I have been flying a Multiplex microJET lately. It is fast, a very smooth flyer and gets really small in an eyeblink. It has a long nose, big leading edge extension (LEX) and a almost a zero sweep (mac) outer panel. I noticed an interesting thing yesterday. During the later stages of the battery condition I fed in back stick until I had full aft stick. The airplane was flying level and completely steerable with the "ailevators".

However there was a small but noticeable (if you looked close enough) oscillation in the pitch attitude of the airplane that also showed up as an oscillation of the sound of the motor (very noticeable and same frequency as pitch bobble). It would appear to be the inner section of the wing going through an airflow separation and reattachment and which showed up as a flow difference at the pusher prop. If the inner section were staying attached and the outer panel separating then the airplane would bobble without the sound variation.

As soon as the new wears off I am thinking of trying some strakes, vortex generators, small fixed inner LE slat perhaps, and see if this characteristics can be modified.

Unlike a lot of things we do to models where we have no way of measuring if the mods were successful, at least the sound gives an indication of whether or not the mods would be workable.

I do recommend the microJET as a really fun airplane. I have a mechanical heart valve that you can hear as a click when there is no other sound around. I noticed a very rapid increase in click rate while flying the airplane, it is a real adrenalin maker.