Wing area calculate from desired stall speed. First of all convert the stall speed in mph to feet per second by multiplying by 1,47.
For example, if desired stall speed is 60 mph, Vs = 1,47 x 60 = 88,2 fps
Wing area is:
Where
S - wing area, square feet GW - gross weight, pounds p - Density of air, at sea level = 0,00238 slugs/cubic feet Vs - stall speed, feet per second CL - lift coefficient
The maximum lift coefficient that the reasonably expect for other configurations. For a conventional aircraft without flaps CL = 1,15 - 1,45, for conventional aircraft with plain flaps CL = 1,6, for conventional aircraft with slotted flaps CL = 2,1, for a STOL aircraft using large Fowler flaps CL = 3, for canard aircraft, cannot use flaps CL = 1,15, for flying wing, cannot use flaps for high lift CL = 0,85.
For example, if gross weight is 2500 lbs, desired stall speed is 88,2 fps, lift coefficient is 1,2, wing area is:
It must be pointed out that for an aircraft with a canard, the toral wing area includes the area of the canard. For the conventional aircraft and the flying wing wing area represents only the area of the wing.