Question

You are given four statements about the NACA airfoil with code “XYZZ”:



The X stands for the camber as percentage of the wing chord length.

The Y indicates the thickness of the airfoil.

When ZZ is 00, then the NACA-code is non-realistic.

When XY is 00, then the airfoil is a symmetric airfoil.

Answer 1

The NACA airfoil designation system is a way to classify airfoils based on specific numerical codes that represent their geometrical features. Let's examine the statements given about the NACA airfoil code "XYZZ":

1. **The X stands for the camber as a percentage of the wing chord length.**
- **True**: In the NACA 4-digit airfoil code, the first digit (X) indicates the maximum camber as a percentage of the chord length.

2. **The Y indicates the thickness of the airfoil.**
- **True**: In the NACA 4-digit airfoil code, the second digit (Y) represents the maximum thickness of the airfoil as a percentage of the chord length.

3. **When ZZ is 00, then the NACA-code is non-realistic.**
- **False**: A NACA airfoil code ending in "00" does have a valid interpretation; it typically corresponds to an airfoil with a certain camber and thickness but no specific refinements (like camber or length modifications).

4. **When XY is 00, then the airfoil is a symmetric airfoil.**
- **True**: If the first two digits (XY) are both 0, it indicates that the airfoil is symmetric, as there is no camber (X=0) and the thickness is specified as part of the standard asymmetric airfoil designation.

In summary, the truths of the statements are:
1. True
2. True
3. False
4. True