Ok, I'm a numbers guy and I came across this formula for a Piper Archer.
Manouvering speed (Va) for a given weight can be calculated as a % of the Va at max gross weight.
Their example used 2550-Lbs for max gross weight, and 1634 for the "given" weight. Va at max gross weight was 113-Kts. and their calculation came up with 92 (92.7) Kts.
So, First find the % to decrease Va by,
(1 - (given weight / max gross weight))/2
a decrease of 18-%,
113 - (.18*113) = 92.7 (92-Kts.)
My question is, does the proportional % thing apply to any aircraft (at least light single engine type anyway) as a universal formula or does it apply only to the one airplane?



