# Why flaps can deflect up to 25°+ without stalling the wings? [duplicate]

According to this graph,plain flaps have their highest Cl at about 2 and stalls at about 15°,my question is how then do airplane flaps reach 25°+ of delflection when this gragh clearly states that stall is at 15°?

• The flaps being deployed 25 degrees doesn't mean your AOA is now 25 degrees... My Cessna can deploy flaps up to 40 degrees. – Ron Beyer Jun 20 '18 at 19:13
• @Sanchises: I agree, but the answer in the other question is rather terse and deserves a more complete explanation. This is probably the reason for the new question. – Peter Kämpf Jun 20 '18 at 22:40
• @Peter I've agree (I was just trying out how short answers rather than answer-as-a-comment would be received). Regardless, they're duplicates. Perhaps close the other as a dupe of this one? – Sanchises Jun 21 '18 at 6:05
• @Sanchises: Well, I voted to close this one and wrote a more complete answer for the other question. – Peter Kämpf Jun 21 '18 at 8:58

The X-axis this is the angle of attack of the wing and not the angle of deflection of the flap. When the angle of deflection of the flap is 25%, the angle of attack of the wing will be much less.

The flaps increase the camber of the wing, not the angle of attack.

I agree the graph can be misread to mean it's the flap airfoil's angle of attack. However, from its content, it's quite clear it refers to the wing's angle - cL=2 is inconsistent with any short airfoil at a=0.