- #1
RandomGuy88
- 404
- 6
Does anyone know how to determine the leading-edge radius of an airfoil using just the x y coordinates.
Can the Leading-Edge Radius of an Airfoil be Determined from X Y Coordinates?
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Discussion Overview
The discussion revolves around determining the leading-edge radius of an airfoil using its x-y coordinates. Participants explore various methods, including analytical approaches and software tools, while addressing specific cases related to NACA airfoil series.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
Main Points Raised
- One participant inquires about methods to determine the leading-edge radius from x-y coordinates.
- Another suggests performing a curve fit to find the leading-edge radius analytically.
- A participant mentions using XFoil to analyze a NACA 0012 airfoil, outlining steps to access its features.
- There is a request for information on outputting the leading-edge radius value from XFoil for use in coding, indicating a preference for automation over manual entry.
- One participant provides a formula for calculating the leading-edge radius based on the maximum thickness of a NACA 4 series airfoil, specifically R_{LE}=1.1019t^{2}.
- Another participant discusses the possibility of deriving the thickness distribution from x-y coordinates if the airfoil is a NACA 4 series, referencing a specific equation from a source text.
- A later reply questions the applicability of the provided equation for airfoils that do not conform to the NACA four-digit profile, particularly in relation to modern aircraft designs.
Areas of Agreement / Disagreement
Participants express varying methods and opinions on determining the leading-edge radius, with no consensus reached on the best approach or the applicability of specific formulas to non-NACA profiles.
Contextual Notes
Some assumptions regarding the airfoil type and its characteristics remain unaddressed, and the discussion includes unresolved questions about the generalizability of the provided equations to modern airfoil designs.
- #2
- 3,482
- 1,293
You could just do a curve fit and then find it analytically...
- #3
AIR&SPACE
- 100
- 0
I know you can do it in XFoil...
ie:
1) Start XFoil
2) type "NACA 0012"
3) type "OPER"
4) hit "enter/return" key
5) type "GDES"
6) a window pops up:
ie:
1) Start XFoil
2) type "NACA 0012"
3) type "OPER"
4) hit "enter/return" key
5) type "GDES"
6) a window pops up:
- #4
RandomGuy88
- 404
- 6
Do you know if there is a way to output the value of rLE from XFOIL. I need the value of the leading edge radius for a code I am writing and would prefer to not have to enter that value manually..
- #5
AIR&SPACE
- 100
- 0
I knew I'd find it eventually... had to find my book first.
Essentially, if you have a NACA 4 series then NACA ABCD, where CD gives the max thickness, t.
Then: R_{LE}=1.1019t^{2}
Essentially, if you have a NACA 4 series then NACA ABCD, where CD gives the max thickness, t.
Then: R_{LE}=1.1019t^{2}
- #6
AIR&SPACE
- 100
- 0
And if all you have is x-y coordinates then you should be able to find 't' by the thickness distribution (assuming you know it's a NACA 4-series)
\pm y_{t}=\frac{t}{0.20}\left(0.29690 \sqrt{x}-0.12600x-0.35160x^{2}+0.28430x^{3}-0.10150x^{4}\right)
The source: Theory of wing sections: including a summary of airfoil data By Ira H. Abbott, Albert Edward Von Doenhoff
\pm y_{t}=\frac{t}{0.20}\left(0.29690 \sqrt{x}-0.12600x-0.35160x^{2}+0.28430x^{3}-0.10150x^{4}\right)
The source: Theory of wing sections: including a summary of airfoil data By Ira H. Abbott, Albert Edward Von Doenhoff
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- #7
akallabeth
- 1
- 0
Hey! had more or less the same problem, do you think the equation given by Abbott gives an appropriate value if it's not a NACA four digit profile ? For example for normal nowadays aircrafts ? (I don't know what kind of profile I have)
Last edited:
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