This has been an excellent discussion. Most everything that I've read rings pretty much true.
I'd like to merely emphasize what I have felt for years was one of the biggest "institutionalized roadblocks" to effective stunt flying there is; the belief that there is inherent value in flying at a particular lap time ... most generally, a lap time that is way too slow to use effectively.
I think the germ of this concept was formed clear back with the original Nobler article that was titled something like "Stunting can be slow" or something like that. Up to the Nobler era stunters tended to fly pretty quickly with large engines, skinny wings and no flaps. The Stuntwagon actually bragged about stunting at around 100 MPH.
George Aldrich's revelation that you could fly effectively somewhat slower was an eye opener and his success in doing so resulted in nothing less than a revolution in the approach to stunt flying. All of a sudden it was not only OK not to fly "zippy" patterns, it was "the" thing to do.
Unfortunately, like many such revolutions, the myths tended to overwhelm the facts and talk such as six second laps on a Fox .35 powered Nobler started to be taken as gospel. As Phil and Lou and others have pointed out here, successful flight of a Fox .35 powered, 40 oz or less airplane on 60' or less of line at such lap times is pretty much the stuff of cartoons. The physics just don't work out.
The residue of such legend has, nonetheless, instilled itself into the collective stunt consciousness with the implicit belief that slower is better and that he that flies the slowest lap times should receive some sort of award for doing so.
Number one, I've yet to see a plaque or plastic trophy handed out for the slowest lap times and, number two, it is seldom true that airplanes fly better at a slower speed than they do at a higher speed. We need the lift thing for our tricks and lift goes up as the square of airspeed. To suggest that we are better off the slower we go flies in the face of the physics.
Like everything else in stunt, optimum lap times are a compromise between many factors, including but not limited to: the lift necessary based on the wing loading, the power available to overcome the drag produced by the creation of the lift, the "Netzeband Wall" (a good example of which I judged last weekend with Larry Wong's OTS entry at a local Vintage Meet in Napa), and ... most important of all ... the pilot's ability to fly effectively and precisely to garner the most possible points from his/her particular assortment of compromises.
The search for ever slower lap times can often be counterproductive. Unless a ship "locks in" to the necessary pitch rates and can be trimmed to maintain constant radius loops and corners with little pilot input, errors and corrections to them will be both more numerous and more evident. The slower you go the more the time available for the judges to notice errors and degrade the resulting score. Thus, the pilot who flies slower lap times simply because he can complete a "recognizable" pattern at those speeds may in fact be harming the bottom line (his score on the scoreboard) by doing so.
No matter what anyone says, flying slower makes the ship more susceptible to inclement conditions. Turbulence and winds will effect the flight path more: in turbulence because of reduced inertia to overcome the bouncing; in winds because whatever the level of winds they are a greater percentage of slower speeds than of higher thus making the disparity in ground speeds (lap times -- what the pilot sees and feels) greater.
Here again, my old saw about the importance of airplane trim becomes a major factor. An airplane in good trim can be flown effectively at higher speeds because its response is predictable and uniform. The pilot needn't make physical adjustments to the "probable" response of a poorly trimmed ship. Thus flying faster is much less of an issue. This is also why a well trimmed ship can handle even the worst of winds that keep a lot of guys with more questionable ships on the ground. The speed variation can be dealt with, again, because of the linearity and predictability of response.
Probably the ideal is to fly a well trimmed stunter no slower than what is comfortable for the pilot's personal physical limitations to fly comfortably to the best of his ability. Artificial attempts to fly slower for the sake of flying slower are unlikely to prove beneficial in the long run and the trophies for doing are not only rare but not very pretty.
Ted