UAK04 AIRFOIL
By Keith Kie, Vandenberg (California)
Airfoil Design Updates
(...) I returned to the drawing board with airfoil design, making several significant changes based on our previous discussion.
Performance Profile
This iteration reduces lift in exchange for significantly reduced drag (Cd of ~ 0.005). The primary focus was safety and speed:
Safety Focus: I prioritized flattening the stall curve as much as possible, which means the wing will only "mush" instead of dropping a wing or edge. This provides the pilot with maximum time to react. The moment coefficient is kept very close to zero.
Speed & Efficiency: This design achieves maximum safety while also being the fastest airfoil I have ever created. While it does lose out on peak lift (CLmax ~1.5), this is a necessary trade-off for the desired safety and speed profile.
Technical Details
As you noted previously, I created a closed trailing edge (TE) version, which I have attached. Implementing the closed TE reduced the CLmax by ~ 0.1, which I consider an acceptable loss given the overall performance gains.
I also took an extremely conservative approach to laminar flow stability. You won't have to worry about performance degradation in turbulent or dirty conditions; the design was intentionally finalized down to an Ncrit of 1.0. This is equivalent to the most turbulent air on the planet, meaning the airfoil should not fail due to dirt, grime, sticks, or any other contamination.
I hope the open-source paragliding community can make excellent use of this design.
All the best,
Keith in California
UAK04_closedTE.dat
By Keith Kie, Vandenberg (California)
Airfoil Design Updates
(...) I returned to the drawing board with airfoil design, making several significant changes based on our previous discussion.
Performance Profile
This iteration reduces lift in exchange for significantly reduced drag (Cd of ~ 0.005). The primary focus was safety and speed:
Safety Focus: I prioritized flattening the stall curve as much as possible, which means the wing will only "mush" instead of dropping a wing or edge. This provides the pilot with maximum time to react. The moment coefficient is kept very close to zero.
Speed & Efficiency: This design achieves maximum safety while also being the fastest airfoil I have ever created. While it does lose out on peak lift (CLmax ~1.5), this is a necessary trade-off for the desired safety and speed profile.
Technical Details
As you noted previously, I created a closed trailing edge (TE) version, which I have attached. Implementing the closed TE reduced the CLmax by ~ 0.1, which I consider an acceptable loss given the overall performance gains.
I also took an extremely conservative approach to laminar flow stability. You won't have to worry about performance degradation in turbulent or dirty conditions; the design was intentionally finalized down to an Ncrit of 1.0. This is equivalent to the most turbulent air on the planet, meaning the airfoil should not fail due to dirt, grime, sticks, or any other contamination.
I hope the open-source paragliding community can make excellent use of this design.
All the best,
Keith in California
UAK04_closedTE.dat