Ribblet Airfoil For the B model

[kestrel]

A constant chord wing naturally stalls near the center with a delayed stall a the tips. an elliptical is prone to stalling all at once.

[noema]

This article says, he used the GA30 series (12% thickness ratio) and asked Harry to make it thicker.

"Barrows checked with Riblett before building any ribs. After hearing the airfoil’s mission, Riblett asked why he didn’t pick the 6% camber. “That was the thing about Harry,” Barrows said. “You could call him up and discuss things. I explained that with the Patrol’s great big flaps, I’ve got all the camber I need on takeoff and landing, and he agreed with me. And then Riblett went the extra mile. The 13.5% thickness ratio wasn’t in his book, so Riblett ran the numbers on his computer and sent Barrows all of the points. “The airfoil has been great!” Barrows said."

https://www.kitplanes.com/the-airfoil-adventures-of-harry-riblett/