calculation of lift and drag forces

T=[( η *p)^2*2*π*R^2*ρ]^0.3333

where, T = Thrust (in newtons)

η= Propeller hover efficiency

= 0.7 to 0.8; is typically for uninstalled low pitch propellers

P= shaft power

= voltage*current*motor efficiency (in watts)

π =3.14159

R= Propeller radius (in metres)

ρ= air density

= 1.22 kg/m3


try this equation and hope it helps you.