Foil section at low Reynolds numbers.

[whaletail38]

Can anyone suggest good foil sections to investigate at very low reynolds numbers, approximately 50,000 please?

[daiquiri]

Try to look for a research work by Dieter and Althaus, the title is "Profilpolaren für den Modellflug". It is a very nice work on different low-Re profiles, used for aeromodels. It is in german, but the language of graphs is universal.

[markdrela]

Originally Posted by whaletail38

Can anyone suggest good foil sections to investigate at very low reynolds numbers, approximately 50,000 please?

Not enough information. You need to specify a desired Cl range and any structural thickness constraints.

[whaletail38]

The desired cl range is 0.2 to 0.4 and the tickness to cord can go down to as little as 6%. Leeway angles up to 5 degrees.

[markdrela]

Originally Posted by whaletail38

The desired cl range is 0.2 to 0.4 and the tickness to cord can go down to as little as 6%. Leeway angles up to 5 degrees.

Since you mention leeway, I assume you mean cl = +/-0.2 to +/-0.4 (i.e. a symmetric section). What you want is a thin RC glider tail airfoil. The HT08 or HT12 or HT13 should work well. http://www.charlesriverrc.org/articl...t-airfoils.htm
These have 100% laminar flow in your cl range, and hence are completely immune to low-Re effects, since laminar separation resistance is independent of Re. So if this is for an RC sailboat, they will work OK no matter how low the wind speed.
These show how to hand-sand them accurately in wood, without templates:
http://www.charlesriverrc.org/articl.../tail_sand.pdf
http://www.charlesriverrc.org/articl...il_shaping.pdf

[whaletail38]

Thankyou very much. I'll check these sections out.

[lazeyjack]

Originally Posted by markdrela

Since you mention leeway, I assume you mean cl = +/-0.2 to +/-0.4 (i.e. a symmetric section). What you want is a thin RC glider tail airfoil. The HT08 or HT12 or HT13 should work well. http://www.charlesriverrc.org/articl...t-airfoils.htm
These have 100% laminar flow in your cl range, and hence are completely immune to low-Re effects, since laminar separation resistance is independent of Re. So if this is for an RC sailboat, they will work OK no matter how low the wind speed.
These show how to hand-sand them accurately in wood, without templates:
http://www.charlesriverrc.org/articl.../tail_sand.pdf
http://www.charlesriverrc.org/articl...il_shaping.pdf

thanks
Stu