Adjusting Your Nine Lives Wing For Aoa

[@Doudouille.Z]

Dumb question : when using a gurney flap, we measure AOA with or without the gurney ? I would say without but jut to be sure... Thanks NLR

[@johnnycichowski8493]

without the gurney

[@Doudouille.Z]

@@johnnycichowski8493 thanks a lot 🙏

[@besikgeorgemenabde6582]

How about when ground is never perfectly leveled?

[@Resultsraceworks]

Is the drag and downforce data in lbs? Is it per foot of wing?

[@ninelivesracing]

yes and it's for a 70" wing

[@Resultsraceworks]

@@ninelivesracing ok, that’s total downforce for 70” of wing.

[@WIll52561]

Is stall angle relative to ground speed? Meaning could I run high aoa for lower speed events like autox and stay below that relative ground speed that would induce stall conditions?

[@recklessrickey9513]

Critical angle of attack (stall angle) remains the same at all speeds until transonic airflow regimes when assuming uninterrupted airflow. Higher angle of attack can be used in lower speed events so long as the AOA does not exceed critical AOA. Lower angle of attack can be used in high speed track situations to reduce drag on the straights. An easy way to find critical AOA is to tape string Soc yarn to the underside of the wing and go for a drive. If the strings are neatly lined up the airflow is still attached. Continue increasing AOA until the yarns tumble. This is the critical AOA and the wing is stalled. 0 degrees is least drag and least downforce while right before stall is the greatest downforce with most drag. This is the highest AOA that is effective for a wing before downforce immensely drops off and drag is multiplied

[@bpinitiatives]

Are the Lift/Drag data provided on the BIG WANG based on 2D aerofoil analysis, or was an entire wing with end plates analyzed in 3D?