Work out stall speed instantly with clear inputs, formula shown and shareable results.
Stall speed comes from setting lift equal to weight at the maximum lift coefficient: V equals the square root of 2W divided by rho, wing area and CLmax. It therefore rises with the square root of weight and falls as CLmax increases when flaps are extended.
Stall speed
Vs = sqrt(2 x W x g / (rho x S x CLmax))
Aviation results are planning estimates only. Always verify take-off, landing, fuel, weight and balance figures against the certified Aircraft Flight Manual, current performance charts and applicable aviation regulations before flight.
By the square root of the weight ratio. A 10% heavier aircraft stalls about 5% faster.
It is the certification-based margin (Vref = 1.3 Vso) that keeps enough manoeuvre and gust margin during the approach and flare.