Isegi vigurlennuks ettenähtud purilennukite püsivus ja juhitavus muutub ümberpööratud asendis halvaks, mis omakorda raskendab piloteerimist selililennus.
An aerofoil in which the camber of the upper and lower surfaces are the same is referred to as symmetrical and is most often found in aerobatic aircraft intended for inverted flight.
