A small aeroplane of mass 1040kg is flying horizontally. The total area of the wings in 10m². Air has a velocity 50m / s below the wings. The velocity of the air above the wings such that the weight of the aeroplane could be balanced is ________ (density of air $=1.3\mathrm{kg}/{\mathrm{m}}^3\mathrm{g}=10\mathrm{m}/{\mathrm{s}}^2$)