spiral slipstream--that's when you can spit a chaw from the pool table to the spittoon-without hitting the guy at the end of the bar.
Those who fly /have flown a LOT of pattern --already know that as much as all this is fun to fantasize - in the real world -a pattern
plane is constantly changing heading and attitude
Count the seconds where absolutely unchanged attitudes are held --don't forget the hold corrections needed for a breeze/wind.
For years - attempts have been made to come up with magic design where the effects of prop/ trim etc., can be cancelled
No one has done it - and it will never be done.
Simple reason is that unlike a computer model where the breezes and airpockets and temperatures are -non existant -- the model at a contest must be capable of ADAPTING--constantly .
The best design -is simply one which can be moved-in any axis easily and smoothly.
Trying to cancel a applied force such as the "twisted column of air" is futile --it is constantly changing in speed and direction
Maybe not in some airliner chugging along at a fixed speed /altitude load etc., but the contest model has a completely different set of priorities
Setting engine thrust to x angle -may work for one flier yet be a terrible hinderance for another .
The "easy" setup if the plane is light - agile - is one which is reasonably neutral - typically on the stable side of neutral --with enough built in drag AFT such that the model changes little in speed thru up/down lines.
The more constant the speed - the less difference will be seen in any maneuver. also the LESS the model will tend to fall off line in power maneuvers -such as upward lines.
setting the plane up zero zero zero ain't all bad especially with some current radios where the throttle can be mixed to add corrective trim (very delicately).
Sorry - no theories -no conjectures -just past experiences.