Guidelines for placement of yarn strips on wing for airflow/stall study ?

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Gregory Perkins

Well-Known Member
May 25, 2019
I am helping a buddy with a newly built low wing Rans RV9 that stalls about 70 mph.

I want to tape some yarn strips on top of the wing so that we can observe stall progression and
development as well as Best L/D AOA flying etc. I was going to tape them all in a straight line but then considered that several previous yarns pieces could affect the airflow to the following yarn placements.

I normally opt for AOA vane indicators for this kind of study but buddy doesnt want to stick anything else to the wings.

Any tips or pointers or instructions for yarn placement would be appreciated