About Decalage — R/C Sailplanes

Decalage and How It Might Affect You

Decalage is the term used to describe the relationship or angle between a wing and a horizontal control surface on the tail. This angle is critical to how your plane flies — get it wrong and your plane will either be uncontrollable or very sluggish.

A positive decalage means the wing has a higher angle of attack than the tail. Most sailplanes fly best with a small positive decalage. If the decalage is too great, the plane will be very stable but won't penetrate well in wind. If the decalage is too small or negative, the plane may be unstable in pitch.

The relationship between decalage and CG position is important — adjusting one often requires adjusting the other. You can check your setup with a dive test.