While flying horizontally, the weight of the plane = to the lift:
Lift = ½Aρ(U² - V²)
where A = area of wings = 12 m²
and ρ = density of medium = 1.29 kg/m³
and U = velocity over upper surface = 152 m/s
and V = velocity over lower surface = 140 m/s
Plugging in values, find weight = Lift = ½Aρ(U² - V²) L=27121 N = 27.121 kN