meaning that that maximum weight to be carried by the wing[mainly] is the weight [in terms of total load factor] that the wing carries at the stall i.e the ratio of W/S is increased to a maximum; this gives rise to the fact that a stall at 1Vs loads the wing with a maximum 1 'g' however at 2Vs an accelerated stall g of 4 g based on the relation ship Vsn = Vs[n [load factor]^1/2
Va is computed similarly except that n [any load factor] is replaced by the design limit load N therefore Va represents the speed that if a stall occurs the wing loading will not exceed design limit loads,...this is a mathematical certainty at odds a bit with the somewhat artificial/ statistical world of design standards [as JT always says 'a line in the sand'] in both cases the Change in Load factor DeltaN i= q*delta AoA but....
in FAR 25. [340???] the worst gust assumed [Uref] to impact the airframe are alleviated i.e statistically assumed to build up gradually reach maximal intensity then decay gradually but in reality in extreme turbulence the gust may be sharpedged and result in an instantaneous increases in AOA this will result in higher than assumed load factors ---hence Vra/Tp becomes very very artificial and only speeds near Va can protect you,...in reality for Extreme turbulence it may just be better to stall
the British suck at horse hooey
