Beautiful airfoils !

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by topspeed100, Jan 19, 2011.

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  1. Jan 19, 2011 #1

    topspeed100

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  2. Jan 19, 2011 #2

    topspeed100

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    Last edited: Jan 19, 2011
  3. Jan 20, 2011 #3

    DeepStall

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    Are you looking at these for the aircraft in your avatar, and using The World of Krauss aerodynamic data? That data looks like it is all calculated at Reynolds numbers < 10^5 or lower -- probably not relevant for your design (it's closer to normal for model aircraft). Most manned aircraft operate at Re=5 x 10^5 or higher -- big difference! See links off this page for info on what aircraft use what airfoil: UIUC Airfoil Data Site
     
  4. Jan 20, 2011 #4

    topspeed100

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    Yeah I am looking at the Krauss data..seemlike the Gemini performs better the higher the Reynolds number is; Airfoil Investigation Database - Showing GEMINI (smoothed)

    I also have to make possibly 2 R/C models before the real one...first to see if there is fundamentally something wrong and then to study taxiing and stall + aerobatic caracteristics near the real one size..and structrures how to make it efficient and strong.

    The symbolic value of a small model is also good..just seeing it 3D for real...sorta.

    UIUA is one I used already to get the data.
     
  5. Jan 20, 2011 #5

    topspeed100

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    Airfoil Investigation Database - Showing naca-2414 the NACA 2414 looks sorta slow to me...its dragcoefficient as an object does not please me. NACA 65 ( 2 ) 415 looks better ( only the moment seems hard ) http://www.worldofkrauss.com/foils/1657 .

    http://www.worldofkrauss.com/foils/1419 GOE 679 ( if you meant this ) looks even worse in this dragcoefficient aspect point of view.

    But you are right the Gemini has weird polars.

    Wortmann FX 61-147 looks awesome too, but it has vanished from Krauss investigations ?

    http://www.ae.illinois.edu/m-selig/ads/afplots/fx61147.gif

    Plane using it flew in 1968 already ?

    http://en.wikipedia.org/wiki/Akaflieg_Stuttgart_FS-25

    ....but the one using it in 1953 crashed; http://en.wikipedia.org/wiki/Akaflieg_Stuttgart_FS-23

    is it dangerous ?
     
    Last edited: Jan 20, 2011
  6. Jan 20, 2011 #6

    HumanPoweredDesigner

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    Yes, the GOE is much better for slow gliders, not your speedster. What cruise Cl are you planning to use?

    As for the naca 65:
    Airfoil Investigation Database - Showing NACA 65(2)-215
    Maybe the low Re data is not showing any good laminar flow effects that would appear at higher Re. But compared head to head with the naca 2414 in this database, the 2414 has a lower minimum drag coefficient. And it has a much lower drag coefficient than the gemini.


    And if I'm wrong about this database being valuable for comparing airfoils head to head, I hope someone lets me know.
     
  7. Jan 20, 2011 #7

    orion

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    All the investigations at that site are for model size aircraft. Not applicable to anything larger and contrary to what you posted above, using low Rn data to extrapolate to full scale application is not directly possible since relationships are rarely linear or simply scalable.
     
  8. Jan 20, 2011 #8

    topspeed100

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  9. Jan 20, 2011 #9

    topspeed100

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    Right and when in 65 215 why not 65 212 as well..straight to the jet age ? If I get the Jetcat 200 engines I go for that foil !!!

    And if I enhance them turbines I go for this; http://www.ae.illinois.edu/m-selig/ads/afplots/naca65210.gif

    I have to get the wheel retracted before that.



    The cruise Cl I have ?...I have to ask my friend Karoliina about it ! DESIGN|A|PLANE: Relation of cruise Cl and wing loading

    Cruise Cl seems like an important matter..it sorta defines the incident mounting angle and size of the wing.
     
    Last edited: Jan 20, 2011
  10. Jan 20, 2011 #10

    topspeed100

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    But there is one aspect that makes it slightly easier to study high speed behaviour..you can actually fly a small model at well beyond mach 1 or 2...relatively speaking that is. See if I make a 1/12 scale FNXII ( avatar byrd ) leave the wheels away and install solid plywood 65(2)210 wing and use a heavy duty rubberband and a sling I can make it go 150 km/h..that is 1800 km/h ( 1125 mph ) scale speed. I won't get supersonic data out of the test, but I'll sure get lotsa data of the stability of the design at high speed.

    Don't I ?
     
    Last edited: Jan 27, 2011
  11. Jan 27, 2011 #11

    topspeed100

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