[Attachment(s) from Dennis Cox included below]
OK, I'm trying to size MLM rudders... and to that end, I'm trying to get up to speed with JavaFoil. For a reality check, I am first trying to re-create Rick's numbers from his message of August 4th and 5th concerning the NACA 07-310 SYM foil.
I'd supply an input file, but I can find a Save button that saves everything. They seem to save independent things. So, here's the steps I did. All other settings are the default.
JavaFoil 2.16
Geometry Tab
- Select NACA 07-series
- Changed Number of Points to 101
- Changed thickness to 10%
- Changed Design Lift Coefficient 0.3
- Pressed, "Create Airfoil"
- Copied the foil coordinates into Excel where I have the spread sheet mirror the front points before the 50% line.
- Copied the adjusted foil coordinates back into JavaFoil
- Pressed "Update View"
See screen Geometry.jpg screen shot and coordinate file NACA 07-310 SYM.txt.
Options Tab - To simulate sea water and other things.
- Changed Density to 1025 kg/m^3
- Changed Viscosity to 0.00000105 m^2/s
- Changed Speed of Sound to 1522 m/s
- Aspect Ratio 4
Polar Tab
- Changed first & last Reynolds Number to 10E6
- Surface Finish: smooth finish
- Changed first Angle of Attack -10 degrees
- Changed last Angle of Attack 10 degrees
- Changed Angle of Attack step: 0.5 degrees
- Pressed Analyze It!
The Results
See attached Excel Results.xls. To summarize: the maximum L/D ratio I found was only 16.6 and lowest Cd was 0.009. Versus Rick's findings of 27 and 0.004 respectively.
What have I not configured properly???????
Thanks,
Dennis
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Attachment(s) from Dennis Cox
1 of 1 Photo(s)
2 of 2 File(s)
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