Recently we have added a feature to the site that lets you make your own airfoils using HAVF inputs.
This tool takes any coordinates in HAVF format, and allows you to make airfoils with them, specifically in coordinate form. You can then either copy and paste the data directly off the page, or download the airfoil as a “.dat” file after the airfoil coordinates are produced by the site.
The book we published last year (Holbrook Aerospace Airfoil Vector Format), includes a library of 1583 airfoils in both HAVF and coordinate format, and also several algorithms to create your own airfoils in DAT form, from HAVF. But, those features are not immediately useful. You may not have a system that can run matlab, or interpret the mathmatical formulae provided. Even if you did, maybe it’s just not worth the time, if there is something that already works.
So for convenience, and also as part of an effort to add more advanced functionality to the site in this case, and for future cases, we will offer this service for free, hopefully indefinitely if possible. No purchase or login necessary.
In general this tools should allow you to more directly connect what you are designing in CAD, and what you are optimizing or simulating as an engineer. But the use cases could include…
- Enhancing the “resolution” or coordinate count of existing popular airfoils
- Adjusting the trailing edge of airfoils to achieve a precise trailing edge thickness in CAD, achieving high DFM (design for manufacture)
- Create entirely new airfoils in CAD, and generate a DAT file to simulate that airfoil
- Mix two existing airfoils to create a new one by averaging the values of two HAVF inputs
- Adjust an existing airfoil to a new thickness by scaling only Y values
- Transition accurately between two airfoils over a curved loft, not by averaging the HAVF values, but incrementally changing from one HAVF to another
- Create more fair airfoil comparisons, by never comparing airfoils with different coordinate counts again
- Never simulate an airfoil with less than 200 points again
- Fix panelling issues in existing airfoils
- Skip draw order errors on airfoil import… forever
- etc…
Example 1: Simple Clark Y
This is a clarky Y, but instead of being made with 6 segment splines, it’s made with 3 segments. It also has less sig-figs, but is extremely compact, and can make a 1,000 coordinate airfoil if you wish, since any version of an HAVF foil is an actual curve, it can be rendered into infiite poitns. To keep the website from being overloaded, we have a limit here of 1000. For this input we use only 100. Because we are not adjusting for a specific chord, and trailing edge thickness, the trailing edge geometry does not change from the initial HAVF input, and the chord and trailing edge values will not effect the output.
#input
1 0.002 0.195 0.190 0 0.032 0 0 0 0.046 0.170 0.030 1 0.002
#output snipet
1.000000000000000 0.002000000000000
0.952428680000000 0.012868576000000
0.906301440000000 0.022929408000000
0.861598360000000 0.032205152000000
0.818299520000000 0.040718464000000
0.776385000000000 0.048492000000000
0.735834880000000 0.055548416000000
0.696629240000000 0.061910368000000
0.658748160000000 0.067600512000000
0.622171720000000 0.072641504000000
0.586880000000000 0.077056000000000
0.552853080000000 0.080866656000000
...
Example 2: Simple Clark Y Adjusted
Taking example 1, and adjusting it for a 10 meter chord, with a 3mm thick trailing edge. The result looks much the same, but when the DAT file is scaled to 10 [m], it will have exactly a 3mm thick trailing edge.
#input
1 0.002 0.195 0.190 0 0.032 0 0 0 0.046 0.170 0.030 1 0.002
#output snipet
1.000000000000000 0.000150000000000
0.952428680000000 0.011127370800000
0.906301440000000 0.021292646400000
0.861598360000000 0.030668571600000
0.818299520000000 0.039277891200000
0.776385000000000 0.047143350000000
0.735834880000000 0.054287692800000
0.696629240000000 0.060733664400000
0.658748160000000 0.066504009600000
0.622171720000000 0.071621473200000
0.586880000000000 0.076108800000000
...
Example 3: Library Clark Y
When we use the book, we can find the ClarkY on a page like this, it’s easy to find with “Ctrl F” in the PDF file. It includes all the thickness and camber data we could want, as well as coordinate data that we can try to match. The array can be easily copied off the bottom of the page. You can see the output from the website is matching up, so we have verified that we can recreate the models in the book.
#input
1.00000000 0.00059900 0.73069340 0.06487666 0.53528756 0.09646533 0.27739071 0.11851621 0.07800814 0.10333985 0.00000000 0.02000000 0.00000000 0.00000000 0.00000000 -0.03684287 0.08808350 -0.04477845 0.27775606 -0.01978895 0.86852988 -0.00797793 0.91764014 -0.00324365 1.00000000 -0.00059900
#output snipet
1.000000000000000 0.000599000000000
0.968105401588451 0.008119768355800
0.936975144047896 0.015268813620408
0.906499630867031 0.022064109465232
0.876582664290049 0.028520932243057
0.847140749118900 0.034651984248540
0.818102408840166 0.040467522420405
0.789407514076515 0.045975492485341
0.761006623362770 0.051181668543606
0.732860336246564 0.056089798096337
...