Damn mate, good job! This tool is growing into something powerful!PrfctChaos wrote: ↑Mon Apr 12, 2021 1:45 amHi All,
In other news, the profile selection tool has gotten another upgrade. 3rd upgrade for those keeping score.
1st major version, Aug 2020, included only NACA4 and NACA 5 profiles, around 1000 profiles.
2nd major version, Sep 2020, added basically all the airfoils one can find on Airfoils.com, so up to around 2500 airfoils. Lift induced drag was also added.
Now for the 3rd major version:
In previous versions, the calculation was fairly two dimensional. That means that the average chord length was calculated for the wing and then all lift / drag calculations were based on that single average chord length. So some specific behaviour of the profiles at the extremes of the wing might be missed / ignored (long chord in the middle of the wing and short chord at the wingtips).
The program has now moved to more detailed 2.5d approach. Where the wing is chopped into 10 sections (from middle to the tip), each of these sections are then analysed seperately, before being added together again to find the optimum for the wing as a whole. What it means is:
- The program can now use the correct Reynolds numbers for the bigger chords in the middle of the wing and for the smaller chords nearer the tips. Thus better accuracy. And profile selections where certain parts of the wing would have stalled can be avoided.
- It also means that calculations can accurately be performed for various wing plan shapes. (Typical choices are Elliptical, Tapered or Custom). Induced drag is still only estimated, the required Oswald factor for a given plan shape needs to be entered manually. However, parasitic drag is calculated accurately.
- Wingtip washout can now be calculated accurately (when it comes to parasitic drag). Since each of the 10 sections can be rotated to their respective Angle of attacks for washout.
This does not change the results significantly, but one will notice some small differences. Here is a example with Spirus' wing from the previous page. Comparing Version 2 and Version 3 results.
Capture - Spiru 700 mm x 800.PNG
Capture - Spiru 700 mm x 800Ver3.PNG
Sort of what this does, it's actually a great tool! It could save many hours of modeling... But I don't see an option to change the foil profile which is basically the whole point of this postZachMoves wrote: Check out WingHopper.com! A great compliment to this tool. Perhaps we can combine them somehow?
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