about something like a micro UAV where you have a size limitation, so you can't make the wing bigger and yet you also have to carry an array of equipment onboard? Of course you put a motor in that is as powerful as you can find, but even Li-poly batteries are heavy and as mentioned before, you cannot make the wing bigger to compensate. It is here where a "flat plate" airfoil doesn't quite cut it anymore and every trick in the aerodynamicist's book has to be used to get the lift required while still limiting drag so your limited engine power can be used to the maximum. Things such as flexible membrane wings enter the picture, and to get the most out of all of these, thousands of hours of analysis and wind tunnel work is required. It is more than just designing something that "will fly" - duration and range, both of which depend on aerodynamic and power system efficiency are just as important, and the final design has to comply with a long series of specifications.

Finally, I have never encountered an airplane or model on which CG location did not matter. As some have said, under certain circumstances the range of workable CG locations may be wider than on others, and sometimes a small amount of instability may even be acceptable, but it always matters. I guess whatever works for you is fine, but I think your words may deceive beginners that all they need to do is build it light, give it lots of power, and not to worry about CG.