Hai-Lee
Old and Bold RC PILOT
I do not know if you have decided as yet but it not you could consider a KFM3(+) wing but with twin motors, (tractor), mounted in the wing LEs. This position would assist greatly with the balance requirements.
To make the wing extremely robust a couple of CF tubes buried in the wing would make it very hard to destroy. The streamer could mount on the rear centre fin as per standard or conventional aircraft.
TO make best use of the extra weight of the second motor differential thrust could be included to allow the bird to almost spin horizontally in level flight or even snap into a banked turn when required!.
Just a thought!
Have fun!
