I need tips to choose an Airfoil

[Lucke]

Hello Guys,

I need some tips to choose a good airfoil to a electric Park Flyers.

I need airfoils to fly, low and slow, with a good Cl/Cd,I think that the Eppler 193 and Clark Y are good for this.

I need to know how to choose an airfoil for this type of model,

Thanks,

Lucas

[Ollie]

Use a very thin (less than 8% thickness) airfoil with 2% 3% camber mean line. Only worry the airfoil pick if the exact contour can be built by you.

[BMatthews]

Clark Y is as good as any. Many others like the Eppler 193 will suffer from the covering sag as mentioned by Ollie.

If you want to fly slower then choose some of the very thin and undercambered airfoils like the free flight modellers use. Look into the Benedek 6306, 7457, 8356 or Geottingen 79, 124 or 184 or MVA123 or 173 or one of the latest Wakefield airfoils the SOKOLOV. All these profiles are from Profili2. These are all thin and should be built using thin but hard upper and lower spars of 1/16 x 1/4 flat webbed with 1/32 sheet and with upper and lower surface turbulator spars. Two in front of the main spar and one behind to help support the covering better.

[Lucke]

Ok ! Thanks for help !!

I´ll design the Polar Curves on the Profili for these profiles and choose the best to me.

Thnaks !

Lucke

[acvar]

Not sure what construction method/materials you are using, but you want an airfoil that is as thin as structually possible with a relatively high amount of chamber for the envolope you seek. Here is an example of what you should be shooting for using a very simple fanfold construction. As you increase the chord of the wing you will need to add open space to the area between the fold, but the basic construction is the same.