A Lancair builder has collected a list of links to tech papers, e.g. NLF215F

Link:

Interesting technical papers

There is link to the NLF215F airfoil tech paper. It was particularly interesting. Now I understood the philosophy of the profile – I was always wondering, why this profile has the low drag bucket at so high Cl (around 0.5) rather than what is realized in cruise with small aircraft (up to 0.2). But, it seems, that this airfoil is designed to be used with -10 degrees flaps. With those, the low drag bucket gets into the cruise area. Heureka.

Here is a direct link to the paper:
http://www.n91cz.com/Interesting_Technical_Reports/NASA-81-tp1865.pdf

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    • N91CZ
    • October 9th, 2008

    You are correct. The use of negative flaps also greatly reduces the pitching moment of the section in cruise.
    I’ve used the following two charts during presentations when discussing this concept relative to Lancair performance.

    http://www.n91cz.com/Interesting_Technical_Reports/flap-10.emf

    http://www.n91cz.com/Interesting_Technical_Reports/flap0.emf

    • N91CZ
    • October 9th, 2008

    You are correct. The use of negative flaps also greatly reduces the pitching moment of the section in cruise.
    I’ve used the following two charts during presentations when discussing this concept relative to Lancair performance.

    http://www.n91cz.com/Interesting_Technical_Reports/flap-10.emf

    http://www.n91cz.com/Interesting_Technical_Reports/flap0.emf

    • N91CZ
    • October 9th, 2008

    http://www.n91cz.com/
    Interesting_Technical_Reports/
    flap0.emf
    http://www.n91cz.com/
    Interesting_Technical_Reports/
    flap-10.emf

    • N91CZ
    • October 9th, 2008

    http://www.n91cz.com/
    Interesting_Technical_Reports/
    flap0.emf
    http://www.n91cz.com/
    Interesting_Technical_Reports/
    flap-10.emf

    • Karoliina Salminen
    • November 7th, 2008

    Thanks for your comment. I will look at your links!

    • Karoliina Salminen
    • November 7th, 2008

    Thanks for your comment. I will look at your links!

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