Originally posted by point 76
On the Airbus 320 /321 though there is the anomaly of turbulence penetration speed ( granted thats for severe turbulence )being 275Kts for the 320 but 305 Kts for the 321( basically the same wing but of course heavier aircraft ).It means you actually have to speed up in the 321 rather than slow down. Wondering what the logic behind that is ? The Mach number for turbulence penetration is the same at M0.76.
Those are sea level numbers for EAS I think? The logic is simply the increased weight - the rules defining
Vb specify that it cannot be less than K*Vs1g where K is the square root of the 'g' developed under the influence of the design gust velocity. In other words the aircraft must not stall when hit by the design gust. So greater weight, greater
Vb. That is today's wording; the rules as written in 1985 said the same thing in different words.