My comment on your picture was meant as a joke ! Ok, for the advantages of the beanie, there is a BIG difference in airflow between a FLAT surface (original cabin top) and the rounded Beanie (top of wing shape). First, the top cabin is right in front of the stab + elevator and anything that will help the airflow is a big PLUS !
On my 701 without the Beanie, the elevator would lose effectiveness real fast when speed decreased on landing. The result would be a sudden nose drop to the ground.
To fix this, I installed the Beanie and the elevator VGs. Now, I can hold the nose wheel up almost to a stop and the nose wheel lifts up real quickly on takeoff; almost immediately after applying power.
Added benefit to the Beanie : you gain some headroom too (i am 1m87) !
For the wing fences, they supposedly help when banking hard at low speed keeping the airflow flowing from front to back on the main wing. This I haven't experienced much so far. Bush planes and fire planes use them extensively I don't know if the 701 would ever need them but I wanted to try them to see and I had those slats brackets hanging there doing nothing...
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